疏水木质纤维气凝胶制备及吸油机理解析

Subsea oil exploitation, crude oil marine transportation, and inland canals transportation always caused the oil spill, which pollutes the large-area watershed and seriously threatens to the fragile marine and inland river eco-environment. The main approach to dealing with oil spill is absorbing by using some absorbents. The application of traditional oil absorbents is restricted by their low absorbing and keeping oil efficiency, and poor oil recovery ability after oil absorption. Considering the large specific area and high porosity of lignocellulose aerogel, it is proposed to dissolve the lignocellulose in LiCl/DMSO solution, then hydrophobic modify by esterification, and fabricate lignocellulose aerogel with high specific area and great oil-adsorption ability by semi-interpenetrating polymer networking of lignocellulose and oil-wet polymer which is composed of methyl methacrylate (MMA) and butyl acrylate (BA) in the presence of N,N-methylenebisacrylamide (MBA) as the crosslinker. In order to grasp the fabricating and performance regulating methods of lignocellulose aerogel, the esterification and polymer networking technology, the oil-adsorption kinetics of lignocellulose aerogel, as well as the oil-adsorption and retention performance will intensive studied in the lignocellulose solution system. Subsequently, the oil absorption process and regularity of lignocellulose aerogel are going to be in-depth reveled, and its oil absorption mechanism will be elucidated finally. All these work will make contribution to the theoretical foundation for the development of environmental friendly advanced oil absorption material.

深海采油、原油海运及内河运输经常造成漏油事件，造成大面积、大流域水体污染，严重威胁脆弱的海洋和内陆水系生态环境。目前处理溢油的方法主要为材料吸附，传统吸油材料吸油保油效率低且后续回油性差，大面积应用受到限制。鉴于木质纤维气凝胶巨大的比表面积和极高的孔隙率，项目拟通过LiCl/DMSO对木质纤维进行溶解处理、酯化疏水改性，并在此体系下将油性单体MMA/BA进行自由基聚合及MBA交联，制备出具有高比表面积、高吸油性能的木质纤维网络与亲油高分子网络半互穿结构的气凝胶试样。研究木质纤维在全溶体系下进行酯化改性和亲油高分子网络构建工艺技术、木质纤维气凝胶的吸附动力学、吸油与保油性能，掌握全溶体系下木质纤维气凝胶网络构建及性能调控方法，揭示木质纤维气凝胶吸油历程及规律，阐明木质纤维气凝胶的吸油与保油机理，为开发环境友好型高性能吸油材料提供理论依据。

深海采油、原油海运及内河运输经常造成漏油事件，造成大面积、大流域水体污染，严重 威胁脆弱的海洋和内陆水系生态环境。目前处理溢油的方法主要为材料吸附，传统吸油材料吸油保油效率低且后续回油性差，大面积应用受到限制。鉴于木质纤维气凝胶巨大的比表面积和极高的孔隙率，本研究采用LiCl/DMSO溶液溶解含疏水性内源或外源木质素的木质纤维原料，再经溶剂置换凝胶化、硬脂酰氯酯化改性或添加油性单体甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）和交联剂N,N-亚甲基双丙烯酰胺（MBA）进行半互穿聚合交联等处理过程，获得一系列具有疏水亲油性的木质纤维物理气凝胶、木质纤维素酯气凝胶和半互穿网络气凝胶，并利用FT-IR、TG、SEM、BET、光学接触角、流变仪等检测手段表征气凝胶的化学结构、热稳定性、微观构造、多孔性、力学强度及疏水吸油性等相关性能，探讨木质纤维气凝胶对油品的吸油历程及吸附动力学行为规律，解析木质纤维气凝胶的吸油机理。结果表明，疏水性内源木质素的存在可提高木质纤维物理气凝胶的热稳定性，但会限制纤维素和半纤维素的解离，导致气凝胶孔隙结构不均匀；而外源木质素可提高气凝胶力学强度、比表面积和亲油疏水性能。对木质纤维素酯气凝胶而言，木质纤维先经硬脂酰氯酯化改性后凝胶化过程中，随着酯化试剂用量的提高，气凝胶疏水吸油性能得以改善，但其力学强度降低，凝胶网络结构疏松，比表面积下降；若先凝胶化后酯化改性，则对气凝胶三维网络结构的影响较小。对木质纤维半互穿网络气凝胶而言，单体MMA和BA与交联剂MBA所形成的聚合交联网络与木质纤维网络以半互穿方式共存，引入单体聚合交联网络有助于提高气凝胶的力学强度和疏水吸油性能。此外，对木质纤维素酯气凝胶和半互穿网络气凝胶吸附煤油的过程进行吸附动力学模型和粒内扩散模型模拟发现，两种气凝胶的吸油过程更符合准二级吸附动力学模型，即吸附速率受化学吸附机理控制，且吸附过程包括表面吸附、孔内缓慢扩散以及吸附脱附动态平衡。