摘要
以阳离子型染料亚甲基蓝(MB)废水为研究对象,采用钴介体电催化(MEO/Co(Ⅱ))与PO4^3-协同作用体系(简称PO4^3--MEO/Co(Ⅱ)体系),进行MB电催化降解实验,研究Co2+浓度、电流密度、pH值、电解质浓度等因素对PO4^3--MEO/Co(Ⅱ)体系电催化降解MB的效果,并对其分解产物及机理进行了分析与探讨.结果表明:①PO4^3--MEO/Co(Ⅱ)体系主要的氧化性中间产物为Co^3+,同时存在少量羟基自由基及过磷酸盐.②PO4^3-与MEO/Co(Ⅱ)体系之间具有明显的协同催化作用.PO4^3--MEO/Co(Ⅱ)体系在40 min内对MB的降解率高达100%,是钴介电体系降解率的1.2倍,直接电化学氧化体系降解率的5倍.③Co2+浓度、电流密度及pH值对PO4^3--MEO/Co(Ⅱ)体系氧化性能影响较大,而PO4^3-浓度、电解质浓度对PO4^3--MEO/Co(Ⅱ)体系的氧化性能影响较小.④PO4^3--MEO/Co(Ⅱ)体系对MB的降解过程为:先从MB分子的N-C连接处断键,形成吩噻嗪、2-氨基-5-(N-甲基甲酰胺)苯磺酸及N1,N1-二甲基-1,4二氨苯等物质;然后将其降解为苯胺、苯酚、苯磺酸等;最终分解成CO2和水等无机物.⑤PO4^3--MEO/Co(Ⅱ)体系对MB的降解机理为:通过铂钛电极直接电催化,以及Co^3+、过磷酸根、羟基自由基的间接氧化,其中,起主导作用的是Co3+的电催化氧化.
To take cationic dye methylene blue(MB) wastewater as an example to conduct electrocatalysis degradation experiments by using synergy reaction system of PO4^3- and cobalt ions electrocatalysis(MEO/Co(Ⅱ) system)(for short: PO4^3--MEO/Co(Ⅱ)) system).This study investigated the electrocatalysis degradation effect of PO4^3--MEO/Co(Ⅱ) system on MB under different conditions by changing the factors below: Co^2+ concentration, current density, pH value, concentration of electrolyte and etc.. In the meantime, the degradation products and the breakdown mechanism were discussed. The results showed that ① The main oxidizing intermediate products were Co3+ ions, and a small amount of hydroxyl radicals and phosphate existing in the PO4^3--MEO/Co(Ⅱ) system. ②There was an obvious synergistic catalytic role happening in PO4^3- and MEO/Co(Ⅱ) system. The degradation rate of PO4^3--MEO/Co(Ⅱ) system on MB within 40 minutes was as high as 100%. Its degradation rate was five times that of the direct electrocatalysis oxidation system and 1.2 times that of MEO/Co(Ⅱ) system.③ The concentration of cobalt ion, current density and pH value had a great impact on oxidation performance in the PO4^3--MEO/Co(Ⅱ) system. While the impact of the concentration of PO4^3- and electrolyte on oxidation performance was relatively weaker. ④ The possible degradation process of MB in the PO■-MEO/Co(Ⅱ) system was as follows: Firstly, the bond in the N-C junction of the MB molecule was broken and intermediate substances were produced, such as phenothiazine, 2-amino-5-(N-methyl formamide) benzene sulfonic acid and N1,N1-dimethyl-1,4 diaminobenzene. Then the intermediates would be degraded to aniline, phenol and benzene sulfonic acid, and eventually decomposed into inorganic substances such as CO2 and water. ⑤The degradation mechanism of PO4^3--MEO/Co(Ⅱ) system on MB was the combination of direct electricatalysis on the platinum titanium electrode, with indirect oxidation of the intermediates oxidants like Co^3+, perphosphoric acid root and hydroxyl radical. The dominant mechanism was the electrocatalysis and its oxidation of Co^3+.
作者
李冬梅
张权
喻子真
梁奕聪
冯力
李栩灏
李绍秀
LI Dongmei;ZHANG Quan;YU Zizhen;LIANG Yicong;FENG Li;LI Xuhao;LI Shaoxiu(Faculty of Civil and Transportation Engineering,Guangdong University of Technology,Guangzhou 510006;Guangzhou Alcanta International College,Guangzhou 511458)
出处
《环境科学学报》
CAS
CSCD
北大核心
2020年第4期1223-1233,共11页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.51108094,51378129)
广东省自然科学基金(No.2017A030313321,2015A030313494)
广东省高教厅-普通高校特色创新类项目(No.2016KTSCX035)。
作者简介
责任作者:李冬梅(1972-),女,E-mail:1170951456@qq.com。
