摘要
Abstract
Boron-doped diamond(BDD)electrodes have been widespread applied in the treatment of refractory organic pollutants for their advantages of efficient production of hydroxyl radical(·OH)and high stability.However,chlorate(ClO3-)and perchlorate(ClO4-),which are toxic by-products produced in the process of electrolysis of chlorine-containing medium,is one of the key obstacles to the application of BDD electrodes.In this work,we developed a method to use two-electron water oxidation reaction(2e-WOR)assisted electrochemical oxidation with BDD to inhibit ClO3- and ClO4- formation in the water treatment,meanwhile,studied the degradation effects of atrazine(ATZ),which was one of the most popular herbicides as a model organic pollutant.The results indicated that the presence of NaHCO3 effectively promoted the production of H2O2 by 2e-WOR,which decreased the concentration of active chlorate(AC),ClO3- and ClO4-.The concentration of AC was reduced by 60.3％in the presence of 10mmol/L NaHCO3,the suppression rates of ClO3-and ClO4- were 10.2％and 39.2％.Adding 50mmol/L and100mmol/L NaHCO3 resulted in a decrease of 60.0％and 72.50％in the ClO3-accumulation rate and 66.2％and 72.60％in the ClO4- accumulation rate.The mechanism of suppression of ClO3-and ClO4- by 2e-WOR was as followed.Firstly,H2O2 which was produced by 2e WOR decreased the concentration of the key intermediate—AC by reacting with it,which reduced the concentration of ClO3-and ClO4-.Secondly,HCO3 competed with ClO3-for OH,then reduced the conversion rate of ClO3-to ClO4-.The appropriate concentration of NaHCO3 was conducive to the degradation of ATZ.The addition of NaHCO3 was improved by 27.2％and 53.8％in the presence of 10mmol/L and 50mmol/L NaHCO3,Scavenging experiment indicated that the addition of NaHCO3 was beneficial to the improvement of degradation of ATZ in the homogeneous solution.关键词
电化学/电解/废水/降解/掺硼金刚石电极/氯酸盐/高氯酸盐Key words
electrochemistry/electrolysis/waste water/degradation/boron doped diamond electrode/chlorate/perchlorate分类
资源环境
