Pre-hydrolysis kraft dissolving pulp from Bambusa vulgaris and Dendrocalamus asper bamboos biomass

Pre-hydrolysis kraft dissolving pulp from Bambusa vulgaris and Dendrocalamus asper bamboos biomass | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Pre-hydrolysis kraft dissolving pulp from Bambusa vulgaris and Dendrocalamus asper bamboos biomass Marcelo Moreira Costa, Weslley Henrique Martins Silva, Ricardo Carvalho Bittencourt, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2070228/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In Brazil, bamboo emerges as a potential non-wood raw material as alternative lignocellulosic biomasses source, since this crop has high rusticity and productivity. It grows even in poor soil and shortage of water conditions, and it has a harvest cycle close to 2 years. This study aimed to produce dissolving pulp from the bamboo species Bambusa vulgaris and Dendrocalamus asper seeking to optimize the process conditions, in order to obtain a final product with the specification’s parameters for viscose grade. Bamboo chips of Bambusa vulgaris and Dendrocalamus asper with 2 years old were submitted to pre-hydrolysis kraft pulping process. After pre-hydrolysis kraft pulping Bambusa vulgaris showed screened yield of 34.2% and a xylan content of 3,47% and Dendrocalamus asper showed screened yield of 34,7% and a xylan content of 2,65. Based on these results, only Dendrocalamus asper was selected and bleached. After optimizing the bleaching process the final kappa number of 0.20, viscosity of 465 dm 3 /kg and 90.6% brightness were obtained for Dendrocalamus asper . Were achieved 1,76% of xylan, 98,1% of glycan and 0.10% of ash content. Was concluded that Dendrolocamus asper can be applied for the production of dissolving pulp. The CCE stage, under the established conditions, did not show to be efficient in removing the xylans from Dendrocalamus Asper brown pulp. On the other hand, further work is needed to optimize the main stages of the process, such as the pre-hydrolysis connected to kraft pulping, as well as the stabilization of carbohydrates chains against bleaching oxidants. bamboo biomass xylan content ECF bleaching Figures Figure 1 Figure 2 1. Introdution The emergence of new technologies, in line with the demand for innovation and sustainability, has brought the use of lignocellulosic biomasses as an alternative raw material for non-woody fiber. Therefore, the need arose to implement the use of cellulosic biomass on an industrial scale in the most diverse sectors of the forest production chain. Among some motivating factors are the need to complement the production of wood raw material, the optimization of processes, the possible reduction of costs, competition between different forest sectors and the edaphoclimatic conditions of the planting sites. On the world stage, Brazil is the second largest producer and largest exporter of cellulosic pulp obtained through wood delignification (IBÁ 2019 ). For this purpose, Eucalyptus and Pinus species are the most used worldwide. This segment currently represents about 1.3% of the Brazilian national GDP and 6.9% of the industrial GDP, and is therefore considered a sector that maximizes the country's economy. Although Brazil has a planted area of eucalyptus that exceeds 5.6 million hectares, there are factors that increase the need to obtain alternative sources of production, such as the trends of increasing wood processing costs and competition with other industrial sectors (Borges et al. 2018 ). The average productivity of bamboo biomass can vary between 20 to 90 t/ha (曹明勇 2016). Brazil has 1.5 million hectares of native and planted bamboo forests with 258 different species. The genera Bambusa and Dendrocalamus have good agricultural productivity, 25t/ha on average (Guarnetti 2013 ). Bamboo emerges as a possibility for use as an alternative lignocellulosic raw material in Brazil because it is a crop with high occurrence in Brazilian soil, short harvest cycles, good adaptability even in poorly fertile soils and high productivity per hectare (Reubens 2010 ; Xuhe 2003 ). In Brazil, according to the List of Species of Brazilian Flora, there are 258 species of bamboo and, according to data measured by the Ecological-Economic Zoning (ZEE) of Acre, this state has drawn attention for having the largest native bamboo forest in the world, presenting about 180 thousand square kilometers of forests with the presence of the plant. The use of bamboo for the production of conventional cellulosic pulp is already a reality in the Asian market. In Brazil, the company Itapajé used Bambusa vulgaris for the production of paperboard, however, the industrial application is still incipient in western countries. Bamboo fibers have intermediate values of fiber length and wall thickness in relation to the Pinus spp. and the Eucalyptus spp. It may be used to production of short fiber pulp and long fiber pulp simultaneously (Júnior et al. 2019 ) This characteristic makes bamboo a good material for pulping, paper and dissolving pulp. Dissolving pulp is a chemically refined, bleached 90% pure cellulose compound with low hemicellulose and lignin content (Chen et al. 2016 ).End uses include such as cellophane and rayon, cellulose esters, cellulose ethers, and grafted or crosslinked cellulose derivatives. Bamboo may be used as a potential resource for dissolving pulp production. However, its hemicellulose content is higher than that of traditional wood species. Therefore, it is challenging to use bamboo for dissolving pulp production. Dissolving pulp quality mainly depends on the pulping process, in addition to the properties of the raw material. Currently, the pre-hydrolysis Kraft pulping process is one of the primary methods for producing dissolving pulp due to its high efficiency in lignin and hemicellulose removals (Chen et al. 2016 ). In addition, compared to wood, bamboo contains a higher silica content. Silica generates problems during pulping and bioconversion processes, causing complications in effluent streams. Therefore, the low silica content in raw materials is of great importance in expanding the use of bamboo. The production of dissolving pulp is expanding in Brazil. Currently, the largest consumption of this product is concentrated in the Asian continent, representing about 77% of world demand and, due to the high capacity of forestry production, an investment of 7.5 billion reais is estimated for new projects for the production of wood. dissolving pulp in Brazil, which can generate thousands of jobs directly and indirectly (FIEP 2016 ). A clear example of the expansion of the sector in the country is the association between the companies Lenzing and Duratex, creating LD Celulose Co., which will be inaugurated in 2022, in Minas Gerais. The overall fiber yield for the production of dissolving pulp is rarely above 35% (Batalha et al. 2012 ), pulps must contain a high content of alpha-cellulose (95 to 98%) and relatively low contents of hemicelluloses (< 4%) and lignin (< 0.05%). The intrinsic viscosity of dissolving pulp viscose grade should be in the range of 400 to 600 mL/g (Duan et al. 2015 ; Strunk et al. 2012 ). The PHK procedure features a combination of acidic (pre-hydrolysis) and alkaline (kraft cooking) conditions. The pre-hydrolysis step causes the depolymerization of hemicelluloses, allowing a greater degree of delignification in kraft cooking (Sixta 2006 ). Finally, the brown pulp is sent to the bleaching stages, in order to achieve the desired purity. Therefore, the interest in studying the applicability of bamboo as an alternative source for the production of soluble pulp is justified, identifying the viability of the process, species that are chemically more favorable to kraft cooking and technological solutions that remedy the challenges of working with this culture. 2. Materials And Methods 2.1. Materials For this study, the species Bambusa vulgaris and Dendrocalamus asper were selected as an alternative fibrous source. The lignocellulosic biomass used comes from Federal University of Vicosa (UFV). Vicosa city is located at Minas Gerais, between between the latitudes of 20º 60' S to 20º 90' S and between the longitudes of 43º 10' W to 42º 90' W, at an average altitude of 650 meters (Silva 2021 ). The predominant climate in the city is tropical, with rainfall during the summer and an average annual temperature of 19°C, ranging between 14°C and 32°C (Prado et al. 2020 ). The bamboo stalks collected were between 2 and 3 years old at planting, and the cut was performed above the first node. The experiments were carried out at the Pulp and Paper Laboratory (LPC). Bamboo samples were converted into chips, with approximate dimensions of 15 mm wide, 20 mm long and 4 mm thick. Subsequently, identified and stored to ensure the integrity of the material. 2.2. Methods To produce bamboo dissolving pulp, the pre-hydrolysis kraft (PHK) pulping process was applied. In order to select the most suitable species for production, in which it presented the predetermined final characteristics, several analyzes were carried out on the bamboo chips and pulp produced. Two different bleaching sequences were applied to the brown pulp, in which we sought to observe the efficiency of the cold alkaline extraction step during the process. Table 1 describes the parameters to be analyzed and their respective standard procedures. Table 1 Gravimetric analyzes performed on both bamboo species Parameter Procedure Black liquor pH Tappi T211 om-93 Black liquor residual effective alkali SCAN N2:88 Whiteness TAPPI T452 om-99 Intrinsic Viscosity TAPPI T230 cm-89 Carbohydrates SCAN-CM 71:09 Kappa number Tappi T 236 cm-85 Manual sheet formation Tappi T 218 sp-97 Lignin Klason method – TAPPI 222 om – 83 Extractives TAPPI T 264 om – 82 2.2.1. Pre-hydrolysis kraft (PHK) pulping procedure The process was carried out with a mass of 600 grams of dried chips in an MK digester, electrically heated and equipped with electronic controls connected to the computer and to peripheral equipment. The temperature data obtained were monitored every minute, making it possible to establish the profile of factor P and factor H at the end of cooking. The P factor is the relationship between time and temperature during the pre-hydrolysis stage (Jia et al. 2022 ). The H factor is a variable developed to express cooking time and temperature (Segura and Silva Júnior 2010 ). The cooking white liquor was prepared as the alkaline loading conditions of sodium hydroxide and sodium sulfide changed. The pre-hydrolysis kraft pulping procedure is described (Table 2) by four steps including (1) autohydrolysis; (2) neutralization; (3) kraft pulping and (4) washing process. Table 2 Conditions applied during the