Advanced fabrication and characterization of thin-film composite polyamide membranes for superior performance in reverse osmosis desalination

Thin film composite (TFC) polyamide membranes are crucial for efficient reverse osmosis (RO) desalination, offering high selectivity and permeability. This study investigates the fabrication and optimization of TFC membranes on polysulfone supports, focusing on their structural, morphological, and performance properties for enhanced desalination efficiency using the phase inversion technique, a method that enables precise control over membrane structure. Key fabrication parameters including the concentrations of m-phenylene diamine (MPD) and trimesoyl chloride (TMC), and the immersion times for both monomers were systematically varied to investigate their impact on membrane hydrophilicity, morphology, and structure. Hydrophilicity was assessed via contact angle measurements, Scanning electron microscopy was used to characterize the morphology (SEM), and structural properties were analyzed by Fourier-transform infrared spectroscopy (FTIR). The RO membranes' desalination performance was evaluated by measuring water flux and salt rejection in a cross-flow setup with saline water (10,000 ppm) under controlled processing conditions. Results indicated that variations in MPD and TMC concentrations, as well as immersion times, significantly influenced membrane hydrophilicity and pore structure, affecting water flux and salt rejection. The maximum salt rejection and water flux for the prepared thin film composite reverse osmosis membrane were 98.6% and 19.1 L/m² h, respectively obtained at m-phenylenediamine concentration of 2 wt% and tri mesoyl chloride concentration of 0.1 wt/v reacted for 1 min. The study provides insights into optimizing TFC-RO membrane fabrication parameters to enhance desalination efficiency, highlighting the potential of these membranes for high-performance RO desalination applications.