磁性温敏/电敏智能纳米水凝胶作正渗透汲取剂的行为表现及其机理

Recent studies show that forward osmosis (FO) membrane processes may be a sustainable and efficient technology for water/wastewater treatment and seawater desalination. The existing conventional FO processes are always associated with: 1) internal concentration polarization that would significantly reduce the osmotic driving force, and 2) difficulty in separating draw solute from permeate and recycling draw solute for reuse. Nano-hydrogel, a novel "smart" macromolecular material, has been reported to be capable of reversible volume change by absorbing and releasing water in response to external stimuli. They can be a class of promising FO draw solutes after modification (e.g., functional design). The ojective of this reserch is to develop environment-sensitive magnetic nano-hydrogels and use them as draw solutes in the FO process. We will incorporate water-based magnetic fluid and strong ionic comonomer into conventional thermo-sensitive nano-hydrogels (which can be made with a mature preparation technology) to develop magnetic thermo- and electric-sensitive smart nano-hydrogels (MTESSNHs). We will then use these nano-hydrogels in the FO system to: (1) improve the performance of draw solution by limiting internal concentration polarization (ICP) and enhancing water flux, and (2) use the fast magnetic/temperature/electric response of the nano-hydrogels to release product water in a cost-effective and energy conservative way. We will characterize the nano-hydrogels, including composition, structure, sensitivity, osmotic pressure as well as their performance in the FO process (including water flux, membrane fouling, energy consumption for regeneration, etc). Furthermore, we will explore the fundamental relationships among the characteristics of MTESSNHs and FO performance to fill the knowledge gap of the new FO system and to extend smart hydrogel applications in the environmental field.

正渗透(FO)被认为是一种可持续性的高效非传统水处理膜技术，但正渗透存在由内部浓差极化严重造成的膜通量低，及汲取液再生能耗高的问题。纳米水凝胶，一种新型智能高分子，在外部环境刺激下，能进行可逆地吸水－释水，经功能设计，是一种极具潜力的正渗透汲取剂。对此，本项目提出开发用于正渗透系统的具有强吸水性和快速环境响应性的纳米水凝胶，将水基磁流体、强离子基团引入制备技术较成熟的温敏纳米凝胶，合成磁性温敏/电敏智能纳米水凝胶，一方面增强汲取剂渗透压，减小或消除内部浓差极化，提高膜通量；另一方面，有利于实现快速的磁场/温度/电场响应，降低再生能耗。表征其组成、结构与刺激响应性、渗透压之间的关系，探索其在FO系统中的行为表现(膜通量、膜污染、再生能耗等)，阐明其组成结构与FO系统行为表现的内在机理，为FO系统的高性能化提供新的方法和理论基础，同时拓展和丰富智能水凝胶在环境中的应用。

正渗透(FO)被认为是一种可持续性的高效非传统水处理膜技术，但正渗透存在由内部浓差极化严重造成的膜通量低，及汲取液再生能耗高的问题。纳米水凝胶，一种新型智能高分子，在外部环境刺激下，能进行可逆地吸水－释水，经功能设计，是一种极具潜力的正渗透汲取剂。对此，研究以提高膜通量和降低再生能耗为目的，开发用于正渗透系统的具有强吸水性和快速环境响应性的纳米水凝胶为目的，将水基磁流体、强离子基团引入制备技术较成熟的温敏纳米凝胶，合成磁性温敏/电敏智能纳米水凝胶，一方面增强汲取剂渗透压，减小或消除内部浓差极化，提高膜通量；另一方面，有利于实现快速的磁场/温度/电场响应，降低再生能耗。重点研究凝胶在FO系统中的行为表现，探索其组成、结构与刺激响应性、渗透压之间的关系，阐明其在FO系统中的内在机理。同时初步探索了水凝胶对水中磷和重金属的回收，以拓展和丰富智能水凝胶在环境中的应用。