pulping process (P factor of 1296 and H factor of 4142) Process steps Temperature (° C) Time (min) EA (%) L/C Ratio Autohydrolysis 170 117 + 120 - 3:1 Neutralization 170 30 + 30 3 + 3 3:1 Kraft pulping 180 15 + 120 14–24 5:1 Washing 90 15 3 6:1 Autohydrolysis aims to remove the hemicelluloses from the bamboo chips, being carried out with water at P factor of 1296. Under these conditions, acetic acid release from bamboo xylan, reducing the pH of the medium, leading to the degradation of hemicelluloses. The autohydrolysis liquor was extracted from the digester, followed for neutralization, at 170ºC. Neutralization step was being divided into two stages of 30 minutes, wherein was used liquor with EA 3.0%. The liquor from initial displacement of autohydrolysis liquor was extracted from the digester. The liquor from the second neutralization stage remained, going on to the kraft pulping stage. The kraft pulping process was carry out in order to achieve kappa number 10 ± 2, by adjusting EA charge, at a fixed H factor of 4142. Finally, washing process consists of using a liquor with 3% EA. 2.2.2. Pulp disintegration and washing After washing the chips inside the laboratory digester, sequentially, the material was sent to the Hydro Pulper, for 2 minutes. At this stage of the process, the cellulose fibers were individualized and the black liquor contained inside the chips was diluted in water and subsequently extracted from the material. Subsequently, the cellulosic pulp was sent to the laboratory scrubber. This equipment aims to separate the purified cellulosic pulp from the amount of waste generated, selectively removing the contaminating material from the pulp generated during the process. The tailings can be of fibrous origin, from chips that have not been properly cooked, or of non-fibrous origin. There are several applications for tailings, but for this to occur, a careful characterization is necessary. Among the various applications for this material, we can mention composting (Barretto 2008 ). After the previous step, the tailings were removed from the scrubber and their mass was measured. Then the purified cellulosic pulp is placed in suitable nylon bags and transported to a laboratory centrifuge for 10 minutes. This step consists of removing the excess water contained in the cellulosic pulp. The “clods” of cellulose formed during the centrifugation stage will be disintegrated, which increases the specific surface area of the material, which in turn facilitates its drying, increasing the reactivity of the particles in future analyses. To perform the kappa number analysis, a sheet of cellulose fibers was produced in a sheet former. The kappa number is the volume, in milliliters, of a 0.1N KmnO4 solution needed to react with the lignin present in an amount in grams of cellulosic pulp (Colodette et al. 2014 ). 2.2.3. Gravimetric analysis In order to evaluate the results of dissolving pulp production, the total yield and screened yield were measured, all of them on a dry wood mass basis. Respectively, these parameters can be measured according to equations (3), (4) and (5). Equation 3: $${Y}_{T}\left(\%\right)=\frac{{{m}_{D}}_{Cel}}{{{m}_{D}}_{Chips}}\times 100$$ Where Y T (%) is total yield in percentage, m DCel is cellulose dry mass and m DChips is chips dry mass. Equation 4: $$TC\left(\%\right)=\frac{{{m}_{D}}_{T}}{{{m}_{D}}_{Chips}}\times 100$$ Where TC (%) is tailings content in percentage and m DT is tailings dry mass. Equation 5: $${Y}_{S}\left(\%\right)=\frac{{{m}_{D}}_{{Cel}_{S}}}{{{m}_{D}}_{Chips}}\times 100$$ Where Y S (%) is screened yield in percentage ans m DCelS is screened cellulose dry mass. The other analyzes are described in Table 2, together with their respective standards. 2.2.4. Pulp bleaching The bleaching of the brown pulp occurred in such a way that it was possible to optimize the use of chemical reagents, in a way that conserves the carbohydrates present in the material. The first sequence introduced was: CCE – D 0 – (EP) – D 1 – D 2 . Table 3 presents the parameters of this process. During the entire procedure, the material consistency was 12.0% for the first sequence and 10.0% for the second sequence. Table 3 General bleaching CCE – D 0 – (EP) – D 1 – D 2 sequence conditions Parameters CCE Do (EP) D 1 D 2 Consistency (%) 12 12 12 12 12 Temperature ( o C) 40 60 80 80 70 Reaction time (min) 30 60 60 180 180 ClO 2 (kg/t) - 0,22 KN* - 10 5 NaOH (kg/t) 80 - 10 ? ? H 2 SO 4 , (kg/t) - ** - - - H 2 O 2 , (kg/t) - - 3 - - final pH 13,5 2,0–2,5 10,2 4,0–4,5 5,5 * KN = Kappa number; ** Use or not of H2SO4 for pH adjustment In a second moment, the CCE step was replaced by the use of a chelator, this sequence being described as: Q – (OO) – D 0 – (EP) – D 1 – D 2 (Table 4). Table 4 General bleaching Q – (OO) – D 0 – (EP) – D 1 – D 2 sequence conditions Parameters Q (O/O) Do (EP) D 1 D 2 Consistency (%) 10 10 12 12 12 12 Temperature ( o C) 70 80/100 60 80 80 80 Reaction time (min) 60 15/60 60 60 120 120 Pressure (kPa) - 600 - - - - O 2 (kg/t) - 20 - - - - Chelator (kg/t) 6 - - - - - ClO 2 (kg/t) - - 0,22 KN* - ** 5 NaOH (kg/t) - 20 - 10 *** *** H 2 SO 4 , (kg/t) 1 - *** - - - H 2 O 2 , (kg/t) - - - 3 - - final pH 5 > 10,5 2–2,5 10 4–4,5 5,5 *KN = Number Kappa **Otimizado para cada amostra chegar na alvura 90%ISO *** H 2 SO 4 ou NaOH para ajuste de pH The cold caustic extraction (CCE) step, recognized for its hemicellulose removal function, was carried out at 40ºC for 30 minutes. In this step, 80 kg/t of NaOH was added as a chemical reagent. The delignification with chlorine dioxide (D 0 ) took place at a temperature of 60ºC and a time of 60 minutes. In this second step, 0.22 kg/t of ClO 2 was added to the material. The third step, alkaline extraction with hydrogen peroxide (EP), had a temperature of 80ºC for 60 minutes, with the addition of 10 kg/t of NaOH and 3 kg/t of H 2 O 2 . The bleaching step with chlorine dioxide (D 1 ) was carried out at 80ºC for 180 minutes, with 10 kg/t of ClO 2 being added. Finally, the next step of bleaching with chlorine dioxide (D 2 ) was carried out at a temperature of 70ºC for 180 minutes, with the addition of 5 kg/t of ClO 2 . For the second sequence, with the replacement of the CCE step, the step containing the chelator (Q) was carried out with the temperature at 70ºC for 60 minutes. For the second stage of this sequence, the application of Oxygen (OO) was carried out in two stages, with temperatures of 80ºC and 100ºC, for 15 minutes and 60 minutes, respectively. In this step, 20 kg/t of O2 and 20 kg/t of NaOH were added. 3. Results And Discussion 3.1. Bamboo chemical composition Among the characteristics of wood, the chemical composition can directly influence the yield of the pulp produced, the final product quality and the consumption of reagents (Bassa 2006 ). Figure 1 shows the values of the tests for chemical characterization of the species Dendrocalamus asper and Bambusa vulgaris . Xylans and lignins are undesirable in this process because they decrease reactivity and act as contaminants during the process (Martino 2015 ). It was observed that the most present carbohydrates in bamboo chips are glycan and xylan. Once the chemical characterization of bamboo chips was measured, the basic density, lignin content and S/G ratio were determined. These parameters are shown in Fig. 2. Table 5 Basic density, lignin content and S/G ratio Sample Basic Density (kg/m3) Lignin (%) S/G Syringyl Guaiacyl P-Hydroxyphenyl D. asper 452 16,8 16,1 5,5 1,05 B. vulgaris 487 12,1 17,7 5,4 0,69 The basic density of Bambusa vulgaris chips is higher, which indicates that this material may have a greater resistance to the cooking liquor impregnation. The S/G ratio found for Dendrocalamus asper was higher, which indicates that lignin tends to be cleaved more easily, since it has a less condensed structure. Through the analysis of ash and elemental chemical composition of the chips (Table 7 ) it is possible to notice very similar values between the species, especially in relation to ash and compounds insoluble in HCl. Table 6 Analysis of ash and chips elemental chemical composition Sample Ashes (%) Insoluble HCl (%) Metals (mg/Kg) Ca Mg Fe Cu Na K D. asper 2,47 0,27 101 146 11,59 2,34 155 111 B. vulgaris 2,47 0,22 87 151 8,66 2,53 123 111 3.2. PHK process performance Once the cooking conditions were determined, the production process could be started. In order to compare the two bamboo species, the kappa number and the screened yield of the brown pulp were considered determinant parameters to evaluate the productive viability of the samples. Regarding Dendrocalamus asper , Fig. 2 shows the behavior of this species in relation to effective alkali (EA), kappa number and screened yield. It can be seen (Fig. 2) that when the lowest level of alkaline load was applied, the sample presented higher values of kappa number and screened yield. On the other hand, under drastic cooking conditions, we obtained lower values of these same parameters. The above result is explained by the degree of degradation of lignin, cellulose and hemicellulose in the material. Under more severe conditions, the constituents of the chips remained in the pulp in smaller amounts, when compared to the milder conditions. For the species Bambusa vulgaris (Fig. 2b) it was observed that both parameters evaluated showed the same tendency of Dendrocalamus asper (Fig. 2a). In this study, the tailings content presented by the two bamboo species was 0.0%, in the entire range of applied alkaline load. Table 7 shows the brown pulp characterization produced from the two bamboo species. Due to the comparison between them, was considered the cooking condition in which kappa number 10 ± 2 has been reached. Although the species Bambusa vulgaris has a lower kappa number, higher brightness and higher viscosity, it can be seen that this species has a lower level of purified yield and higher content of xylans compared to other species. Comparison between the brown pulps of different bamboo species Table 7 Comparison between the brown pulps of different bamboo species Sample P Factor Kappa number Screened yield (%) Brightness (%ISO) Intrinsic Viscosity (dm 3 /kg) Insoluble Lignin (%) Carbohydrates (%) Glyc 1 Xyl 2 D. asper 1296 11 34,7 33,8 535 1,38 95,6 2,65 B. vulgaris 1296 12 34,2 32,8 728 1,6 94,7 3,47 1: Glycan; 2: Xylan 3.3. ECF bleaching process performance To complete the process, these pulps were bleached, thus allowing a more accurate analysis of the samples. In table 8 we evaluate the final results, allowing the selection of the most suitable species for the production of dissolving pulp. During the bleaching process, the sequence CCE - D 0 - (EP) - D 1 - D 2 was applied. It was observed that the viscosity of the species