Shujie Zheng, Jiani Yao, Ying Huang, Jiaqi Ren, Yang Hou, Bin Yang, Lecheng Lei, Jianjie Fu, Abdulaziz Al-Anazi, Guibin Jiang, Zhongjian Li
{"title":"氯离子对 Cr(III)-EDTA 电化学解络合和降解的影响:HO- 和 RCS 的反应机制。","authors":"Shujie Zheng, Jiani Yao, Ying Huang, Jiaqi Ren, Yang Hou, Bin Yang, Lecheng Lei, Jianjie Fu, Abdulaziz Al-Anazi, Guibin Jiang, Zhongjian Li","doi":"10.1016/j.jhazmat.2024.135636","DOIUrl":null,"url":null,"abstract":"<p><p>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<sup>-</sup> significantly improves the efficiency of electrochemically removing Cr(III)-organic complexes through generated reactive chlorine species (RCS). In the electrochemical chlorine (EC/Cl<sub>2</sub>) process, extensive experimentation revealed that ClO<sup>•</sup> plays a dominant role in the degradation of Cr(III)-EDTA, surpassing the effects of free chlorine, direct electrooxidation, HO<sup>•</sup>, and other RCS. Density functional theory calculations indicated that RCS, primarily Cl<sup>•</sup> and ClO<sup>•</sup>, preferentially oxidize the ligand in Cr(III)-EDTA via H-abstraction, whereas HO<sup>•</sup> 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<sub>2</sub> were also assessed, including Cl<sup>-</sup> concentration, current density, and pH. Real industrial wastewater was employed as a reaction matrix to evaluate the application of the EC/Cl<sub>2</sub> 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<sup>-</sup>-containing industrial wastewater.</p>","PeriodicalId":94082,"journal":{"name":"Journal of hazardous materials","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Impacts of chloride ions on the electrochemical decomplexation and degradation of Cr(III)-EDTA: Reaction mechanisms of HO<sup>•</sup> and RCS.\",\"authors\":\"Shujie Zheng, Jiani Yao, Ying Huang, Jiaqi Ren, Yang Hou, Bin Yang, Lecheng Lei, Jianjie Fu, Abdulaziz Al-Anazi, Guibin Jiang, Zhongjian Li\",\"doi\":\"10.1016/j.jhazmat.2024.135636\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>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<sup>-</sup> significantly improves the efficiency of electrochemically removing Cr(III)-organic complexes through generated reactive chlorine species (RCS). In the electrochemical chlorine (EC/Cl<sub>2</sub>) process, extensive experimentation revealed that ClO<sup>•</sup> plays a dominant role in the degradation of Cr(III)-EDTA, surpassing the effects of free chlorine, direct electrooxidation, HO<sup>•</sup>, and other RCS. Density functional theory calculations indicated that RCS, primarily Cl<sup>•</sup> and ClO<sup>•</sup>, preferentially oxidize the ligand in Cr(III)-EDTA via H-abstraction, whereas HO<sup>•</sup> 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<sub>2</sub> were also assessed, including Cl<sup>-</sup> concentration, current density, and pH. Real industrial wastewater was employed as a reaction matrix to evaluate the application of the EC/Cl<sub>2</sub> 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<sup>-</sup>-containing industrial wastewater.</p>\",\"PeriodicalId\":94082,\"journal\":{\"name\":\"Journal of hazardous materials\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-10-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of hazardous materials\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1016/j.jhazmat.2024.135636\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2024/8/25 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of hazardous materials","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1016/j.jhazmat.2024.135636","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/8/25 0:00:00","PubModel":"Epub","JCR":"","JCRName":"","Score":null,"Total":0}
Impacts of chloride ions on the electrochemical decomplexation and degradation of Cr(III)-EDTA: Reaction mechanisms of HO• and RCS.
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/Cl2) 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/Cl2 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/Cl2 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.