Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Jiangxi Academy of Eco-Environmental Sciences and Planning, Nanchang 330000, China.
J Hazard Mater. 2023 Oct 5;459:132178. doi: 10.1016/j.jhazmat.2023.132178. Epub 2023 Jul 28.
Sustainable and cost-effective semiconducting photocathodes of microbial electrolysis cells (MECs) are attractively promising for efficient treatment of actual industrial wastewaters containing complex recalcitrant organics and multiple heavy metals. Herein carbon dots/graphitic carbon nitride (CDs/g-CN) photocathodes were employed to achieve efficient treatment of actual etching terminal wastewater (ETW) with simultaneous H production in MECs, allowing the effluent meeting national discharge standards (GB39731-2020). The progressively in-situ deposited heavy metals on the CDs/g-CN photocathodes, formed as metal oxides/CDs/g-CN after simple calcinations, further enhanced the ETW treatment (recalcitrant organics mineralization: 42.2 mg/L/h vs. 35.5 mg/L/h; heavy metal removal: Cu(II): 9.9 mg/L/h vs. 7.4 mg/L/h, Ni(II): 4.7 mg/L/h vs. 3.5 mg/L/h, Zn(II): 0.7 mg/L/h vs. 0.5 mg/L/h) and H production (0.1138 m/m/d vs. 0.0662 m/m/d). The importation of heavy metals, formed as metal oxides/CDs/g-CN altered the proportion of reactive oxidative species and thus promoted mineralization of recalcitrant organics, besides offering additional electrochemical removal of heavy metals with simultaneous more H production. This study demonstrates a new feasible protocol for achieving efficient ETW treatment, and gives a comprehensive appreciation of the effect of in-situ deposited heavy metals on the CDs/g-CN photocathodes, which has a profound effect on subsequent ETW treatment with simultaneous H production.
微生物电解池（MEC）中可持续且具有成本效益的半导体光阴极对于有效处理含有复杂难降解有机物和多种重金属的实际工业废水具有很大的前景。本文采用碳点/石墨相氮化碳（CDs/g-CN）光阴极实现了在 MEC 中同时高效处理实际的刻蚀终端废水（ETW）并产氢，使出水达到国家排放标准（GB39731-2020）。重金属逐渐原位沉积在 CDs/g-CN 光阴极上，经过简单煅烧后形成金属氧化物/CDs/g-CN，进一步增强了 ETW 的处理效果（难降解有机物矿化：42.2mg/L/h 比 35.5mg/L/h；重金属去除：Cu(II)：9.9mg/L/h 比 7.4mg/L/h，Ni(II)：4.7mg/L/h 比 3.5mg/L/h，Zn(II)：0.7mg/L/h 比 0.5mg/L/h）和产氢（0.1138m/m/d 比 0.0662m/m/d）。重金属的引入形成了金属氧化物/CDs/g-CN，改变了活性氧化物种的比例，从而促进了难降解有机物的矿化，同时提供了电化学去除重金属的附加作用，从而产生更多的氢气。本研究为实现高效 ETW 处理提供了一种新的可行方案，并全面评估了原位沉积重金属对 CDs/g-CN 光阴极的影响，这对随后的 ETW 处理和同步产氢具有深远的影响。
