【摘要】 为研究新型羟基磷灰石基固化剂SPC对污染土的真实修复效果,以甘肃省某Pb,Zn和Cd污染场地为对象,设计采用掺量8%的SPC进行现场异位固化稳定化(S/S)技术修复.修复前后进行现场动力锥贯入测试以分析土层贯入阻力值.同时钻取现场土样进行多组室内试验如土含水率、p H值、单一及连续浸提试验,以评价污染土和固化土理化、重金属浸出毒性、重金属形态分布特性之间的差异情况,并讨论SPC固定Pb,Zn和Cd的机理.结果显示:SPC固化污染土呈现中度碱性(p H=8.86~9.41),其含水率低于未固化污染土;同时SPC修复能够有效固定土中弱酸提取态Pb,Zn和Cd,使其转为更为稳定的残渣态,进而显著降低了污染土的重金属浸出毒性;此外,SPC异位S/S技术可明显提高污染土贯入阻力,不同深度处相较于修复前的贯入阻力增幅最高可达4.7倍.更多还原

【Abstract】 To study the actual effects on new hydroxyapatite based binder superphosphate and calciumoxide( SPC) for contaminated soils remediation,ex-situ solidification/stabilization( S/S) using8% SPC was performed on a Pb,Zn and Cd contaminated sites in Gansu Province of China. Before and after remediation,field dynamic cone penetration tests were conducted by measuring soil penetration resistance( Rs). Additionally,a series of laboratory tests,including water content,soil p H,single,and sequential extraction procedures were performed on core samples to investigate the differences in physicochemical,metal leachability and metal speciation properties betw een untreated and stabilized soils. The immobilization mechanisms of Pb,Zn and Cd by SPC were also discussed. The results show that SPC stabilized soils have moderately alkalinity with soil p H ranges from 8. 86 to9. 41,and low er water contents than untreated soils; SPC remediation significantly transforms the exchangeable fractions of Pb,Zn and Cd into more,insoluble residual fractions,resulting in the low er metal leachability. Furthermore,ex-situ SPC S/S can significantly increase Rs,and the maximum increase is 4. 7 times higher than the untreated soils.更多还原