Dendrocalamus asper was higher and lower carbohydrate degradation during the process. Since previously, after the PHK process, the viscosity of the species Bambusa vulgaris had been shown to be higher. Table 8 Bleached pulp of different bamboo species comparison Sample Kappa number Brightness (%ISO) Intrinsic Viscosity (dm 3 /kg) Carbohydrates (%) Glic 1 Xil 2 Dendrocalamus asper 0,20 89,6 373 97,2 2,64 Bambusa vulgaris 0,20 91,2 437 96,5 3,48 1: Glycan; 2: Xilan Another important parameter is the xylan content, which was higher for the species Bambusa vulgaris . This characteristic is considered essential for the selection and indication of the species Dendrocalamus asper as the best for the production of dissolving pulp, since hemicellulose is a compound considered inappropriate for the final product. It is important to emphasize that, despite using the CCE step in the process, there was no significant variation in the xylan content after the bleaching process, when compared to the content found in the brown pulp. 3.4. PHK process optimization In this step, the autohydrolysis was replaced by an acid pre-hydrolysis, performed with the addition of 3% acid, together with the bleaching sequence Q – (OO) – D 0 – (EP) – D 1 – D 2 . The comparison with the autohydrolysis process, in which the sequence CCE - D0 - (EP) - D1 - D2 was used to bleach the brown pulp, is presented in Table 9 (brown pulp) and Table 10 (bleached pulp). Table 9 Effect of acid pre-hydrolysis on the brown pulp of Dendrocalamus asper Procedure EA% Kappa number P factor H Factor Screened yield (%) Intrinsic Viscosity (dm 3 /kg) Carbohydrates (%) Glyc 1 Xyl 2 Autohydrolysis 16,0 10,8 1296 4142 34,7 535 95,6 2,65 Acid pre-hydrolysis 3 16,0 11,9 1296 4142 32,0 461 96,8 1,69 Acid pre-hydrolysis 3 19,0 19,1 1296 802 35,0 996 95,5 1,76 Acid pre-hydrolysis 3 19,0 13,4 260 802 42,4 1297 93,6 5,04 Acid pre-hydrolysis 4 19,0 14,6 260 802 44,3 1279 90,5 8,30 1: Glycans 2: Xylans 3: Formic acid 4: Glacial acetic acid The formic acid action allowed a greater degradation of xylans. Consequently, there was a loss of screened yield. The pre-hydrolysis liquor pH was measured, showing values of 3.6 for autohydrolysis and 3.4 for acidic pre-hydrolysis. After the production of the brown pulp, the material runed on to the bleaching process in order to verify the need to implement the CCE step. The results are shown in Table 10. Table 10 Effect of acid pre-hydrolysis on Dendrocalamus asper bleached pulp. Procedure Kappa number Brightness (%ISO) Intrinsic Viscosity (dm 3 /kg) Carbohydrates (%) Glic 1 Xil 2 Autohydrolysis 0,1 89,6 373 97,2 2,64 Acid pre-hydrolysis 3 0,1 88,7 357 98,1 1,67 Acid pre-hydrolysis 3 0,2 90,6 465 98,1 1,76 Acid pre-hydrolysis 3 0,2 91,9 597 94,7 4,9 Acid pre-hydrolysis 4 0,13 91,9 563 91,6 8,1 1: Glycans 2: Xylans 3: Formic acid 4: Glacial acetic acid In both procedures, there were no significant losses of xylan content, evidencing that the CCE step during the brown pulp bleaching is not necessary during the process. Comparing all the results obtained, the sample in which the xylan content was equivalent to 1.76 was considered ideal, since it presented intrinsic viscosity, brightness and hemicellulose content within acceptable parameters for viscose grade. Table 11 presents the inorganic characteristics of the sample, showing the content of some metals. Unlike what is found in the literature, in this research extremely low values were found for the content of insoluble components in HCl. Table 11 Elemental analysis of Dendrocalamus asper bleached pulp Ashes (%) HCl Insoluble (%) Na (mg/kg) K (mg/kg) Ca (mg/kg) Mg (mg/kg) Mn (mg/kg) Fe (mg/kg) Cu (mg/kg) 0,1137 0,004 414 9,98 27,9 25,2 0,36 14,4 2,2 4. Conclusions Due to the lower content of xylans and the higher screened yield presented after the PHK process, the species Dendrocalamus asper proved to be more suitable for the production of dissolving pulp than the species Bambusa vulgaris , reaching the viscose grade. For this, factor P equivalent to 1296, factor H equal to 802, effective alkali at 19.0% and white liquor sulfidity equal to 35.0% were used. The variation of the P factor drastically influences the degradation of hemicelluloses, so that the higher its value more efficient this compound extraction will be. Formic Acid was more efficient in the degradation of hemicelluloses when compared to Acetic Acid. There was no significant variation in the carbohydrate bleached pulp contents when compared to the brown pulp. This indicates that all hemicellulose capable of being removed was extracted before the bleaching process. The CCE step was not necessary during the bleaching process of the brown pulp. Viscosity as well as xylan content are highly influenced by the yield of purified pulp produced. During the entire process, both species did not present tailings levels, which were equivalent to 0.0%. Further works such as the pre-hydrolysis connected to kraft pulping, reaction activities of dissolving pulp, optimization of bleaching conditions, optimization of cooking conditions and stabilization of carbohydrates chains against bleaching oxidants are necessary in order to achieve maximum efficiency of the process and adequacy to the viscose grade. Declarations ACKNOWLEDGMENT The present work was carried out with the support of the Coordination for the Improvement of Higher Education Personnel - Brazil (CAPES), Pulp and Paper Laboratory (LCP-UFV), Department of Forest Engineering (DEF-UFV) and Federal University of Viçosa (UFV). References Barretto VCdM (2008) Industrial residues from pulp and paper mill on soil fertility and eucalypt development. Doctoral Thesis, Universidade Estadual Paulista (UNESP) Bassa AGMC (2006) Mixtures of Eucalyptus grandis x Eucalyptus urophylla, Eucalyptus globulus and Pinus taeda wood chips for the production of kraft pulp through Lo-Solids® process. Master's Dissertation, Universidade de São Paulo Batalha LAR, Colodette JL, Gomide JL, Barbosa LCA, Maltha CRA, Gomes FJB (2012) Dissolving pulp production from bamboo BioResources 7:0640-0651 Borges FP, Colodette JL, Gomes FJB (2018) Use of bamboo as alternative feedstock in the obtaining of cellulose pulp for the manufacture of sackraft packing paper. 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INBAR Working Paper, Beijing, Segura TES, Silva Júnior FG (2010) Influence of Factor H and alkaline load on kraft pulping of Corymbia citriodora. Paper presented at the VI Simpósio de Pós-Graduação em Ciências Florestais/II Simpósio de Ciência e Tecnologia do RJ, Rio de Janeiro Silva KL (2021) Comparison between reference evapotranspiration estimation methods for the municipality of Viçosa-MG. Dissertation, Universidade Federal de Viçosa Sixta H (2006) Handbook of Pulp vol 2. WILEY-VCH VERLAG, Germany Strunk P, Lindgren Å, Eliasson B, Agnemo R (2012) Chemical changes of cellulose pulps in the processing to viscose dope Cellul Chem Technol 46:559-569 Xuhe C (2003) Promotion of bamboo for poverty alleviation and economic development Journal of Bamboo and Rattan 2:345-350 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2070228","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":137101171,"identity":"68d615e7-68bc-4056-bf85-2cad7341e05a","order_by":0,"name":"Marcelo Moreira Costa","email":"","orcid":"","institution":"Federal University of Viçosa","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Marcelo","middleName":"Moreira","lastName":"Costa","suffix":""},{"id":137101172,"identity":"864229fa-990e-4be4-a30f-e2b9ea8c6aa8","order_by":1,"name":"Weslley Henrique Martins Silva","email":"","orcid":"","institution":"Federal University of Viçosa","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Weslley","middleName":"Henrique Martins","lastName":"Silva","suffix":""},{"id":137101173,"identity":"59aa6bce-d458-4181-af36-b8964e5aaea3","order_by":2,"name":"Ricardo Carvalho Bittencourt","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYDACZhDBxsBgwIwQY3zAYAMUIayFmbEBKsRswJCGRwsDTAsDQgubBD4t5u3MDz9XlNkwmLPzH3/wcYednMHt88eqeRIOM5hLH8CqReYwm7HkmXNpDJbNzIyNM88kGxucS2a7DdJi2ZeAVYsEMw+DZGPbYQaDw8yMzbxtBxI3nGFmu837I43B4Ax2hwG1MP+Ea/kL1VLMk4BXCxvCFkaoFmaeBBs8WtjMLBvOpfEA/WI4s7ctGegzZmPJOQk2PJY9OLTwH358s6HMRs6c/+CDDz/b7OT4zjA+/PAmQULOnAe7FhjAlCagYRSMglEwCkYBPgAA/bdPvqycAOMAAAAASUVORK5CYII=","orcid":"","institution":"Federal University of Viçosa","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Ricardo","middleName":"Carvalho","lastName":"Bittencourt","suffix":""},{"id":137101174,"identity":"b21b318a-fe7c-42a3-870e-28a35c27b36f","order_by":3,"name":"Felipe Pedersoli Borges","email":"","orcid":"","institution":"Federal University of Viçosa","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Felipe","middleName":"Pedersoli","lastName":"Borges","suffix":""},{"id":137101175,"identity":"50dbbd24-6d61-4e64-9e06-75ddd92f79a5","order_by":4,"name":"Priscila Moreira Silva","email":"","orcid":"","institution":"Federal University of Viçosa","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Priscila","middleName":"Moreira","lastName":"Silva","suffix":""},{"id":137101176,"identity":"c2f5cf3a-b997-4f6a-bf13-8de95dc90a99","order_by":5,"name":"Sebastião Renato Valverde","email":"","orcid":"","institution":"Federal University of Viçosa","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sebastião","middleName":"Renato","lastName":"Valverde","suffix":""}],"badges":[],"createdAt":"2022-09-15 19:59:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2070228/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2070228/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":26727123,"identity":"3a03161c-e8db-49cc-aab9-a52f8f7bac61","added_by":"auto","created_at":"2022-09-20 20:50:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":26192,"visible":true,"origin":"","legend":"\u003cp\u003eBamboo chips chemical characterization\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-2070228/v1/c1aed9ed14ec5809e422d729.png"},{"id":26727124,"identity":"ab6615d4-b2b0-4261-b391-d84e90c9b142","added_by":"auto","created_at":"2022-09-20 20:50:41","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":105134,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of alkaline load variation for \u003cem\u003eDendrocalamus asper \u003c/em\u003e(a) and \u003cem\u003eBambusa vulgaris \u003c/em\u003e(b)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-2070228/v1/dfb2db4dc0d5ad96be607edd.png"},{"id":27308889,"identity":"f3a3409d-d2bd-43d5-b0a8-3acc183451c8","added_by":"auto","created_at":"2022-10-04 08:44:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":712824,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2070228/v1/5eb0fd10-3650-47e8-b91b-9ee9936dd365.