Fenton reagent oxidation treatment of nitropyrazole wastewater

Fenton reagent oxidation treatment of nitropyrazole wastewater | 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 Fenton reagent oxidation treatment of nitropyrazole wastewater Liu Ming, ZHANG Shuai, ZHENG Rushui, ZHAO Linxiu, CAO Duanlin, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1857115/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 this paper, Fenton reagent was used to oxidize 3,4-dinitropyrazole wastewater, and the effects of FeSO 4 •7H 2 O dosage, H 2 O 2 dosage, initial pH, reaction time and reaction temperature on the treatment effect were studied.The results show that the oxidation of Fenton reagent can effectively remove 3,4-dinitropyrazole from nitropyrazole wastewater. When the dosage of FeSO 4 •7H 2 O is 13.2g•L − 1 and the dosage of H 2 O 2 is 82mL•L − 1 . When the initial pH is 2, the reaction time is 120min and the reaction temperature is 30℃, the removal rate of 3,4-dinitropyrazole in the wastewater reaches 97%, and the removal rate of COD reaches 62.9%;The reaction kinetics study showed that the degradation of 3,4-dinitropyrazole in the reaction process conformed to the second-order kinetic model;UV-Vis absorption spectrum analysis showed that the absorbance of wastewater samples before and after treatment decreased significantly.After the Fenton oxidation treatment, the water quality of the wastewater changed and the biodegradability of the wastewater was significantly improved. 3 4-dinitropyrazole Fenton oxidation nitropyrazole wastewater reaction kinetics COD Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction The treatment of organic wastewater has always been a difficult problem in water environment governance, and it is also a focus of attention of scientists at home and abroad. Therefore, this topic is based on the concept of green environmental protection to carry out research on nitropyrazole wastewater treatment. 3,4-Dinitropyrazole (DNP) is an energetic compound with excellent properties that can replace TNT as a carrier for molten-cast explosives. During the preparation of DNP, a large amount of organic waste water will be produced(Zhao et al.2010) According to the synthesis process, the waste water may contain a variety of organic compounds and a large amount of waste acid(Xue et al.2015)The main organic compounds are 3,4-dinitropyrazole, a very small amount of 1,3-dinitropyrazole, 3,5-dinitropyrazole, etc. These organic pollutants are highly toxic(Zhang et al.2015), difficult to biochemically degrade(Zhao et al.2010), and direct discharge will cause serious harm to the ecological environment and human health. Therefore, effective treatment of nitropyrazole wastewater is essential for improving the ecological environment and protecting human health. significant. At present, the main treatment methods for organic wastewater by domestic and foreign scholars are adsorption method, extraction method, electrochemical method, advanced oxidation method(Chang et al.2007), anaerobic-aerobic biological method, etc.Among them, the adsorption method and the extraction method are physical treatment methods. These methods are characterized by simple operation and fast reaction, but at the same time, the material cost is high and there will be secondary pollution.Electrochemical method belongs to chemical treatment method. This kind of method has fast reaction rate and high pollution concentration tolerance, but it has high energy consumption and high industrial operation cost and is not easy to popularize.Anaerobic-aerobic biological method belongs to biological treatment technology. Biological method is easy to operate and manage, with low construction and maintenance costs, and is not easy to cause secondary pollution. However, due to the high amount of toxic substances in this type of wastewater, it is not suitable for direct biochemical treatment.Fenton's reagent oxidation method belongs to advanced oxidation method. Fenton oxidation method (Yin et al.2012) is a chemical treatment technology, which has the advantages of simple equipment, convenient operation, complete reaction and no secondary pollution, etc., and can mineralize organic matter into carbon dioxide and water. Or other low-toxic substances, which have broad application prospects.The role of Fenton oxidation in water treatment mainly includes oxidation and coagulation.Oxidation means that under the combined action of Fe 2+ and H 2 O 2 under acidic conditions, hydroxyl radicals with strong oxidizing ability (Feng et al.2012) are generated. OH reacts with organic matter. The redox potential of hydroxyl radicals is 2.8V, second only to fluorine ( 2.87 V), which can achieve the purpose of oxidative decomposition of organic matter in water.The main equations of the Fenton reaction are shown in equations ( 1 ) ~ (4). The Fe(OH) 3 colloid generated in the reaction has the functions of flocculation and adsorption, which can remove some organic substances in the water(Zhang et al.2005) There is no literature report on the treatment of nitropyrazole-containing wastewater by Fenton oxidation. Fe 2+ +H 2 O 2 + H + →Fe 3+ +H 2 O+·OH (1) Fe 2+ +·OH→Fe 3+ +OH − (2) ·OH + H 2 O 2 →·HO 2 + H 2 O (3) ·OH + R-H→·R + H 2 O (4) In this study, the nitropyrazole wastewater was treated by Fenton's reagent(Matta et al.2007) oxidation method.The nitropyrazole wastewater treatment object is the wastewater generated from the nitration of 3-nitropyrazole mixed acid to obtain 3,4-dinitropyrazole.The nitropyrazole-containing wastewater was treated by Fenton reagent oxidation, and the effects of FeSO 4 •7H 2 O dosage, H 2 O 2 dosage, initial pH of solution, reaction time and reaction temperature on the treatment effect were investigated. The practical application of azole wastewater (Zhang et al.2012) provides technical support and theoretical basis. Experimental Materials And Methods Experimental materials and instruments The nitropyrazole wastewater comes from the wastewater (pH = 1) produced after the nitration of 3-nitropyrazole(Zhu et al.2012)mixed acid to obtain 3,4-dinitropyrazole.Ferrous sulfate heptahydrate (FeSO 4 •7H 2 O) and sodium hydroxide (NaOH) are of analytical grade; hydrogen peroxide (H 2 O 2 , mass fraction 30%) is of excellent grade;Constant temperature oscillator (HZQ-F160A, Shanghai Yiheng Scientific Instrument Co., Ltd.); Multi-parameter water quality analyzer (DGB-401, Shanghai INESA Scientific Instrument Co., Ltd.); UV-Vis Spectrophotometer (TU-1900, Beijing Pudong Electric Co., Ltd.) Analytical General Instruments Co., Ltd.);High performance liquid chromatography (LC98-1, Beijing Thermal Analysis Instrument Technology Development Co., Ltd.). Experimental method Due to the high concentration of pollutants in wastewater, the wastewater was diluted 10 times for treatment in this study.Take 30 mL of the above-mentioned wastewater without pH adjustment into a 100 mL conical flask, add a certain amount of FeSO 4 •7H 2 O to dissolve it, then add a certain amount of H 2 O 2 , and place it in a constant temperature oscillator (150r•min -1 ) to react for a certain time, and after the reaction is complete, take a sample to detect the concentration of 3,4-dinitropyrazole in the wastewater.Sodium hydroxide (0.5mol•L -1 ) was used to adjust the pH of the solution to 7–8 to completely precipitate iron ions. After standing for 30 min, the supernatant was taken for COD detection. Since the composition of the wastewater is simple, the change in the content of 3,4-dinitropyrazole is used to represent the treatment effect of the wastewater treated by the Fenton method(Zhang et al.2012) . Analysis method The content of 3,4-dinitropyrazole in water samples before and after treatment was calculated by high performance liquid chromatography. The detection wavelength was 260 nm, the mobile phase ratio was acetonitrile: acetic acid water = 35%: 65%, the flow rate was 1.0 mL·min -1 , and the injection volume was 20 