Preparation and characterization of carbon black coated membranes for the treatment of saline water by membrane distillation

Abstract

Membrane distillation (MD) is a promising approach to address water scarcity due to its capacity to achieve high water recovery in desalination. However, high energy consumption and decline in permeate flux are key issues of MD desalination. Nanophotonic materials like carbon black (CB) have been used to improve MD performance and reduce energy consumption in the presence of sunlight. In this article, we investigated different coating procedures for the formation of a uniform layer of CB particles on polytetrafluoroethylene (PTFE) and polyvinylidene fluoride membranes. The coated membranes were manufactured and characterized using Fourier-transform infrared spectroscopy and scanning electron microscopy. Contact angle measurements demonstrated an increase in hydrophilicity after CB was added. Both types of membranes exhibited an increase in permeate flux and salt rejection with the addition of CB, with the PTFE membrane coated with 0.5% of CB having the highest water flux, reaching 14.6 L/m² h (LMH) compared to a commercial control having a flux of 8.0 LMH. The effects of different parameters on the performance of the hydrophilic CB-coated PTFE membrane were examined. The results demonstrated that the CB coating developed can be advantageous to improve the performance of MD membranes.