Janus membranes for membrane distillation: Recent advances and challenges

Abstract

Membrane distillation (MD) is a promising hybrid thermal-membrane separation technology that can efficiently produce freshwater from seawater or contaminated wastewater.However, the relatively low flux and the presence of fouling or wetting agents in feed solution negate the applicability of MD for long term operation. In recent years, 'two-faced' membranes or Janus membranes have shown promising potential to decrease wetting and fouling problem of common MD system as well as enhance the flux performance. In this review, a comprehensive study was performed to investigate the various fabrication, modification, and novel design processes to prepare Janus membranes and discuss their performance in desalination and wastewater treatment utilizing MD. The promising potential, challenges and future prospects relating to the design and use of Janus membranes for MD are also tackled in this review.

Graphene Oxide and its Derivatives for Gas Separation Membranes

“…A brilliant 2D carbon-based material was discovered via a micromechanical cleavage 'scotch-tape' approach in 2004 [19,20]. Extraordinary properties of graphene encouraged researchers to utilize this carbon-based material in several fields, including hydrogen storage, batteries, conductors, solar cells, capacitors, fuel cells, biosensing, drug delivery, catalysis, transistors, and composite materials [21][22][23].…”

“…The preparation of graphene is generally divided into two main methods: the top-down method, started with graphite, and the bottom-up method, started with carbon-based sources [21,24,25]. For creating the pores on the graphene sheet, one of the following methods including focused electron beam irradiation, focused ion beam irradiation, ultraviolet-induced oxidative etching, ion bombardment, chemical oxidative etching, oxygen plasma etching, block copolymer lithography, and nanosphere lithography, which are known as top-down meth-ods, have been used [26].…”

Analysis of Polyvinylidene Fluoride Membranes Fabricated for Membrane Distillation

“…On the other hand, fouling and scale formation are also serious problems that reduce the flux and lifespan of MD membranes. The pretreatment of feed water as well as physical/chemical cleaning may be applied to mitigate the adverse impact of fouling and scaling [29]. Nevertheless, it is also important to improve the fouling resistance of MD membranes by surface modifications [29].…”

“…The pretreatment of feed water as well as physical/chemical cleaning may be applied to mitigate the adverse impact of fouling and scaling [29]. Nevertheless, it is also important to improve the fouling resistance of MD membranes by surface modifications [29]. To prevent adsorptive fouling caused by hydrophobic organic matters, MD membranes should be rather hydrophilic.…”

Surfaces with Adjustable Features—Effective and Durable Materials for Water Desalination

“…The ideal membrane material is required to be not only hydrophobic and porous to prevent wetting, but also thermally and chemically stable, and durable in long-term operations. For that reason, more efforts have been made to produce highly effective materials e.g., superhydrophobic nanofibrous membranes with the electrospinning method for MD purpose [6][7][8], polymeric membranes by different modifications, including the interference in the structure and composition by co-casting or lamination to produce finally dual-layer membranes, e.g., Janus materials [9][10][11][12]. These treatments have allowed the modification of both the roughness and chemistry of the materials.…”