Remediation of lead-contaminated sediment by biochar-supported nano-chlorapatite: Accompanied with the change of available phosphorus and organic matters
2018
Huang, Danlian | Deng, Rui | Wan, Jia | Zeng, Guangming | Xue, Wenjing | Wen, Xiaofeng | Zhou, Chengyun | Hu, Liang | Liu, Xigui | Xu, Piao | Guo, Xueying | Ren, Xiaoya
Some rivers in China have been seriously contaminated due to the discharge of lead (Pb) smelting wastewater. In this study, biochar-supported nano-chlorapatite (BC-nClAP) was synthesized to immobilize Pb in contaminated sediment. The remediation effect of BC-nClAP on Pb-contaminated sediment was evaluated through batch experiments and the materials were characterized by x-ray diffraction, scanning electron microscope, Brunner-Emmet-Teller and electronic differential system. It was found that BC-nClAP can transform Pb effectively from labile fraction into stable fraction with a maximum transformation efficiency increasing to 94.1% after 30 days of treatment, and the stabilization efficiency of toxicity characteristic leaching procedure reached 100% only after 16 days of treatment. The content of available phosphorus (AP) in the sediments treated by BC-nClAP was much less than that treated by nClAP, which indicated a lower risk of eutrophication and suggested the dissolution-precipitation mechanism involved in Pb immobilization. BC-nClAP presented the best immobilization efficiency of Pb and the content of organic matters in BC-nClAP treated samples increased the most, thus the OM might play an important role during the Pb immobilization.
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