超滤木质纤维水解液通量衰减过程与木素污染膜的作用机制

Although membrane technology can be used to separate hemicellulose from lignocellulose hydrolysate to promote the feasibility of high value utilization, membrane fouling caused by lignin in the hydrolysate is still the bottleneck of restricting its engineering application. A research about the problem of flux decline caused by lignin in in ultrafiltration (UF) of lignocellulose hydrolysate will be performed systematically in this project. The kinetics of membrane fouling under the conditions of constant hydrolysate concentration and increasing hydrolysate concentration will be investigated, and the effects of concentration improvement and concentration polarization on membrane permeability will be studied. The interaction between lignin，non-lignin pollutants and membrane will be explored from the perspective of electrochemistry in order to illustrate the adsorption mechanism of pollutants on membrane surface. The forming process of lignin gel layer will be analyzed, and the nature of the membrane surface contamination will be revealed. The dynamic accumulation process of lignin in the membrane will be studied, and the relevant dynamic adsorption models will be established. Lignin deposition pattern will be represented at a micro level and combining with the electrochemical properties of lignin and membrane to illustrate the functional mechanism of membrane pore fouling. At last, the dynamic process of flux decline and formation mechanism of the membrane fouling caused by lignin will be revealed by balancing the main factors affecting membrane permeability. The successful implementation of the present research will provide a theoretical basis for the development of membrane pollution control technology, and promote engineering application of membrane technology in the field of biorefinery.

膜技术可实现木质纤维水解液中半纤维素的有效分离，提升其高值化利用的可行性，但水解液中的木素组分会造成膜通量衰减，引发膜污染。本项目拟对木质纤维水解液超滤工艺中通量衰减过程和木素引发的膜污染问题开展系统性研究。研究水解液在恒定浓度、递增浓度模式下的膜污染动力学过程，探讨水解液浓度递增和浓差极化对通量的影响。从电化学的角度探究木素、非木素污染物和膜材料之间的相互作用关系，阐明污染物在膜表面的吸附作用机理，并对木素凝胶层的形成过程进行探讨，揭示膜表面污染的本质。研究木素污染物在膜相中的动态积累过程，建立吸附动学模型；从微观层面表征膜孔内部的木素沉积，结合木素、膜的电化学性质，阐明膜孔堵塞的作用机制。综合权衡影响膜通量的主要因素，诠释膜通量衰减过程与木素污染膜的作用机制。本研究可以为木质纤维水解液超滤过程中膜污染控制技术的开发提供理论支撑，促进膜技术在生物质精炼领域的工程化应用。

超滤技术可实现木质纤维水解液中有机组分的有效分离，提升其高值化利用的可行性，超滤过程中的膜污染会诱发通量衰减，成为膜分离在该领域广泛应用的主要障碍。本项目对木质纤维水解液超滤中的通量衰减问题以及水解液有机组分的功能化应用开展了系统性研究。研究了水解液的超滤跨膜动力学过程；鉴定了引发膜污染的主要污染物；分析了水解液中木素浓度的递增规律和析出现象；表征了木素凝胶层的形成过程和木素组分在污染膜表面的分布；重点研究了影响膜通量的关键因子(浓差极化、电荷密度、膜污染)，阐明了木质纤维水解液超滤过程中通量衰减的作用机制。同时，还对超滤分离的水解液有机组分的功能应用以及水解液的荧光性能的做了分析和研究。本项目可为膜技术在生物质精炼领域的工程化应用提供理论支持。在本项目的资助下，发表SCI论文11篇，国家发明专利授权1项，申请5项，培养硕士研究生3名，邀请国内外专家交流并讲座4次，参加国际学术会议1次，国内学术会议1次。