活性炭纤维/泡沫镍阴极的电化学工艺除藻效能
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摘要
蓝藻爆发问题长期严重影响饮用水安全,为此,发展有效的技术控制和减少藻类的繁殖尤为迫切.以钛基铂电极(Pt/Ti)为阳极,活性炭纤维/泡沫镍电极(ACF/Ni)为阴极,通过考察阴极材料(ACF/Ni和不锈钢)、铁投加浓度及价态对电化学除藻的影响,探究Pt/Ti-ACF/Ni-Fe~(2+)电化学体系对藻类的去除效果和机制.结果表明,当Fe~(2+)投加浓度为0.05 mmol/L、电流密度为50 mA/cm~2、极板间距为1.0 cm、初始pH为6.0、初始藻细胞密度为1.2×10~9～1.4×10~9个/L时,电化学处理15 min,藻细胞的去除率为93%.基于对各实验中铁离子浓度、H_2O_2浓度及pH的分析,·OH的间接检测,ACF的红外光谱分析,藻细胞和ACF/Ni的电镜扫描以及ACF的比表面积分析,探究Pt/Ti-ACF/Ni-Fe~(2+)电化学体系的除藻机理.在Pt/Ti-ACF/Ni-Fe~(2+)电化学除藻体系中,H_2O_2通过电化学还原在ACF/Ni阴极表面高效产生,反应过程中产生固相铁附着于ACF表面并发生Fe(Ⅲ)还原为Fe(Ⅱ)的反应,同时产生羟基自由基,电化学除藻的主要机理是均相电Fenton和非均相电Fenton反应.
Since the pollution of algae blooms has seriously affected drinking water safety for a long time, it is urgent to develop effective techniques to control and reduce algal reproduction. By using Pt/Ti anode and ACF/Ni cathode, effects of the parameters such as cathode materials(ACF/Ni and stainless steel) as well as the concentration and valence state of iron added on the electrochemical removal of algae were investigated to explore the removal efficiency and mechanism of algae in the Pt/Ti-ACF/Ni-Fe~(2+) electrochemical system. Results showed that under the conditions of Fe~(2+) concentration of 0.05 mmol/L, current density of 50 mA/cm~2, inter-electrode gap of 1.0 cm, initial pH of 6.0, and initial algal cell density of 1.2×10~9-1.4×10~9 cells/L, 93% of the algae cells were removed in 15 min. Based on the analyses of ferric ion concentration, H_2O_2 concentration, and pH in the experiments, indirect detection of ·OH, FTIR analysis of ACF, SEM images of algae, and ACF/Ni and BET analyses of ACF, mechanism of algae removal was revealed in the Pt/Ti-ACF/Ni-Fe~(2+) system. H_2O_2 was generated efficiently through electrochemical reduction on the surface of the ACF/Ni cathode, the iron in solid phase generated during the reaction was precipitated on the surface of ACF/Ni cathode with the electrochemical reduction of Fe(Ⅲ) to Fe(Ⅱ), and meanwhile ·OH would be generated in the Pt/Ti-ACF/Ni-Fe~(2+) algae removal system. Heterogeneous and homogenous electro-Fenton processes were the main mechanism in the Pt/Ti-ACF/Ni-Fe~(2+) algae removal system.
Since the pollution of algae blooms has seriously affected drinking water safety for a long time, it is urgent to develop effective techniques to control and reduce algal reproduction. By using Pt/Ti anode and ACF/Ni cathode, effects of the parameters such as cathode materials(ACF/Ni and stainless steel) as well as the concentration and valence state of iron added on the electrochemical removal of algae were investigated to explore the removal efficiency and mechanism of algae in the Pt/Ti-ACF/Ni-Fe~(2+) electrochemical system. Results showed that under the conditions of Fe~(2+) concentration of 0.05 mmol/L, current density of 50 mA/cm~2, inter-electrode gap of 1.0 cm, initial pH of 6.0, and initial algal cell density of 1.2×10~9-1.4×10~9 cells/L, 93% of the algae cells were removed in 15 min. Based on the analyses of ferric ion concentration, H_2O_2 concentration, and pH in the experiments, indirect detection of ·OH, FTIR analysis of ACF, SEM images of algae, and ACF/Ni and BET analyses of ACF, mechanism of algae removal was revealed in the Pt/Ti-ACF/Ni-Fe~(2+) system. H_2O_2 was generated efficiently through electrochemical reduction on the surface of the ACF/Ni cathode, the iron in solid phase generated during the reaction was precipitated on the surface of ACF/Ni cathode with the electrochemical reduction of Fe(Ⅲ) to Fe(Ⅱ), and meanwhile ·OH would be generated in the Pt/Ti-ACF/Ni-Fe~(2+) algae removal system. Heterogeneous and homogenous electro-Fenton processes were the main mechanism in the Pt/Ti-ACF/Ni-Fe~(2+) algae removal system.
