基于抗粘附/杀菌双功能切换的自防御型反渗透膜模块化构建与性能调控

Biofouling of polyamide reverse osmosis (RO) membranes is one of the primary problems of membrane-based desalination technology, which restricts the widespread application of this technology for a long time. Therefore, it is of great research significance and application value to perform antimicrobial modification on RO membrane surface. This project proposes the “self-defense” antimicrobial concept for RO membrane surface, and the bacteria proliferation/death-triggered pH changes in biofilm microenvironment are chosen as the endogenous stimulus. This project designs an antimicrobial surface for RO membrane with time-compatible anti-adhesive/bactericidal factors, and the antimicrobial mechanism based on the reversible switch and peak-stagger synergy of the dual functions is established. As a result, the RO membrane surface will exhibit sustainable and intelligent antimicrobial property, and the limitations of the antimicrobial surfaces with single factor or space-compatibility-typed dual factors will be overcome. This project develops a modular construction strategy for the antimicrobial functional layer of RO membrane. The introduction of mediator molecule with two functional groups enables the effective immobilization of antimicrobial factor on membrane surface, and lays the structure foundation for membrane property regulation. The effects of the molecular forms of antimicrobial factor and the chemical structures of mediator molecules on antimicrobial properties are investigated to clarify the dual structure-function relationships, and to establish the feedback regulation mechanism. This project aims at providing the research basis and theoretical support for developing novel antimicrobial polyamide RO membranes, from the angles of design principle and modification method.

聚酰胺反渗透膜的生物污染是膜法淡化技术面临的主要问题之一，长期以来制约着该技术的进一步推广应用。因此，对反渗透膜表面进行抗菌修饰具有重要的研究意义与应用价值。本项目提出反渗透膜表面自防御抗菌概念，以细菌增殖/死亡导致的生物膜内微环境pH变化作为内源性刺激，设计抗粘附/杀菌双因子时间兼容型反渗透膜抗菌表面，建立双功能可逆切换、错峰协同抗菌机制，实现膜表面可持续、智能化抗菌，从而克服反渗透膜单一因子型以及双因子空间兼容型抗菌表面的局限。本项目研究反渗透膜抗菌功能层模块化构建方法，引入双官能团介导分子实现膜表面抗菌因子的有效固载，并奠定膜性能调控的结构基础。探究抗菌因子分子形态以及介导分子化学结构对反渗透膜抗菌性能的影响，明确其间的双重构效关系，建立反馈调节机制。本项目旨在从设计原理以及修饰方法的角度为发展新型抗菌聚酰胺反渗透膜提供研究基础与理论支撑。

膜污染是海水/苦咸水脱盐过程中亟待解决的核心问题之一，其显著劣化了膜性能以及产水经济性。而如何简便、稳健地解决这一实际难题仍然是一个挑战。本研究采用快捷的一步共沉积策略在膜表面引入了一种新型的聚多巴胺（PDA）/β-丙氨酸（βAla）/Cu2+三元均相金属-有机杂化层，旨在有效减轻淡化过程中的膜污染。金属离子通过多齿螯合作用均匀分布在连续有机网络中，β-丙氨酸作为介导分子显著提高了膜表面Cu2+的负载量。通过优化沉积时间，降低了修饰层的存在对膜分离性能的不利影响。前述三元体系将抗粘附和抑菌因子有机结合。基于对水通量、污染物静/动态粘附情况以及膜-污染物相互作用能的分析，发现亲水性的PDA/βAla连续相能够显著抑制有机污染物以及微生物在膜表面的富集。同时，膜表面负载的Cu2+有效阻断了微生物的增殖，进一步遏制了生物污染。经过验证，修饰层具有良好的可持续性和稳定性，这为膜材料在实际场景下的应用奠定了基础。鉴于该方法具有简易、稳健的特点，其有望成为一种具有普适性的聚合物膜原位抗污改性技术。