Purification of polluted air from toluene vapor using catalytic oxidation and photocatalytic methods

Purification of polluted air from toluene vapor using catalytic oxidation and photocatalytic methods | 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 Purification of polluted air from toluene vapor using catalytic oxidation and photocatalytic methods Fatemeh Khoshpasand, Mehrdad keshavarz, Ahmad Nikpay, Maryam madandar This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3878366/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 Introduction : Indoor air quality and it’s side effects have increased the prevalence of emerging diseases and cancer. Due to its widespread use in industrial products, Toluene is an organic solvent that has a high potential for release and various health effects. Various methods, including catalytic oxidation and photocatalytic oxidation, have been proposed to limit VOCs in indoor environments. One of the most effective and cost-effective catalysts used in air purification is manganese oxides (Mn x O y ), which are effective in converting organic compounds into water, carbon dioxide, and other low-risk compounds at room temperature. Photocatalytic oxidation of pollutants is also economically and environmentally popular. Material and methods The aim of this study was compared the efficiency of catalytic oxidation and photocatalytic removal of toluene from polluted air at room temperature on aluminum mesh in a glass reactor with dimensions of 20 cm height, 7 cm outer diameter, and 6 cm inner diameter. After preparing the surface of the used beds, the airflow containing pollutants was introduced into the beds, and the concentration of toluene was measured before and after of pass through from bed surface. The results were analyzed using descriptive statistics, one-way analysis of variance, and efficiency and capacity equations. Results The results showed a reduction in toluene concentration by catalytic and photocatalytic methods at room temperature. The photocatalytic reactor had better removal efficiency at a high flow rate (5.45 L/min) and low concentration (4.27 ppm), while MnO 2 had better performance at a medium concentration (13.87 ppm) and flow rate (3.30 L/min), and KMnO 4 had better performance at high concentration (44.28 ppm) and flow rate (5.48 L/min). Conclusion Catalytic oxidation and photocatalytic methods have suitable efficiency and capability for removing volatile organic compounds at low concentrations that we mainly face in indoor environments. We can choose the desired surface area for catalytic or photocatalytic beds depending on the pollutant concentration and flow rate. photocatalytic oxidation MnO2 KMnO4 Air purifier Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1 Introduction With the change in lifestyle over the past few decades, the health effects of indoor air quality that was showed such as sick building syndrome, increased prevalence of emerging diseases and cancer have received attention[ 1 – 3 ]. To reffrence of the United States Environmental Protection Agency 1 ’s estimate “The indoor air pollution is 5 to 10 times higher than outdoor pollution”[ 4 – 6 ]. Activities such as smoking, painting, cooking, etc. probably, emite all-around of volatile organic compounds [ 7 , 8 ]. Toluene is an organic solvent that has high emission potential and various health effects due to its widespread use in industrial products[ 9 – 11 ]. Various methods have been proposed for controlling exposure to indoor volatile organic compounds. General ventilation, surface absorption, non-thermal plasma, ozone treatment, catalytic oxidation, and photocatalytic methods are some of these methods [ 12 – 16 ]. Becauce of cost-effective, effective method for converting organic compounds into water and carbon dioxide, and other low-risk compounds at room temperature related to catalytic oxidation [ 17 , 18 ]. This method is based on a catalyst-coated surface with a large area[ 19 , 20 ]. The catalyst either has inherent catalytic oxidation properties at room temperature or its activation operation is performed by photocatalytic means in the presence of an activating agent such as ultraviolet radiation. The catalyst and it’s substrate are important in function of catalyst. The ability of the catalyst depends on its type, size, shape, and size distribution[ 19 ]. Due to the high cost and unavailability of expensive metals such as platinum, palladium, and rhodium, as few of these metals as possible should be used in making catalysts[ 21 , 22 ]. Manganese oxides (Mn x O y ) are among the most effective and cost-efficient catalysts used in air purification, as they increase the surface reactivity of oxygen and enhance the catalyst's ability to remove organic compounds [ 23 ]. The high efficiency of Mn x O y in removing air pollutants is attributed to its multi-capacity structure and oxygen motion in the metal oxide network[ 24 , 25 ]. The presence of cation vacancies in the manganese oxide structure improves its efficiency in removing pollutant compounds. The presence of vacant sites for cations in the structure of manganese oxide improves its efficiency in removing pollutants. For the adsorption of VOCs on the activated carbone, the combined of the adsorption-catalytic method has been considered and studies have reported near 100% formaldehyde removal efficiency on MnO x /AC catalysts[ 26 , 27 ]. Photocatalytic oxidation of pollutants is economically and environmentally attractive[ 28 ]. In this method, a photon with suitable energy collides with a semiconductor-like compound such as titanium dioxide, and an electron is transferred from the outer orbital layer to the conduction layer. In successive reactions, hydroxyl ions produced oxidize organic