Composite PVA/PVDF pervaporation membrane for concentrated brine desalination: Salt rejection, membrane fouling and defect control

Linking defects, hierarchical porosity generation and desalination performance in metal–organic frameworks

“…In the composite membrane, the presence of MOF in PVA layer mainly promotes the water uptake, without compromising the salt rejection efficiency, which is dominated by the polymeric PVA section. 21 It should be noted that it is difficult to draw a direction comparison with the literature on pervaporation desalination membranes due to different operational parameters applied (Table S6 † ), the membrane in this work still one of the best performing polymer-based pervaporation membranes, with the highest salt rejection and good scalability. In addition, it should be noted that further process optimization can improve the membrane productivity, e.g.…”

“…In terms of membrane processes, the treatment of highly concentrated brine is technically challenging and energy demanding, as conventional pressure-driven filtration membrane is not a viable option due to the high osmotic pressure that must be overcome. 21 The concentrated brine can also lead to rapid scaling and pore blocking for the membrane distillation process. Alternatively, membrane pervaporation is a promising technique, which has been extensively investigated for organic solvent separation and dehydration.…”

“…22 The dense pervaporation membranes can effectively mitigate the scaling problem; but they still suffer from low desalination productivity and poor operational stability with brine feeds. 21 …”

Structures, Properties, and Performances—Relationships of Polymeric Membranes for Pervaporative Desalination

“…In order to compare the pervaporative desalinating efficiencies of GA crosslinked PVA membranes supported on PVDF, two types PVA coated PVDF membranes were prepared individually by dip- and cast-coating methods [123]. Of these, one set of composite membranes were prepared by dip-coating of PVDF hollow fibers, ensuring only single-side coating of hollow fibers by sealing the hollow fiber membrane prior to dip-coating (Figure 9a).…”

“…In this regard, the hydrophilic groups in GO accelerated the rate of solvent and non-solvent exchange during phase-inversion process [176]. Influence of pore characteristics and micro-defects can contribute significantly in the performance of PVA-PVDF composite membranes [123]. In this context, pore size and structure of PVDF can be altered depending on the PVA concentration in dipping solution.…”