µL. UV-Vis spectrophotometer; measure the UV-Vis absorption spectrum of the water samples before and after treatment in the range of 190–1100 nm. The formula for calculating the removal rate of DNP in wastewater samples is as follows: $$\text{D}\text{N}\text{P} \text{r}\text{e}\text{m}\text{o}\text{v}\text{a}\text{l} \text{r}\text{a}\text{t}\text{e}=\frac{{\text{D}\text{N}\text{P}}_{1}-{\text{D}\text{N}\text{P}}_{2}}{{\text{D}\text{N}\text{P}}_{1}}\text{x}100\text{%}$$ In the formula, DNP 1 is the DNP concentration in the water sample before treatment, and DNP 2 is the DNP concentration in the water sample after treatment. Experimental Results And Discussion Influence of FeSO 4 •7H 2 O dosage on treatment effect Under the conditions that the initial pH of the solution is 1, the dosage of H 2 O 2 is 90 mL•L -1 , the reaction time is 120 min, and the reaction temperature is 25 ℃, the dosage of FeSO 4 •7H 2 O is studied for the removal rate of organic DNP and COD in the nitropyrazole wastewater. The results are shown in Fig. 1 . It can be seen from Fig. 1 that when the dosage of FeSO 4 •7H 2 O increased from 0.1g to 0.4g, the DNP removal rate increased from 34–96%, and the COD removal rate increased from 11–33%. When the dosage of FeSO 4 •7H 2 O continued to increase to 0.5g, the DNP removal rate did not change much.This is because when the Fe 2+ concentration in the solution is relatively low, the utilization rate of H 2 O 2 is not high, the generated •OH is less, and the organic matter cannot be completely oxidized, resulting in a low DNP removal rate.The reason for the low removal rate of COD may be that the generated OH oxidizes the organic macromolecules into small organic molecules and does not completely mineralize into CO 2 and H 2 O.As the dosage of FeSO 4 •7H 2 O increases, the generated •OH gradually increases, and the DNP removal rate increases accordingly. When the dosage of FeSO 4 •7H 2 O exceeds 0.4g, the generated •OH is too late to interact with the organic matter. During the reaction, the accumulated •OH reacted with each other to generate water, so that the DNP removal rate did not change much. Therefore, the optimal dosage of FeSO 4 •7H 2 O is selected as 0.4g in the experiment. Influence of H 2 O 2 dosage on treatment effect When the initial pH of the solution was 1, the dosage of FeSO 4 •7H 2 O was 0.4 g, the reaction time was 120 min, and the reaction temperature was 25°C, the effect of the dosage of H 2 O 2 (Wu et al.2003)on the removal rate of organic matter DNP and COD in nitropyrazole wastewater was studied. Influence(Wang et al.2008), the results are shown in Fig. 2 . It can be seen from Fig. 2 that when the dosage of H 2 O 2 increases from 50mL•L -1 to 82mL•L -1 , the DNP removal rate increases from 81–87%, and the COD removal rate increases from 19–26%.Continue to increase the dosage of H 2 O 2 , the DNP removal rate gradually decreased. The insignificant change in COD removal rate may be caused by incomplete mineralization of some organic matter.This is because with the increase of H 2 O 2 concentration, the hydroxyl radical•OH content in the solution increases, resulting in the increase of DNP removal rate with the increase of H 2 O 2 dosage; when the H 2 O 2 concentration exceeds 82mL•L -1 , •OH and Excess H 2 O 2 reacts to generate water and oxygen, which reduces the removal rate of DNP. Therefore, the optimal dosage of H 2 O 2 was selected as 82mL•L -1 in the experiment. Influence of reaction time on treatment effect When the initial pH of the solution was 1, the dosage of FeSO 4 •7H 2 O was 0.4 g, the dosage of H 2 O 2 was 90 mL•L -1 , and the reaction temperature was 25°C, samples were taken every 30 minutes to study the reaction time (Wang et al.2001) of p-nitropyrazole wastewater. The effect of DNP and COD removal rate of medium organics is shown in Fig. 3 . As can be seen from Fig. 3 , 120 min before the reaction, the reaction speed is fast, the DNP removal rate increases rapidly from 0 to 89%, and the COD removal rate increases from 0 to 43%; when the reaction time increases from 120 min to 150 min, the DNP removal rate increases. Slowly, the removal rate of COD increased from 45–45.5%; the removal rate of DNP was basically unchanged, so it can be considered that the reaction reached equilibrium at 120 min.This is due to the rapid reaction rate of the first 120 min to generate enough OH, and the organic matter is rapidly decomposed; H 2 O 2 is almost completely consumed from 120 min to 150 min, less OH is generated, and the removal rate of DNP and COD does not change significantly; therefore, the experimental selection is relatively low. The optimal reaction time is 120 min. Influence of initial pH of wastewater on treatment effect Sodium hydroxide was used to adjust the initial pH of the solution to 1, 2, 3, and 3.5, the dosage of FeSO 4 •7H 2 O was 0.4 g, the dosage of H 2 O 2 was 90 mL•L -1 , and the reaction temperature was 25 ℃ and the reaction time was 120 min. The effect of pH on the removal rate of organic DNP and COD in nitropyrazole wastewater(Hermosilla et al.2009), the results are shown in Fig. 4 . As can be seen from Fig. 4 , when the initial pH of the solution increased from 1 to 2, the DNP removal rate increased from 72–99%, DNP was basically not detected in the sample, and the COD removal rate increased from 44–58%.When the pH of the solution is lower than 2, according to the principle of Fenton reaction, the H + concentration in the solution is too high, which cannot make Fe 3+ reduce to Fe 2+ in a timely and effective manner, destroying the equilibrium system of Fe 3+ and Fe 2+ , and hindering the catalytic reaction. When the pH of the solution exceeds 2, H 2 O 2 is unstable and easily decomposes to generate oxygen and water, which reduces the removal effect of DNP and COD. Therefore, the optimal initial pH of the experiment is about 2. Influence of reaction temperature on treatment effect The initial pH of the solution was 1, the dosage of FeSO 4 •7H 2 O was 0.4g, the dosage of H 2 O 2 was 90mL•L -1 , and the reaction time was 120min, and the reaction temperatures were 20℃, 30℃, 40℃, and 50℃, respectively. The effect of (Kusic et al.2006) on the removal rate of organic DNP and COD in nitropyrazole wastewater, the results are shown in Fig. 5 . As can be seen from Fig. 5 , when the reaction temperature increased from 20°C to 30°C, the DNP removal rate increased from 90–97%, and the COD removal rate increased from 39–43%. Continuing to heat up the DNP and COD removal rates began to decrease.This is because the activity of •OH increases with the increase of temperature, which promotes the rapid reaction of •OH with organic matter in water; when the temperature is higher than 30°C, the increase of temperature will accelerate the ineffective decomposition of H 2 O 2 , which is not conducive to the generation of •OH, The removal rate of DNP and COD decreased, so the optimal reaction temperature was selected as 30℃. Validation results of better process conditions From the above single factor research results, the optimal process conditions were obtained: the dosage of FeSO 4 •7H 2 O was 0.4g, the dosage of H 2 O 2 was 82mL•L -1 , the reaction time was 120 min, the initial pH was about 2, and the reaction temperature was 30 ℃(Zhou et al.2008) . Using the above conditions to verify the results, the water quality changes before and after wastewater treatment were obtained, and the results are shown in Table 1 . Table 1 Verification results of better process conditions Before processing After processing removal rate COD(mg·L − 1 ) 386 143 62.9% DNP(mg·ml − 1 ) pH 3 1 0.08 7–8 97% — Table 1 shows the water quality changes before and after nitropyrazole wastewater treatment.It can be seen that the removal rate of DNP in the treated water samples reached 97%, the COD in the wastewater decreased from 386 mg·L -1 to 143 mg·L -1 , and the COD removal rate was 62.9%. The change of the water quality of the wastewater made the wastewater biodegradable. performance was significantly improved(Zhou et al.2005) Analysis of reaction kinetics In this study, a pseudo-first-order kinetic equation and a pseudo-second-order kinetic equation were used to fit the process of DNP removal by Fenton oxidation.