compounds into mineral oxides[ 26 , 29 ]. In this study the efficiency of catalytic and photocatalytic oxidation in removing toluene vapor from polluted air was compared at the room temperature on a bed of Stainless steel webnet. [1] U.S. EPA (The United States Environmental Protection Agency) 2 Material and methods This study was implemented on a tabletop reactor with a height of 20 cm, an outer diameter of 7 cm, and an inner diameter of 6 cm. The photocatalytic bed was prepared using titanium dioxide nanoparticles from Evonik Industries AG under the trade name Aeroxide, while the catalytic bed was prepared using potassium permanganate and manganese oxide from Brenntag and Sigma-Aldrich. For the deposition of titanium dioxide nanoparticles and manganese oxide catalytic nanoparticles on an alumina substrate, 15 milliliters of ethanol were added to each nanoparticle and take time for 30 minutes in an ultrasonic bath to achieve a thick and uniform slurry. The catalysts were deposited on aluminum meshes by immersion method. The fixation and calcination process was carried out at 270 degrees Celsius for 3 hours. To prepare the adsorbent-catalytic substrate, KMnO 4 was first fixed on activated carbon. For this purpose, 2 grams of KMnO 4 were mixed with 20.8 milliliters of water and then added to a solution containing 4 grams of modified activated carbon with persidine [ 26 ], and the resulting mixture was passed through filter paper. A G15T8 UVC lamp with a power of 8 watts (main wavelength of 280 nanometers) was used to activate the photocatalyst (Fig. 1). The intensity of radiation measured by the UV Light meter model LUTRON UVC-254 was 1.07 micro-watts per square centimeter in the farthest part of the surface and all directions. The concentration of toluene was determined dynamically using a vacuum hose. The required airflow was divided into two main and secondary branches after passing through a silica gel filter and flow regulation. The main branch created negative pressure by passing through the vacuum hose, which was used to draw toluene vapors for concentration. To ensure precise control of the concentration, the toluene container was kept under controlled temperature conditions and a set of needle valves was used to achieve the desired concentration range (10–40 ppm). To determine the surface adsorption effect and other unknown factors affecting the removal of certain concentrations of toluene from 2–5 liters per minute airflows while the ultraviolet lamp in the photocatalytic reactor was off, all three reactors were entered. when the output concentration of pollutant get to one tenth of the input concentration in the adsorption-catalytic bed (KMnO 4 and activated carbon) was considered the breakthrough point of the absorbent and its saturation absorption capacity. The efficiency and removal capacity of photocatalysis were evaluated under conditions where the UVC lamp was on and certain concentrations of toluene passed through 2–5 liters per minute airflows. Toluene concentration measurements at inlet and outlet beds were performed by injecting a 200-microliter gas sample into an Agilent Technologies 7890B GC with an FID detector. During the experiment, the temperature of the inlet and outlet air in the bed was measured by an alcohol thermometer, and the airflow rate was through a Ki MR3A02SVVT volumetric flowmeter. In each study, after ensuring that flow and concentration conditions matched study objectives, the flow and concentration was measured at inlet and outlet of beds. was introduced into beds and toluene concentration at inlet and outlet beds was measured. To achieve suitable repeatability, the sampling process was repeated until achieving repeatable results (at least three times). Statistical experimental design (DOE 2 ) was conducted using the central composite design (CCD 3 ) method with 5 levels using Design Expert 7 software. Based on initial estimates and independent parameters (concentration and airflow), a total of 13 tests were determined. Results were analyzed using descriptive statistics, one-way analysis of variance, and performance and capacity relationships. [2] Design of Experiments [3] Central Composite Design 3 Results The relationship between removal efficiency and elimination capacity of TiO 2 bed surface was R 2 ≥ 99%. The effect of independent variables of concentration and air flow on catalytic efficiency and removal capacity is presented in Figs. 2 and 3. Based on the two-dimensional graphs obtained from the data, the highest removal efficiency in the photocatalytic process was observed at low concentration and high flow rate (Fig. 2), while the highest elimination capacity was observed at high concentration and low flow rate (Fig. 3). The removal efficiency varied between 18–55% for concentration range of 10–40 ppm and airflow rate of 2–5 L/min. By reducing the concentration to 4.27 ppm and increasing the air flow rate to 5.45 L/min, the removal efficiency reached its maximum value of 55.83%. A linear and significant correlation (R 2 ≥ 97%) was observed between removal efficiency and elimination capacity with independent variables of concentration and flow rate in catalytic removal of toluene from air stream over MnO 2 catalyst. The effect of independent variables of concentration and air flow rate on catalytic removal efficiency and capacity is presented in Figs. 4 and 5. The highest removal efficiency (34.41%) was achieved at an average concentration of 13.87 ppm and an airflow rate of 3.30 L/min. The highest toluene elimination capacity on MnO 2 catalytic bed is at concentrations higher than 25 ppm and flow rates of 5 L/min. Toluene removal in the presence of KMnO 4 catalyst and activated carbon showed a significant and linear relationship between removal