快速的工业化和城市化导致地下水和地下土壤中污染物的浓度升高,对人类和生态系统构成越来越大的危害。大多数污染物的转化与三价铁(氢)氧化物的矿物学密切相关。三价铁(氢)氧化物的硫化是缺氧环境中最重要的生物地球化学反应之一,导致三价铁(氢)氧化物的还原溶解和重结晶,并进一步影响铁相关污染物的转化。本文对三价铁(氢)氧化物的硫化过程和相关污染物的转化进行了全面的综述。这篇综述介绍了三价铁(hyr)氧化物与溶解的硫化物之间的详细反应机理,并阐明了这些因素(例如三价铁(氢)氧化物的结晶度,硫化物浓度与三价铁(hydr)氧化物的表面积浓度之比)控制表面缔合Fe(II)的形成,硫化铁矿物,以及次生矿物的转化。然后,我们总结了地下水和地下土壤中存在的各种典型环境相关污染物的转化机制,包括重金属,金属(类)氧阴离子(砷,锑,铬),放射性核素(铀,tech),有机污染物和磷酸盐/硝酸盐物种。污染物转化的一般机制涉及释放的组合,还原和再吸附/掺入过程,其具体途径高度依赖于污染物本身的性质和硫化程度。此外,将我们的知识扩展到就地修复的挑战,并确定了进一步的研究需求。
Rapid industrialization and urbanization have resulted in elevated concentrations of contaminants in the groundwaters and subsurface soils, posing a growing hazard to humans and ecosystems. The transformation of most contaminants is closely linked to the mineralogy of ferric (hydr)oxides. Sulfidation of ferric (hydr)oxides is one of the most significant biogeochemical reactions in the anoxic environments, causing reductive dissolution and recrystallization of ferric (hydr)oxides and further affecting the transformation of iron-associated contaminants. This paper provides a comprehensive review on the sulfidation process of ferric (hydr)oxides and the transformation of relevant contaminants. This review presents detailed reaction mechanisms between ferric (hydr)oxides and dissolved sulfide, and elucidates the factors (e.g. crystallinity of ferric (hydr)oxides, the ratio of sulfide concentration to the surface area concentration of ferric (hydr)oxides) that control the formation of surface associated Fe(II), iron sulfide minerals, as well as transformation of secondary minerals. Then, we summarized the transformation mechanisms of a variety of typical environmentally relevant contaminants existing in groundwater and subsurface soils, including heavy metals, metal(loid) oxyanions (arsenic, antimony, chromium), radionuclides (uranium, technetium), organic contaminants and phosphate/nitrate species. The general mechanisms of contaminant transformation involve a combination of release, reduction and re-adsorption/incorporation processes, the specific pathway of which is highly dependent on the properties of the contaminant itself and the extent of sulfidation. Moreover, the challenge of extending our knowledge towards in situ remediation, as well as further research needs are identified.