Department of Environmental Engineering, Chosun University, Gwangju 61452, Republic of Korea.
Department of Civil and Environmental Engineering, Pusan National University, Busan 46241, Republic of Korea.
Chemosphere. 2018 May;199:459-467. doi: 10.1016/j.chemosphere.2018.01.090. Epub 2018 Feb 3.
Lead (Pb) and zinc (Zn) contaminated rice paddy soil was stabilized using natural (NSF) and calcined starfish (CSF). Contaminated soil was treated with NSF in the range of 0-10 wt% and CSF in the range of 0-5 wt% and cured for 28 days. Toxicity characteristic leaching procedure (TCLP) test was used to evaluate effectiveness of starfish treatment. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analyses were conducted to investigate the mechanism responsible for effective immobilization of Pb and Zn. Experimental results suggest that NSF and CSF treatments effectively immobilize Pb and Zn in treated rice paddy soil. TCLP levels for Pb and Zn were reduced with increasing NSF and CSF dosage. Comparison of the two treatment methods reveals that CSF treatment is more effective than NSF treatment. Leachability of the two metals is reduced approximately 58% for Pb and 51% for Zn, upon 10 wt% NSF treatment. More pronounced leachability reductions, 93% for Pb and 76% for Zn, are achieved upon treatment with 5 wt% CSF. Sequential extraction results reveal that NSF and CSF treatments of contaminated soil generated decrease in exchangeable/weak acid Pb and Zn soluble fractions, and increase of residual Pb and Zn fractions. Results for the SEM-EDX sample treated with 5 wt% CSF indicate that effective Pb and Zn immobilization is most probably associated with calcium silicate hydrates (CSHs) and calcium aluminum hydrates (CAHs).
利用天然沸石（NSF）和煅烧海星（CSF）稳定含铅（Pb）和锌（Zn）的水稻田污染土壤。用 NSF 处理污染土壤，其用量范围为 0-10wt%，CSF 用量范围为 0-5wt%，并养护 28 天。采用毒性特征浸出程序（TCLP）试验来评价海星处理的效果。采用扫描电子显微镜-能谱（SEM-EDX）分析来研究有效固定 Pb 和 Zn 的机理。实验结果表明，NSF 和 CSF 处理可有效固定处理后的水稻田土壤中的 Pb 和 Zn。随着 NSF 和 CSF 用量的增加，TCLP 中 Pb 和 Zn 的水平降低。两种处理方法的比较表明，CSF 处理比 NSF 处理更有效。经 10wt% NSF 处理后，两种金属的浸出率分别降低了约 58%（Pb）和 51%（Zn）。经 5wt% CSF 处理后，浸出率分别降低了 93%（Pb）和 76%（Zn），降低更为显著。顺序提取结果表明，污染土壤经 NSF 和 CSF 处理后，可交换/弱酸溶性 Pb 和 Zn 减少，而残留的 Pb 和 Zn 增加。经 5wt% CSF 处理的 SEM-EDX 样品的结果表明，Pb 和 Zn 的有效固定可能与硅酸钙水合物（CSHs）和铝酸钙水合物（CAHs）有关。
