沉积物中砷的氧化机制及再分配研究

The behavior of arsenic at sediment-water interfaces and its fate in environment are significantly affected by speciation transform of arsenic. Due to the complex nature of sediment, the regulations and mechanisms of arsenic oxidation in weak oxidizing environment have not been fully understood so far. This project will use the sediments from Jinzhou Bay as the typical sediment to investigate arsenic oxidation and redistribution at sediment-water interface. The project will focus on the mechanism of arsenic oxidation and reaction regulation which are coupled with the main factors of effecting arsenic oxidation and mobilization. XAS, XRD, FTIR, XPS etc. will be employed to characterize the nature of sediment minerals and arsenic speciation. The objectives of this project are to shed more light on the molecular-level mechanism of geochemical processes of arsenic in typical sediment. Successful implementation of this project will help further studying and predicting of mobilization and the fate of arsenic in arsenic contaminated sediments, and is theoretically and practically important to efficient control of arsenic pollution and establishing of remediation technologies.

砷污染沉积物氧化还原条件变化导致的砷赋存形态转化强烈影响砷的固液界面行为及其环境归趋。沉积物砷在微氧化环境中的氧化反应规律与过程机制及砷氧化对其迁移的影响一直未得到清晰认识，尤其缺乏沉积物复杂体系多种影响因素共存时砷微氧化过程的系统研究。本项目以锦州湾砷污染沉积物为对象，通过砷氧化和释放过程涉及的主要沉积物组分和影响因素耦合，从简单至复杂体系，系统研究沉积物主要成分（金属氧化物及有机质等）对还原态砷（亚砷酸、硫代亚砷酸、硫化砷、含砷黄铁矿等）的化学氧化反应过程，揭示氧化反应规律，阐释氧化过程机制，搞清砷氧化反应对其固－液和固－固再分配的影响，并利用XAS、XRD、FTIR等手段从分子尺度揭示与沉积物矿物结构转化相偶联的沉积物中砷的地球化学行为机理。项目的成功实施将有助于理解地表水沉积物中砷的地球化学循环过程及其机理，并为水体沉积物砷的地球化学循环过程调控和砷污染治理方法建立提供理论依据。

砷污染沉积物氧化还原条件变化导致的砷赋存形态转化强烈影响砷的固-液界面行为及其环境归趋。本项目围绕着沉积物砷在微氧化环境中的氧化反应规律、过程机制及砷氧化对其迁移的影响这些重要问题，对液/固相砷在单一氧化剂/催化剂作用下、固相砷在两种氧化剂/催化剂协同氧化作用下和固相砷在有/无光照条件、氧化-还原切换条件下再悬浮时砷的形态变化及引起的再分配过程进行了系统实验研究和理论分析，阐明或部分阐明了沉积物中砷的氧化过程机制以及砷氧化反应对其固-液/固-固再分配的影响规律，促进了地表水沉积物中砷的地球化学循环过程领域中某些问题的解决。已发表科学论文25篇（其中SCI收录论文17篇，EI收录论文2篇）并获得1项国家发明专利。