efficiency and elimination capacity with independent variables at the catalyst surface (R 2 ≥ 99%). The highest elimination capacity was observed at an airflow rate of 4 L/min and a concentration of 40 ppm, while the removal efficiency was raised at an airflow rate of 2 L/min and a concentration of 40 ppm. Higher concentrations (40 ppm and flow rate of 2 L/min) had a greater impact on the maximum elimination capacity (Fig. 7), while lower flow rates (2 L/min) had better removal efficiency (Fig. 6). Airflow had the greatest effect on the catalytic toluene removal efficiency and capacity. The photocatalytic reactor had better removal efficiency at high flow rates (5.45 L/min) and low concentrations (4.27 ppm), while MnO 2 at average concentrations (13.87 ppm and 3.30 L/min) and KMnO 4 at high concentrations (44.28 ppm) with low flow rates (2.48 L/min) showed better performance. 4 Discussion The results of this study indicate a reduction in the concentration of toluene through catalytic and photocatalytic methods at room temperature. The finding shows with increase of concentration, removal efficiency was decreased, and at the optimal operating point (input concentration of 4.27 ppm and an airflow rate of 5.45 L/min), the removal efficiency reached 55.83%. This is because as the input concentration of pollutants increases and considering the reaction rate, filling of adsorption of surface’s site was occurded, and leaving no room for more pollutants to be accepted. In a study by Liang (2012), an increase in the input concentration of toluene resulted in a decrease in removal efficiency from 85–30%[ 30 ]. Various studies have also reported a decrease in toluene removal efficiency with increasing concentration, which is consistent with this study[ 27 , 29 , 31 ]. Generally, photocatalytic removal efficiency improves at low concentrations and high air flow rates. Airflow has a two-way relationship with removal efficiency. Increasing airflow reduces the thickness of the boundary layer at low concentrations and increases the likelihood of pollutant transfer to photocatalytic oxidation sites. A similar scenario is observed at high concentrations and low airflow rates, where pollutant transfer to catalytic oxidation sites increases due to prolonged exposure time. Since photocatalytic process depend on surface chemistry, the number of available active sites and pollutant transfer to active sites, and product transfer to airflow are important factors that affected removal efficiency. However, reducing the air flow rate and increasing concentration can cause disturbance in the mass transfer process and reduce removal efficiency[ 32 ]. Wang Xingfu et al. reported on formaldehyde removal from the air using a modified aluminum foam photocatalytic bed with TiO 2 at room temperature, which was observed same with the results of this study [ 33 ]. The results of catalytic removal in a modified MnO 2 bed indicate that as the concentration increases, the removal efficiency decreases from 32–25%, which is consistent with the findings of Shayegan's study on a carbon-based surface where the removal efficiency decreased from 45% to less than 20% when observed the increasing of elementary concentration from 150 ppm to 1000 ppm [ 33 ]. With increasing concentration, the rate of catalytic oxidation initially increased and then decreased due to the production of CO 2 and H 2 O and blockage of active catalytic sites, reducing removal efficiency. For increasing of mass transfer on the catalyst surface, it’s may obtain when air flow increase inside the reactor and causes turbulent flow [ 2 , 34 , 35 ]; however, with reducing residence time, products will have less opportunity to transfer to active sites, which will be accompanied by a wider range of incompletely decomposed compounds in the air stream. Unlike photocatalytic reactions, activated carbon-KMnO 4 catalyst beds had the highest removal efficiency (98%) at high concentrations and low airflow rates. The capacity of activated carbon for adsorption of organic compounds is not deniable, when the surface of activated carbon is relatively rough and porous, creating open pores that have significant potential for improving adsorption capacity[ 35 ]. Potassium permanganate also can oxidize VOC compounds[ 35 ]. Studies combining activated carbon with KMnO 4 was resulted in an increase in formaldehyde removal efficiency and a stronger adsorbent for reducing formaldehyde concentrations in indoor environments[ 35 ]. At the same flow rate, as the input concentration of formaldehyde increased, the absorption time decreased, which is same with the results of this study. In this study, air flow rate had the greatest impact on efficiency and adsorption capacity. Thus, the surface bed had better performance in absorbing pollutants at low air flow rate and high concentration. It appears that the structure of potassium permanganate particles in combination with numerous activated carbon pores is the main reason for suitable removal efficiency at high concentrations. Due to oxidative reactions, potassium permanganate was placed in activated carbon pores. The absorption time of activated carbon depends on the pollutant input rate; therefore, with reduced air flow rate and increased retention time, activated carbon-potassium permanganate had more opportunities to absorb pollutants. As a result, they can be considered a suitable option at high concentrations with low air flow rate. Multiple studies have investigated the effect of bed shape on catalytic and photocatalytic oxidation reactions, with results indicating that surface roughness leads to turbulence in the airflow at the bed surface and enhances mass transfer to oxidation sites [ 27 , 32 , 36 ]. Vohra studied the impact of roughness