Fabrication, characterization, and performance evaluation of polysulfone nanocomposite membranes containing different sizes of ZIF-8 to desalination and heavy metals removal from wastewater

•Development of innovative PSU/ZIF-8 membranes using different sizes of ZIF-8 as additives.•Optimizing the particle size of ZIF-8 for maximizing membrane efficiency in water decontamination.•Employing FTIR, XRD, TGA, FE-SEM, EDAX, AFM, and CA for membranes characterization.•Investigating the impact of ZIF-8 Size on membrane performance in desalination, heavy metal removal, and antifouling. Due to nanotechnology’s emergence and the development of nanocomposite membranes, membrane technologies have gained significant attention in recent years. This research aims to develop a nanocomposite membrane containing ZIF-8 based on polysulfone (PSU) to remove pollutants present in wastewater. This study used a phase inversion method to prepare the desired membrane, and ZIF-8 with different sizes of 14, 23, 65, 144, and 262 nm were added to the PSU. The successful preparation of these nanocomposites was confirmed using techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The morphology of the prepared nanocomposites was examined using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX), atomic force microscopy (AFM), and contact angle (CA). According to the results from performance evaluation tests, the membrane containing ZIF-8 with a size of 14 nm had the best performance. It could remove sodium and magnesium cations from water at a pressure of 7 bar with an efficiency of 57.35 % and 59.50 %, respectively. The investigations related to the removal of heavy metals also demonstrated that this membrane could remove lead by 96.25 % at a pressure of 7 bar. The removal efficiency of the membranes containing ZIF-8 in the size of 14 nm for copper, nickel, and chromium is 90.56 %, 78.81 %, and 67.10 %, respectively. Therefore, it can be claimed that the membranes, including lower sizes of ZIF-8 exhibit high efficiency in practical cases of heavy metal removal.