Development of hierarchical surface roughness on porous poly (vinylidene fluoride) membrane for membrane distillation process

Abstract

The surface hydrophobicity of a poly (vinylidene fluoride) membrane was increased through the phase separation of polycarbonate (PC) solution on the membrane surface. A variety of characterization techniques including surface contact angle measurement, scanning electron microscopy, liquid entry pressure measurement, atomic force microscopy, porosity measurement, pore size measurement, and attenuated total reflectance‐Fourier transform infrared spectroscopy were performed to investigate the membrane surface modification. According to the results, the formation of PC deposits on the membrane surface provided hierarchical structures consisting of micro and nanoscale roughness which enhanced the surface hydrophobicity. Direct contact membrane distillation (DCMD) experiments, in which an aqueous solution of sodium chloride (3.5 wt%) resembling the seawater was used as feed, were carried out to assess the performance of membranes. This surface modification technique led to the improved pore wetting resistance of the coated membrane in DCMD application. This novel method is believed to have a great potential to apply on a wide variety of membranes for MD application.

Poly(ether‐block‐amide) membrane with deformability and adjustable surface hydrophilicity for water purification

“…The porous material possesses high specific surface area inside, which can produce abundance of adsorption sites. [ 30–35 ] This structural feature is beneficial to improve the efficiency of ice purification. Obviously, the morphology of the internal pores has an influence on the purification efficiency.…”

The fluorinated SiO2 self‐assembly surface of epoxy resin with excellent insulating and superhydrophobic properties

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Recent Progress on Tailoring and Modification of Membranes for Membrane Distillation: A Review

“…Phase separation is shown to be a cost-effective and easy method of increasing surface roughness without using low surface energy modifiers to improve the hydrophobicity of the membrane. Rabiei et al [91] have successfully enhanced the membrane surface's hydrophobicity through the phase separation of the PC solution on the PVDF membrane. Figure 3 present the SEM images of the membranes coated with different concentrations of the PC solution.…”