on turbulent airflow and suggested that catalyst immobilization on non-uniform and rough surfaces improves catalytic removal performance[ 37 ]. It appears that aluminum mesh beds are suitable for control systems in photocatalytic and catalytic processes due to their low weight, affordability, porosity, and low resistance to air flow. 5 Conclusion For side effects of VOCs in the whole of world and decrease of inherent’disadvantage of it, Catalytic oxidation and photocatalytic methods have proven to be effective and capable of removing volatile organic compounds at low concentrations, which are mainly encountered in internal conditions. Depending on the pollutant concentration and flow rate, the desired catalytic and photocatalytic bed surface can be selected to prevent reduce energy usage and cost. In high flow rates and low concentrations, the photocatalytic reactor showed better removal efficiency and with an average concentration of pollution MnO 2 had done the efficiency implement, while in high concentrations and low flow rates, the KMnO 4 catalyst showed better removal efficiency. Declarations Research funding This study is done as a research project in related with support of Qazvin University of Medical Sciences thorough all stages. Good for the University for technical assistance in the experimental examination. Conflict of interest statement The authors declare no conflicts of interest regarding this article. Author Contribution Conceptualization and writing-orginaldraft: FK, MK, MM; investigation and writing-review and editing: FK; methodology and formal analysis: FK, MK,MM; visualization: FK, MK, MM; supervision and project administration:AN. Data availability statement The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request References Yu, B., et al., Review of research on air-conditioning systems and indoor air quality control for human health. International journal of refrigeration, 2009. 32(1): p. 3–20. Salvadó-Estivill, I., D.M. 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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-3878366","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":268158210,"identity":"ba70b3ee-b161-4eb6-9957-b33b2624f7cb","order_by":0,"name":"Fatemeh Khoshpasand","email":"","orcid":"","institution":"Qazvin University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Fatemeh","middleName":"","lastName":"Khoshpasand","suffix":""},{"id":268158211,"identity":"efd45b91-cf74-4387-9740-718c40be2d8d","order_by":1,"name":"Mehrdad keshavarz","email":"","orcid":"","institution":"Qazvin University of Medical 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05:02:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":25088,"visible":true,"origin":"","legend":"\u003cp\u003ephoto removal efficiency of toluene influenced by concentration and flow rate\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/70616fa69be0e569835cd0eb.png"},{"id":50010950,"identity":"ac8204c4-6070-41ab-83f6-e92241b85d7b","added_by":"auto","created_at":"2024-01-23 05:02:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":26558,"visible":true,"origin":"","legend":"\u003cp\u003eThe effects of concentration and airflow on the elimination capacity of toluene .\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/3619589fd5146330fdf3c68e.png"},{"id":50011068,"identity":"90e68ad8-e227-450f-9f4d-5034ada4d390","added_by":"auto","created_at":"2024-01-23 05:10:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":24704,"visible":true,"origin":"","legend":"\u003cp\u003eThe MnO\u003csub\u003e2\u003c/sub\u003e catalytic removal efficiency of toluene influenced by concentration and flow rate\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/77fbfd9a98cfaef21a36786c.png"},{"id":50011069,"identity":"ec45c47b-8363-4ca6-8bf9-6155eebcce15","added_by":"auto","created_at":"2024-01-23 05:10:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":26877,"visible":true,"origin":"","legend":"\u003cp\u003eThe effects of concentration and airflow on the catalytic elimination capacity of MnO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/7ae82148730849ea30775e0c.png"},{"id":50010951,"identity":"5d15f6b5-dac5-4d1c-a155-c93a6a7a50f3","added_by":"auto","created_at":"2024-01-23 05:02:39","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":27488,"visible":true,"origin":"","legend":"\u003cp\u003eperformance of removal efficiency of the activated carbon-KMnO\u003csub\u003e4 \u003c/sub\u003eby considering the effects of concentration and airflow\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/77f12e7224f3ac9e165cf8e7.png"},{"id":50010953,"identity":"6c14fbb4-57fa-4519-9510-1b0a07185eee","added_by":"auto","created_at":"2024-01-23 05:02:39","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":23471,"visible":true,"origin":"","legend":"\u003cp\u003eThe effects of concentration and airflow on the catalytic elimination capacity of activated carbon-KMnO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/510a451ae6b644b8347b2ec5.png"},{"id":50357625,"identity":"e70352f3-6a66-407d-a6f1-0d9ea5255b77","added_by":"auto","created_at":"2024-01-30 09:24:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1073449,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3878366/v1/135d7655-0353-4f9f-b772-742cc117b6b0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Purification of polluted air from toluene vapor using catalytic oxidation and photocatalytic methods","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eWith the change in lifestyle over the past few decades, the health effects of indoor air quality that was showed such as sick building syndrome, increased prevalence of emerging diseases and cancer have received attention[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. To