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Pre-hydrolysis kraft dissolving pulp from Bambusa vulgaris and Dendrocalamus asper bamboos biomass","fulltext":[{"header":"1. Introdution","content":"\u003cp\u003eThe emergence of new technologies, in line with the demand for innovation and sustainability, has brought the use of lignocellulosic biomasses as an alternative raw material for non-woody fiber. Therefore, the need arose to implement the use of cellulosic biomass on an industrial scale in the most diverse sectors of the forest production chain. Among some motivating factors are the need to complement the production of wood raw material, the optimization of processes, the possible reduction of costs, competition between different forest sectors and the edaphoclimatic conditions of the planting sites.\u003c/p\u003e \u003cp\u003eOn the world stage, Brazil is the second largest producer and largest exporter of cellulosic pulp obtained through wood delignification (IB\u0026Aacute; \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). For this purpose, Eucalyptus and Pinus species are the most used worldwide. This segment currently represents about 1.3% of the Brazilian national GDP and 6.9% of the industrial GDP, and is therefore considered a sector that maximizes the country's economy. Although Brazil has a planted area of eucalyptus that exceeds 5.6\u0026nbsp;million hectares, there are factors that increase the need to obtain alternative sources of production, such as the trends of increasing wood processing costs and competition with other industrial sectors (Borges et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe average productivity of bamboo biomass can vary between 20 to 90 t/ha (曹明勇 2016). Brazil has 1.5\u0026nbsp;million hectares of native and planted bamboo forests with 258 different species. The genera Bambusa and Dendrocalamus have good agricultural productivity, 25t/ha on average (Guarnetti \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eBamboo emerges as a possibility for use as an alternative lignocellulosic raw material in Brazil because it is a crop with high occurrence in Brazilian soil, short harvest cycles, good adaptability even in poorly fertile soils and high productivity per hectare (Reubens \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Xuhe \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). In Brazil, according to the List of Species of Brazilian Flora, there are 258 species of bamboo and, according to data measured by the Ecological-Economic Zoning (ZEE) of Acre, this state has drawn attention for having the largest native bamboo forest in the world, presenting about 180 thousand square kilometers of forests with the presence of the plant. The use of bamboo for the production of conventional cellulosic pulp is already a reality in the Asian market. In Brazil, the company Itapaj\u0026eacute; used Bambusa vulgaris for the production of paperboard, however, the industrial application is still incipient in western countries.\u003c/p\u003e \u003cp\u003eBamboo fibers have intermediate values of fiber length and wall thickness in relation to the Pinus spp. and the Eucalyptus spp. It may be used to production of short fiber pulp and long fiber pulp simultaneously (J\u0026uacute;nior et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) This characteristic makes bamboo a good material for pulping, paper and dissolving pulp. Dissolving pulp is a chemically refined, bleached 90% pure cellulose compound with low hemicellulose and lignin content (Chen et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).End uses include such as cellophane and rayon, cellulose esters, cellulose ethers, and grafted or crosslinked cellulose derivatives.\u003c/p\u003e \u003cp\u003eBamboo may be used as a potential resource for dissolving pulp production. However, its hemicellulose content is higher than that of traditional wood species. Therefore, it is challenging to use bamboo for dissolving pulp production.\u003c/p\u003e \u003cp\u003eDissolving pulp quality mainly depends on the pulping process, in addition to the properties of the raw material. Currently, the pre-hydrolysis Kraft pulping process is one of the primary methods for producing dissolving pulp due to its high efficiency in lignin and hemicellulose removals (Chen et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). In addition, compared to wood, bamboo contains a higher silica content. Silica generates problems during pulping and bioconversion processes, causing complications in effluent streams. Therefore, the low silica content in raw materials is of great importance in expanding the use of bamboo.\u003c/p\u003e \u003cp\u003eThe production of dissolving pulp is expanding in Brazil. Currently, the largest consumption of this product is concentrated in the Asian continent, representing about 77% of world demand and, due to the high capacity of forestry production, an investment of 7.5\u0026nbsp;billion reais is estimated for new projects for the production of wood. dissolving pulp in Brazil, which can generate thousands of jobs directly and indirectly (FIEP \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA clear example of the expansion of the sector in the country is the association between the companies Lenzing and Duratex, creating LD Celulose Co., which will be inaugurated in 2022, in Minas Gerais.\u003c/p\u003e \u003cp\u003eThe overall fiber yield for the production of dissolving pulp is rarely above 35% (Batalha et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), pulps must contain a high content of alpha-cellulose (95 to 98%) and relatively low contents of hemicelluloses (\u0026lt;\u0026thinsp;4%) and lignin (\u0026lt;\u0026thinsp;0.05%). The intrinsic viscosity of dissolving pulp viscose grade should be in the range of 400 to 600 mL/g (Duan et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Strunk et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe PHK procedure features a combination of acidic (pre-hydrolysis) and alkaline (kraft cooking) conditions. The pre-hydrolysis step causes the depolymerization of hemicelluloses, allowing a greater degree of delignification in kraft cooking (Sixta \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Finally, the brown pulp is sent to the bleaching stages, in order to achieve the desired purity.\u003c/p\u003e \u003cp\u003eTherefore, the interest in studying the applicability of bamboo as an alternative source for the production of soluble pulp is justified, identifying the viability of the process, species that are chemically more favorable to kraft cooking and technological solutions that remedy the challenges of working with this culture.\u003c/p\u003e"},{"header":"2. Materials And Methods","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003e2.1. Materials\u003c/h2\u003e\n \u003cp\u003eFor this study, the species \u003cem\u003eBambusa vulgaris\u003c/em\u003e and \u003cem\u003eDendrocalamus asper\u003c/em\u003e were selected as an alternative fibrous source. The lignocellulosic biomass used comes from Federal University of Vicosa (UFV). Vicosa city is located at Minas Gerais, between between the latitudes of 20\u0026ordm; 60\u0026apos; S to 20\u0026ordm; 90\u0026apos; S and between the longitudes of 43\u0026ordm; 10\u0026apos; W to 42\u0026ordm; 90\u0026apos; W, at an average altitude of 650 meters (Silva \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). The predominant climate in the city is tropical, with rainfall during the summer and an average annual temperature of 19\u0026deg;C, ranging between 14\u0026deg;C and 32\u0026deg;C (Prado et al. \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e). The bamboo stalks collected were between 2 and 3 years old at planting, and the cut was performed above the first node.\u003c/p\u003e\n \u003cp\u003eThe experiments were carried out at the Pulp and Paper Laboratory (LPC). Bamboo samples were converted into chips, with approximate dimensions of 15 mm wide, 20 mm long and 4 mm thick. Subsequently, identified and stored to ensure the integrity of the material.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec4\"\u003e\n \u003ch2\u003e2.2. Methods\u003c/h2\u003e\n \u003cp\u003eTo produce bamboo dissolving pulp, the pre-hydrolysis kraft (PHK) pulping process was applied. In order to select the most suitable species for production, in which it presented the predetermined final characteristics, several analyzes were carried out on the bamboo chips and pulp produced. Two different bleaching sequences were applied to the brown pulp, in which we sought to observe the efficiency of the cold alkaline extraction step during the process. Table\u0026nbsp;1 describes the parameters to be analyzed and their respective standard procedures.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 1\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eGravimetric analyzes performed on both bamboo species\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Taba\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eParameter\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eProcedure\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBlack liquor pH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTappi T211 om-93\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBlack liquor residual effective alkali\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSCAN N2:88\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWhiteness\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTAPPI T452 om-99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIntrinsic Viscosity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTAPPI T230 cm-89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCarbohydrates\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSCAN-CM 71:09\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKappa number\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTappi T 236 cm-85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManual sheet formation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTappi T 218 sp-97\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLignin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKlason method \u0026ndash; TAPPI 222 om \u0026ndash; 83\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eExtractives\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTAPPI T 264 om \u0026ndash; 82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cdiv class=\"Section3\" id=\"Sec5\"\u003e\n \u003ch2\u003e2.2.1. Pre-hydrolysis kraft (PHK) pulping procedure\u003c/h2\u003e\n \u003cp\u003eThe process was carried out with a mass of 600 grams of dried chips in an MK digester, electrically heated and equipped with electronic controls connected to the computer and to peripheral equipment. The temperature data obtained were monitored every minute, making it possible to establish the profile of factor P and factor H at the end of cooking. The P factor is the relationship between time and temperature during the pre-hydrolysis stage (Jia et al. \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e). The H factor is a variable developed to express cooking time and temperature (Segura and Silva J\u0026uacute;nior \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e). The cooking white liquor was prepared as the alkaline loading conditions of sodium hydroxide and sodium sulfide changed. The pre-hydrolysis kraft pulping procedure is described (Table\u0026nbsp;2) by four steps including (1) autohydrolysis; (2) neutralization; (3) kraft pulping and (4) washing process.