期刊
CHEMOSPHERE
卷 194, 期 -, 页码 360-369出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2017.11.182
关键词
Iron sulfide; Biochar; Cr(Vl) immobilization; Reduced toxicity; Soil remediation
资金
- Tianjin Research Program of Application Foundation and Advanced Technology [15JCYBJC53800]
- National Natural Science Foundation of China [41503085, 41473070]
- Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education of China [[2015]1098]
- National Water Pollution Control and Treatment Science and Technology Major Project [2015ZX07203-011-06]
- 863 achievement transformation program in Tianjin [14RCHZSF00144]
Biochar supported carboxymethyl cellulose (CMC)-stabilized nanoscale iron sulfide (FeS) composite (CMC-FeS@biochar) was prepared and tested for immobilization of hexavalent chromium Cr(Vl) in soil. Results of UV vis and transmission electron microscopy (TEM) showed that the backbone of biochar suppressed the aggregation of FeS, resulting in smaller particle size and more sorption sites than bare FeS. The composite at a dosage of 2.5 mg per gram soil displayed an enhanced Cr(VI) immobilization efficiency (a 94.7% reduction in the toxicity characteristic leaching procedure (TCLP) based leachability and a 95.6% reduction in the CaCl2 extraction) compared to plain biochar and bare FeS. Sequential extraction procedure (SEP) and X-ray photoelectron spectroscopy (XPS) analysis suggested that CMC-FeS@biochar promoted the conversion of more accessible Cr (exchangeable and carbonate-bound fractions) into the less accessible forms (iron-manganese oxides-bound, organic material-bound, and residual fractions) to reduce the toxicity of Cr(VI) and that surface sorption and reduction were dominant mechanisms for Cr(VI) immobilization. CMC-FeS@biochar greatly reduced the bioavailability of Cr(VI) to wheat and earthworms (Eisenia fetida). Moreover, the application of CMC-FeS@biochar enhanced soil organic matter content and microbial activity. This work highlighted the potential of CMC-FeS@biochar composite as a low-cost, green, and effective amendment for immobilizing Cr(VI) in contaminated soils and improving soil properties. (C) 2017 Elsevier Ltd. All rights reserved.
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