( ZohKD et al.2002) The pseudo-first-order kinetic equation can be expressed as: $$\text{ln}\frac{{C}_{\text{t}}}{{C}_{0}}=-{k}_{1}\text{t}+{C}_{1}$$ 1 The pseudo-second-order kinetic equation can be expressed as: $$\frac{1}{{C}_{\text{t}}}=-{k}_{2}\text{t}+{C}_{2}$$ 2 In the formula: C t is the DNP concentration after the reaction, mg•ml-1; C 0 is the DNP concentration before the reaction, mg•ml − 1 ; k 1 is the pseudo-first-order kinetic reaction rate constant, min − 1 ; k 2 is the pseudo-second-order reaction Kinetic constant, L•(mg•min) −1 ; t is the reaction time min. Table 2 Dynamic fitting results at different temperatures temperature /℃ Pseudo-first-order kinetic equation Pseudo-second-order kinetic equation k 1 /min − 1 R 2 1 k 2 /(L · (mg · min) −1 ) R 2 2 20 0.0136 0.9497 0.0303 0.9908 30 0.0163 0.9709 0.0489 0.9757 40 0.0116 0.8529 0.0310 0.9782 Table 2 shows the kinetic fitting results of Fenton's oxidative degradation of DNP.It can be seen from the above table that under the condition that the dosage of FeSO 4 •7H 2 O is 0.4g, the dosage of H 2 O 2 is 82mL•L − 1 , and the initial pH is 2, at three different temperatures, the correlation of the pseudo-second-order kinetic equation The coefficients (R 2 2 ) are all larger than the correlation coefficients (R 2 1 ) of the pseudo-first-order kinetic equation under the same conditions, indicating that the pseudo-second-order kinetic equation can better describe the process of Fenton oxidation to remove DNP. UV spectral analysis of wastewater samples before and after treatment Figure 6 shows the UV-Vis absorption spectra of the water samples before and after treatment. It can be seen that the raw water samples before treatment have strong absorption in the UV-Vis region. When the absorption wavelength is 210 nm, the absorbance is 1.86, indicating that the water samples contain A large number of nitroaromatic compounds.After Fenton oxidation, the absorbance of water samples at 210 nm decreased from 1.86 to 0.37, and at 260 nm was the absorption wavelength of DNP. After Fenton oxidation, the absorbance decreased from 0.7 to 0. It shows that Fenton's reagent can oxidatively remove most of the organic pollutants absorbed in the visible region, and Fenton's reagent can effectively remove DNP from nitropyrazole wastewater. Conclusion Fenton oxidation system can effectively remove DNP from nitropyrazole wastewater. Under the conditions that the initial pH is 2, the temperature is 30℃, the dosage of H 2 O 2 is 82ml•L -1 , the dosage of FeSO 4 •7H 2 O is 0.4g, and the reaction is 120 min, there is a better removal effect, and the removal of DNP The removal rate reached 97%, and the COD removal rate was 62.9%. The removal process of DNP in Fenton oxidation followed a pseudo-second-order kinetic equation. Through the analysis of UV-visible absorption spectrum, it was concluded that the absorbance of the water sample was significantly reduced after Fenton oxidation treatment in the UV-visible region of the raw water sample before treatment. Declarations Acknowledgements ：We would like to express our sincere appreciation to editors and anonymous reviewers for valuable suggestions and corrections. Author Contributions：“All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [LiuMing], [ZhangShuai] [ZhengRushui] [ZhaoLinxiu] [CaoDuanlin] [ShengFanfan] and [LiYongxiang]. The first draft of the manuscript was written by [LiuMing] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.” Funding ： “The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.” Data availability：All data generated or analyzed during this study were included in this published article. Ethics approval and consent to participate: Not applicable in this paper Consent to publish: Not applicable in this paper Consent to participate Not applicable in this paper. Conflict of interest:The authors declare no competing interests. References Chang Shuangjun, Liu Yucun.(2007) Study on the treatment of TNT explosive wastewater by supercritical water oxidation [J]. Energetic Materials, 15(3): 285-288. Feng Jiao, Wu Yaoguo, Zhang Na(2012). Research progress on the degradation of organic pollutants by zero-valent iron-Fenton reagent system [J]. Chemical Environment Protection, 32(5):413-418. Hermosilla D．，Cortijo M．，Huang C．P．(2009)Optimizing thetreatment of landfill leachate by conventional Fenton and photo-Fenton processes． Science of the Total Environment， 407(11): 3473-3481 H. Kusic, N. Koprivanac, L. Srsan, Azo dye(2006) degradation using Fenton type processesassisted by UV irradiation: a kinetic study, Journal of photochemistry andphotobiology 181(2006) 195–202. MATTA R, HANNA K, CHIRON S.(2007) Fenton-like oxidation of 2,4,6-trinitrotoluene using different iron minerals[J]. Science of theTotal Environment, 385(1):242-251. DOI:10.1016/j.scitotenv.2007.06.030. Wang Luochun, Wen Renqin.(2001) Treatment of refractory organic wastewater with Fenton reagent and its application. Environmental Science, 27(3): 11-14 Wang Zhongyou, Ye Zhengfang, Wang Chengyun, etc.(2008) Treatment of TNT red water by vacuum distillation coupled with immobilized microorganisms. Chinese Environmental Science, 28(10):883-887 Wu Yaoguo, Jiao Jian, Zhao Dawei, etc. (2003)Advanced oxidation technology for explosives wastewater treatment. Energetic Materials, 11(3): 166-169 Xue Jiangpeng, Wang Jianzhong, Zhao Quanlin, et al.(2015) Oxidation of Fenton’s reagent to treat explosives-contaminated soil leachate [J]. Chinese Journal of Environmental Engineering, 9(9): 4365-4370. YIN W, WU J, LI P, et al.(2012) Experimental study of zero-valent iron induced nitrobenzene reduction in groundwater: The effectsof pH, iron dosage, oxygen and common dissolved anions[J]. Chemical Engineering Journal, 184(3):198-204. DOI:10.1016/j.cej.2012.01.030. ZHANG H, CHOI H J, HUANG C P. (2005)Optimization of Fenton process for the treatment of landfillleachate[J].JournalofHazardousMaterials, 125(1):166-174. DOI:10.1016/j.jhazmat.2005.05.025. ZHANG M, LIU G H, SONG K, et al. (2015)Biological treatment of 2,4,6-trinitrotoluene (TNT) red water by immobilized anaerobic-aerobicmicrobial filters[J]. Chemical Engineering Journal, 259:876-884. DOI:10.1016/j.cej.2014.08.041. Zhang Mohe, Ye Zhengfang, Zhao Quanlin, et al.(2012) Iron-carbon micro-electrolysis pretreatment of TNT red water [J]. Chinese Journal of Environmental Engineering, 6(9): 3115-3120. Zhang Yihe，Wei Fangfang，Xing Jing，et al．(2012) Adsorption behavior and removal of organic materials from TNT red water by lignite activated carbon． Journal Residuals Science Technology， 9(3): 121-129 ZHAO Q, YE Z, ZHANG M. (2010)Treatment of 2,4,6-trinitrotoluene (TNT) red water by vacuum distillation[J]. Chemosphere, 80(8):947-950. DOI:10.1016/j.chemosphere.2010.05.004. Zhao Quanlin, Ye Zhengfang, Wang Zhongyou, et al.(2010) Research progress of TNT wastewater treatment [J]. Environmental Chemistry, 29(5): 796-801. Zhou T , Li Y , Ji J , Wong FS , Lu X . (2008)Oxidation of 4-chlorophenol in a heteroge- neous zero valent iron/H2O2 Fenton-like system: kinetic, pathway and effect factors. Sep PurifTechnol2008,62:551–8 . Zhou Y L, Yuan F Y.(2005) Application of Fenton method and Fenton method in the treatment of explosive wastewater [J]. Science and technology intelligence development and economy, 15(15):172-174. Zhu Shini，Liu Guohua，Ye Zhengfang，et al．(2012) Reduction ofdinitrotoluenesulfonates in TNT red water using nanoscalezerovalentiron particles． Environmental Science and PollutionResearch, 19(6): 2372-2380 ZohKD,StenstromMK. (2002)Fenton oxidation ofhexahydro1,3,5-trinitro1,3,5triazine(RDX) and octahydrol,3,5,7・tetranitrol, 3,5,7-tetrazocine(HMX)[J].Water Research, 36(5): 1331-1341. 