基于同步辐射技术研究土壤铁氧化物固定重金属分子机制的进展

铁氧化物在土壤中广泛赋存,因其比表面积大,对重金属具有很强的吸附固定能力,深刻影响着土壤重金属的形态转化过程.因此,研究土壤铁氧化物对重金属的固定机制,对于深入理解重金属在土壤系统中的环境化学行为以及评估污染土壤重金属生物有效性具有重要意义.然而,采用传统的吸附模型和化学提取法研究土壤铁氧化物固定重金属的机制具有明显的局限性,无法从分子水平上阐明其固定机制.同步辐射技术在环境土壤学的应用显著推进了在分子水平上认识土壤铁氧化物吸附重金属及其受典型环境因子影响的分子机制.本文主要从同步辐射技术的发展历程、模拟系统和实际土壤系统中铁氧化物在多种因素影响下对重金属固定的分子机制等方面进行了综述,同时对同步辐射技术的未来发展趋势及其在该研究领域的应用进行了展望.

Molecular sequestration mechanisms of heavy metals by iron oxides in soils using synchrotron based techniques: A review

Iron oxides, widely distributed in soils, have large specific surface areas and strong affinity to heavy metals, and thus play a significant role in the transformation of heavy metals in soils. To understand the environmental behaviors of heavy metals and assess their bioavailability in contaminated soils, it is important to investigate the sequestration mechanisms of heavy metals by iron oxides. The traditional methods, including adsorption modeling and chemical extraction fractionation, have obvious limitations and provide little information on the sequestration mechanisms of heavy metal by iron oxides at the molecular level. The application of synchrotron-based techniques in environmental soil science has greatly enhanced the molecular-level understanding of the immobilization mechanisms of heavy metals by iron oxides under various environmental conditions. Here, we reviewed the development of synchrotron-based techniques and summarized the molecular sequestration mechanisms of heavy metals by iron oxides in model and real soil systems under various environmental factors. The future development of synchrotron-based techniques and their applications were prospected.