reffrence of the United States Environmental Protection Agency\u003ca class=\"FNLink\" href=\"#Fn1\" id=\"#FNLinkFn1\"\u003e1\u003c/a\u003e\u0026rsquo;s estimate \u0026ldquo;The indoor air pollution is 5 to 10 times higher than outdoor pollution\u0026rdquo;[\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Activities such as smoking, painting, cooking, etc. probably, emite all-around of volatile organic compounds [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Toluene is an organic solvent that has high emission potential and various health effects due to its widespread use in industrial products[\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Various methods have been proposed for controlling exposure to indoor volatile organic compounds. General ventilation, surface absorption, non-thermal plasma, ozone treatment, catalytic oxidation, and photocatalytic methods are some of these methods [\u003cspan additionalcitationids=\"CR13 CR14 CR15\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Becauce of cost-effective, effective method for converting organic compounds into water and carbon dioxide, and other low-risk compounds at room temperature related to catalytic oxidation [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. This method is based on a catalyst-coated surface with a large area[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The catalyst either has inherent catalytic oxidation properties at room temperature or its activation operation is performed by photocatalytic means in the presence of an activating agent such as ultraviolet radiation. The catalyst and it\u0026rsquo;s substrate are important in function of catalyst. The ability of the catalyst depends on its type, size, shape, and size distribution[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Due to the high cost and unavailability of expensive metals such as platinum, palladium, and rhodium, as few of these metals as possible should be used in making catalysts[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Manganese oxides (Mn\u003csub\u003ex\u003c/sub\u003eO\u003csub\u003ey\u003c/sub\u003e) are among the most effective and cost-efficient catalysts used in air purification, as they increase the surface reactivity of oxygen and enhance the catalyst's ability to remove organic compounds [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The high efficiency of Mn\u003csub\u003ex\u003c/sub\u003eO\u003csub\u003ey\u003c/sub\u003e in removing air pollutants is attributed to its multi-capacity structure and oxygen motion in the metal oxide network[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The presence of cation vacancies in the manganese oxide structure improves its efficiency in removing pollutant compounds. The presence of vacant sites for cations in the structure of manganese oxide improves its efficiency in removing pollutants. For the adsorption of VOCs on the activated carbone, the combined of the adsorption-catalytic method has been considered and studies have reported near 100% formaldehyde removal efficiency on MnO\u003csub\u003ex\u003c/sub\u003e/AC catalysts[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Photocatalytic oxidation of pollutants is economically and environmentally attractive[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. In this method, a photon with suitable energy collides with a semiconductor-like compound such as titanium dioxide, and an electron is transferred from the outer orbital layer to the conduction layer. In successive reactions, hydroxyl ions produced oxidize organic compounds into mineral oxides[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study the efficiency of catalytic and photocatalytic oxidation in removing toluene vapor from polluted air was compared at the room temperature on a bed of Stainless steel webnet.\u003c/p\u003e\n\u003cp\u003e[1] U.S. EPA (The United States Environmental Protection Agency)\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"2 Material and methods","content":"\u003cp\u003eThis study was implemented on a tabletop reactor with a height of 20 cm, an outer diameter of 7 cm, and an inner diameter of 6 cm. The photocatalytic bed was prepared using titanium dioxide nanoparticles from Evonik Industries AG under the trade name Aeroxide, while the catalytic bed was prepared using potassium permanganate and manganese oxide from Brenntag and Sigma-Aldrich. For the deposition of titanium dioxide nanoparticles and manganese oxide catalytic nanoparticles on an alumina substrate, 15 milliliters of ethanol were added to each nanoparticle and take time for 30 minutes in an ultrasonic bath to achieve a thick and uniform slurry. The catalysts were deposited on aluminum meshes by immersion method. The fixation and calcination process was carried out at 270 degrees Celsius for 3 hours. To prepare the adsorbent-catalytic substrate, KMnO\u003csub\u003e4\u003c/sub\u003e was first fixed on activated carbon. For this purpose, 2 grams of KMnO\u003csub\u003e4\u003c/sub\u003e were mixed with 20.8 milliliters of water and then added to a solution containing 4 grams of modified activated carbon with persidine [\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e], and the resulting mixture was passed through filter paper. A G15T8 UVC lamp with a power of 8 watts (main wavelength of 280 nanometers) was used to activate the photocatalyst (Fig.\u0026nbsp;1).