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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-1857115","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":145015846,"identity":"65e6c299-2d6b-41ed-98e5-05ab606f27de","order_by":0,"name":"Liu Ming","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1klEQVRIiWNgGAWjYBACNobzHx98/GMjZ9/MfIA4LXyMB4wNZzakGRuwsyUQp0WO+YCZMG/D4UQDfh4DIh3GdiCNmXcHc4I5M8/HG28Y7OR0Gwhp4Tlw7OHcM2x5ls28my3nMCQbmx0gpEXiYLvBGzaeYobDvNukeRgOJG4jqEX+MZsED5tEYsNhnmdEamE4xibJ22aQuOEwDxuxWs4wG844k2As2cxmbDnHgAi/yDecYXzwoeK/HD//4Yc33lTYyRHUggIkiI0aZC2k6hgFo2AUjIIRAQByMUEc1uTLoAAAAABJRU5ErkJggg==","orcid":"","institution":"North University of China","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Liu","middleName":"","lastName":"Ming","suffix":""},{"id":145015847,"identity":"3e2b6fbc-d8f7-43d2-9069-3b976ce9781d","order_by":1,"name":"ZHANG Shuai","email":"","orcid":"","institution":"North University of China","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"ZHANG","middleName":"","lastName":"Shuai","suffix":""},{"id":145015848,"identity":"549e4c22-d040-4ae6-a36f-8c9802aa6009","order_by":2,"name":"ZHENG Rushui","email":"","orcid":"","institution":"North University of China","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"ZHENG","middleName":"","lastName":"Rushui","suffix":""},{"id":145015849,"identity":"88acd123-d324-4d4c-84b5-618bbd6a8598","order_by":3,"name":"ZHAO Linxiu","email":"","orcid":"","institution":"North University of China","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"ZHAO","middleName":"","lastName":"Linxiu","suffix":""},{"id":145015850,"identity":"2c7f1f23-2254-41ce-b706-56fef5955577","order_by":4,"name":"CAO Duanlin","email":"","orcid":"","institution":"North University of China","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"CAO","middleName":"","lastName":"Duanlin","suffix":""},{"id":145015851,"identity":"7bedf93e-05bc-4536-a01c-6a232f983a6d","order_by":5,"name":"SHENG Fanfan","email":"","orcid":"","institution":"North University of China","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"SHENG","middleName":"","lastName":"Fanfan","suffix":""},{"id":145015852,"identity":"97853566-c1cc-4604-ac69-9d506ff8442e","order_by":6,"name":"LI Yongxiang","email":"","orcid":"","institution":"North University of China","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"LI","middleName":"","lastName":"Yongxiang","suffix":""}],"badges":[],"createdAt":"2022-07-14 08:42:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1857115/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1857115/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":28060158,"identity":"5f458b9b-4007-4055-9531-57e7984c618c","added_by":"auto","created_at":"2022-10-20 19:34:09","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":51869,"visible":true,"origin":"","legend":"\u003cp\u003eInfluence of FeSO\u003csub\u003e4\u003c/sub\u003e • 7H\u003csub\u003e2\u003c/sub\u003eO dosage on treatment effect（a. DNP removal rate；b. COD removal rate）\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/8caea26f40dcd2d9421a1fea.png"},{"id":28060159,"identity":"9ff92a55-7dd1-4095-979f-5eff9ffbf70a","added_by":"auto","created_at":"2022-10-20 19:34:09","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":55038,"visible":true,"origin":"","legend":"\u003cp\u003eInfluence of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e dosage on treatment effect（a. DNP removal rate；b. COD removal rate）\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/040d6e73ae2d785b479336eb.png"},{"id":28060162,"identity":"a45c0832-b2e7-4544-af3b-2949ce005e3c","added_by":"auto","created_at":"2022-10-20 19:34:09","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":45633,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of reaction time on treatment effect（a. DNP removal rate；b. COD removal rate）\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/1be863873f2dfebac34961a5.png"},{"id":28060163,"identity":"9cbbcae4-4a84-4798-810c-cd34e494ab46","added_by":"auto","created_at":"2022-10-20 19:34:09","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":55110,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of initial pH on treatment effect（a. DNP removal rate；b. COD removal rate）\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/8155018f702b0719115e90fa.png"},{"id":28060326,"identity":"468e4596-240f-4c09-bd86-219904022f74","added_by":"auto","created_at":"2022-10-20 19:39:09","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":54643,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of reaction temperature on treatment effect（a. DNP removal rate；b. COD removal rate）\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/ff2ceec9d5e1e150105a580b.png"},{"id":28060325,"identity":"d447b429-1f38-40a1-b1b8-f16e2b2f382e","added_by":"auto","created_at":"2022-10-20 19:39:09","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":10922,"visible":true,"origin":"","legend":"\u003cp\u003eUV-vis spectrogram of water sample before and after reaction\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/f0b0685fd50a795eb745e1d4.png"},{"id":29158471,"identity":"758365de-2c47-4479-8850-8dd944f4faf3","added_by":"auto","created_at":"2022-11-16 22:54:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":647089,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1857115/v1/155b29f3-1a4d-4ba3-98fe-241eca32db03.pdf"}],"financialInterests":"","formattedTitle":"Fenton reagent oxidation treatment of nitropyrazole wastewater","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe treatment of organic wastewater has always been a difficult problem in water environment governance, and it is also a focus of attention of scientists at home and abroad. Therefore, this topic is based on the concept of green environmental protection to carry out research on nitropyrazole wastewater treatment. 3,4-Dinitropyrazole (DNP) is an energetic compound with excellent properties that can replace TNT as a carrier for molten-cast explosives. During the preparation of DNP, a large amount of organic waste water will be produced(Zhao et al.2010) According to the synthesis process, the waste water may contain a variety of organic compounds and a large amount of waste acid(Xue et al.2015)The main organic compounds are 3,4-dinitropyrazole, a very small amount of 1,3-dinitropyrazole, 3,5-dinitropyrazole, etc. These organic pollutants are highly toxic(Zhang et al.2015), difficult to biochemically degrade(Zhao et al.2010), and direct discharge will cause serious harm to the ecological environment and human health. Therefore, effective treatment of nitropyrazole wastewater is essential for improving the ecological environment and protecting human health. significant.\u003c/p\u003e \u003cp\u003eAt present, the main treatment methods for organic wastewater by domestic and foreign scholars are adsorption method, extraction method, electrochemical method, advanced oxidation method(Chang et al.2007), anaerobic-aerobic biological method, etc.Among them, the adsorption method and the extraction method are physical treatment methods. These methods are characterized by simple operation and fast reaction, but at the same time, the material cost is high and there will be secondary pollution.Electrochemical method belongs to chemical treatment method. This kind of method has fast reaction rate and high pollution concentration tolerance, but it has high energy consumption and high industrial operation cost and is not easy to popularize.Anaerobic-aerobic biological method belongs to biological treatment technology. Biological method is easy to operate and manage, with low construction and maintenance costs, and is not easy to cause secondary pollution. However, due to the high amount of toxic substances in this type of wastewater, it is not suitable for direct biochemical treatment.Fenton's reagent oxidation method belongs to advanced oxidation method. Fenton oxidation method (Yin et al.2012) is a chemical treatment