Effects of hydrophilic CuO nanoparticles on properties and performance of PVDF VMD membranes

In this study, composite membranes of hydrophilic CuO and CaCO3 nanopartides and polyvinylidene fluoride (PVDF) were developed by phase inversion method. The fabricated membranes were subjected to different characterizations including morphology study, pore size, porosity, and thickness measurement, wettability and surface roughness analysis. The membrane performance was examined in terms of pure water flux in vacuum membrane distillation (VMD), salt rejection, and liquid entry pressure of water (LEPw). It was found that the membrane performance was optimized when 1.0 to 2.0 wt.% of CuO nanoparticles were embedded into the PVDF matrix via enhancing the membrane structure through enlarging surface pores and thickening the finger-like layer (in other words, thinning of the sponge-like layer). As a result, flux increased by 153.4% at the feed temperature of 27.5 degrees C and vacuum pressure of 12 kPa, when 2.0 wt.% of the CuO nanoparticles were embedded in PVDF. Membrane selectivity did not drop as a result of the CuO nanopartides incorporation and was more than 99.99%. All the nanocomposite membranes showed reasonable contact angle and LEPw, which proved appropriateness of the fabricated membranes for VMD application. Regarding the type of hydrophilic nanomaterials, CuO demonstrated better performance than CaCO3 in terms of membrane permeability improvement. (C) 2015 Elsevier B.V. All rights reserved.