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 2\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eConditions applied during the pulping process (P factor of 1296 and H factor of 4142)\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabb\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eProcess steps\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTemperature (\u0026deg; C)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime (min)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eEA (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eL/C Ratio\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAutohydrolysis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e170\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e117\u0026thinsp;+\u0026thinsp;120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNeutralization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e170\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u0026thinsp;+\u0026thinsp;30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u0026thinsp;+\u0026thinsp;3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKraft pulping\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e180\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u0026thinsp;+\u0026thinsp;120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u0026ndash;24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5:1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWashing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6:1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eAutohydrolysis aims to remove the hemicelluloses from the bamboo chips, being carried out with water at P factor of 1296. Under these conditions, acetic acid release from bamboo xylan, reducing the pH of the medium, leading to the degradation of hemicelluloses. The autohydrolysis liquor was extracted from the digester, followed for neutralization, at 170\u0026ordm;C. Neutralization step was being divided into two stages of 30 minutes, wherein was used liquor with EA 3.0%. The liquor from initial displacement of autohydrolysis liquor was extracted from the digester. The liquor from the second neutralization stage remained, going on to the kraft pulping stage. The kraft pulping process was carry out in order to achieve kappa number 10\u0026thinsp;\u0026plusmn;\u0026thinsp;2, by adjusting EA charge, at a fixed H factor of 4142. Finally, washing process consists of using a liquor with 3% EA.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec6\"\u003e\n \u003ch2\u003e2.2.2. Pulp disintegration and washing\u003c/h2\u003e\n \u003cp\u003eAfter washing the chips inside the laboratory digester, sequentially, the material was sent to the Hydro Pulper, for 2 minutes. At this stage of the process, the cellulose fibers were individualized and the black liquor contained inside the chips was diluted in water and subsequently extracted from the material.\u003c/p\u003e\n \u003cp\u003eSubsequently, the cellulosic pulp was sent to the laboratory scrubber. This equipment aims to separate the purified cellulosic pulp from the amount of waste generated, selectively removing the contaminating material from the pulp generated during the process.\u003c/p\u003e\n \u003cp\u003eThe tailings can be of fibrous origin, from chips that have not been properly cooked, or of non-fibrous origin.\u003c/p\u003e\n \u003cp\u003eThere are several applications for tailings, but for this to occur, a careful characterization is necessary. Among the various applications for this material, we can mention composting (Barretto \u003cspan class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eAfter the previous step, the tailings were removed from the scrubber and their mass was measured. Then the purified cellulosic pulp is placed in suitable nylon bags and transported to a laboratory centrifuge for 10 minutes. This step consists of removing the excess water contained in the cellulosic pulp.\u003c/p\u003e\n \u003cp\u003eThe \u0026ldquo;clods\u0026rdquo; of cellulose formed during the centrifugation stage will be disintegrated, which increases the specific surface area of the material, which in turn facilitates its drying, increasing the reactivity of the particles in future analyses.\u003c/p\u003e\n \u003cp\u003eTo perform the kappa number analysis, a sheet of cellulose fibers was produced in a sheet former.\u003c/p\u003e\n \u003cp\u003eThe kappa number is the volume, in milliliters, of a 0.1N KmnO4 solution needed to react with the lignin present in an amount in grams of cellulosic pulp (Colodette et al. \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec7\"\u003e\n \u003ch2\u003e2.2.3. Gravimetric analysis\u003c/h2\u003e\n \u003cp\u003eIn order to evaluate the results of dissolving pulp production, the total yield and screened yield were measured, all of them on a dry wood mass basis. Respectively, these parameters can be measured according to equations (3), (4) and (5).\u003c/p\u003e\n \u003cp\u003eEquation 3:\u003c/p\u003e\n \u003cdiv class=\"Equation\" id=\"Equa\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e$${Y}_{T}\\left(\\%\\right)=\\frac{{{m}_{D}}_{Cel}}{{{m}_{D}}_{Chips}}\\times 100$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere Y\u003csub\u003eT\u003c/sub\u003e (%) is total yield in percentage, m\u003csub\u003eDCel\u003c/sub\u003e is cellulose dry mass and m\u003csub\u003eDChips\u003c/sub\u003e is chips dry mass.\u003c/p\u003e\n \u003cp\u003eEquation 4:\u003c/p\u003e\n \u003cdiv class=\"Equation\" id=\"Equb\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e$$TC\\left(\\%\\right)=\\frac{{{m}_{D}}_{T}}{{{m}_{D}}_{Chips}}\\times 100$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere TC (%) is tailings content in percentage and m\u003csub\u003eDT\u003c/sub\u003e is tailings dry mass.\u003c/p\u003e\n \u003cp\u003eEquation 5:\u003c/p\u003e\n \u003cdiv class=\"Equation\" id=\"Equc\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e$${Y}_{S}\\left(\\%\\right)=\\frac{{{m}_{D}}_{{Cel}_{S}}}{{{m}_{D}}_{Chips}}\\times 100$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere Y\u003csub\u003eS\u003c/sub\u003e (%) is screened yield in percentage ans m\u003csub\u003eDCelS\u003c/sub\u003e is screened cellulose dry mass.\u003c/p\u003e\n \u003cp\u003eThe other analyzes are described in Table\u0026nbsp;2, together with their respective standards.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec8\"\u003e\n \u003ch2\u003e2.2.4. Pulp bleaching\u003c/h2\u003e\n \u003cp\u003eThe bleaching of the brown pulp occurred in such a way that it was possible to optimize the use of chemical reagents, in a way that conserves the carbohydrates present in the material. The first sequence introduced was: CCE \u0026ndash; D\u003csub\u003e0\u003c/sub\u003e \u0026ndash; (EP) \u0026ndash; D\u003csub\u003e1\u003c/sub\u003e \u0026ndash; D\u003csub\u003e2\u003c/sub\u003e. Table 3 presents the parameters of this process. During the entire procedure, the material consistency was 12.0% for the first sequence and 10.0% for the second sequence.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 3\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eGeneral bleaching CCE \u0026ndash; D\u003csub\u003e0\u003c/sub\u003e \u0026ndash; (EP) \u0026ndash; D\u003csub\u003e1\u003c/sub\u003e \u0026ndash; D\u003csub\u003e2\u003c/sub\u003esequence conditions\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabc\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eParameters\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCCE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDo\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e(EP)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eConsistency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTemperature (\u003csup\u003eo\u003c/sup\u003eC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReaction time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e180\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e180\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClO\u003csub\u003e2\u003c/sub\u003e (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,22 KN*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNaOH (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e?\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e?\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003efinal pH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,0\u0026ndash;2,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4,0\u0026ndash;4,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5,5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e\u003cem\u003e*\u003c/em\u003eKN\u0026thinsp;=\u0026thinsp;Kappa number; ** Use or not of H2SO4 for pH adjustment\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eIn a second moment, the CCE step was replaced by the use of a chelator, this sequence being described as: Q \u0026ndash; (OO) \u0026ndash; D\u003csub\u003e0\u003c/sub\u003e \u0026ndash; (EP) \u0026ndash; D\u003csub\u003e1\u003c/sub\u003e \u0026ndash; D\u003csub\u003e2\u003c/sub\u003e (Table 4).