针对小型企业工业炉窑VOCs低浓度、不连续的排放特点,以商用活性炭为吸附材料,采用自制Pd-Ce/Al2O3双元催化剂开展工业炉窑VOCs废气吸附-脱附-催化一体化净化技术研究,通过BET、SEM和TG表征手段对吸脱附再生前后的活性炭进行表征测试。...针对小型企业工业炉窑VOCs低浓度、不连续的排放特点,以商用活性炭为吸附材料,采用自制Pd-Ce/Al2O3双元催化剂开展工业炉窑VOCs废气吸附-脱附-催化一体化净化技术研究,通过BET、SEM和TG表征手段对吸脱附再生前后的活性炭进行表征测试。以甲苯为探针分子,考察不同脱附时间、烟气稀释倍数、催化温度及烟气循环次数对该工艺净化甲苯废气性能的影响。研究表明100℃下热脱附1 h即可将吸附物质基本脱除,催化温度为320℃时,甲苯即可完全催化氧化;系统循环操作10~15次后,活性炭材料在100℃下焙烧6 h进行彻底再生,具有最好的经济效益。表征结果表明,经多次热再生后,活性炭孔道存在部分坍塌,比表面积由889 m 2/g降至688 m 2/g,孔容由0.50 mL/g降至0.37 mL/g,孔径无明显变化,均在2.2 nm左右;这与SEM观察到的活性炭表面褶皱减少相吻合,说明多次热再生后活性炭孔道存在一定程度的坍塌,但依然保持介孔特性;TG曲线中再生后活性炭失重曲线略低于新鲜活性炭,进一步证明多次热再生对活性炭孔道结构存在一定的破坏性。展开更多
Background,aim,and scope Owing to the rapid development of modernisation and urbanisation,living standards have gradually improved.However,the widespread use of high-energy-consuming indoor appliances and furniture ha...Background,aim,and scope Owing to the rapid development of modernisation and urbanisation,living standards have gradually improved.However,the widespread use of high-energy-consuming indoor appliances and furniture has made indoor environments a primary environmental problem affecting human health.Sick building syndrome(SBS)and building-related illness(BRI)have occurred,and indoor air conditions have been extensively studied.Common indoor pollutants include CO,CO_(2),volatile organic compounds(VOCs)(such as the formaldehyde and benzene series),NOx(NO and NO_(2)),and polycyclic aromatic hydrocarbons(PAHs).VOCs have replaced SO_(2)as the“The Fourteenth Five-Year Plan”urban air quality assessment new indicators.Indoor VOCs can cause diseases such as cataract,asthma,and lung cancer.To protect human health,researchers have proposed several indoor air purification technologies,including adsorption,filtration,electrostatic dust removal,ozonation,and plant purification.However,each technology has drawbacks,such as high operating costs,high energy consumption,and the generation of secondary waste or toxic substances.Plant degradation of VOCs as a bioremediation technology has the characteristics of low cost,high efficiency,and sustainability,thereby becoming a potential green solution for improving indoor air quality.This study introduces the research status and mechanism of plant removal of indoor VOCs and provides an experimental basis and scientific guidance for analysing the mechanism of plant degradation of pollutants.Materials and methods This study reviews studies on the harm caused by indoor pollutants to human health and related sources,mainly investigating the degradation of indoor formaldehyde,BTEX(benzene,toluene,ethylbenzene,and xylene)plant mechanisms,and research results.Results Plants can remove VOCs via stomatal and non-stomatal adsorption,interfoliar microbial,rhizosphere microbial,and growth media.Benzene,toluene,and xylene(BTX)are adsorbed by pores,hydroxylated into fumaric acid,and then removed in展开更多
Cooking process can produce abundant volatile organic compounds(VOCs),which are harmful to environment and human health.Therefore,we conducted a comprehensive analysis in which VOCs emissions from multiple cuisines ha...Cooking process can produce abundant volatile organic compounds(VOCs),which are harmful to environment and human health.Therefore,we conducted a comprehensive analysis in which VOCs emissions from multiple cuisines have been sampled based on the simulation and acquisition platform,involving concentration characteristics,ozone formation potential(OFP)and purification efficiency assessments.VOCs emissions varied from 1828.5 to 14,355.1μg/m^(3),with the maximumand minimumvalues fromBarbecue and Family cuisine,respectively.Alkanes and alcohol had higher contributions to VOCs from Sichuan and Hunan cuisine(64.1%),Family cuisine(66.3%),Shandong cuisine(69.1%)and Cantonese cuisine(69.8%),with the dominant VOCs species of ethanol,isobutane and n-butane.In comparison,alcohols(79.5%)were abundant for Huaiyang cuisine,while alkanes(19.7%),alkenes(35.9%)and haloalkanes(22.9%)accounted for higher proportions from Barbecue.Specially,carbon tetrachloride,n-hexylene and 1-butene were the most abundant VOCs species for Barbecue,ranging from 8.8%to 14.6%.The highest OFP occurred in Barbecue.The sensitive species of OFP for Huaiyang cuisine were alcohols,while other cuisines were alkenes.Purification efficiency assessments shed light on the removal differences of individual and synergistic control technologies.VOCs emissions exhibited a strong dependence on the photocatalytic oxidation,with the removal efficiencies of 29.0%–54.4%.However,the high voltage electrostatic,wet purification and mechanical separation techniques played a mediocre or even counterproductive role in the VOCs reduction,meanwhile collaborative control technologies could not significantly improve the removal efficiency.Our results identifiedmore effective control technologies,which were conductive to alleviating air pollution from cooking emissions.展开更多
