高性能生物基功能炭材料的制备及其吸附水体中离子液体的机制

Ionic liquids, a kind of green solvents, have been widely used. Because of this, more and more ionic liquids have been discharged or released into the water systems, and have become a new type of low concentration pollutants. How to efficiently remove these ionic liquids from water will be an important issue to be tackled soon. This project aims to develop a new method of making functionalized carbon materials from agriculture and forestry biomass, and to establish strategies for tuning the surface polarity/properties, the pore size distribution and the oxygen-containing functional groups of the concerned carbon materials. The functionalized carbon materials is not only cheap, but also features well-developed pore structure and a large amount of oxygen-containing functional groups. The potential of the as-made carbon materials from biomass will be explored for adsorption removal of four typical ionic liquids from water. The effect of the chemical composition of the starting materials and the preparation process parameters on the adsorption performance of the carbon materials will be studied in much detail. The adsorption capacity of the concerned carbon materials will be correlated to the pore structure and oxygen-containing functional groups (such as sulfonic group, carboxyl and hydroxyl, etc.), with an aim of revealing the relationship between the molecular size of ionic liquids and hydrophilic/hydrophobic properties. This will lead to a new process for the efficient removal of ionic liquids such as imidazoles ionic liquids from the water system, in which the physical/chemical adsorption mechanism will be studied. Based on these results, the preparation technology of functional carbon materials will be reverse optimized, and the removal ability of ionic liquids also be promoted too. The project will also explore the methods for efficient regeneration and recycling of the carbon materials saturated with ionic liquids after the adsorption, and one option is to explore the potential of making use of them for biomass catalytic degradation.

随着“绿色溶剂”——离子液体的广泛应用，泄漏到水环境中的离子液体已成为一类新型的低浓度污染物，如何高效去除是一个亟待解决的重要课题。本项目拟以廉价的农林生物质为原料，采用原位调控的策略，建立表面极性和孔径分布可调的生物基功能炭材料的制备新方法；系统研究炭材料孔隙结构及含氧官能团(磺酸基、羧基、羟基等)对四类典型离子液体吸附行为的影响；以咪唑类离子液体为例，详细探究离子液体阴、阳离子的尺寸和亲/疏水性等性质参数与吸附效果的关联，阐明生物基炭材料高效吸附去除水溶性离子液体的物理/化学吸附机制；基于以上结论，进一步反向优化功能炭材料的制备工艺，提升生物基功能炭材料对目标离子液体的吸附性能；探索饱和吸附离子液体之炭材料的高效再生和循环使用的方法，揭示吸附离子液体后生物基炭在生物质催化降解方面的应用潜力。

在当前环境问题和能源危机的双重压力下，废弃天然生物质的高效转化和利用备受关注，而随着“绿色溶剂”——离子液体的广泛应用，如何高效去除泄漏到环境中的低浓度离子液体也是一个亟待解决的重要课题。本项目以花生壳、小麦秸秆、玉米秸秆、竹末等大宗农林废弃物为原料，经高温缺氧炭化和KOH/(NH4)2S2O8改性，成功制备了四类十二种具有大的比表面、发达的分级孔隙结构、表面富含大量含氧官能团的高性能生物基功能炭材料吸附剂；项目涉及九种不同阴阳离子组成的离子液体，研究了典型离子液体对小麦发芽的毒性作用，初步总结了离子液体的结构与生物毒性的规律；探讨了炭材料孔隙结构、含氧官能团及离子液体阴、阳离子的尺寸和亲/疏水性等性质参数与吸附效果的关联，并筛选出五种高性能生物质炭吸附剂用于水体中低浓度离子液体的去除，进一步的小麦发芽实验说明生物质炭吸附剂可通过吸附作用而降低/消除离子液体对幼苗的化学毒性，显示出很好的应用前景。随后，将饱和吸附ILs后的生物质功能炭材料作为固体酸催化剂应用于催化水解纤维素为平台化工产品，并以氨基酸质子化离子液体或氨基酸杂化纳米材料作为催化剂催化纤维素水解为葡萄糖、5-羟甲基糠醛（5-HMF）、乙酰丙酸（LA）等平台化工产品。项目进行期间，在Journal of Hazardous Materials、 Chemosphere、ACS Applied Materials & Interfaces和Fuel Processing Technology等期刊共发表研究论文35篇，其中SCI论文33篇，项目直接相关论文16篇；获河南省科技进步奖1项，研究团队获“河南省高校科技创新团队”；申请国家发明专利2项；培养博士生2人，毕业硕士研究生11人。