\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 4\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eGeneral bleaching Q \u0026ndash; (OO) \u0026ndash; D\u003csub\u003e0\u003c/sub\u003e \u0026ndash; (EP) \u0026ndash; D\u003csub\u003e1\u003c/sub\u003e \u0026ndash; D\u003csub\u003e2\u003c/sub\u003esequence conditions\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabd\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eParameters\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eQ\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e(O/O)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDo\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e(EP)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eConsistency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTemperature (\u003csup\u003eo\u003c/sup\u003e C)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80/100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReaction time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15/60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e120\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePressure (kPa)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e600\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eO\u003csub\u003e2\u003c/sub\u003e (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChelator (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClO\u003csub\u003e2\u003c/sub\u003e (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,22 KN*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNaOH (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, (kg/t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003efinal pH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;10,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u0026ndash;2,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u0026ndash;4,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5,5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\"\u003e\n \u003cdiv style=\"text-align: left;\"\u003e*KN\u0026thinsp;=\u0026thinsp;Number Kappa\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\"\u003e\n \u003cdiv style=\"text-align: left;\"\u003e**Otimizado para cada amostra chegar na alvura 90%ISO\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\"\u003e\n \u003cdiv style=\"text-align: left;\"\u003e*** H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e ou NaOH para ajuste de pH\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cdiv\u003e\n \u003cdiv\u003e\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eThe cold caustic extraction (CCE) step, recognized for its hemicellulose removal function, was carried out at 40\u0026ordm;C for 30 minutes. In this step, 80 kg/t of NaOH was added as a chemical reagent.\u003c/p\u003e\n \u003cp\u003eThe delignification with chlorine dioxide (D\u003csub\u003e0\u003c/sub\u003e) took place at a temperature of 60\u0026ordm;C and a time of 60 minutes. In this second step, 0.22 kg/t of ClO\u003csub\u003e2\u003c/sub\u003e was added to the material.\u003c/p\u003e\n \u003cp\u003eThe third step, alkaline extraction with hydrogen peroxide (EP), had a temperature of 80\u0026ordm;C for 60 minutes, with the addition of 10 kg/t of NaOH and 3 kg/t of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e. The bleaching step with chlorine dioxide (D\u003csub\u003e1\u003c/sub\u003e) was carried out at 80\u0026ordm;C for 180 minutes, with 10 kg/t of ClO\u003csub\u003e2\u003c/sub\u003e being added. Finally, the next step of bleaching with chlorine dioxide (D\u003csub\u003e2\u003c/sub\u003e) was carried out at a temperature of 70\u0026ordm;C for 180 minutes, with the addition of 5 kg/t of ClO\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e\n \u003cp\u003eFor the second sequence, with the replacement of the CCE step, the step containing the chelator (Q) was carried out with the temperature at 70\u0026ordm;C for 60 minutes. For the second stage of this sequence, the application of Oxygen (OO) was carried out in two stages, with temperatures of 80\u0026ordm;C and 100\u0026ordm;C, for 15 minutes and 60 minutes, respectively. In this step, 20 kg/t of O2 and 20 kg/t of NaOH were added.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"3. Results And Discussion","content":"\u003cdiv class=\"Section2\" id=\"Sec10\"\u003e\n \u003ch2\u003e3.1. Bamboo chemical composition\u003c/h2\u003e\n \u003cp\u003eAmong the characteristics of wood, the chemical composition can directly influence the yield of the pulp produced, the final product quality and the consumption of reagents (Bassa \u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e). Figure 1 shows the values of the tests for chemical characterization of the species \u003cem\u003eDendrocalamus asper\u003c/em\u003e and \u003cem\u003eBambusa vulgaris\u003c/em\u003e.\u003c/p\u003e\n \u003cp\u003eXylans and lignins are undesirable in this process because they decrease reactivity and act as contaminants during the process (Martino \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). It was observed that the most present carbohydrates in bamboo chips are glycan and xylan.\u003c/p\u003e\n \u003cp\u003eOnce the chemical characterization of bamboo chips was measured, the basic density, lignin content and S/G ratio were determined. These parameters are shown in Fig.\u0026nbsp;2.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 5\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eBasic density, lignin content and S/G ratio\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabe\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSample\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eBasic Density (kg/m3)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eLignin (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eS/G\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSyringyl\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGuaiacyl\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eP-Hydroxyphenyl\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eD. asper\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e452\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1,05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eB. vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e487\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eThe basic density of \u003cem\u003eBambusa vulgaris\u003c/em\u003e chips is higher, which indicates that this material may have a greater resistance to the cooking liquor impregnation. The S/G ratio found for \u003cem\u003eDendrocalamus asper\u003c/em\u003e was higher, which indicates that lignin tends to be cleaved more easily, since it has a less condensed structure.\u003c/p\u003e\n \u003cp\u003eThrough the analysis of ash and elemental chemical composition of the chips (Table \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e) it is possible to notice very similar values between the species, especially in relation to ash and compounds insoluble in HCl.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 6\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eAnalysis of ash and chips elemental chemical composition\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabf\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\" style=\"width: 16.2281%;\"\u003e\n \u003cp\u003eSample\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\" style=\"width: 16.228%;\"\u003e\n \u003cp\u003eAshes (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eInsoluble HCl (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eMetals (mg/Kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eCa\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eMg\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFe\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eCu\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eNa\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eK\u003c/strong\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 16.2281%;\"\u003e\n \u003cp\u003e\u003cem\u003eD. asper\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" style=\"width: 16.228%;\"\u003e\n \u003cp\u003e2,47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e101\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e146\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11,59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2,34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e155\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e111\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 16.2281%;\"\u003e\n \u003cp\u003e\u003cem\u003eB. vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" style=\"width: 16.228%;\"\u003e\n \u003cp\u003e2,47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e151\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8,66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2,53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e111\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec11\" style=\"text-align: center;\"\u003e\n \u003ch2 style=\"text-align: left;\"\u003e3.2. PHK process performance\u003c/h2\u003e\n \u003cp style=\"text-align: left;\"\u003eOnce the cooking conditions were determined, the production process could be started. In order to compare the two bamboo species, the kappa number and the screened yield of the brown pulp were considered determinant parameters to evaluate the productive viability of the samples. Regarding \u003cem\u003eDendrocalamus asper\u003c/em\u003e, Fig.\u0026nbsp;2 shows the behavior of this species in relation to effective alkali (EA), kappa number and screened yield.\u003c/p\u003e\n \u003cp style=\"text-align: left;\"\u003eIt can be seen (Fig. 2) that when the lowest level of alkaline load was applied, the sample presented higher values of kappa number and screened yield. On the other hand, under drastic cooking conditions, we obtained lower values of these same parameters. The above result is explained by the degree of degradation of lignin, cellulose and hemicellulose in the material. Under more severe conditions, the constituents of the chips remained in the pulp in smaller amounts, when compared to the milder conditions. For the species \u003cem\u003eBambusa vulgaris\u003c/em\u003e (Fig. 2b) it was observed that both parameters evaluated showed the same tendency of \u003cem\u003eDendrocalamus asper\u003c/em\u003e (Fig. 2a). In this study, the tailings content presented by the two bamboo species was 0.0%, in the entire range of applied alkaline load.