Volatile organic compounds(VOCs) are typical pollutants that affect air quality.Discharge plasma is thought to be a potential method that can remove VOCs from flue gas.In this experiment,pulsed corona discharge plasma...Volatile organic compounds(VOCs) are typical pollutants that affect air quality.Discharge plasma is thought to be a potential method that can remove VOCs from flue gas.In this experiment,pulsed corona discharge plasma combined with a biological tower was carried out to remove the benzene series,and toluene was selected as the typical VOC.The results indicated that the removal efficiency of toluene by pulsed corona plasma was slightly higher than that of direct current(DC) corona plasma,while its energy efficiency was much higher than DC corona plasma.Under the optimal experimental conditions of pulse voltage 8.5 kV,initial toluene concentration 1400 mg m^(-3),and toluene flow rate of 121h^(-1),the toluene removal efficiency reached 77.11% by the single method of pulsed corona discharge plasma,and the energy efficiency was up to 1.515 g/(kW·h) under the pulse voltage of 4.0 kV.The trickling biofilter was constructed by using the screened and domesticated Acinetobacter baumannii,and the highest toluene removal efficiency by the pulsed corona discharge plasma combined with the trickling biofilter rose up to 97.84%.Part of the toluene was degraded into CO_(2),H_(2)O,and some intermediate products such as o-diphenol under the influence of Acinetobacter baumannii.When the remaining waste gas passed through the discharge plasma reactor,the benzene ring structure could be directly destroyed by the collision between toluene and plasma.Meanwhile,O·,OH·,and some other oxidizing radicals generated by the discharge also join into the oxidative decomposition of toluene and its intermediate products,thereby further improving the removal efficiency of toluene.Therefore,the two-stage plasma-biofilter system not only showed a high toluene removal efficiency,but also had a good energy efficiency.The results of this study will provide theoretical support and technical reference for industrial VOC treatment.展开更多
文摘针对小型企业工业炉窑VOCs低浓度、不连续的排放特点,以商用活性炭为吸附材料,采用自制Pd-Ce/Al2O3双元催化剂开展工业炉窑VOCs废气吸附-脱附-催化一体化净化技术研究,通过BET、SEM和TG表征手段对吸脱附再生前后的活性炭进行表征测试。以甲苯为探针分子,考察不同脱附时间、烟气稀释倍数、催化温度及烟气循环次数对该工艺净化甲苯废气性能的影响。研究表明100℃下热脱附1 h即可将吸附物质基本脱除,催化温度为320℃时,甲苯即可完全催化氧化;系统循环操作10~15次后,活性炭材料在100℃下焙烧6 h进行彻底再生,具有最好的经济效益。表征结果表明,经多次热再生后,活性炭孔道存在部分坍塌,比表面积由889 m 2/g降至688 m 2/g,孔容由0.50 mL/g降至0.37 mL/g,孔径无明显变化,均在2.2 nm左右;这与SEM观察到的活性炭表面褶皱减少相吻合,说明多次热再生后活性炭孔道存在一定程度的坍塌,但依然保持介孔特性;TG曲线中再生后活性炭失重曲线略低于新鲜活性炭,进一步证明多次热再生对活性炭孔道结构存在一定的破坏性。
文摘Background,aim,and scope Owing to the rapid development of modernisation and urbanisation,living standards have gradually improved.However,the widespread use of high-energy-consuming indoor appliances and furniture has made indoor environments a primary environmental problem affecting human health.Sick building syndrome(SBS)and building-related illness(BRI)have occurred,and indoor air conditions have been extensively studied.Common indoor pollutants include CO,CO_(2),volatile organic compounds(VOCs)(such as the formaldehyde and benzene series),NOx(NO and NO_(2)),and polycyclic aromatic hydrocarbons(PAHs).VOCs have replaced SO_(2)as the“The Fourteenth Five-Year Plan”urban air quality assessment new indicators.Indoor VOCs can cause diseases such as cataract,asthma,and lung cancer.To protect human health,researchers have proposed several indoor air purification technologies,including adsorption,filtration,electrostatic dust removal,ozonation,and plant purification.However,each technology has drawbacks,such as high operating costs,high energy consumption,and the generation of secondary waste or toxic substances.Plant degradation of VOCs as a bioremediation technology has the characteristics of low cost,high efficiency,and sustainability,thereby becoming a potential green solution for improving indoor air quality.This study introduces the research status and mechanism of plant removal of indoor VOCs and provides an experimental basis and scientific guidance for analysing the mechanism of plant degradation of pollutants.Materials and methods This study reviews studies on the harm caused by indoor pollutants to human health and related sources,mainly investigating the degradation of indoor formaldehyde,BTEX(benzene,toluene,ethylbenzene,and xylene)plant mechanisms,and research results.Results Plants can remove VOCs via stomatal and non-stomatal adsorption,interfoliar microbial,rhizosphere microbial,and growth media.Benzene,toluene,and xylene(BTX)are adsorbed by pores,hydroxylated into fumaric acid,and then removed in
基金supported by the Open Research Fund Program of State Environmental Protection Key Laboratory of Food Chain Pollution Control(No.FC2021YB03)the Research Foundation for Youth Scholars of Beijing Technology and Business University(No.QNJJ2021-32).
