Non-Isothermal Donnan-Dialysis: a novel method beyond iso-thermal Water pre-Treatment paradigm for Energy Reduction in desalination

海水淡化技术能够从海洋或其他含盐水源（如地下水和工业废水）中获得大量的水。然而，通过脱盐的水处理的能量强度（EI）在许多地区是日益增加的环境、经济和社会问题。利用大量的废热或低品位热资源进行海水淡化装置的预处理是降低能源强度的重要途径。脱盐中的另一个挑战是二价阳离子物质（例如Ca2+、Mg2+）对膜的污染和结垢，这需要化学剂量和预处理，并限制了回收的水的分数。一些现有的预处理技术采用进料和浓缩溶液之间的浓度梯度（Donnan透析）或与离子交换树脂的直接离子交换（IEX）。虽然Donnan透析（D2）是一种经济、简单、节能的过程，但由于其动力学较慢，在工业上没有得到广泛应用。在这里，提出了通过非等温D2加速D2动力学，作为一种超越等温水预处理的新方法，用于通过回收废热作为额外的驱动力来降低脱盐中的能量（NID 2WATER）。该研究员将首先开发一个纳米流体芯片，然后开发一个具有离子选择性膜的D2堆栈，分别从根本上和实际上研究NID2。然后，他将进行理论研究，以严格解释实验数据。该项目不仅将为回收海水淡化厂对海洋环境有害的废热提供解决方案，还将提高我们对通过带电膜进行热渗透的理解。预计实验和理论研究将有助于脱盐在满足世界粮食和水需求以及从脱盐盐水中回收有价值金属方面的应用。

Desalination technology is able to harvest abundant water from the sea or other saline sources such as groundwater and industrial effluents. However, the energy-intensity (EI) of water treatment by desalination is an increasing environmental, economical, and societal concern in many regions. An important way to reduce the energy intensity is to employ large resources of waste heat or lowgrade heat for pretreatment in desalination plants. Another challenge in desalination is the fouling and scaling of membranes by divalent cationic species (e.g. Ca2+, Mg2+) which necessitates chemical dosing and pretreatment and limits the fraction of water recovered. Some existing pretreatment technologies employ the concentration gradient between a feed and concentrate solution(Donnan-dialysis) or direct ion-exchange with ion exchange resins (IEX). Although Donnan-Dialysis (D2) is an economical, simple technological, and energy-saving process, it is not applied widely in industry because of its slow kinetics. Here, it is proposed to accelerate the D2 kinetics by a Non-Isothermal D2 as a novel method beyond iso-thermal WATer pre-treatment for Energy Reductionin desalination (NID2WATER) via recycling the waste heat as an additional driving force. The Fellow will, firstly, develop a nanofluidic chip and then a D2 stack with ion-selective membranes to investigate the NID2 fundamentally and practically, respectively. Then, he will perform a theoretical study to interpret rigorously the experimental data. The project will not only provide a solution for recycling the waste heat from desalination plants that is harmful to the marine environment but also enhance our understanding of thermoosmosis through electrically charged membranes. It is expected that the experimental and theoretical study will contribute to the applications of desalination in meeting world food and water demand and in recovering valuable metals from desalination brines.