Rev Chem Eng 2016; aop *Corresponding author: David Jassby, University of California, Riverside, Bourns Hall A241, Riverside, CA 92521, USA, e-mail: djassby@engr.ucr.edu Avner Ronen and Sharon L. Walker: University of California, Riverside, Bourns Hall A241, Riverside, CA 92521, USA Avner Ronen, Sharon L. Walker and David Jassby* Electroconductive and electroresponsive membranes for water treatment DOI 10.1515/revce-2015-0060 Received October 12, 2015; accepted March 18, 2016 Abstract: In populated, water-scarce regions, seawater and wastewater are considered as potable water resources that require extensive treatment before being suitable for consumption. The separation of water from salt, organic, and inorganic matter is most commonly done through membrane separation processes. Because of perme- ate flux and concentration polarization, membranes are prone to fouling, resulting in a decline in membrane per- formance and increased energy demands. As the physical and chemical properties of commercially available mem- branes (polymeric and ceramic) are relatively static and insensitive to changes in the environment, there is a need for stimuli-reactive membranes with controlled, tunable surface and transport properties to decrease fouling and control membrane properties such as hydrophilicity and permselectivity. In this review, we first describe the appli- cation of electricity-conducting and electricity-responsive membranes (ERMs) for fouling mitigation. We discuss their ability to reduce organic, inorganic, and biological fouling by several mechanisms, including control over the membrane’s surface morphology, electrostatic rejec- tion, piezoelectric vibrations, electrochemical reactions, and local pH changes. Next, we examine the use of ERMs for permselectivity modification, which allows for the optimization of rejection and control over ion transport through the application of electrical potentials and the use of electrostatically charged membrane surfaces. In addition, electrochemical reactions coupled with mem- brane filtration are examined, including electro-oxidation and electro-Fenton reactions, demonstrating the capa- bility of ERMs to electro-oxidize organic contaminates with high efficiency due to high surface area and reduced mass diffusion limitations. When applicable, ERM appli- cations are compared with commercial membranes in terms of energy consumptions. We conclude with a brief discussion regarding the future directions of ERMs and provide examples of several applications such as pore size and selectivity control, electrowettability, and capacitive deionization. To provide the reader with the current state of knowledge, the review focuses on research published in the last 5 years. Keywords: electro-Fenton; electro-oxidation; electroreac- tive conductive membranes; electrostatic repulsive force; hydrogen peroxide; piezoelectric membranes; pore size; wettability. 1 Introduction 1.1 Membrane-based water treatment processes Long-range predictions of water supply and demand predict that more than 40% of the world’s population is likely to be living under severe water stress by 2050, with global water demand projected to increase by 55% between 2000 and 2050 (Marchal et al. 2012). In populated, water- scarce regions limited by natural water resources, seawa- ter and wastewater are used as potable water resources but require extensive treatment before being suitable for drinking (Shannon et al. 2008). The separation of water from salt and other contaminants is most commonly done through membrane separation processes (van der Bruggen et al. 2003). Membranes are semipermeable barriers that provide selectivity in response to a physical or chemical potential gradient (e.g. pressure, concentration gradients, and electric fields) (Buonomenna 2013). Membranes can be divided into dense materials (reverse osmosis [RO] and nanofiltration [NF]) or porous materials (microfiltra- tion [MF] and ultrafiltration [UF]) (Kennedy et al. 2008). Although UF and MF are mainly used for the filtration of submicron-sized particles and organic material, NF and RO are used for the desalination and removal of small charged organic molecules (van der Bruggen et al. 2003). The fastest growing desalination technology is RO, where water is transported through a dense membrane that is impermeable to ions, in response to a pressure gradient.