静态法和微观光谱法研究共存无机/有机配体对Ni(II)在丝光沸石/水界面吸附行为和微观形态的影响机制

The frequency and severity of heavy metal pollutants in surface and ground water are of great concern to scientists due to the potential hazardous effects on freshwater sources. Sorption, diffusion and precipitation reactions at mineral/water interfaces are closely related with the distribution, migration, transformation, accumulation, bioavailability and ecotoxicity of various pollutants in aqueous environment. To precisely predict the mobility and long-term behavior of heavy metal ions in the environment, a microscopic mechanistic understanding of metal speciation and chemical processes at mineral/water interfaces is of fundamental importance. In view of this point, a multiphase environment system containing minerals, heavy metal ions and inorganic/organic ligands (such as CO32-, PO43-, oxalic acid and humic substances etc.) is selected as the research target of this project. Batch technique will be adapted to investigate the effects of contact time and addition sequences on the macroscopic sorption behaviors of Ni(II) at mordenite/water interfaces. In addition, spectrum characterization techniques (ATR-FTIR, XPS and XAFS) and FITEQL model fitting are also combined to determine the interaction mechanisms and microstructures. The project is expected to clarify two main issues from both the macro- and micro- perspectives: (1) the correlative mechanisms between the types of coexist ligands and Ni(II) sorption behaviors at mordenite/water interfaces; and (2) the mechanisms underlying the changes of Ni(II) chemical forms as a function of contact time and addition sequences. The prospective findings in this project will have a meaningful theoretical reference value for predicting the long-term physicochemical behaviors and eco-environmental effects of trace metals in real environmental mediums. Furthermore, the results will provide more accurate scientific basis for the remediation and purification of polluted water.

污染物在矿物表面的的吸附、扩散和沉淀等物理化学反应直接决定其在环境体系中的浓度分布、迁移转化、生物可利用性和毒性。本项目拟以矿物、重金属离子和无机/有机配体 (CO32-和PO43- 等无机阴离子以及草酸、腐殖酸等有机酸) 共存的多相环境体系为研究对象，采用批实验方法研究接触时间和加入次序对Ni(II)在丝光沸石/水界面宏观吸附行为的影响，结合ATR-FTIR、XPS和XAFS等光谱技术以及FITEQL模型拟合确定Ni(II)在多相体系中的吸附形态、作用机理和微观结构。项目预期将从宏观和微观两个层面阐明共存配体与Ni(II)吸附行为之间的关联机制，揭示Ni(II)在丝光沸石表面的化学形态随接触时间和加入次序的变化规律。研究成果对于评估重金属离子的长期物理化学行为和环境生态效应具有重要的理论指导意义，同时可以为实际污染水体的修复提供准确的科学依据。

本项目采用将常规光谱表征、静态批实验、FITEQL表面模型拟合、立体几何理论计算、电子顺磁共振技术、先进X射线吸收谱学分析和统计学F检验相结合的研究方法，深入探讨了共存无机/有机组分对二价重金属离子Ni(II)在粘土矿物/水界面的宏观吸附行为和微观作用机制的影响。此外，项目还探讨了粘土改性复合材料对Ni(II)的吸附性能及其环境去污应用潜力。基于上述研究，从分子水平上深入揭示了水环境化学因素对Ni(II)在矿物/水界面吸附行为和微观作用机制的影响规律，准确阐明了Ni(II)的宏观吸附行为与天然矿物晶体结构和表面物化性质之间的内在关联机制，补充丰富了FITEQL软件参数数据库信息和表面络合模型理论。上述研究成果能够为准确掌握Ni(II)在实际水环境体系中的物理化学行为和生态毒性提供科学的理论依据，同时也能够为发展污染水体的治理修复新方法和新工艺提供重要的参数指导。. 在项目的支持下，在Geochim. Cosmochim. Acta., J. Hazard. Mater., Chem. Eng. J., Environ. Sci. Process. Imp., Rdiochim. Acta, Carbohydr. Polym.和ACS Appl. Mater. Interf.等国际重要SCI源期刊上发表了9篇学术论文，至今总被引频次达到60次。基于本基金项目资助2013年发表在地球化学领域top期刊Geochim. Cosmochim. Acta (2013, 121, 84-104)上的论文得到了国内外同行的关注，至今已经被正面引用评价32次。同时这一研究成果还荣获第二届全国核化学与放射化学青年学术研讨会优秀论文奖，并入选“2013年度上海光源重要成果汇编”。 在项目执行中，培养博士生2名，其中一名获得“国家奖学金”、“三好学生”和“优秀毕业生”等荣誉。培养硕士研究生6名，其中两名已经毕业，另外四名正在负责人所在的苏州大学就读，其中一名硕博连读生在学期间获得了苏州大学专业奖学金一等奖。