纳米级铁碳共沉物对西北农田土壤重金属Cd/Pb的固定吸附作用研究

The influencing mechanism of nano-sized coprecipitation of iron oxide and organic matter on chemical mobility of heavy metals is a hotspot nowadays which is rapidly developing with the growing critical scientific needs for the soil heavy metals pollution control and remediation. This proposal focuses on the adsorption and immobilization of heavy metals in the agricultural soil under the circumstance of Fe-C interaction. The test of Fe-C interaction, soil culture , batch equilibrium adsorption will be conducted to master adsorption rate and immobilized amount of heavy metals in the agricultural soil. We will design three contaminated scenarios(Cd, Pb, and combined Cd / Pb ) and adjust pH value of soil, content of heavy metals and ratio of C and Fe. And then, an economic and feasible scheme about heavy metals control and contaminated soil remediation would be put forward by a pilot-scale test in contaminated site . Based on the research efforts above, this proposal is expected to :i) quantify the effects of organic matters on biochemistry of iron oxide; ii) identify the biochemical behavior(adsorption, transform, immobilization) traits of heavy metals at different external conditions; iii) discover dynamic mechanisms of heavy metals availability under circumstance of different coexist substances; iv) promote scientific understandings on the interaction of ternary system between the nano-sized Fe-C coprecipitation and heavy metals ,and facilitate the development of study on contaminated geochemistry in agricultural soil.

纳米级铁碳共沉物对重金属土壤化学活性的作用研究是目前国际上土壤环境修复领域的热点方向之一。本项目拟选取西北干旱区农田土壤，在Cd、Pb单一污染和复合污染情景下，通过调控土壤pH值、重金属配比与含量、复合作用以及碳铁比率等因素，开展Fe-C相互作用实验、土培实验、批量平衡吸附实验以及场地小区原位修复试验以揭示不同情景和环境下纳米级铁碳共沉物对重金属的吸附和固定效能，比对筛选效果明显、经济可行的重金属污染土壤修复技术方案。此项研究工作，可量化实验条件下土壤有机质对细粒铁氧化物生物化学反应的影响作用，明确农田土壤环境中重金属污染物在外界条件改变状态下的吸附、转化、固定等土壤化学行为特性，推动Fe-C-HMs（重金属）三元体系相互作用这一研究方向在农田土壤重金属污染地球化学研究领域的发展应用。

铁碳共沉物，尤其是纳米级铁碳共沉物对土壤重金属的吸附固定作用研究是国际上土壤环境修复领域的热点方向之一。本项目选取了甘肃省白银市农田背景土壤及污染土壤，通过物理表征、室内模拟，室外小试等方式揭示了 Fe-C 之间相互作用机理，量化了实验室条件下碳的参与对铁氧化物外在表征的重要影响、探究了研究区农田土壤环境中Cd，Pb重金属污染物在不同影响因素下吸附的行为规律、明晰了该环境中重金属污染控制的关键作用条件。基于以上研究内容及目标，项目组有针对地提出了研究区污染农田土壤修复技术方案，培养了10名硕士研究生，在国际、国内期刊上发表学术论文9篇。