\u003c/p\u003e\n\u003cp\u003eThe intensity of radiation measured by the UV Light meter model LUTRON UVC-254 was 1.07 micro-watts per square centimeter in the farthest part of the surface and all directions. The concentration of toluene was determined dynamically using a vacuum hose. The required airflow was divided into two main and secondary branches after passing through a silica gel filter and flow regulation. The main branch created negative pressure by passing through the vacuum hose, which was used to draw toluene vapors for concentration. To ensure precise control of the concentration, the toluene container was kept under controlled temperature conditions and a set of needle valves was used to achieve the desired concentration range (10\u0026ndash;40 ppm). To determine the surface adsorption effect and other unknown factors affecting the removal of certain concentrations of toluene from 2\u0026ndash;5 liters per minute airflows while the ultraviolet lamp in the photocatalytic reactor was off, all three reactors were entered. when the output concentration of pollutant get to one tenth of the input concentration in the adsorption-catalytic bed (KMnO\u003csub\u003e4\u003c/sub\u003e and activated carbon) was considered the breakthrough point of the absorbent and its saturation absorption capacity. The efficiency and removal capacity of photocatalysis were evaluated under conditions where the UVC lamp was on and certain concentrations of toluene passed through 2\u0026ndash;5 liters per minute airflows. Toluene concentration measurements at inlet and outlet beds were performed by injecting a 200-microliter gas sample into an Agilent Technologies 7890B GC with an FID detector. During the experiment, the temperature of the inlet and outlet air in the bed was measured by an alcohol thermometer, and the airflow rate was through a Ki MR3A02SVVT volumetric flowmeter. In each study, after ensuring that flow and concentration conditions matched study objectives, the flow and concentration was measured at inlet and outlet of beds. was introduced into beds and toluene concentration at inlet and outlet beds was measured. To achieve suitable repeatability, the sampling process was repeated until achieving repeatable results (at least three times).\u003c/p\u003e\n\u003cp\u003eStatistical experimental design (DOE\u003ca class=\"FNLink\" href=\"#Fn2\" id=\"#FNLinkFn2\"\u003e2\u003c/a\u003e) was conducted using the central composite design (CCD\u003ca class=\"FNLink\" href=\"#Fn3\" id=\"#FNLinkFn3\"\u003e3\u003c/a\u003e) method with 5 levels using Design Expert 7 software. Based on initial estimates and independent parameters (concentration and airflow), a total of 13 tests were determined. Results were analyzed using descriptive statistics, one-way analysis of variance, and performance and capacity relationships.\u003c/p\u003e\n\u003cp\u003e[2] Design of Experiments\u003c/p\u003e\n\u003cp\u003e[3] Central Composite Design\u003c/p\u003e"},{"header":"3 Results","content":"\u003cp\u003eThe relationship between removal efficiency and elimination capacity of TiO\u003csub\u003e2\u003c/sub\u003e bed surface was R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026ge;\u0026thinsp;99%. The effect of independent variables of concentration and air flow on catalytic efficiency and removal capacity is presented in Figs. 2 and 3.\u003c/p\u003e\n\u003cp\u003eBased on the two-dimensional graphs obtained from the data, the highest removal efficiency in the photocatalytic process was observed at low concentration and high flow rate (Fig. 2), while the highest elimination capacity was observed at high concentration and low flow rate (Fig. 3). The removal efficiency varied between 18\u0026ndash;55% for concentration range of 10\u0026ndash;40 ppm and airflow rate of 2\u0026ndash;5 L/min. By reducing the concentration to 4.27 ppm and increasing the air flow rate to 5.45 L/min, the removal efficiency reached its maximum value of 55.83%. A linear and significant correlation (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026ge;\u0026thinsp;97%) was observed between removal efficiency and elimination capacity with independent variables of concentration and flow rate in catalytic removal of toluene from air stream over MnO\u003csub\u003e2\u003c/sub\u003e catalyst. The effect of independent variables of concentration and air flow rate on catalytic removal efficiency and capacity is presented in Figs. 4 and 5. The highest removal efficiency (34.41%) was achieved at an average concentration of 13.87 ppm and an airflow rate of 3.30 L/min.\u003c/p\u003e\n\n\u003cp\u003eThe highest toluene elimination capacity on MnO\u003csub\u003e2\u003c/sub\u003e catalytic bed is at concentrations higher than 25 ppm and flow rates of 5 L/min. Toluene removal in the presence of KMnO\u003csub\u003e4\u003c/sub\u003e catalyst and activated carbon showed a significant and linear relationship between removal efficiency and elimination capacity with independent variables at the catalyst surface (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026ge;\u0026thinsp;99%). The highest elimination capacity was observed at an airflow rate of 4 L/min and a concentration of 40 ppm, while the removal efficiency was raised at an airflow rate of 2 L/min and a concentration of 40 ppm. Higher concentrations (40 ppm and flow rate of 2 L/min) had a greater impact on the maximum elimination capacity (Fig.\u0026nbsp;7), while lower flow rates (2 L/min) had better removal efficiency (Fig.\u0026nbsp;6). Airflow had the greatest effect on the catalytic toluene removal efficiency and capacity.\u003c/p\u003e\n\u003cp\u003eThe photocatalytic reactor had better removal efficiency at high flow rates (5.45 L/min) and low concentrations (4.27 ppm), while MnO\u003csub\u003e2\u003c/sub\u003e at average concentrations (13.87 ppm and 3.30 L/min) and KMnO\u003csub\u003e4\u003c/sub\u003e at high concentrations (44.28 ppm) with low flow rates (2.48 L/min) showed better performance.