羟基磷灰石对沉积物中重金属释放特性的影响

以羟基磷灰石掺杂前后模拟重金属污染沉积物为研究对象,利用混匀释放实验及化学连续萃取法分析沉积物中重金属的释放特征及形态分布特性,考察了羟基磷灰石对重会属污染沉积物中Cu、zn、Pb、Cd稳定性的影响.结果表明不同来源模拟污染沉积物中松花江沉积物中的重金属最易重新释放,而伊通河沉积物中的重金属释放量最小;同时伊通河沉积物中残渣态重金属的比例较其它沉积物高很多,而可交换态和碳酸盐结合态的重金属比例较其它沉积物低很多,说明同时进入沉积物中的重金属,伊通河沉积物中的重金属相对稳定一些.羟基磷灰石的掺杂不同程度降低了沉积物中重金属的释放能力,促使沉积物中的重金属由较不稳定结合态向较稳定结合态转化,减小了沉积物中重金属的生物可利用性,增强了重金属的稳定性.

Effect of hydroxyapatite on the releasing characteristics of heavy metals in the sediments

Effects of hydroxyapatite on the immobilization of Cu, Zn, Pb and Cd in the polluted sediments were investigated via analyzing the releasing and species distribution characteristics of heavy metals. The releasing feature of heavy metals was measured by releasing experiment and the species distribution feature of heavy metals was determined by chemical sequential extraction procedure. The results indicate that heavy metals in the sediments of Songhua River were more easily released, and less easily released for the sediments of Yitong River. The proportion of heavy metals presented as residual phase in the Yitong River sediments were much higher than that of heavy metals existed as residual phase in the other sediments, and meanwhile heavy metals existed as exchangeable and carbonatic phases in the Yitong River sediments were much less, this implies that heavy metals dumped into the sediments of Yitong River were more stable. The introduction of hydroxyapatite more or less reduced the releasing ability of heavy metals in the polluted sediments, and meanwhile advanced the heavy metals transforming from less stable phases to more stable phases. These results further imply that hydroxyapatite can reduce the bioavailability and enhance the stability of heavy metals in the polluted sediments.