文摘Cooking process can produce abundant volatile organic compounds(VOCs),which are harmful to environment and human health.Therefore,we conducted a comprehensive analysis in which VOCs emissions from multiple cuisines have been sampled based on the simulation and acquisition platform,involving concentration characteristics,ozone formation potential(OFP)and purification efficiency assessments.VOCs emissions varied from 1828.5 to 14,355.1μg/m^(3),with the maximumand minimumvalues fromBarbecue and Family cuisine,respectively.Alkanes and alcohol had higher contributions to VOCs from Sichuan and Hunan cuisine(64.1%),Family cuisine(66.3%),Shandong cuisine(69.1%)and Cantonese cuisine(69.8%),with the dominant VOCs species of ethanol,isobutane and n-butane.In comparison,alcohols(79.5%)were abundant for Huaiyang cuisine,while alkanes(19.7%),alkenes(35.9%)and haloalkanes(22.9%)accounted for higher proportions from Barbecue.Specially,carbon tetrachloride,n-hexylene and 1-butene were the most abundant VOCs species for Barbecue,ranging from 8.8%to 14.6%.The highest OFP occurred in Barbecue.The sensitive species of OFP for Huaiyang cuisine were alcohols,while other cuisines were alkenes.Purification efficiency assessments shed light on the removal differences of individual and synergistic control technologies.VOCs emissions exhibited a strong dependence on the photocatalytic oxidation,with the removal efficiencies of 29.0%–54.4%.However,the high voltage electrostatic,wet purification and mechanical separation techniques played a mediocre or even counterproductive role in the VOCs reduction,meanwhile collaborative control technologies could not significantly improve the removal efficiency.Our results identifiedmore effective control technologies,which were conductive to alleviating air pollution from cooking emissions.
基金financially supported by the National Key Research and Development Program of China(No.2019YFC0214303)the Applied Basic Research Program of Wuhan,China(No.2015060101010068)
文摘Volatile organic compounds(VOCs) are typical pollutants that affect air quality.Discharge plasma is thought to be a potential method that can remove VOCs from flue gas.In this experiment,pulsed corona discharge plasma combined with a biological tower was carried out to remove the benzene series,and toluene was selected as the typical VOC.The results indicated that the removal efficiency of toluene by pulsed corona plasma was slightly higher than that of direct current(DC) corona plasma,while its energy efficiency was much higher than DC corona plasma.Under the optimal experimental conditions of pulse voltage 8.5 kV,initial toluene concentration 1400 mg m^(-3),and toluene flow rate of 121h^(-1),the toluene removal efficiency reached 77.11% by the single method of pulsed corona discharge plasma,and the energy efficiency was up to 1.515 g/(kW·h) under the pulse voltage of 4.0 kV.The trickling biofilter was constructed by using the screened and domesticated Acinetobacter baumannii,and the highest toluene removal efficiency by the pulsed corona discharge plasma combined with the trickling biofilter rose up to 97.84%.Part of the toluene was degraded into CO_(2),H_(2)O,and some intermediate products such as o-diphenol under the influence of Acinetobacter baumannii.When the remaining waste gas passed through the discharge plasma reactor,the benzene ring structure could be directly destroyed by the collision between toluene and plasma.Meanwhile,O·,OH·,and some other oxidizing radicals generated by the discharge also join into the oxidative decomposition of toluene and its intermediate products,thereby further improving the removal efficiency of toluene.Therefore,the two-stage plasma-biofilter system not only showed a high toluene removal efficiency,but also had a good energy efficiency.The results of this study will provide theoretical support and technical reference for industrial VOC treatment.