\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: left;\"\u003eTable 7 shows the brown pulp characterization produced from the two bamboo species. Due to the comparison between them, was considered the cooking condition in which kappa number 10\u0026thinsp;\u0026plusmn;\u0026thinsp;2 has been reached. Although the species \u003cem\u003eBambusa vulgaris\u003c/em\u003e has a lower kappa number, higher brightness and higher viscosity, it can be seen that this species has a lower level of purified yield and higher content of xylans compared to other species. Comparison between the brown pulps of different bamboo species\u003c/p\u003e Table 7\u0026nbsp;\u003cbr\u003eComparison between the brown pulps of different bamboo species\u0026nbsp;\n\u003c/div\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eSample\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eP Factor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eKappa number\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eScreened yield (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eBrightness (%ISO)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eIntrinsic Viscosity (dm\u003csup\u003e3\u003c/sup\u003e/kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eInsoluble Lignin (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eCarbohydrates (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eGlyc\u003csup\u003e1\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eXyl\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003eD. asper\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e34,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e33,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e535\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1,38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e95,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2,65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003eB. vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e34,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e32,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e728\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e94,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3,47\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e1: Glycan; 2: Xylan\u003c/p\u003e\n\u003cdiv class=\"Section2\" id=\"Sec12\"\u003e\n \u003ch2\u003e3.3. ECF bleaching process performance\u003c/h2\u003e\n \u003cp\u003eTo complete the process, these pulps were bleached, thus allowing a more accurate analysis of the samples. In table 8 we evaluate the final results, allowing the selection of the most suitable species for the production of dissolving pulp. During the bleaching process, the sequence CCE - D\u003csub\u003e0\u003c/sub\u003e - (EP) - D\u003csub\u003e1\u003c/sub\u003e - D\u003csub\u003e2\u003c/sub\u003e was applied. It was observed that the viscosity of the species \u003cem\u003eDendrocalamus asper\u003c/em\u003e was higher and lower carbohydrate degradation during the process. Since previously, after the PHK process, the viscosity of the species \u003cem\u003eBambusa vulgaris\u003c/em\u003e had been shown to be higher.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 8\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eBleached pulp of different bamboo species comparison\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabg\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSample\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eKappa number\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eBrightness (%ISO)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eIntrinsic Viscosity (dm\u003csup\u003e3\u003c/sup\u003e/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCarbohydrates (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGlic\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eXil\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eDendrocalamus asper\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e89,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e373\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e97,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2,64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBambusa vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e91,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e437\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e96,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3,48\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e\n \u003cdiv style=\"text-align: left;\"\u003e1: Glycan; 2: Xilan\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eAnother important parameter is the xylan content, which was higher for the species \u003cem\u003eBambusa vulgaris\u003c/em\u003e. This characteristic is considered essential for the selection and indication of the species \u003cem\u003eDendrocalamus asper\u003c/em\u003e as the best for the production of dissolving pulp, since hemicellulose is a compound considered inappropriate for the final product. It is important to emphasize that, despite using the CCE step in the process, there was no significant variation in the xylan content after the bleaching process, when compared to the content found in the brown pulp.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec13\"\u003e\n \u003ch2\u003e3.4. PHK process optimization\u003c/h2\u003e\n \u003cp\u003eIn this step, the autohydrolysis was replaced by an acid pre-hydrolysis, performed with the addition of 3% acid, together with the bleaching sequence Q \u0026ndash; (OO) \u0026ndash; D\u003csub\u003e0\u003c/sub\u003e \u0026ndash; (EP) \u0026ndash; D\u003csub\u003e1\u003c/sub\u003e \u0026ndash; D\u003csub\u003e2\u003c/sub\u003e. The comparison with the autohydrolysis process, in which the sequence CCE - D0 - (EP) - D1 - D2 was used to bleach the brown pulp, is presented in Table\u0026nbsp;9 (brown pulp) and Table\u0026nbsp;10 (bleached pulp).\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 9\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eEffect of acid pre-hydrolysis on the brown pulp of \u003cem\u003eDendrocalamus asper\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabh\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eProcedure\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eEA%\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eKappa number\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eP factor\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eH Factor\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eScreened yield\u003c/p\u003e\n \u003cp\u003e(%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eIntrinsic Viscosity (dm\u003csup\u003e3\u003c/sup\u003e/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCarbohydrates\u003c/p\u003e\n \u003cp\u003e(%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGlyc\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eXyl\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAutohydrolysis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4142\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e535\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e95,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2,65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis \u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11,9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4142\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e461\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e96,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1,69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis \u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e802\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e996\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e95,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1,76\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis \u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e260\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e802\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1297\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e93,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5,04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e260\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e802\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e44,3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1279\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8,30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\"\u003e\n \u003cdiv style=\"text-align: left;\"\u003e1: Glycans 2: Xylans 3: Formic acid 4: Glacial acetic acid\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eThe formic acid action allowed a greater degradation of xylans. Consequently, there was a loss of screened yield. The pre-hydrolysis liquor pH was measured, showing values of 3.6 for autohydrolysis and 3.4 for acidic pre-hydrolysis. After the production of the brown pulp, the material runed on to the bleaching process in order to verify the need to implement the CCE step. The results are shown in Table 10.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 10\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eEffect of acid pre-hydrolysis on \u003cem\u003eDendrocalamus asper\u003c/em\u003e bleached pulp.\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabi\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eProcedure\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eKappa number\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eBrightness (%ISO)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eIntrinsic Viscosity (dm\u003csup\u003e3\u003c/sup\u003e/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCarbohydrates (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGlic\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eXil\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAutohydrolysis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e89,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e373\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e97,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2,64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis \u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e88,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e357\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e98,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1,67\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis \u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e465\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e98,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1,76\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis \u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e91,9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e597\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e94,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4,9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcid pre-hydrolysis\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e91,9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e563\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e91,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8,1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e\n \u003cdiv style=\"text-align: left;\"\u003e1: Glycans 2: Xylans 3: Formic acid 4: Glacial acetic acid\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eIn both procedures, there were no significant losses of xylan content, evidencing that the CCE step during the brown pulp bleaching is not necessary during the process. Comparing all the results obtained, the sample in which the xylan content was equivalent to 1.76 was considered ideal, since it presented intrinsic viscosity, brightness and hemicellulose content within acceptable parameters for viscose grade. Table 11 presents the inorganic characteristics of the sample, showing the content of some metals. Unlike what is found in the literature, in this research extremely low values were found for the content of insoluble components in HCl.