Congo Red Dye Removal by Direct Membrane Distillation using PVDF/PTFE Membrane

Abstract

The ability to use the membrane distillation (MD) technique is envisaged as a promising approach to attain sustainable and reliable clean water supply. In this work, polytetrafluoroethylene/polyvinylidene fluoride (PVDF/PTFE) flat sheet membranes were fabricated via the thermally induced solvent evaporation process. The PVDF/PTFE membrane surface was modified by incorporating methyl functionalized mesoporous silica nanoparticles (MfSNPs). Prior to application, the membranes were characterized with respect to surface and structural morphology, hydrophobicity and overall porosity. Clean water flux measurements were conducted using a direct contact membrane distillation (DCMD) lab-scale experimental setup with deionized water as the feed solution (50 °C) and permeate solution (20 °C). The highest stable pure water flux for the MfSNPS/PVDF/PTFE membranes was 0.0041 L/h m2. The incorporation of the MfNPS did not only improve the fluxes but also induced low wetting properties as shown by the contact angle and LEPw values. The MfSNPs/PVDF/PTFE membranes were highly efficient in removing Congo red dye from water with 99% removal efficiency achieved.