\u003c/p\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eThe results of this study indicate a reduction in the concentration of toluene through catalytic and photocatalytic methods at room temperature. The finding shows with increase of concentration, removal efficiency was decreased, and at the optimal operating point (input concentration of 4.27 ppm and an airflow rate of 5.45 L/min), the removal efficiency reached 55.83%. This is because as the input concentration of pollutants increases and considering the reaction rate, filling of adsorption of surface\u0026rsquo;s site was occurded, and leaving no room for more pollutants to be accepted.\u003c/p\u003e \u003cp\u003eIn a study by Liang (2012), an increase in the input concentration of toluene resulted in a decrease in removal efficiency from 85\u0026ndash;30%[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Various studies have also reported a decrease in toluene removal efficiency with increasing concentration, which is consistent with this study[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGenerally, photocatalytic removal efficiency improves at low concentrations and high air flow rates. Airflow has a two-way relationship with removal efficiency. Increasing airflow reduces the thickness of the boundary layer at low concentrations and increases the likelihood of pollutant transfer to photocatalytic oxidation sites. A similar scenario is observed at high concentrations and low airflow rates, where pollutant transfer to catalytic oxidation sites increases due to prolonged exposure time. Since photocatalytic process depend on surface chemistry, the number of available active sites and pollutant transfer to active sites, and product transfer to airflow are important factors that affected removal efficiency. However, reducing the air flow rate and increasing concentration can cause disturbance in the mass transfer process and reduce removal efficiency[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWang Xingfu et al. reported on formaldehyde removal from the air using a modified aluminum foam photocatalytic bed with TiO\u003csub\u003e2\u003c/sub\u003e at room temperature, which was observed same with the results of this study [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe results of catalytic removal in a modified MnO\u003csub\u003e2\u003c/sub\u003e bed indicate that as the concentration increases, the removal efficiency decreases from 32\u0026ndash;25%, which is consistent with the findings of Shayegan's study on a carbon-based surface where the removal efficiency decreased from 45% to less than 20% when observed the increasing of elementary concentration from 150 ppm to 1000 ppm [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWith increasing concentration, the rate of catalytic oxidation initially increased and then decreased due to the production of CO\u003csub\u003e2\u003c/sub\u003e and H\u003csub\u003e2\u003c/sub\u003eO and blockage of active catalytic sites, reducing removal efficiency. For increasing of mass transfer on the catalyst surface, it\u0026rsquo;s may obtain when air flow increase inside the reactor and causes turbulent flow [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]; however, with reducing residence time, products will have less opportunity to transfer to active sites, which will be accompanied by a wider range of incompletely decomposed compounds in the air stream. Unlike photocatalytic reactions, activated carbon-KMnO\u003csub\u003e4\u003c/sub\u003e catalyst beds had the highest removal efficiency (98%) at high concentrations and low airflow rates. The capacity of activated carbon for adsorption of organic compounds is not deniable, when the surface of activated carbon is relatively rough and porous, creating open pores that have significant potential for improving adsorption capacity[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Potassium permanganate also can oxidize VOC compounds[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStudies combining activated carbon with KMnO\u003csub\u003e4\u003c/sub\u003e was resulted in an increase in formaldehyde removal efficiency and a stronger adsorbent for reducing formaldehyde concentrations in indoor environments[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. At the same flow rate, as the input concentration of formaldehyde increased, the absorption time decreased, which is same with the results of this study. In this study, air flow rate had the greatest impact on efficiency and adsorption capacity. Thus, the surface bed had better performance in absorbing pollutants at low air flow rate and high concentration. It appears that the structure of potassium permanganate particles in combination with numerous activated carbon pores is the main reason for suitable removal efficiency at high concentrations. Due to oxidative reactions, potassium permanganate was placed in activated carbon pores. The absorption time of activated carbon depends on the pollutant input rate; therefore, with reduced air flow rate and increased retention time, activated carbon-potassium permanganate had more opportunities to absorb pollutants. As a result, they can be considered a suitable option at high concentrations with low air flow rate.\u003c/p\u003e \u003cp\u003eMultiple studies have investigated the effect of bed shape on catalytic and photocatalytic oxidation reactions, with results indicating that surface roughness leads to turbulence in the airflow at the bed surface and enhances mass transfer to oxidation sites [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Vohra studied the impact of roughness on turbulent airflow and suggested that catalyst immobilization on non-uniform and rough surfaces improves catalytic removal performance[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. It appears that aluminum mesh beds are suitable for control systems in photocatalytic and catalytic processes due to their low weight, affordability, porosity, and low resistance to air flow.