{"title":"Modulating Fe sites by La in porous MnFe2O4 for enhanced removal of ROX: Synergy of efficient adsorption and PMS activation","authors":"Yukun Si, Dandan Wang, Yuying Han, Congting Sun, Lanlan Xu, Mengfan Chen","doi":"10.1016/j.jhazmat.2024.136600","DOIUrl":null,"url":null,"abstract":"Catalytic-adsorption method is a promising strategy for degrading organoarsenic compounds and removing secondary inorganic arsenic. The method relies significantly on heterogeneous catalysts with selectively adsorption and enhanced peroxymonosulfate (PMS) activation capacity. In this study, active sites for selective adsorption and PMS activations were developed by modulating the Fe-sites in porous MnFe<sub>2</sub>O<sub>4</sub> through La-doping. Synchrotron radiation, EPR, and XPS characterizations confirmed the presence of oxygen vacancies, metal hydroxyl groups <img alt=\"triple bond\" src=\"https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/tbnd.gif\" style=\"vertical-align:middle\"/>M(Fe/Mn/La)-(OH) and the active Fe(II)/Mn(II,III), as well as the fine structure of La occupied sites. Theoretical calculations indicate that the generation of Vo would increase the local electron cloud density of La dopants, leading to the transfer of local electrons into the bulk phase. The electron transfer characteristics result in the raising the d-band center of MnFe<sub>2</sub>O<sub>4</sub> and lowering the Gibbs free energy of the intermediate state, thus promoting <sup>1</sup>O<sub>2</sub> generation. In 3% La-MnFe<sub>2</sub>O<sub>4</sub>/PMS system, 96% ROX (10<!-- --> <!-- -->mg/L) were removed within 35<!-- --> <!-- -->min with the secondary inorganic arsenic levels below 10 μg/L. The rate coefficients <em>k</em> for ROX removal in porous 3%La-MnFe<sub>2</sub>O<sub>4</sub>/PMS is 4.05 times higher than that in MnFe<sub>2</sub>O<sub>4</sub>/PMS. ROX was effectively removed in different water matrices (Liao River, Hun River, and groundwater), demonstrating the practical application potential of 3% La-MnFe<sub>2</sub>O<sub>4</sub>/PMS system. Under continuous flow conditions, an average of 97.9% and 87.3% of ROX were removed from ultrapure water and groundwater, respectively, over a 10-hour continuous run. This study highlights the high-performance spinel La-MnFe<sub>2</sub>O<sub>4</sub> for the synergistic enhancement of PMS activation, secondary arsenic adsorption, and improved mass transfer, contributing to green and safe water treatment strategies.","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"231 1","pages":""},"PeriodicalIF":12.2000,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hazardous Materials","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1016/j.jhazmat.2024.136600","RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
引用次数: 0
Abstract
Catalytic-adsorption method is a promising strategy for degrading organoarsenic compounds and removing secondary inorganic arsenic. The method relies significantly on heterogeneous catalysts with selectively adsorption and enhanced peroxymonosulfate (PMS) activation capacity. In this study, active sites for selective adsorption and PMS activations were developed by modulating the Fe-sites in porous MnFe2O4 through La-doping. Synchrotron radiation, EPR, and XPS characterizations confirmed the presence of oxygen vacancies, metal hydroxyl groups M(Fe/Mn/La)-(OH) and the active Fe(II)/Mn(II,III), as well as the fine structure of La occupied sites. Theoretical calculations indicate that the generation of Vo would increase the local electron cloud density of La dopants, leading to the transfer of local electrons into the bulk phase. The electron transfer characteristics result in the raising the d-band center of MnFe2O4 and lowering the Gibbs free energy of the intermediate state, thus promoting 1O2 generation. In 3% La-MnFe2O4/PMS system, 96% ROX (10 mg/L) were removed within 35 min with the secondary inorganic arsenic levels below 10 μg/L. The rate coefficients k for ROX removal in porous 3%La-MnFe2O4/PMS is 4.05 times higher than that in MnFe2O4/PMS. ROX was effectively removed in different water matrices (Liao River, Hun River, and groundwater), demonstrating the practical application potential of 3% La-MnFe2O4/PMS system. Under continuous flow conditions, an average of 97.9% and 87.3% of ROX were removed from ultrapure water and groundwater, respectively, over a 10-hour continuous run. This study highlights the high-performance spinel La-MnFe2O4 for the synergistic enhancement of PMS activation, secondary arsenic adsorption, and improved mass transfer, contributing to green and safe water treatment strategies.
期刊介绍:
The Journal of Hazardous Materials serves as a global platform for promoting cutting-edge research in the field of Environmental Science and Engineering. Our publication features a wide range of articles, including full-length research papers, review articles, and perspectives, with the aim of enhancing our understanding of the dangers and risks associated with various materials concerning public health and the environment. It is important to note that the term "environmental contaminants" refers specifically to substances that pose hazardous effects through contamination, while excluding those that do not have such impacts on the environment or human health. Moreover, we emphasize the distinction between wastes and hazardous materials in order to provide further clarity on the scope of the journal. We have a keen interest in exploring specific compounds and microbial agents that have adverse effects on the environment.