Photothermally heated and mesh-gridded solar-driven direct contact membrane distillation for high saline water desalination

Photothermally heated and mesh-gridded membrane distillation (PHMD) system is proposed for desalination of high saline aqueous solutions. A triple-layered membrane, composed of a photothermal top nanofibrous layer containing polyacrylonitrile and dispersed carbon black nanoparticles and a polyvinylidene fluoride porous membrane supported on a nonwoven polyester, was prepared. A polypropylene mesh was used to hold the membrane. A 3D numerical simulation of the PHMD system was carried out by COMSOL and the appropriate length of the membrane module was determined. The effects of various operating parameters including solar radiation intensity on the permeate flux and thermal efficiency were investigated. The increase of the feed flow rate reduced both the permeate flux and the thermal efficiency due to the reduction of the residence time of the feed solution on the photothermal membrane module. In addition, the increase of the solar radiation intensity from 500 to 1100 W/m2 and the ambient temperature from 293 to 313 K resulted in a significant enhancement of the permeate flux and thermal efficiency. In general, good agreements were found between the experimental and simulated results.