Enhanced Cr(VI) elimination from water by goethite-impregnated activated carbon coupled with weak electric field.

Bing Li Weiquan Li Qian Zuo Weizhao Yin Ping Li Jinhua Wu

Environ Res

School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, China; The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, China. Electronic address:

Published: May 2024

A weak electric field (WEF) was used to enhance the cycling of iron (Fe) within goethite-impregnated activated carbon, improving the removal of harmful chromium (Cr(VI)) from water.
The study found that the addition of AC helped in transferring electrons, promoting the conversion of Fe(III) to Fe(II), which effectively reduced Cr(VI) to less harmful Cr(III).
The WEF-enhanced system showed significantly better Cr(VI) elimination capacity and longer operational lifespan compared to traditional methods, making it a promising approach for water treatment.

A weak electric field (WEF, 2 mA cm) was employed to promote Fe(III)/Fe(II) cycle on goethite-impregnated activated carbon (FeOOH@AC) filled in a continuous-flow column for enhanced Cr(VI) elimination from water. Surficial analysis and Cr species distribution showed that α-FeOOH of 0.2-1 μm was successfully synthesized and evenly loaded onto AC. Electron transfer from WEF to α-FeOOH was facilitated with AC as electron shuttles, thereby boosting Fe(III) reduction in the α-FeOOH. The generated Fe(II) reduced Cr(VI) and the resultant Cr(III) subsequently precipitated with OH and Fe(III) to form Cr(OH) and (CrFe)(OH). Therefore, the WEF-FeOOH@AC column exhibited a much lower Cr(VI) migration rate of 0.0018 cm PV in comparison with 0.0037 cm PV of the FeOOH@AC column, equal to 104 % higher Cr(VI) elimination capacity and 90 % longer column service life-span. Additionally, under different Cr(VI) loadings by varying either seepage velocities or influent Cr(VI) concentrations, the WEF-FeOOH@AC column maintained 1.0-1.5 folds higher Cr(VI) elimination and 0.9-1.4 folds longer longevity than those of the FeOOH@AC column owing to the interaction between FeOOH@AC and WEF. Our research demonstrated that WEF-FeOOH@AC was a potential method to promote Cr(VI) elimination from water and offer an effective strategy to facilitate Fe(III)/Fe(II) cycle in iron oxides.

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http://dx.doi.org/10.1016/j.envres.2024.118253	DOI Listing

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