多孔分级微纳结构金属氧化物的清洁制备与CO2吸附性能研究

The CO2 emission from fossil-fuel combustion is the important reason which causes climate warming, and its emission reduction has become the focus of environmental problems of the international society. Aiming at the difficult problem of developing adsorbent towards post-combustion CO2 with high temperature from coal-fired power plant, this project proceeds with designing components and structures of supported adsorbent, and one-pot hydrothermal in situ self-assembly method to prepare alkali-functionalized porous supported composite metal oxides including γ-Al2O3, MgO, and Mg-Al calcined layered double hydroxide based materials. These materials have hierarchical micro/nanostructures which include hollow microspheres, core/shell structure, flower-like structure, nanoflake assemblies and nanoflakes, etc. The low cost adsorbet towards CO2 with high temperature which has big adsorption capacity, good selectivity, strong resistant capability towards contaminants, and stable recycle ability will be successfully developed by the research of some basic science issues including adsorption kinetics and thermodynamics, interface interaction, adsorption/desorption mechanisms and the relationship between the structure and the adsorption performance of the typical samples. The adopted one-pot method can convert nontoxic, raw cheap inorganic salts into the desired products which are easily separated from the reaction system fast and efficiently under mild hydrothermal conditions. In comparison with conventional impregnation method with complex process to prepare supported adsorbent, this one-pot method which simplifies the preparation process greatly will enrich the clean preparation method and science of supported composite metal oxides, and promots its applied basic research in the environmental purification field.

化石燃料燃烧排放的CO2是导致全球气候变暖的重要原因，其减排已成为国际社会关注的焦点环境问题。本项目针对燃煤电厂燃烧后烟道气中高温CO2吸附剂的研制难题，从负载型吸附剂的组分和结构设计入手，提出采用一锅水热原位自组装方法清洁制备碱功能化的多孔负载型复合金属氧化物，包括γ-Al2O3、MgO和焙烧态Mg-Al水滑石基空心微球、核壳结构、花状结构、纳米薄片组装体和纳米薄片等分级微纳结构。通过典型样品吸附动力学和热力学、界面作用、吸附/脱附机理和构效关系等基础科学问题的研究，研制出吸附容量大、选择性好、耐污染能力强并具有稳定可循环使用能力的低成本高温CO2吸附剂。本研究采用的一锅法在温和条件下将无毒、廉价的无机盐原料快速、高效地转化为容易从反应体系中分离的产物，较传统浸渍法制备负载型吸附剂的复杂过程大为简化，将丰富负载型复合金属氧化物的清洁制备方法和科学，促进其在环境净化领域中的应用基础研究。

本项目研究了系列多孔γ-Al2O3、MgO及其负载型碱性金属氧化物的可控制备方法，在分析影响其温和清洁制备关键因素的基础上，研究了典型样品吸附/脱附CO2的性能、失效原因以及再生的途径和方法。主要研究内容和结果如下：（1）采用P123辅助溶胶——凝胶法，经随后同时萃取P123和负载的四亚乙基五胺，制备出具有快速吸附动力学和高吸附容量的新型胺基功能化介孔氧化铝（MA）；（2）采用溶剂蒸发诱导自组装法——过量浸渍或等体积浸渍法，从硝酸铝、商业拟薄水铝石制备了系列K-、Na-、Mg-和Ca-等碱（土）金属修饰的MA负载型吸附剂；（3）采用温和溶胶——凝胶法，从拟薄水铝石溶胶-非离子表面活性剂体系成功制备出对CO2吸附性能各异的MA，进一步通过嫁接法等获得了MA基复合载体和TEPA功能化吸附剂；（4）采用温和一锅阳离子——阴离子双水解反应法成功地制备了系列负载型MgO/γ-Al2O3复合材料，Mg/Al-0.2在60°C的动态条件下吸附/脱附循环11次后仍然保持稳定的CO2吸附量1.60mmol•g-1；（5）采用温和无模板水热法、水热——均相水解法等，从硫酸铝、氯化铝、硝酸铝、铝酸钠等无机铝盐成功地制备了空心核/壳和空心微球等系列分级纳米氧化铝和拟薄水铝石吸附材料；（6）采用一步炭化与活化制备方法，从虾壳、花生壳、核桃壳或碧根果壳粉制备活性炭，并实现原位氮参杂，典型样品常温常压下的CO2吸附量达4.51mmol/g，200°C下脱附实现再生后可以循环使用15次以上；（7）结合巨正则系综蒙特卡洛和分子动力学模拟，研究多孔材料的柔性骨架“呼吸作用”与储氢性能之间的关系；通过锂掺杂和结构设计得到8种不同结构的多孔骨架材料，是迄今为止国内外报道的多孔骨架材料中储氢性能最佳的组装结构。本项目对新型负载型碱性多孔γ-Al2O3基复合吸附材料的研制提供了新的思路，对高效金属氧化物吸附功能材料的研制有一定指导意义。共发表论文25篇（含SCI收录论文21篇、JCR期刊Q1区论文6篇、JCR期刊Q2区论文7篇，EI收录论文13篇）；1篇论文入选ESI高被引论文；2篇论文被VerticalNews点评；申请国家发明专利16项，其中6项获授权。