Advanced electrodialysis with monovalent-selective membranes
Chemical-free advanced electrodialysis and membrane modification for tailored desalination and brine management
Desalination is increasingly essential as freshwater demand rises and conventional water sources decline. While current membrane and thermal technologies are mature, future innovation should go beyond lowering energy use and costs. Key opportunities lie in reducing environmental impact by avoiding chemical additions and harmful brine discharge, generating valuable products or selectively removing undesirable compounds from brines, and increasing the added value of desalted water through second uses such as agriculture or aquifer recharge. Advanced electrodialysis (ED) with monovalent-selective membranes enables chemical-free desalination by tailoring ionic compositions using only feedwater and electrical energy. At the same time, opportunities for in-situ and ex-situ membrane modification can further enhance selectivity, robustness, and adaptability of membranes, enabling customized desalination schemes tailored to industrial and environmental needs.
Research challenges
Despite intensive research on maximizing water recovery and even reaching zero liquid discharge (ZLD), full-scale applications remain rare. ZLD approaches often involve recovering solid salts or organics, but these are seldom economically viable except for onsite reuse. Many methods also require significant chemical use (e.g., regeneration agents, acids, antiscalants), leading to high costs and environmental concerns. Our challenge is to develop a desalination scheme that produces high-quality water and multiple concentrate streams with defined specifications, while minimizing chemical inputs and preventing sodium and chloride accumulation. A central challenge is designing and modifying membranes to achieve the desired ion selectivity—either through ex-situ treatment or in-situ modification during operation. Advanced ED with monovalent-selective and modified membranes can selectively separate ions under controlled conditions, enabling sustainable brine management and tailored concentrate production. Bridging laboratory membrane innovations to scalable ED systems is key.
Your assigment
You will develop and test advanced ED configurations for hybrid desalination schemes without the need for added chemicals. Your work will combine ED stack design with membrane modification strategies to optimize ion selectivity and operational performance. Based on feedwater composition (salinity, monovalent/divalent ion ratios, and valuable elements), you will model and design ED configurations that produce tailored concentrate streams. Model parameters will be derived from literature, membrane characterization, and modification experiments. In the laboratory, you will operate an ED setup using both well-defined salt solutions and real industrial feedwaters. You will test how ex-situ and in-situ modification of monovalent-selective membranes affects transport behavior, fouling resistance, and long-term stability. These experiments will validate model assumptions and assess system performance as a preliminary step toward pilot-scale testing.
Your assignment
You will develop and test advanced ED configurations for hybrid desalination schemes without the need for added chemicals. Your work will combine ED stack design with membrane modification strategies to optimize ion selectivity and operational performance. Based on feedwater composition (salinity, monovalent/divalent ion ratios, and valuable elements), you will model and design ED configurations that produce tailored concentrate streams. Model parameters will be derived from literature, membrane characterization, and modification experiments. In the laboratory, you will operate an ED setup using both well-defined salt solutions and real industrial feedwaters. You will test how ex-situ and in-situ modification of monovalent-selective membranes affects transport behavior, fouling resistance, and long-term stability. These experiments will validate model assumptions and assess system performance as a preliminary step toward pilot-scale testing.
Your profile
You have a background in chemical engineering or a related discipline. You have knowledge of water chemistry, electrochemistry, membrane technology, and process modeling. You can perform water quality experiments, membrane modifications, and technology assessments at laboratory and pilot scale.
Keywords: Monovalent-selective membranes; electrodialysis metathesis (EDM); selective electrodialysis (SED); membrane modification; hybrid desalination schemes
Professor/University group/Wetsus supervisor(s): Promotor: Prof. Dr. Adriaan Mels, Environmental Technology, Dept. of Agrotechnology and Food Sciences, Wageningen University
Co-promotor: Dr. Harry Bruning, Environmental Technology, Dept. of Agrotechnology and Food Sciences, Wageningen University
Wetsus supervisor: Dr. Jan W. Post
Project partners: Desalination & Concentrates Theme
Only applications that are complete, in English, and submitted via the application webpage before the deadline will be considered eligible.
Guidelines for applicants: https://phdpositionswetsus.eu/guide-for-applicants/