引文
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[23]WANG Aimin,QU Jiuhui,LIU Huijuan,et al.Mineralization of an azo dye Acid Red 14 by photoelectro-fenton process using an activated carbon fiber cathode[J].Applied Catalysis B Environmental,2008,84(3):393.DOI:10.1016/j.apcatb.2008.04.016
[24]王丽平.ACF/CNT复合材料的制备、表征及其吸附特性研究[D].长沙:中南大学,2012WANG Liping.Investigation on preparation,characterization and adsorption properties of ACF/CNT composites[D].Hunan:Central South University,2012
[25]中西香尔,索罗曼.红外光谱分析100例[M].王绪明,译.北京:科学出版社,1984NAKANISHI K,SOLOMON P H.100 cases were analyzed by infrared spectroscopy[M].WANG Xuming,translate.Beijing:Science Press,1984
[26]杨辉,刘豪,朱德力,等.活性炭纤维联合脱硫脱硝的机理分析[J].中国电机工程学报,2015,35(10):2495 YANG Hui,LIU Hao,ZHU Deli,et al.Mechanism of combined removal of SO2 and NO over activated carbon fibers[J].Proceedings of the CSEE,2015,35(10):2495
[27]刘辉,李平,魏雨,等.红外光谱技术在铁氧化物形成研究中的应用[J].河北师范大学学报(自然科学版),2005,29(3):272 LIU Hui,LI Ping,WEI Yu,et al.Application of IR spectra in the studies on the formation of iron (Hydr)oxides[J].Journal of Hebei Normal University (Natural Science Edition),2005,29(3):272
[2]BRILLAS E,BANOS M á,SKOUMAL M,et al.Degradation of the herbicide 2,4-DP by anodic oxidation,electro-Fenton and photoelectro-Fenton using platinum and boron-doped diamond anodes[J].Chemosphere,2007,68(2):199.DOI:10.1016/j.chemosphere.2007.01.038
[3]WANG Yujing,ZHAO Hongying,CHAI Shouning,et al.Electrosorption enhanced electro-Fenton process for efficient mineralization of imidacloprid based on mixed-valence iron oxide composite cathode at neutral pH[J].Chemical Engineering Journal,2013,223(5):524.DOI:10.1016/j.cej.2013.03.016
[4]曾海燕,李华亮,雷恒毅,等.活性炭纤维电极电还原产H2O2的实验研究[J].环境科学,2011,32(3):711 ZENG Haiyan,LI Hualiang,LEI Hengyi,et al.Study on the electro-generation of H2O2 using an activated carbon fiber[J].Environmental Science,2011,32(3):711
[5]ZHANG Xingwang,FU Jianliang,ZHANG Yi,et al.A nitrogen functionalized carbon nanotube cathode for highly efficient electrocatalytic generation of H2O2 in Electro-Fenton system[J].Separation & Purification Technology,2008,64(1):116.DOI:10.1016/j.seppur.2008.07.020
[6]PANIZZA M,OTURAN M A.Degradation of Alizarin Red by electro-Fenton process using a graphite-felt cathode[J].Electrochimica Acta,2011,56(20):7084.DOI:10.1016/j.electacta.2011.05.105
[7]YAMADA N,YAGUCHI T,OTSUKA H,et al.Development of trickle-bed electrolyzer for on-site electrochemical production of hydrogen peroxide[J].Journal of the Electrochemical Society,1999,146(7):2587.DOI:10.1149/1.1391976
[8]LONG Yujiao,LI Hongna,XING Xuan,et al.Enhanced removal of Microcystis aeruginosa,in BDD-CF electrochemical system by simple addition of Fe2+[J].Chemical Engineering Journal,2017,325:360.DOI:10.1016/j.cej.2017.05.067
[9]GUINEA E,ARIAS C,CABOT P L,et al.Mineralization of salicylic acid in acidic aqueous medium by electrochemical advanced oxidation processes using platinum and boron-doped diamond as anode and cathodically generated hydrogen peroxide[J].Water Research,2008,42(1):499.DOI:10.1016/j.watres.2007.07.046
[10]王爱民,曲久辉,史红星,等.活性碳纤维阴极电芬顿反应降解微囊藻毒素研究[J].高等学校化学学报,2005,26(9):1665 WANG Aimin,QU Jiuhui,SHI Hongxing,et al.Degradation of microcystotoxin by electro-Fenton reaction using an activated carbon fiber cathode[J].Chemical Journal of Chinese Universities,2005,26(9):1665.DOI:10.3321/j.issn:0251-0790.2005.09.013
[11]WANG Huijiao,YUAN Shi,ZHAN Juhong,et al.Mechanisms of enhanced total organic carbon elimination from oxalic acid solutions by electro-peroxone process[J].Water Research,2015,80:20.DOI:10.1016/j.watres.2015.05.024
