Stabilisation of nanoscale zero-valent iron with biochar for enhanced transport and in-situ remediation of hexavalent chromium in soil

Su, Huijie; Fang, Zhanqiang; Tsang, Pokeung Eric; Fang, Jianzhang; Zhao, Dongye

Stabilisation of nanoscale zero-valent iron with biochar for enhanced transport and in-situ remediation of hexavalent chromium in soil

2016

Su, Huijie | Fang, Zhanqiang | Tsang, Pokeung Eric | Fang, Jianzhang | Zhao, Dongye

In this study, a biochar-supported nanoscale zero-valent iron (nZVI@BC) material was used for in situ remediation of hexavalent chromium-contaminated soil. Sedimentation tests and column experiments were used to compare the stability and mobility of nZVI@BC and bare-nZVI. The immobilisation efficiency of chromium, toxic effect of chromium and the content of iron were assessed through leaching tests and pot experiments. Sedimentation tests and transport experiments indicated that nZVI@BC with nZVI to BC mass ratio of 1:1 exhibited better stability and mobility than that of bare-nZVI. The immobilisation efficiency of Cr(VI) and Crtotal was 100% and 92.9%, respectively, when the soil was treated with 8 g/kg of nZVI@BC for 15 days. Moreover, such remediation effectively reduced the leachability of Fe caused by bare-nZVI. In addition, pot experiments showed that such remediation reduced the phytotoxicity of Cr and the leachable Fe and was favourable for plant growth.

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