Membranes with Surface-Enhanced Antifouling Properties for Water Purification

Abstract

Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol), polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted.

Ion transport mechanisms in salt‐doped polymerized zwitterionic electrolytes

“…Zwitterions (ZIs) are small molecule ampholytes, or covalently bonded cations and anions, of zero net charge . Their ionic properties and hydrophilicity have made them targets for use in organic electronics, catalysis, battery electrolytes, surfactants, drug‐delivery, and antifouling coatings, among other applications . ZI‐incorporated polymers (polyZIs) have also been investigated as novel materials for chromatography, drug‐delivery, self‐assembled microstructures, and battery electrolytes …”

Hydrophilic modification of polypropylene ultrafiltration membrane by air‐assisted polydopamine coating

“…For porous membranes like UF, pore size reduction and pore blocking are the major factors influencing the water flux decrease . The decrease of water flux would not only cause inconvenience for practical operation, but also increase the operating costs due to the requirement of membrane cleaning and replacement . Membrane fouling also leads to higher energy needed to keep the membrane performance constant …”

Preparation and characterization of TiO2/Pebax/(PSf‐PES) thin film nanocomposite membrane for humic acid removal from water

“…Accordingly, in the case of composite UF membranes, the use of Pebax copolymer as selective layer can be suitable due to its bicontinuous structure. In this case, water molecules may transfer through poly(tetramethylene oxide) segments …”

“…water molecules may transfer through poly(tetramethylene oxide) segments. 21 The surface fouling is the main challenge in a HA removal via UF process and plays a crucial role on the membrane performance. 22 Fouling leads to a decrease in membrane efficiency and the resultant flux even after backwashing.…”