模拟土壤团聚体中金属离子的吸附-还原解吸

Adsorption/Reductive-Desorption of Metal-ions in Simulated SoilAggregate Systems

通过高分子水凝胶包裹技术,研究了不同的团聚体模拟体系中金属离子的吸附-生物还原解吸机制。结果表明:无定形铁矿物模拟团聚体对于金属离子的吸附量高于针铁矿模拟团聚体,且交联密度1.0%包裹组金属离子吸附量小于0.3%包裹组。在希瓦氏菌的作用下,凝胶包裹的铁矿物体系中亚铁浓度先升高后下降,而铁矿物上吸附的Cu2+和Mn2+则随着生物还原作用而解吸释放;针铁矿组的解吸量低于无定形铁矿物,而交联密度高的1.0%包裹组金属离子解吸量高于0.3%包裹组。在凝胶包裹的水稻土团聚体体系中,生物还原作用同样会引起铜/镍/钴/锰离子的溶出,从而影响土壤环境中重金属污染的迁移转化。

Hydrolgel encapsulation technique was applied to the investigation of mechanisms of adsorption-reductive desorption of metal ions in different simulated systems of soil aggregates. Findings of the investigation suggested that the adsorption of metal ion onto hydrogel encapsulated amorphous iron mineral was higher than that onto hydrogel encapsulated goethite,and the adsorption amount dropped as cross-linker density increased. It was also found that during the incubation with Shewanella,concentration of Fe2＋ was initially increased and then decreased,while Cu2＋ and Mn2＋ were released from hydrogel encapsulated iron minerals,and the desorption amount of metal ions from goethite rose as cross-linker density increased;meanwhile,the system containing hydrogel encapsulated paddy-field soil aggregates,biological reduction also resulted in the desorption of Cu2＋/Ni2＋/Co2＋/Mn2＋,which impacted the transfer and transformation of heavy metal pollution in soil environment.