通过测定铝盐水解及形态捕捉等温过程四元体系四面体相图指导合成纯聚铝化合物并解析其晶体结构研究聚铝形态的演变机理

铝盐水解聚合形态的结构及其演变规律既是探明铝系絮凝剂作用机理、合成高效混凝剂的重要科学问题，也是地球环境中铝迁移转化和铝污染防治的重大科学问题，但却困扰了科学家近百年。因每一温度下都是多种形态并存其分布时刻变化，因而从中离析纯聚铝化合物很难，得到适合解结构的单晶更难。由于结构已知的聚铝形态数量有限，所以单体铝究竟如何演变成氢氧化铝迄今尚无统一认识。本项目将在前三个项目所测200℃及以下三元体系三角相图指导下制备出74种聚铝化合物，解析出57种晶体结构，纠正了4种文献报道的错误结构，归纳出可反映所有已发现聚铝形态形成演变过程的综合演变机理，总结出“拼挂摆移”聚合模型和理论及局部碱化度对称均衡原理的基础上，测定100℃及以下铝盐水解及形态捕捉等温过程四元体系四面体相图，合成更多纯聚铝化合物，培养更多单晶并解析其结构，从而为最终得出有说服力的完整统一的聚铝形态形成演变机理和聚合模型理论做贡献。

The hydrolyzed and polymerized species and their evolution rules of Al salts is not only an important scientific problem for revealing the action mechanisms of Al-series flocculants and for synthesizing the highly efficient coagulants, but also a significant scientific problem for understanding the transport and transformation law of Al in the global environment and for preventing Al pollution, however, the problem has perplexed scientists for a century. Because various species coexist in a hydrolyzed Al solution at each temperature, the distribution of every species is going to change from moment to moment, it is difficult to isolate pure compounds from the solution and more difficult to grow a large enough single-crystal for structure solving. Also, because the structurally known Al species are very limited, how an Al monomer is developed into Al(OH)3 has still not been reached to a consensus. In our three accomplished NNSF projects (two district science foundation projects and one surface project), 74 polyaluminum compounds were prepared under the direction of the AlCl3-Al(OH)3-H2O, Al2(SO4)3-Al(OH)3-H2O, AlBr3-Al(OH)3-H2O and AlI3-Al(OH)3-H2O ternary systems triangular phase diagrams determined at 25~200℃, 75~100℃, 50~75℃and 25~50℃, respectively; 57 crystal structures were solved; 4 wrong structures reported in literatures were corrected; one comprehensive evolution mechanism that may reflect the formation and evolution processes of all aluminum species found so far were summarized, a SSSS (Splicing, Suspending, Swinging and Slipping) polymerization model and theory and a LBDSE (Local Basification Degree Symmetrical Equalization) principle were summed up. Based on these achievements, this project will determine the tetrahedral phase diagrams of the AlCl3-Al2(SO4)3-Al(OH)3-H2O and Na2SO4-Al2(SO4)3-Al(OH)3-H2O quaternary systems in the processes of Al salts being hydrolyzed and their polymeric species being captured at a constant temperature, synthesize more pure polyaluninum compounds under the directions of so-obtained tetrahedral phase diagrams, grow more single-crystals and solve their structures. The final target of this project is to do our best for obtaining a convictive, complete and unified evolution mechanism, polymerization model and theory of polyaluminum species.