\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eTable 11\u0026nbsp;\u003c/p\u003e\n \u003cp style=\"text-align: center;\"\u003eElemental analysis of \u003cem\u003eDendrocalamus asper\u003c/em\u003e bleached pulp\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tabj\" style=\"border-collapse: collapse; margin: 0px auto;\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAshes (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHCl Insoluble (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNa\u003c/p\u003e\n \u003cp\u003e(mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eK\u003c/p\u003e\n \u003cp\u003e(mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCa (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMg (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMn (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFe\u003c/p\u003e\n \u003cp\u003e(mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCu (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,1137\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e414\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9,98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27,9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25,2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\n\u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eDue to the lower content of xylans and the higher screened yield presented after the PHK process, the species \u003cem\u003eDendrocalamus asper\u003c/em\u003e proved to be more suitable for the production of dissolving pulp than the species \u003cem\u003eBambusa vulgaris\u003c/em\u003e, reaching the viscose grade. For this, factor P equivalent to 1296, factor H equal to 802, effective alkali at 19.0% and white liquor sulfidity equal to 35.0% were used. The variation of the P factor drastically influences the degradation of hemicelluloses, so that the higher its value more efficient this compound extraction will be. Formic Acid was more efficient in the degradation of hemicelluloses when compared to Acetic Acid. There was no significant variation in the carbohydrate bleached pulp contents when compared to the brown pulp. This indicates that all hemicellulose capable of being removed was extracted before the bleaching process. The CCE step was not necessary during the bleaching process of the brown pulp. Viscosity as well as xylan content are highly influenced by the yield of purified pulp produced. During the entire process, both species did not present tailings levels, which were equivalent to 0.0%.\u003c/p\u003e \u003cp\u003eFurther works such as the pre-hydrolysis connected to kraft pulping, reaction activities of dissolving pulp, optimization of bleaching conditions, optimization of cooking conditions and stabilization of carbohydrates chains against bleaching oxidants are necessary in order to achieve maximum efficiency of the process and adequacy to the viscose grade.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eACKNOWLEDGMENT\u003c/h2\u003e \u003cp\u003eThe present work was carried out with the support of the Coordination for the Improvement of Higher Education Personnel - Brazil (CAPES), Pulp and Paper Laboratory (LCP-UFV), Department of Forest Engineering (DEF-UFV) and Federal University of Vi\u0026ccedil;osa (UFV).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBarretto VCdM (2008) Industrial residues from pulp and paper mill on soil fertility and eucalypt development. Doctoral Thesis, Universidade Estadual Paulista (UNESP)\u003c/li\u003e\n\u003cli\u003eBassa AGMC (2006) Mixtures of Eucalyptus grandis x Eucalyptus urophylla, Eucalyptus globulus and Pinus taeda wood chips for the production of kraft pulp through Lo-Solids\u0026reg; process. Master\u0026apos;s Dissertation, Universidade de S\u0026atilde;o Paulo\u003c/li\u003e\n\u003cli\u003eBatalha LAR, Colodette JL, Gomide JL, Barbosa LCA, Maltha CRA, Gomes FJB (2012) Dissolving pulp production from bamboo BioResources 7:0640-0651\u003c/li\u003e\n\u003cli\u003eBorges FP, Colodette JL, Gomes FJB (2018) Use of bamboo as alternative feedstock in the obtaining of cellulose pulp for the manufacture of sackraft packing paper. The Journal of Engineering and Exact Sciences 4:0405-0411\u003c/li\u003e\n\u003cli\u003eCao MY (2016) Study on bamboo biomass and primary productivity features with Changning county. Thesis, Central South University of Forestry and Technology\u003c/li\u003e\n\u003cli\u003eChen C et al. (2016) Cellulose (dissolving pulp) manufacturing processes and properties: A mini-review. BioResources 11:5553-5564\u003c/li\u003e\n\u003cli\u003eColodette JL, Gomide JL, Gomes FJB (2014) Wood Quality: A Key Element for Production of High Yield and High Bleachability Eucalypt Kraft Pulp. O Papel: revista mensal de tecnologia em celulose e papel 75:63\u003c/li\u003e\n\u003cli\u003eDuan C, Li J, Ma X, Chen C, Liu Y, Stavik J, Ni Y (2015) Comparison of acid sulfite (AS)- and prehydrolysis kraft (PHK)-based dissolving pulps. Cellulose 22:4017-4026 doi:10.1007/s10570-015-0781-1\u003c/li\u003e\n\u003cli\u003eFIEP (2016) Management and Sustainability Report: 2015. Federa\u0026ccedil;\u0026atilde;o das Ind\u0026uacute;strias do Estado do Paran\u0026aacute;., Curitiba\u003c/li\u003e\n\u003cli\u003eGuarnetti RL (2013) Cogeneration of Electricity Using Bamboo in Brazil: Technical Aspects, Economic and Environmental. Doctoral Thesis, Universidade de S\u0026atilde;o Paulo\u003c/li\u003e\n\u003cli\u003eIB\u0026Aacute; (2019) 2019 Report. Ind\u0026uacute;stria Brasileira de \u0026Aacute;rvores, \u003c/li\u003e\n\u003cli\u003eJia W, Zhou M, Yang C, Zhang H, Niu M, Shi H (2022) Evaluating process of auto-hydrolysis prior to kraft pulping on production of chemical pulp for end used paper-grade products Journal of Bioresources and Bioproducts doi:https://doi.org/10.1016/j.jobab.2022.05.002\u003c/li\u003e\n\u003cli\u003eJ\u0026uacute;nior EAB et al. (2019) Bamboo kraft pulping Advances in Forestry Science 6:791-796 doi:http://dx.doi.org/10.34062/afs.v6i4.8361\u003c/li\u003e\n\u003cli\u003eMartino DC (2015) Dissolving pulp production from eucalypt and sugarcane bagasse by organosolv and prehydrolysis Kraft processes. Doctoral Thesis, Universidade Federal de Vi\u0026ccedil;osa\u003c/li\u003e\n\u003cli\u003ePrado LB, Fialho ES, Santos LGF (2020) Remote sensing and the urban climate: a research perspective through the surface thermal field, in the central area of the municipality of Vi\u0026ccedil;osa \u0026ndash; MG. Revista Brasileira de Climatologia 27\u003c/li\u003e\n\u003cli\u003eReubens R (2010) Bamboo in sustainable contemporary design. INBAR Working Paper, Beijing, \u003c/li\u003e\n\u003cli\u003eSegura TES, Silva J\u0026uacute;nior FG (2010) Influence of Factor H and alkaline load on kraft pulping of Corymbia citriodora. Paper presented at the VI Simp\u0026oacute;sio de P\u0026oacute;s-Gradua\u0026ccedil;\u0026atilde;o em Ci\u0026ecirc;ncias Florestais/II Simp\u0026oacute;sio de Ci\u0026ecirc;ncia e Tecnologia do RJ, Rio de Janeiro \u003c/li\u003e\n\u003cli\u003eSilva KL (2021) Comparison between reference evapotranspiration estimation methods for the municipality of Vi\u0026ccedil;osa-MG. Dissertation, Universidade Federal de Vi\u0026ccedil;osa\u003c/li\u003e\n\u003cli\u003eSixta H (2006) Handbook of Pulp vol 2. WILEY-VCH VERLAG, Germany\u003c/li\u003e\n\u003cli\u003eStrunk P, Lindgren \u0026Aring;, Eliasson B, Agnemo R (2012) Chemical changes of cellulose pulps in the processing to viscose dope Cellul Chem Technol 46:559-569\u003c/li\u003e\n\u003cli\u003eXuhe C (2003) Promotion of bamboo for poverty alleviation and economic development Journal of Bamboo and Rattan 2:345-350\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"bamboo biomass, xylan content, ECF bleaching","lastPublishedDoi":"10.21203/rs.3.rs-2070228/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2070228/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn Brazil, bamboo emerges as a potential non-wood raw material as alternative lignocellulosic biomasses source, since this crop has high rusticity and productivity. It grows even in poor soil and shortage of water conditions, and it has a harvest cycle close to 2 years. This study aimed to produce dissolving pulp from the bamboo species \u003cem\u003eBambusa vulgaris and Dendrocalamus asper\u003c/em\u003e seeking to optimize the process conditions, in order to obtain a final product with the specification\u0026rsquo;s parameters for viscose grade. Bamboo chips of \u003cem\u003eBambusa vulgaris and Dendrocalamus asper\u003c/em\u003e with 2 years old were submitted to pre-hydrolysis kraft pulping process. After pre-hydrolysis kraft pulping \u003cem\u003eBambusa vulgaris\u003c/em\u003e showed screened yield of 34.2% and a xylan content of 3,47% \u003cem\u003eand Dendrocalamus asper\u003c/em\u003e showed screened yield of 34,7% and a xylan content of 2,65. Based on these results, only \u003cem\u003eDendrocalamus asper\u003c/em\u003e was selected and bleached. After optimizing the bleaching process the final kappa number of 0.20, viscosity of 465 dm\u003csup\u003e3\u003c/sup\u003e/kg and 90.6% brightness were obtained for \u003cem\u003eDendrocalamus asper\u003c/em\u003e. Were achieved 1,76% of xylan, 98,1% of glycan and 0.10% of ash content. Was concluded that \u003cem\u003eDendrolocamus asper\u003c/em\u003e can be applied for the production of dissolving pulp. The CCE stage, under the established conditions, did not show to be efficient in removing the xylans from \u003cem\u003eDendrocalamus Asper\u003c/em\u003e brown pulp. On the other hand, further work is needed to optimize the main stages of the process, such as the pre-hydrolysis connected to kraft pulping, as well as the stabilization of carbohydrates chains against bleaching oxidants.\u003c/p\u003e","manuscriptTitle":"Pre-hydrolysis kraft dissolving pulp from Bambusa vulgaris and Dendrocalamus asper bamboos biomass","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-09-20 20:50:39","doi":"10.21203/rs.3.rs-2070228/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"99b8ad0d-4dd1-430b-bd98-84ad5b0973c7","owner":[],"postedDate":"September 20th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-10-04T08:44:21+00:00","versionOfRecord":[],"versionCreatedAt":"2022-09-20 20:50:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2070228","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2070228","identity":"rs-2070228","version":["v1"]},"buildId":"FbvkV6FR0MCFSLy54lSbu","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}