Synthesis of novel PVDF-co-PTFE membranes for ethanol–water separation using vacuum membrane distillation

Abstract

Vacuum membrane distillation (VMD) is an intriguing technique that has the potential to separate ethanol from an ethanol–water mixture. The goal of this work was to synthesize hydrophobic polyvinylidene fluoride–polytetrafluoroethylene (PVDF–PTFE) hybrid membranes that could be used in VMD. For membrane synthesis via phase inversion, the outcomes of different solvents, namely N-methyl-2-pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc), and dimethylformamide (DMF), as well as PTFE loading in PVDF dope solution were also evaluated. The desired membrane hydrophobicity was ensured by increasing contact angle from 69° to 135°. The obtained average maximum pore size fell between 0.19 μm and 0.22 μm. Plenty of work has been done on how the performance of the synthesized membrane depends on the VMD operating parameters (ethanol concentration, flow rate, feed temperature, and permeate pressure). The highest separation factor of 37.68 was offered by the membrane synthesized using DMF as a solvent, while the membrane synthesized with the help of DMAc solvent had the most increased ethanol flux of 10.55 kg m−2 h−1. A thorough report has been made on understanding membrane morphologies and VMD performance.