\u003c/p\u003e"},{"header":"5 Conclusion","content":"\u003cp\u003eFor side effects of VOCs in the whole of world and decrease of inherent\u0026rsquo;disadvantage of it, Catalytic oxidation and photocatalytic methods have proven to be effective and capable of removing volatile organic compounds at low concentrations, which are mainly encountered in internal conditions. Depending on the pollutant concentration and flow rate, the desired catalytic and photocatalytic bed surface can be selected to prevent reduce energy usage and cost. In high flow rates and low concentrations, the photocatalytic reactor showed better removal efficiency and with an average concentration of pollution MnO\u003csub\u003e2\u003c/sub\u003e had done the efficiency implement, while in high concentrations and low flow rates, the KMnO\u003csub\u003e4\u003c/sub\u003e catalyst showed better removal efficiency.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e \u003cb\u003eResearch funding\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThis study is done as a research project in related with support of Qazvin University of Medical Sciences thorough all stages. Good for the University for technical assistance in the experimental examination.\u003c/p\u003e\u003cp\u003e \u003ch2\u003eConflict of interest statement\u003c/h2\u003e \u003cp\u003eThe authors declare no conflicts of interest regarding this article.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConceptualization and writing-orginaldraft: FK, MK, MM; investigation and writing-review and editing: FK; methodology and formal analysis: FK, MK,MM; visualization: FK, MK, MM; supervision and project administration:AN.\u003c/p\u003e\u003ch2\u003eData availability statement\u003c/h2\u003e \u003cp\u003eThe data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eYu, B., et al., Review of research on air-conditioning systems and indoor air quality control for human health. 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Qom University of Medical Sciences Journal, 2013. 7(2): p. 17\u0026ndash;26.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVohra, A., Photocatalytic disinfection of indoor air: Effect of relative humidity and surface roughness of photocatalytic reactor. 2005: University of Florida.\u003c/span\u003e\u003c/li\u003e\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":"photocatalytic oxidation, MnO2, KMnO4, Air purifier","lastPublishedDoi":"10.21203/rs.3.rs-3878366/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3878366/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction\u003c/h2\u003e \u003cp\u003e: Indoor air quality and it\u0026rsquo;s side effects have increased the prevalence of emerging diseases and cancer. Due to its widespread use in industrial products, Toluene is an organic solvent that has a high potential for release and various health effects. Various methods, including catalytic oxidation and photocatalytic oxidation, have been proposed to limit VOCs in indoor environments. One of the most effective and cost-effective catalysts used in air purification is manganese oxides (Mn\u003csub\u003ex\u003c/sub\u003eO\u003csub\u003ey\u003c/sub\u003e), which are effective in converting organic compounds into water, carbon dioxide, and other low-risk compounds at room temperature. Photocatalytic oxidation of pollutants is also economically and environmentally popular.\u003c/p\u003e\u003ch2\u003eMaterial and methods\u003c/h2\u003e \u003cp\u003eThe aim of this study was compared the efficiency of catalytic oxidation and photocatalytic removal of toluene from polluted air at room temperature on aluminum mesh in a glass reactor with dimensions of 20 cm height, 7 cm outer diameter, and 6 cm inner diameter. After preparing the surface of the used beds, the airflow containing pollutants was introduced into the beds, and the concentration of toluene was measured before and after of pass through from bed surface. The results were analyzed using descriptive statistics, one-way analysis of variance, and efficiency and capacity equations.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe results showed a reduction in toluene concentration by catalytic and photocatalytic methods at room temperature. The photocatalytic reactor had better removal efficiency at a high flow rate (5.45 L/min) and low concentration (4.27 ppm), while MnO\u003csub\u003e2\u003c/sub\u003e had better performance at a medium concentration (13.87 ppm) and flow rate (3.30 L/min), and KMnO\u003csub\u003e4\u003c/sub\u003e had better performance at high concentration (44.28 ppm) and flow rate (5.48 L/min).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eCatalytic oxidation and photocatalytic methods have suitable efficiency and capability for removing volatile organic compounds at low concentrations that we mainly face in indoor environments. We can choose the desired surface area for catalytic or photocatalytic beds depending on the pollutant concentration and flow rate.\u003c/p\u003e","manuscriptTitle":"Purification of polluted air from toluene vapor using catalytic oxidation and photocatalytic methods","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-23 05:02:35","doi":"10.21203/rs.3.rs-3878366/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":"812302ad-36d5-45a5-93d7-0c7b73e3df89","owner":[],"postedDate":"January 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-01-30T09:16:26+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-23 05:02:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3878366","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3878366","identity":"rs-3878366","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}