technology, which has the advantages of simple equipment, convenient operation, complete reaction and no secondary pollution, etc., and can mineralize organic matter into carbon dioxide and water. Or other low-toxic substances, which have broad application prospects.The role of Fenton oxidation in water treatment mainly includes oxidation and coagulation.Oxidation means that under the combined action of Fe\u003csup\u003e2+\u003c/sup\u003e and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e under acidic conditions, hydroxyl radicals with strong oxidizing ability (Feng et al.2012) are generated. OH reacts with organic matter. The redox potential of hydroxyl radicals is 2.8V, second only to fluorine ( 2.87 V), which can achieve the purpose of oxidative decomposition of organic matter in water.The main equations of the Fenton reaction are shown in equations (\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) ~ (4). The Fe(OH)\u003csub\u003e3\u003c/sub\u003e colloid generated in the reaction has the functions of flocculation and adsorption, which can remove some organic substances in the water(Zhang et al.2005) There is no literature report on the treatment of nitropyrazole-containing wastewater by Fenton oxidation.\u003c/p\u003e \u003cp\u003eFe\u003csup\u003e2+\u003c/sup\u003e+H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;H\u003csup\u003e+\u003c/sup\u003e\u0026rarr;Fe\u003csup\u003e3+\u003c/sup\u003e+H\u003csub\u003e2\u003c/sub\u003eO+\u0026middot;OH (1)\u003c/p\u003e \u003cp\u003eFe\u003csup\u003e2+\u003c/sup\u003e+\u0026middot;OH\u0026rarr;Fe\u003csup\u003e3+\u003c/sup\u003e+OH\u003csup\u003e\u0026minus;\u003c/sup\u003e (2)\u003c/p\u003e \u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003ch2\u003e\u0026middot;OH\u0026thinsp;+\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u0026rarr;\u0026middot;HO\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO (3)\u003c/h2\u003e \u003cdiv id=\"Sec3\" class=\"Section3\"\u003e \u003ch2\u003e\u0026middot;OH\u0026thinsp;+\u0026thinsp;R-H\u0026rarr;\u0026middot;R\u0026thinsp;+\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO (4)\u003c/h2\u003e \u003cp\u003eIn this study, the nitropyrazole wastewater was treated by Fenton's reagent(Matta et al.2007) oxidation method.The nitropyrazole wastewater treatment object is the wastewater generated from the nitration of 3-nitropyrazole mixed acid to obtain 3,4-dinitropyrazole.The nitropyrazole-containing wastewater was treated by Fenton reagent oxidation, and the effects of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO dosage, H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e dosage, initial pH of solution, reaction time and reaction temperature on the treatment effect were investigated. The practical application of azole wastewater (Zhang et al.2012) provides technical support and theoretical basis.\u003c/p\u003e "},{"header":"Experimental Materials And Methods","content":"\u003cp\u003e\u003cstrong\u003eExperimental materials and instruments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe nitropyrazole wastewater comes from the wastewater (pH\u0026thinsp;=\u0026thinsp;1) produced after the nitration of 3-nitropyrazole(Zhu et al.2012)mixed acid to obtain 3,4-dinitropyrazole.Ferrous sulfate heptahydrate (FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO) and sodium hydroxide (NaOH) are of analytical grade; hydrogen peroxide (H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, mass fraction 30%) is of excellent grade;Constant temperature oscillator (HZQ-F160A, Shanghai Yiheng Scientific Instrument Co., Ltd.); Multi-parameter water quality analyzer (DGB-401, Shanghai INESA Scientific Instrument Co., Ltd.); UV-Vis Spectrophotometer (TU-1900, Beijing Pudong Electric Co., Ltd.) Analytical General Instruments Co., Ltd.);High performance liquid chromatography (LC98-1, Beijing Thermal Analysis Instrument Technology Development Co., Ltd.).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExperimental method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDue to the high concentration of pollutants in wastewater, the wastewater was diluted 10 times for treatment in this study.Take 30 mL of the above-mentioned wastewater without pH adjustment into a 100 mL conical flask, add a certain amount of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO to dissolve it, then add a certain amount of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, and place it in a constant temperature oscillator (150r\u0026bull;min\u003csup\u003e-1\u003c/sup\u003e) to react for a certain time, and after the reaction is complete, take a sample to detect the concentration of 3,4-dinitropyrazole in the wastewater.Sodium hydroxide (0.5mol\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e) was used to adjust the pH of the solution to 7\u0026ndash;8 to completely precipitate iron ions. After standing for 30 min, the supernatant was taken for COD detection. Since the composition of the wastewater is simple, the change in the content of 3,4-dinitropyrazole is used to represent the treatment effect of the wastewater treated by the Fenton method(Zhang et al.2012) .\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnalysis method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe content of 3,4-dinitropyrazole in water samples before and after treatment was calculated by high performance liquid chromatography. The detection wavelength was 260 nm, the mobile phase ratio was acetonitrile: acetic acid water\u0026thinsp;=\u0026thinsp;35%: 65%, the flow rate was 1.0 mL\u0026middot;min\u003csup\u003e-1\u003c/sup\u003e, and the injection volume was 20 \u0026micro;L. UV-Vis spectrophotometer; measure the UV-Vis absorption spectrum of the water samples before and after treatment in the range of 190\u0026ndash;1100 nm.\u003c/p\u003e\n\u003cp\u003eThe formula for calculating the removal rate of DNP in wastewater samples is as follows:\u003c/p\u003e\n\u003cdiv class=\"Equation\" id=\"Equa\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e$$\\text{D}\\text{N}\\text{P} \\text{r}\\text{e}\\text{m}\\text{o}\\text{v}\\text{a}\\text{l} \\text{r}\\text{a}\\text{t}\\text{e}=\\frac{{\\text{D}\\text{N}\\text{P}}_{1}-{\\text{D}\\text{N}\\text{P}}_{2}}{{\\text{D}\\text{N}\\text{P}}_{1}}\\text{x}100\\text{%}$$\u003c/div\u003e\u003c/div\u003e\u003cp\u003eIn the formula, DNP\u003csub\u003e1\u003c/sub\u003e is the DNP concentration in the water sample before treatment, and DNP\u003csub\u003e2\u003c/sub\u003e is the DNP concentration in the water sample after treatment.\u003c/p\u003e"},{"header":"Experimental Results And Discussion","content":"\u003cdiv class=\"Section3\" id=\"Sec4\"\u003e\n \u003cdiv class=\"Section4\" id=\"Sec5\"\u003e\n \u003ch2\u003eInfluence of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO dosage on treatment effect\u003c/h2\u003e\n \u003cp\u003eUnder the conditions that the initial pH of the solution is 1, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is 90 mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, the reaction time is 120 min, and the reaction temperature is 25 ℃, the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO is studied for the removal rate of organic DNP and COD in the nitropyrazole wastewater. The results are shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eIt can be seen from Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e that when the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO increased from 0.1g to 0.4g, the DNP removal rate increased from 34\u0026ndash;96%, and the COD removal rate increased from 11\u0026ndash;33%. When the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO continued to increase to 0.5g, the DNP removal rate did not change much.This is because when the Fe\u003csup\u003e2+\u003c/sup\u003e concentration in the solution is relatively low, the utilization rate of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is not high, the generated \u0026bull;OH is less, and the organic matter cannot be completely oxidized, resulting in a low DNP removal rate.The reason for the low removal rate of COD may be that the generated OH oxidizes the organic macromolecules into small organic molecules and does not completely mineralize into CO\u003csub\u003e2\u003c/sub\u003e and H\u003csub\u003e2\u003c/sub\u003eO.As the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO increases, the generated \u0026bull;OH gradually increases, and the DNP removal rate increases accordingly. When the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO exceeds 0.4g, the generated \u0026bull;OH is too late to interact with the organic matter. During the reaction, the accumulated \u0026bull;OH reacted with each other to generate water, so that the DNP removal rate did not change much. Therefore, the optimal dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO is selected as 0.4g in the experiment.