Nanofiltration-Inspired Janus Membranes with Simultaneous Wetting and Fouling Resistance for Membrane Distillation.

Membranes with robust antiwetting and antifouling properties are highly desirable for membrane distillation (MD) of wastewater. Herein, we have proposed and demonstrated a highly effective method to mitigate wetting and fouling by designing nanofiltration (NF)-inspired Janus membranes for MD applications. The NF-inspired Janus membrane (referred to as PVDF-P-CQD) consists of a hydrophobic polyvinylidene fluoride (PVDF) membrane and a thin polydopamine/polyethylenimine (PDA/PEI) layer grafted by sodium-functionalized carbon quantum dots (Na-CQDs) to improve its hydrophilicity.

Can Composite Janus Membranes with an Ultrathin Dense Hydrophilic Layer Resist Wetting in Membrane Distillation?

Tackling membrane wetting is an ongoing challenge for large-scale applications of membrane distillation (MD). Herein, composite Janus MD membranes comprising an ultrathin dense hydrophilic layer are developed by layer-by-layer assembling cationic polyethyleneimine and anionic poly(sodium 4-styrenesulfonate) polyelectrolytes on a hydrophobic polyvinylidene fluoride substrate. Using surfactant-containing saline water as the feed with low surface tension, experiments reveal that the number of polyelectrolyte layers, rather than surface wettability or surface charge, determines the anti-wetting performance of the composite Janus membranes.

Design of omniphobic interfaces for membrane distillation - A review.

Membrane distillation (MD) has a great potential in treating high salinity industrial wastewater due to its unique characteristics. Nevertheless, the implementation of MD for industrial wastewater reclamation must be conducted with precaution because low-surface-tension contaminates in feed solutions may easily wet the membranes. In recent years, omniphobic membranes that exhibit strong repellence towards liquids with a wide range of surface tensions have been proposed as a promising solution to deal with the wetting problem.

Advanced Anti-Fouling Membranes for Osmotic Power Generation from Wastewater via Pressure Retarded Osmosis (PRO).

A facile and versatile approach was demonstrated for the fabrication of low-fouling pressure retarded osmosis (PRO) membranes for osmotic power generation from highly polluted wastewater. A water-soluble zwitterionic random copolymer with superior hydrophilicity and unique chemistry was molecularly designed and synthesized via a single-step free-radical polymerization between 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-aminoethyl methacrylate hydrochloride (AEMA). The P[MPC- co-AEMA] copolymer was then chemically grafted onto the surface of PES/Torlon hollow fibers via amino groups coupling of poly(AEMA) with the polyimide structures of Torlon, leaving the zwitterions of poly(MPC) in the feed solution.

Omniphobic Hollow-Fiber Membranes for Vacuum Membrane Distillation.

Management of produced water from shale gas production is a global challenge. Vacuum membrane distillation (VMD) is considered a promising solution because of its various advantages. However, low-surface-tension species in produced water can easily deposit on the membrane surface and cause severe fouling or wetting problems.

Freeze desalination of seawater using LNG cold energy.

With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.