Desalination Performance of Multi-Walled Carbon Nanotubes Added Polymeric Nanocomposite Membrane

Abstract

Desalination is the most promising technology to resolve present water scarcity issues and improvement is required to increase its productivity and various other drawbacks including lower water flux, membrane fouling, and high-energy requirements. Currently available desalination membranes exhibits a water flux of 18–34 L/m².h. Modification of the existing membranes can enhance its performance and thereby makes it efficient for desalination. In this investigation, introduction of Polyvinyl pyrrolidone was aimed to enhance the permeability of the Polysulfone membrane, given that the membrane’s water flux is predominantly influenced by its porosity. Further modification of the membrane was done by adding functionalized multi-walled carbon nanotubes onto the polyamide layer over the polysulfone membrane to improve the salt removal efficiency. The fabricated membranes were characterized by its swelling, porosity, water uptake, surface roughness, contact angle, morphology and surface chemistry. The performance of the fabricated membrane for desalination was evaluated using a cross flow filtration experimental setup. The characterization studies confirmed the modification of hydrophobic polysulphone membrane to hydrophilic by the addition of functionalised multi-walled carbon nanotubes (MWCNTs). The findings demonstrated that the membrane with 0.01% w/v of MWCNTs exhibited enhanced water flux at 42 L/m².h with a salt rejection of 92%. The performance of the used membrane was retained by conducting regeneration study using acid cleaning. This study will be helpful for water managers to come out with a better method to fabricate membranes for desalination.