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec6\"\u003e\n \u003ch2\u003eInfluence of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e dosage on treatment effect\u003c/h2\u003e\n \u003cp\u003eWhen the initial pH of the solution was 1, the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO was 0.4 g, the reaction time was 120 min, and the reaction temperature was 25\u0026deg;C, the effect of the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e(Wu et al.2003)on the removal rate of organic matter DNP and COD in nitropyrazole wastewater was studied. Influence(Wang et al.2008), the results are shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eIt can be seen from Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e that when the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e increases from 50mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e to 82mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, the DNP removal rate increases from 81\u0026ndash;87%, and the COD removal rate increases from 19\u0026ndash;26%.Continue to increase the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, the DNP removal rate gradually decreased. The insignificant change in COD removal rate may be caused by incomplete mineralization of some organic matter.This is because with the increase of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e concentration, the hydroxyl radical\u0026bull;OH content in the solution increases, resulting in the increase of DNP removal rate with the increase of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e dosage; when the H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e concentration exceeds 82mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, \u0026bull;OH and Excess H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e reacts to generate water and oxygen, which reduces the removal rate of DNP. Therefore, the optimal dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was selected as 82mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e in the experiment.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec7\"\u003e\n \u003ch2\u003eInfluence of reaction time on treatment effect\u003c/h2\u003e\n \u003cp\u003eWhen the initial pH of the solution was 1, the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO was 0.4 g, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was 90 mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, and the reaction temperature was 25\u0026deg;C, samples were taken every 30 minutes to study the reaction time (Wang et al.2001) of p-nitropyrazole wastewater. The effect of DNP and COD removal rate of medium organics is shown in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eAs can be seen from Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, 120 min before the reaction, the reaction speed is fast, the DNP removal rate increases rapidly from 0 to 89%, and the COD removal rate increases from 0 to 43%; when the reaction time increases from 120 min to 150 min, the DNP removal rate increases. Slowly, the removal rate of COD increased from 45\u0026ndash;45.5%; the removal rate of DNP was basically unchanged, so it can be considered that the reaction reached equilibrium at 120 min.This is due to the rapid reaction rate of the first 120 min to generate enough OH, and the organic matter is rapidly decomposed; H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is almost completely consumed from 120 min to 150 min, less OH is generated, and the removal rate of DNP and COD does not change significantly; therefore, the experimental selection is relatively low. The optimal reaction time is 120 min.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec8\"\u003e\n \u003ch2\u003eInfluence of initial pH of wastewater on treatment effect\u003c/h2\u003e\n \u003cp\u003eSodium hydroxide was used to adjust the initial pH of the solution to 1, 2, 3, and 3.5, the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO was 0.4 g, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was 90 mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, and the reaction temperature was 25 ℃ and the reaction time was 120 min. The effect of pH on the removal rate of organic DNP and COD in nitropyrazole wastewater(Hermosilla et al.2009), the results are shown in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eAs can be seen from Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e, when the initial pH of the solution increased from 1 to 2, the DNP removal rate increased from 72\u0026ndash;99%, DNP was basically not detected in the sample, and the COD removal rate increased from 44\u0026ndash;58%.When the pH of the solution is lower than 2, according to the principle of Fenton reaction, the H\u003csup\u003e+\u003c/sup\u003e concentration in the solution is too high, which cannot make Fe\u003csup\u003e3+\u003c/sup\u003e reduce to Fe\u003csup\u003e2+\u003c/sup\u003e in a timely and effective manner, destroying the equilibrium system of Fe\u003csup\u003e3+\u003c/sup\u003e and Fe\u003csup\u003e2+\u003c/sup\u003e, and hindering the catalytic reaction. When the pH of the solution exceeds 2, H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is unstable and easily decomposes to generate oxygen and water, which reduces the removal effect of DNP and COD. Therefore, the optimal initial pH of the experiment is about 2.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec9\"\u003e\n \u003ch2\u003eInfluence of reaction temperature on treatment effect\u003c/h2\u003e\n \u003cp\u003eThe initial pH of the solution was 1, the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO was 0.4g, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was 90mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, and the reaction time was 120min, and the reaction temperatures were 20℃, 30℃, 40℃, and 50℃, respectively. The effect of (Kusic et al.2006) on the removal rate of organic DNP and COD in nitropyrazole wastewater, the results are shown in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eAs can be seen from Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e, when the reaction temperature increased from 20\u0026deg;C to 30\u0026deg;C, the DNP removal rate increased from 90\u0026ndash;97%, and the COD removal rate increased from 39\u0026ndash;43%. Continuing to heat up the DNP and COD removal rates began to decrease.This is because the activity of \u0026bull;OH increases with the increase of temperature, which promotes the rapid reaction of \u0026bull;OH with organic matter in water; when the temperature is higher than 30\u0026deg;C, the increase of temperature will accelerate the ineffective decomposition of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, which is not conducive to the generation of \u0026bull;OH, The removal rate of DNP and COD decreased, so the optimal reaction temperature was selected as 30℃.