摘要
采用掺硼金刚石(BDD)阳极和Ti阴极构建动态电活化过二硫酸盐(PDS)体系,对腐殖酸(HA)存在情况下含溴副产物的转化情况进行研究。通过循环伏安扫描、自由基猝灭实验等方法对电活化体系的作用机理和含溴副产物的生成路径进行分析;考察了初始PDS投加量、电流密度及初始pH对电活化PDS体系中含溴副产物生成规律的影响。结果表明,当反应溶液中HA浓度为3.0 mg/L(以TOC计)、溴离子质量浓度为1.0 mg/L、PDS浓度为5.0 mmol/L、电流密度为20 mA/cm^(2)、pH值为7.0时,体系内均检测到溴酸盐和溴代有机副产物(Br-DBPs)的生成,120 min内最高分别生成4.11μmol/L和1.02μmol/L;体系内生成的复合自由基氧化剂(OH·和SO4^(·-))是含溴无机、有机副产物生成转化的动因。增大PDS投加量、提高活化电流密度,均可一定程度增加溶液内活性物质的生成量,提升电活化体系的氧化能力,从而加速Br-DBPs生成并同步矿化的反应过程;酸性反应环境有利于控制含溴副产物生成总量,但也使得体系内Br-DBPs(特别是溴代乙酸)具有更高的生成趋势。实际使用时,操作条件应综合处理效率、运行成本、健康风险等因素合理确定操作条件。
The electrochemically activated persulfate(PDS)system was constructed with boron-doped diamond(BDD)anode and Ti cathode to study the transformation of bromide in the presence of humic acid(HA).The mechanism of the electroactive system and the generation path of brominated by-products were analyzed through scanning cyclic voltammetry and free radical quenching experiments.The effects of initial PDS dosage,current density,and initial pH on the formation of brominated by-products in the electroactive PDS system were investigated.The results show that bromate and brominated organic by-products(Br-DBPs)were detected in the system when HA concentration in the reaction solution was 3.0 mg/L(in TOC),bromine ion concentration was 1.0 mg/L,PDS concentration was 5.0 mmol/L,current density was 20 mA/cm^(2),and pH was 7.0 in the reaction solution,and the highest concentration was 4.11 and 1.02μmol/L,respectively,within 120 min.The transformation of bromine was mainly caused by the complex radical oxidants(OH·and SO4^(·-))produced in the system.With the increase of PDS dosage and activation current density,the production of active substances in the solution was increased within a certain range,and the oxidizability of the electrical activation system was improved.Thus,the reaction process of Br-DBPs generation and synchronous mineralization was accelerated.The optimmum pH range for controlling the total production of brominated byproducts was acidic;however,Br-DBPs(especially bromoacetic acid)also showed a higher generation trend in acidic reaction environment.Therefore,in actual use,the operating conditions should be reasonably determined by considering the factors such as degradation efficiency,operating cost,and health risks of produced water.
作者
张冬艺
张峰
李红艳
王朝旭
崔佳丽
崔建国
ZHANG Dongyi;ZHANG Feng;LI Hongyan;WANG Chaoxu;CUI Jiali;CUI Jianguo(College of Environmental Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Municipal Engineering Graduate Student Education Innovation Center,Taiyuan 030024,China)
出处
《太原理工大学学报》
CAS
北大核心
2021年第2期177-185,共9页
Journal of Taiyuan University of Technology
基金
国家自然科学青年基金资助项目(51408397)
山西省自然科学基金资助项目(201801D121275,201701D121126)
山西省社会发展科技攻关项目(201803D31046)。
关键词
电活化
过二硫酸盐
硫酸根自由基
羟基自由基
含溴副产物
electrochemically activated
persulfate
sulfate radical
hydroxyl radical
brominated by-products
