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Improved Electron Efficiency of Zero-Valent Iron towards Cr(VI) Reduction after Sequestering in Al2O3 Microspheres
Wang, Chuan1; Wang, Sha2,3; Song, Cheng2,3; Liu, Hong2,3; Yang, Jingxin1
2022-07-01
摘要Zero-valent iron (ZVI) is widely used for groundwater remediation, but suffers from high electron consumption because of its free contact with non-target substrates such as O-2. Here, ZVI-ALOX particles were prepared via in situ NaBH4 aqueous-phase reduction of ferrous ions (Fe2+) preabsorbed into Al2O3 microspheres. The electron efficiency (EE) and long-term performance of the material were improved by sequestering ZVI in the interspace of the Al2O3 microspheres (ZVI-ALOX). During long-term (350 days) continuous flow, Cr(VI) was removed to below the detection limit for over 23 days. Based on the high reactivity of ZVI towards Cr(VI), the EE of ZVI-ALOX was evaluated by measuring its Cr(VI) removal efficiency at neutral pH and comparing it with that of ZVI. The results showed that the EE of ZVI-ALOX during long-term continuous flow could reach 39.1%, which was much higher than that of ZVI (8.68%). The long-term continuous flow results also demonstrated that treatment of the influent solution achieved higher EE values than in the batch mode, where the presence of dissolved oxygen reduced EE values. At lower pollutant concentrations, the sequestering of ZVI was beneficial to its performance and long-term utility. In addition, measurement of the acute toxicity of treated column effluent using the indicator organism Photobacterium phosphoreum T-3 showed that ZVI-ALOX could reduce the toxicity of 5 mg/L Cr(VI) solution by similar to 70% in 350 d. The results from this study provide a basis for the development of permeable reactive barriers for groundwater remediation based on sequestered ZVI.
关键词electron efficiency zero-valent iron ZVI sequestered Al2O3 composite
DOI10.3390/ijerph19148367
发表期刊INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
卷号19期号:14页码:10
通讯作者Yang, Jingxin(yangjx@gzhu.edu.cn)
收录类别SCI
WOS记录号WOS:000832141500001
语种英语