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec10\"\u003e\n \u003ch2\u003eValidation results of better process conditions\u003c/h2\u003e\n \u003cp\u003eFrom the above single factor research results, the optimal process conditions were obtained: the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO was 0.4g, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was 82mL\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, the reaction time was 120 min, the initial pH was about 2, and the reaction temperature was 30 ℃(Zhou et al.2008) .\u003c/p\u003e\n \u003cp\u003eUsing the above conditions to verify the results, the water quality changes before and after wastewater treatment were obtained, and the results are shown in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eVerification results of better process conditions\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBefore processing\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAfter processing\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eremoval rate\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\u003eCOD(mg\u0026middot;L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e386\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e143\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDNP(mg\u0026middot;ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\n \u003cp\u003epH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003cp\u003e7\u0026ndash;8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e97%\u003c/p\u003e\n \u003cp\u003e\u0026mdash;\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\u003eTable \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e shows the water quality changes before and after nitropyrazole wastewater treatment.It can be seen that the removal rate of DNP in the treated water samples reached 97%, the COD in the wastewater decreased from 386 mg\u0026middot;L\u003csup\u003e-1\u003c/sup\u003e to 143 mg\u0026middot;L\u003csup\u003e-1\u003c/sup\u003e, and the COD removal rate was 62.9%. The change of the water quality of the wastewater made the wastewater biodegradable. performance was significantly improved(Zhou et al.2005)\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec11\"\u003e\n \u003ch2\u003eAnalysis of reaction kinetics\u003c/h2\u003e\n \u003cp\u003eIn this study, a pseudo-first-order kinetic equation and a pseudo-second-order kinetic equation were used to fit the process of DNP removal by Fenton oxidation.( ZohKD et al.2002)\u003c/p\u003e\n \u003cp\u003eThe pseudo-first-order kinetic equation can be expressed as:\u003c/p\u003e\n \u003cdiv class=\"Equation\" id=\"Equ1\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e$$\\text{ln}\\frac{{C}_{\\text{t}}}{{C}_{0}}=-{k}_{1}\\text{t}+{C}_{1}$$\u003c/div\u003e\n \u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eThe pseudo-second-order kinetic equation can be expressed as:\u003c/p\u003e\n \u003cdiv class=\"Equation\" id=\"Equ2\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e$$\\frac{1}{{C}_{\\text{t}}}=-{k}_{2}\\text{t}+{C}_{2}$$\u003c/div\u003e\n \u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eIn the formula: C\u003csub\u003et\u003c/sub\u003e is the DNP concentration after the reaction, mg\u0026bull;ml-1; C\u003csub\u003e0\u003c/sub\u003e is the DNP concentration before the reaction, mg\u0026bull;ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e; k\u003csub\u003e1\u003c/sub\u003e is the pseudo-first-order kinetic reaction rate constant, min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e; k\u003csub\u003e2\u003c/sub\u003e is the pseudo-second-order reaction Kinetic constant, L\u0026bull;(mg\u0026bull;min)\u003csup\u003e\u0026minus;1\u003c/sup\u003e; t is the reaction time min.\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDynamic fitting results at different temperatures\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003etemperature /℃\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePseudo-first-order kinetic equation\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePseudo-second-order kinetic equation\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\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ek\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e /min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eR\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ek\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e /(L\u003cem\u003e\u0026middot;\u003c/em\u003e(mg\u003cem\u003e\u0026middot;\u003c/em\u003emin)\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eR\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0136\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.9497\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0303\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.9908\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0163\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.9709\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0489\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.9757\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0116\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.8529\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0310\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.9782\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eTable \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e shows the kinetic fitting results of Fenton\u0026apos;s oxidative degradation of DNP.It can be seen from the above table that under the condition that the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO is 0.4g, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is 82mL\u0026bull;L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and the initial pH is 2, at three different temperatures, the correlation of the pseudo-second-order kinetic equation The coefficients (R\u003csup\u003e2\u003c/sup\u003e\u003csub\u003e2\u003c/sub\u003e) are all larger than the correlation coefficients (R\u003csup\u003e2\u003c/sup\u003e\u003csub\u003e1\u003c/sub\u003e) of the pseudo-first-order kinetic equation under the same conditions, indicating that the pseudo-second-order kinetic equation can better describe the process of Fenton oxidation to remove DNP.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section4\" id=\"Sec12\"\u003e\n \u003ch2\u003eUV spectral analysis of wastewater samples before and after treatment\u003c/h2\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e shows the UV-Vis absorption spectra of the water samples before and after treatment. It can be seen that the raw water samples before treatment have strong absorption in the UV-Vis region. When the absorption wavelength is 210 nm, the absorbance is 1.86, indicating that the water samples contain A large number of nitroaromatic compounds.After Fenton oxidation, the absorbance of water samples at 210 nm decreased from 1.86 to 0.37, and at 260 nm was the absorption wavelength of DNP. After Fenton oxidation, the absorbance decreased from 0.7 to 0. It shows that Fenton\u0026apos;s reagent can oxidatively remove most of the organic pollutants absorbed in the visible region, and Fenton\u0026apos;s reagent can effectively remove DNP from nitropyrazole wastewater.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eFenton oxidation system can effectively remove DNP from nitropyrazole wastewater. Under the conditions that the initial pH is 2, the temperature is 30℃, the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is 82ml\u0026bull;L\u003csup\u003e-1\u003c/sup\u003e, the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO is 0.4g, and the reaction is 120 min, there is a better removal effect, and the removal of DNP The removal rate reached 97%, and the COD removal rate was 62.9%.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThe removal process of DNP in Fenton oxidation followed a pseudo-second-order kinetic equation.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThrough the analysis of UV-visible absorption spectrum, it was concluded that the absorbance of the water sample was significantly reduced after Fenton oxidation treatment in the UV-visible region of the raw water sample before treatment.