High performance PTFE and pp membranes for red sea water desalination using direct contact membrane distillation

Hydrophobic microporous flat sheet membranes made of poly tetrafluoroethylene (PTFE) and poly propylene (PP) were explored for desalting real Red Sea water using direct contact membrane distillation (DCMD) process. This paper describes the highest ever reported flux performance while using real seawater as a feed solution and deionized water as a permeate solution. Membranes were characterized for their surface morphology, water contact angle, thickness, pore size and pore size distribution. Water vapor flux performances were studied by varying feed solution and permeate temperatures, maintaining all the other operating parameters constant. Water vapor flux as high as 82.4 kg.m^-2.h^-1 with 99.99% salt rejection was obtained using PTFE membrane at a feed inlet temperature of 80 °C and other optimized conditions and using a locally designed and fabricated module, which is the highest flux compared to any other commercially available membranes tested in MD process using real seawater as a feed solution. Various components from the feed solution, deposited on the membrane surface were analyzed using Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectrometry (EDX).