首页|两电子水氧化反应抑制掺硼金刚石电极氧化有机物过程中氯酸盐和高氯酸盐的生成

两电子水氧化反应抑制掺硼金刚石电极氧化有机物过程中氯酸盐和高氯酸盐的生成

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掺硼金刚石(BDD)具有羟基自由基(·OH)产率高、稳定性好的优点,作为电极材料被广泛应用于难降解有机物的处理.但BDD电极在处理含氯介质时产生的高毒性副产物——氯酸盐(ClO3-)和高氯酸盐(ClO4-)是限制其广泛应用的关键障碍之一.本文通过两电子水氧化反应(2e-WOR)来控制BDD电极氧化过程中ClO3-和ClO4-的产生.同时,以一种广泛使用的除草剂——阿特拉津(ATZ)为模型污染物,探究2e-WOR对有机物降解效果的影响.研究表明,NaHCO3作为电解质可以有效催化BDD电极上的2e-WOR,进而降低电解过程中活性氯、ClO3-和ClO4-的浓度.添加10mmol/LNaHCO3后,活性氯浓度下降了 60.3%,ClO3-和ClO4-的生成速率常数分别下降10.2%和39.2%.当添加50mmol/L和100mmol/L NaHCO3时,活性氯的生成被完全抑制,ClO3-的生成速率常数分别降低了 60.0%和72.5%,ClO4-的生成速率常数分别降低了 66.2%和72.6%.2e-WOR对ClO3-和ClO4-抑制作用的机理有两个方面:①2e-WOR产生的H2O2与活性氯反应,降低了关键中间物的浓度,进而控制了 ClO3-和ClO4-的生成;②HCO3-与ClO3-竞争·OH反应,降低了 ClO3-向ClO4-的转化速率.研究发现,适量添加NaHCO3有利于ATZ的降解.添加10mmol/L和50mmol/L NaHCO3后,ATZ的降解动力学常数分别提高了 27.2%和53.8%.甲醇猝灭实验表明,NaHCO3的添加促进了溶液本体中ATZ的降解.
Two-electron water oxidation reaction assisted electrochemical oxidation with boron doped diamond to inhibit ClO3- and ClO4- formation
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.

electrochemistryelectrolysiswaste waterdegradationboron doped diamond electrodechlorateperchlorate

丁嘉、吴文琦、李鹏程

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上海市政工程设计研究总院(集团)有限公司,上海 200082

浙江大学环境与资源学院,浙江杭州 310012

国家电网杭州供电公司,浙江杭州 310000

电化学 电解 废水 降解 掺硼金刚石电极 氯酸盐 高氯酸盐

2024

化工进展
中国化工学会,化学工业出版社

化工进展

CSTPCD北大核心
影响因子:1.062
ISSN:1000-6613
年,卷(期):2024.43(4)
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