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High-performance sulfosuccinic acid cross-linked PVA composite pervaporation membrane for desalination

Zhang, Rui, Liang, Bin, Qu, Ting, Cao, Bing, Li, Pei
Environmental technology 2019 v.40 no.3 pp. 312-320
asymmetric membranes, brackish water, crosslinking, desalination, freshwater, pervaporation, polyacrylonitrile, polyvinyl alcohol, reverse osmosis, seawater, sodium chloride, temperature, ultrafiltration
Pervaperation (PV), as a novel technology, has shown great promise in fresh water production from salty water. However, the low water flux of the present membranes hinders their practical applications. Here, a new type of PV composite membrane, consisting of a selective skin layer fabricated from poly(vinyl alcohol) (PVA) cross-linked by sulfosuccinic acid and a porous support layer using a commercial polyacrylonitrile (PAN) ultrafiltration membrane, was developed for applications in desalination. The separation performance of S-PVA/PAN composite PV membranes with different S-PVA layer thicknesses was tested in detail. The best result showed a water flux of 27.9 kg m⁻² h⁻¹ with a salt rejection of 99.8%, which was obtained at a vacuum of 100 Pa and temperature of 70°C when separating a 35,000 ppm NaCl solution. The S-PVA/PAN composite membranes could also be used for the desalination of high-concentration (100,000 ppm) NaCl solutions with a water flux of 11.2 kg m⁻² h⁻¹ with a salt rejection of 99.8%. Moreover, a stable desalination performance was obtained for a 120 h operation time. This study shows the possibility of using PV in desalination applications for seawater, brackish water and reverse osmosis concentrate treatment.