Zheng Shujie, Yao Jiani, Huang Ying, Ren Jiaqi, Hou Yang, Yang Bin, Lei Lecheng, Fu Jianjie, Al-Anazi Abdulaziz, Jiang Guibin, Li Zhongjian
School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China.
Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China; Zhejiang Academy of Science & Technology for Inspection & Quarantine, Zhejiang, China.
J Hazard Mater. 2024 Oct 5;478:135636. doi: 10.1016/j.jhazmat.2024.135636. Epub 2024 Aug 25.
The removal of Cr(III)-organic complexes, encompassing both decomplexation and ligand degradation, presents significant challenges in industrial wastewater treatment. As one of the most common anions in wastewater, Cl significantly improves the efficiency of electrochemically removing Cr(III)-organic complexes through generated reactive chlorine species (RCS). In the electrochemical chlorine (EC/Cl) process, extensive experimentation revealed that ClO plays a dominant role in the degradation of Cr(III)-EDTA, surpassing the effects of free chlorine, direct electrooxidation, HO, and other RCS. Density functional theory calculations indicated that RCS, primarily Cl and ClO, preferentially oxidize the ligand in Cr(III)-EDTA via H-abstraction, whereas HO trends to attack the Cr atom through electron transfer. The influential factors on the degradation efficiency of Cr(III)-EDTA, Cr(VI) yield, and total organic carbon removal in EC/Cl were also assessed, including Cl concentration, current density, and pH. Real industrial wastewater was employed as a reaction matrix to evaluate the application of the EC/Cl process for treating Cr(III)-EDTA, accompanied by energy efficiency calculations. Additionally, a two-chamber reactor was established to simultaneously oxidize Cr(III)-EDTA at the anode and reduce Cr(VI) at the cathode. This study provided insight into developing RCS-dominated AOPs to effectively decomplex and decompose organic Cr(III)-complexes in Cl-containing industrial wastewater.
去除Cr(III)-有机络合物，包括解络合和配体降解，在工业废水处理中面临重大挑战。作为废水中最常见的阴离子之一，Cl通过生成的活性氯物种（RCS）显著提高了电化学去除Cr(III)-有机络合物的效率。在电化学氯化（EC/Cl）过程中，大量实验表明，ClO在Cr(III)-EDTA的降解中起主导作用，超过了游离氯、直接电氧化、HO和其他RCS的影响。密度泛函理论计算表明，RCS主要是Cl和ClO，优先通过氢原子提取氧化Cr(III)-EDTA中的配体，而HO则倾向于通过电子转移攻击Cr原子。还评估了EC/Cl中影响Cr(III)-EDTA降解效率、Cr(VI)产率和总有机碳去除的因素，包括Cl浓度、电流密度和pH值。以实际工业废水为反应基质，评估EC/Cl工艺处理Cr(III)-EDTA的应用，并进行了能量效率计算。此外，建立了双室反应器，在阳极同时氧化Cr(III)-EDTA，在阴极还原Cr(VI)。本研究为开发以RCS为主导的高级氧化工艺以有效解络合和分解含Cl工业废水中的有机Cr(III)络合物提供了见解。
