绿藻表面聚合物富集砷的微界面行为及影响机制

The adverse ecological and health effects caused by arsenic is one of the pollution problems of pressing concern worldwide. How to remove arsenic with anti-pollution green algae in highly arsenic contaminated area and how to resolve arsenic enrichment risks through water-algae-fish food chain in agricultural arsenic pollution area, have warranted to elucidate the micro-interface behavior of pollutants in multi-phase systems and the regulation mechanism. The proposed study chooses four arsenic species and four representative green algae to observe micro-morphology of EPS（extracellular polymeric substances） released by algae, to identify the disturbance mechanism of arsenic to the stability of colloid layer with varied constitutes of EPS by micro-surface characteristic technologies. Techniques of molecular separating, trace determination, light and energy spectrum will be used to study the arsenic species at EPS-algae interface and colloid coagulation. The impact of EPS on As adsorption and accumulation, as well as the competitive binding of As on surface functional groups of EPS will be examined. Work proposed in this study will be the first attempt to reveal the migration and bioaccumulation behavior of inorganic/organic arsenic on EPS-algae micro-surface. In the view of micro-interfacial morphology and surface energy changes, the phase-migration, bioaccumulation behavior and limited factors of the typical inorganic and organic arsenic on the interfaces of water-EPS-algae is to be solved. Results from this study will provide a solid and insightful scientific basis for arsenic pollution control and aquatic standards amendment in China.

砷(As)污染及其经食物链而造成的健康危害已被科学证实，高砷污染区如何利用耐污绿藻超富集除砷？农业砷药污染区如何解决水-绿藻-鱼食物链的砷富集健康风险？为此需解答砷在水-胞外表面聚合物(EPS)-藻多相微界面生态污染化学行为及影响。本项目拟选4种典型形态砷和4种代表性绿藻，建立微界面表征技术，解析绿藻自释放EPS的微界面构型，明确砷对不同EPS构成的胶质相界面稳定性影响及机制；运用分子分离、痕量测定和光谱能谱技术，探究砷在藻EPS界面赋存形态和胶粒聚沉作用，研究EPS表面砷富集与释放及其影响因素、As-EPS-藻胶体表面官能团竞争性结合及影响机制，阐明典型无机与有机砷在胞外聚合物-绿藻微界面相际迁移规律与富集归趋。从微界面形态和表面能量变化新视角，解答典型无机与有机砷在水-EPS-藻三相微界面的相际迁移、吸附富集行为及限制性影响因素，为我国水体砷污染控制技术与水生态安全标准提供科学依据。

本项目通过四种代表性绿藻对四种典型形态砷的吸附吸收实验，建立了胞外表面聚合物(EPS)分子分离、无机砷(iAs)痕量测定、iAs-EPS光谱能谱计算等微界面表征技术，阐明蛋白核小球藻EPS界面与iAs主要赋存形态As(III,V)的吸附吸收动力学关系，解析绿藻自释放EPS的微界面主要官能团构型，进一步揭示了不同EPS构成的胶质相界面稳定性受pH和iAs浓度影响，从微界面形态和表面能量变化新视角，解答As-EPS-藻胶体表面官能团竞争性结合及影响机制，为微界面生态砷污染化学行为研究，提供了无机砷在水-胞外表面聚合物(EPS)-藻多相迁移规律的科学实验数据与形态学证据。