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgements ：We would like to express our sincere appreciation to editors and anonymous reviewers for valuable suggestions and corrections.\u003c/p\u003e\n\u003cp\u003eAuthor Contributions：\u0026ldquo;All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [LiuMing], [ZhangShuai] [ZhengRushui] [ZhaoLinxiu] [CaoDuanlin] [ShengFanfan] and [LiYongxiang]. The first draft of the manuscript was written by [LiuMing] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u0026rdquo;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u0026ldquo;The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u0026rdquo;\u003c/p\u003e\n\u003cp\u003eData availability：All data generated or analyzed during this study were included in this published article.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate: Not applicable in this paper\u003c/p\u003e\n\u003cp\u003eConsent to publish: Not applicable in this paper\u003c/p\u003e\n\u003cp\u003eConsent to participate Not applicable in this paper.\u003c/p\u003e\n\u003cp\u003eConflict of interest:The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eChang Shuangjun, Liu Yucun.(2007) Study on the treatment of TNT explosive wastewater by supercritical water oxidation [J]. Energetic Materials, 15(3): 285-288.\u003c/li\u003e\n\u003cli\u003eFeng Jiao, Wu Yaoguo, Zhang Na(2012). Research progress on the degradation of organic pollutants by zero-valent iron-Fenton reagent system [J]. Chemical Environment Protection, 32(5):413-418.\u003c/li\u003e\n\u003cli\u003eHermosilla D．，Cortijo M．，Huang C．P．(2009)Optimizing thetreatment of landfill leachate by conventional Fenton and photo-Fenton processes． Science of the Total Environment， 407(11): 3473-3481\u003c/li\u003e\n\u003cli\u003eH. Kusic, N. Koprivanac, L. Srsan, Azo dye(2006) degradation using Fenton type processesassisted by UV irradiation: a kinetic study, Journal of photochemistry andphotobiology 181(2006) 195\u0026ndash;202.\u003c/li\u003e\n\u003cli\u003eMATTA R, HANNA K, CHIRON S.(2007) Fenton-like oxidation of 2,4,6-trinitrotoluene using different iron minerals[J]. Science of theTotal Environment, 385(1):242-251. DOI:10.1016/j.scitotenv.2007.06.030.\u003c/li\u003e\n\u003cli\u003eWang Luochun, Wen Renqin.(2001) Treatment of refractory organic wastewater with Fenton reagent and its application. Environmental Science, 27(3): 11-14\u003c/li\u003e\n\u003cli\u003eWang Zhongyou, Ye Zhengfang, Wang Chengyun, etc.(2008) Treatment of TNT red water by vacuum distillation coupled with immobilized microorganisms. Chinese Environmental Science, 28(10):883-887\u003c/li\u003e\n\u003cli\u003eWu Yaoguo, Jiao Jian, Zhao Dawei, etc. (2003)Advanced oxidation technology for explosives wastewater treatment. Energetic Materials, 11(3): 166-169\u003c/li\u003e\n\u003cli\u003eXue Jiangpeng, Wang Jianzhong, Zhao Quanlin, et al.(2015) Oxidation of Fenton\u0026rsquo;s reagent to treat explosives-contaminated soil leachate [J]. Chinese Journal of Environmental Engineering, 9(9): 4365-4370. \u003c/li\u003e\n\u003cli\u003eYIN W, WU J, LI P, et al.(2012) Experimental study of zero-valent iron induced nitrobenzene reduction in groundwater: The effectsof pH, iron dosage, oxygen and common dissolved anions[J]. Chemical Engineering Journal, 184(3):198-204. DOI:10.1016/j.cej.2012.01.030.\u003c/li\u003e\n\u003cli\u003eZHANG H, CHOI H J, HUANG C P. (2005)Optimization of Fenton process for the treatment of landfillleachate[J].JournalofHazardousMaterials, 125(1):166-174. DOI:10.1016/j.jhazmat.2005.05.025.\u003c/li\u003e\n\u003cli\u003eZHANG M, LIU G H, SONG K, et al. (2015)Biological treatment of 2,4,6-trinitrotoluene (TNT) red water by immobilized anaerobic-aerobicmicrobial filters[J]. Chemical Engineering Journal, 259:876-884. DOI:10.1016/j.cej.2014.08.041.\u003c/li\u003e\n\u003cli\u003eZhang Mohe, Ye Zhengfang, Zhao Quanlin, et al.(2012) Iron-carbon micro-electrolysis pretreatment of TNT red water [J]. Chinese Journal of Environmental Engineering, 6(9): 3115-3120.\u003c/li\u003e\n\u003cli\u003eZhang Yihe，Wei Fangfang，Xing Jing，et al．(2012) Adsorption behavior and removal of organic materials from TNT red water by lignite activated carbon． Journal Residuals Science Technology， 9(3): 121-129\u003c/li\u003e\n\u003cli\u003eZHAO Q, YE Z, ZHANG M. (2010)Treatment of 2,4,6-trinitrotoluene (TNT) red water by vacuum distillation[J]. Chemosphere, 80(8):947-950. DOI:10.1016/j.chemosphere.2010.05.004.\u003c/li\u003e\n\u003cli\u003eZhao Quanlin, Ye Zhengfang, Wang Zhongyou, et al.(2010) Research progress of TNT wastewater treatment [J]. Environmental Chemistry, 29(5): 796-801.\u003c/li\u003e\n\u003cli\u003eZhou T , Li Y , Ji J , Wong FS , Lu X . (2008)Oxidation of 4-chlorophenol in a heteroge- neous zero valent iron/H2O2 Fenton-like system: kinetic, pathway and effect factors. Sep PurifTechnol2008,62:551\u0026ndash;8 .\u003c/li\u003e\n\u003cli\u003eZhou Y L, Yuan F Y.(2005) Application of Fenton method and Fenton method in the treatment of explosive wastewater [J]. Science and technology intelligence development and economy, 15(15):172-174.\u003c/li\u003e\n\u003cli\u003eZhu Shini，Liu Guohua，Ye Zhengfang，et al．(2012) Reduction ofdinitrotoluenesulfonates in TNT red water using nanoscalezerovalentiron particles． Environmental Science and PollutionResearch, 19(6): 2372-2380\u003c/li\u003e\n\u003cli\u003eZohKD,StenstromMK. (2002)Fenton oxidation ofhexahydro1,3,5-trinitro1,3,5triazine(RDX) and octahydrol,3,5,7・tetranitrol, 3,5,7-tetrazocine(HMX)[J].Water Research, 36(5): 1331-1341.\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":"3,4-dinitropyrazole, Fenton oxidation, nitropyrazole wastewater, reaction kinetics, COD","lastPublishedDoi":"10.21203/rs.3.rs-1857115/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1857115/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this paper, Fenton reagent was used to oxidize 3,4-dinitropyrazole wastewater, and the effects of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO dosage, H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e dosage, initial pH, reaction time and reaction temperature on the treatment effect were studied.The results show that the oxidation of Fenton reagent can effectively remove 3,4-dinitropyrazole from nitropyrazole wastewater. When the dosage of FeSO\u003csub\u003e4\u003c/sub\u003e\u0026bull;7H\u003csub\u003e2\u003c/sub\u003eO is 13.2g\u0026bull;L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and the dosage of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is 82mL\u0026bull;L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. When the initial pH is 2, the reaction time is 120min and the reaction temperature is 30℃, the removal rate of 3,4-dinitropyrazole in the wastewater reaches 97%, and the removal rate of COD reaches 62.9%;The reaction kinetics study showed that the degradation of 3,4-dinitropyrazole in the reaction process conformed to the second-order kinetic model;UV-Vis absorption spectrum analysis showed that the absorbance of wastewater samples before and after treatment decreased significantly.After the Fenton oxidation treatment, the water quality of the wastewater changed and the biodegradability of the wastewater was significantly improved.\u003c/p\u003e","manuscriptTitle":"Fenton reagent oxidation treatment of nitropyrazole wastewater","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-10-20 19:34:07","doi":"10.21203/rs.3.rs-1857115/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":"5b16e6e3-18df-4b3f-8275-5f66d11d44c8","owner":[],"postedDate":"October 20th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-11-16T22:54:28+00:00","versionOfRecord":[],"versionCreatedAt":"2022-10-20 19:34:07","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1857115","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1857115","identity":"rs-1857115","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}