生物质三维碳凝胶/钛酸盐纳米复合材料对铷、铯的高选择性吸附及作用机理研究

There are many kinds of rare metal ions such as Rb+, Cs+ in salt lakes, which widely distribute in Qinghai salt lakes. The comprehensive utilization of saline resources, special reclaimed utilization of rare element such as rubidium and cesium resources, have aroused much attention with the development of Qinghai saline exploitable resources. Inorganic exchanger based on nano titanates (NTs) show specific selectivity for rubidium and cesium ions in salt loaded solutions. The nano structure and specific surface area are the main factors to influence the high adsorption capacity of NTs, and NTs are not suitable for loading the column. The three-dimensional (3D) biomass carbonaceous gels (CGs) as CG monoliths not only assure a large specific surface areas, good chemical compatibility and high thermal stabilities for promising supports of NTs but also guarantee trouble-free separation of the adsorbents from solutions. In this proposal, the 3D CGs–based composite adsorbent will be synthesized using NTs as the adsorption-active component and CGs as the matrix material. We're ready to synthesize the 3D biomass carbonaceous gels/nano titanates (CGs/NT) composite materials by incorporating NTs into the networks of CGs by hydrothermal method. To study the relationship between process parameters and the properties of CGs/NT composite, and to explore CGs/NT's adsorption capacity and the mechanism, dynamic and static methods are used to investigate the adsorption of Rb+, Cs+ by the CGs/NT compounds in salt loaded solutions. The influence of competitive ions, pH and temperature etc. on the adsorption of Rb+, Cs+ ions onto CGs/NT will be studied through kinetic curves, adsorption isotherms and column techniques. Also, the eluting property, regeneration and reusability of CGs/NT will be examined to evaluate its potential application. The results show the driection for the development of new nano materials and new technologies for the separation and extraction of rubidium and cesium resources in Saline Lake.

青海盐湖含有丰富的铷、铯资源，对铷、铯的提取和分离已成为盐湖化工科学的研究热点。作为对铷、铯离子具有很好选择吸附性的纳米钛酸盐(NTs)材料，其纳米结构及大比表面积是获得高吸附容量的主要因素，但纳米粉体不适于装柱。生物质三维碳凝胶(CGs)具有复杂的网络结构与良好的化学兼容性，能提高NTs的比表面积与抗团聚性能，且易于分离。本项目拟以CGs为骨架，通过水热法将NTs包覆在碳凝胶表面，合成具有特殊孔径结构的三维碳凝胶/纳米钛酸盐(CGs/NT)复合材料。通过研究CGs/NT复合材料制备工艺参数及其与结构和性能之间的关系，探索其吸附性能与作用机理。采用静态与动态吸附法考察CGs/NT复合材料的对Rb+、Cs+的吸附性能，研究竞争离子、溶液酸碱性、温度等对Rb+、Cs+的选择性影响；研究CGs/NT复合材料的脱附和循环利用性能。开发适于盐湖铷、铯资源分离提取的新型纳米材料和新技术。

青海盐湖中含有丰富的铷、铯资源，实现对铷、铯的分离提取，有效的利用盐湖资源。本项目主要通过生物质三维碳凝胶（CGs）与钛酸盐（NTs）纳米材料复合，CGs基体提高了NTs的比表面积与抗团聚性能，并且该材料适宜装柱分离。我们研究了水热法合成三维碳凝胶/纳米钛酸盐（CGs/NT）复合材料；结合材料结构与性能筛选优化制备工艺，研究了吸附分离作用机理；并实际应用于卤水中铷铯的吸附分离，研究了CGs/NT复合材料的吸附性能与循环利用性能。在项目的支持下，课题成员申请2项专利，在Environ. Sci. Nano、Chem. Eng. J.、RSC Adv.、ACS Sustain. Chem. Eng.和Chemosphere等国际SCI期刊上发表了26篇学术论文，研究结果受到国内外同行的广泛关注。培养了多名研究生，其中一名博士生获得奥加诺奖学金。