[12]XIA Guangsen,WANG Yujue,WANG Bin,et al.The competition between cathodic oxygen and ozone reduction and its role in dictating the reaction mechanisms of an electro-peroxone process[J].Water Research,2017,118:26.DOI:10.1016/j.watres.2017.04.005
[13]赵纯,张帅,周宇,等.阴极电场增强活性炭纤维[KG-*5]-[KG-*5]臭氧体系去除水中硝基苯[J].环境科学,2017,38(1):212 ZHAO Chun,ZHANG Shuai,ZHOU Yu,et al.Cathode electric field enhanced removal of nitrobenzene from aqueous solution based on activated carbon fibers (ACF)-ozone technique[J].Environmental Science,2017,38(1):212.DOI:10.13227/j.hjkx.201607054
[14]郑西强,刘群,陈云峰.活性炭纤维对水中微囊藻毒素的吸附性能[J].环境工程学报,2013,7(10):3802ZHENG Xiqiang,LIU Qun,CHEN Yunfeng.Adsorption performance of activated carbon fiber to microcystins in water[J].Chinese Journal of Environmental Engineering,2013,7(10):3802
[15]曲久辉,刘会娟.水处理电化学原理与技术[M].北京:科学出版社,2007QU Jiuhui,LIU Huijuan.Principles and techniques of water treatment electrochemistry[M].Beijing:Science Press,2007
[16]卢强.涂层钛电极的制备及其降解废水中硝基苯的研究[D].南京:南京理工大学,2011 LU Qiang.Study on preparation of Ti-coated electrode and its application in degradation of nitrobenzene in wastewater[D].Nanjing :Nanjing University of Science & Technology,2011
[17]张建华.镀铂钛电极的研究[J].广东有色金属学报,2000,10(2):108ZHANG Jianhua.Study on platinum-coated titanium electrode[J].Journal of Guangdong Non-Ferrous Metals,2000,10(2):108
[18]李彩霞,张素素,何平,等.掺杂金刚石电极及电化学应用研究进展[J].功能材料,2017,48(8):7LI Caixia,ZHANG Susu,HE Ping,et al.Research progress on doped diamond electrode and electrochemical application[J].Journal of Functional Materials,2017,48(8):7
[19]陈聪.新型镍电极电芬顿法预处理印染废水效能研究[D].哈尔滨:哈尔滨工业大学,2015CHEN Cong.Effectiveness research on using E-Fenton with new type of Ni electrode to pretreat dyeing printing wasterwater[D].Harbin:Harbin Institute of Technology,2015
[20]ISHIBASHI K I,FUJISHIMA A,WATANABE T,et al.Detection of active oxidative species in TiO2,photocatalysis using the fluorescence technique[J].Electrochemistry Communications,2000,2(3):207.DOI:10.1016/S1388-2481(00)00006-0
[21]MARTíNEZ-HUITLE C A,BRILLAS E.Decontamination of wastewaters containing synthetic organic dyes by electrochemical methods:A general review[J].Applied Catalysis B Environmental,2015,166/167(3/4):603.DOI:10.1016/j.apcatb.2008.09.017
[22]HU Jingjing,SUN Jie,YAN Junkun,et al.A novel efficient electrode material:Activated carbon fibers grafted by ordered mesoporous carbon[J].Electrochemistry Communications,2013,28(1):67.DOI:10.1016/j.elecom.2012.11.034
[23]WANG Aimin,QU Jiuhui,LIU Huijuan,et al.Mineralization of an azo dye Acid Red 14 by photoelectro-fenton process using an activated carbon fiber cathode[J].Applied Catalysis B Environmental,2008,84(3):393.DOI:10.1016/j.apcatb.2008.04.016
[24]王丽平.ACF/CNT复合材料的制备、表征及其吸附特性研究[D].长沙:中南大学,2012WANG Liping.Investigation on preparation,characterization and adsorption properties of ACF/CNT composites[D].Hunan:Central South University,2012
[25]中西香尔,索罗曼.红外光谱分析100例[M].王绪明,译.北京:科学出版社,1984NAKANISHI K,SOLOMON P H.100 cases were analyzed by infrared spectroscopy[M].WANG Xuming,translate.Beijing:Science Press,1984
[26]杨辉,刘豪,朱德力,等.活性炭纤维联合脱硫脱硝的机理分析[J].中国电机工程学报,2015,35(10):2495 YANG Hui,LIU Hao,ZHU Deli,et al.Mechanism of combined removal of SO2 and NO over activated carbon fibers[J].Proceedings of the CSEE,2015,35(10):2495
[27]刘辉,李平,魏雨,等.红外光谱技术在铁氧化物形成研究中的应用[J].河北师范大学学报(自然科学版),2005,29(3):272 LIU Hui,LI Ping,WEI Yu,et al.Application of IR spectra in the studies on the formation of iron (Hydr)oxides[J].Journal of Hebei Normal University (Natural Science Edition),2005,29(3):272