FeS–biochar and Zn(0)–biochar for remediation of redox-reactive contaminants |
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Authors: | Yong-Deuk Seo Seok-Young Oh Rajesh Rajagopal Kwang-Sun Ryu |
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Institution: | Department of Civil and Environmental Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610 South Korea, Fax: +82-52-259-2629, +82-52-259-2752 ; Department of Chemistry, University of Ulsan, Ulsan 44610 South Korea |
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Abstract: | To enhance the removal of redox-reactive contaminants, biochars including FeS and Zn(0) were developed via pyrolysis. These biochars significantly promoted the removal of 2,4-dichlorophenol (DCP) by means of sorption and reduction. Compared to direct reduction with FeS and Zn(0), the formation of reduction intermediates and product was enhanced from 21% and 22% of initial DCP concentration to 41% and 52%, respectively. 2,4-Dinitrotoluene (DNT), chromate (CrO42−) and selenate (SeO42−) were also reductively transformed to reduction products (e.g., 2,4-diaminotoluene DAT], Cr3+, and selenite SeO32−]) after they sorbed onto the biochars including FeS and Zn(0). Mass recovery as DAT, Cr3+ and selenite was 4–20%, 1–3%, and 10–30% under the given conditions. Electrochemical and X-ray analyses confirmed the reduction capability of the biochars including FeS and Zn(0). Fe and S in the FeS–biochar did not effectively promote the reductive transformation of the contaminants. Contrastingly, the stronger reducer Zn(0) yielded faster reductive transformation of contaminants over the Zn(0)-containing biochar, while not releasing high concentrations of Zn2+ into the aqueous phase. Our results suggest that biochars including Zn(0) may be suitable as dual sorbents/reductants to remediate redox-reactive contaminants in natural environments.To enhance the removal of redox-reactive contaminants, biochars including FeS and Zn(0) were developed via pyrolysis. |
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