Advanced Functionalization of Polysulfone Membranes with Green-Synthesized Silica (Si) and Silica-Silver (Si-Ag) Nanocomposites for Water Desalination and Environmental Applications

Polymer membranes like polysulfone (PSU) are widely employed in desalination due to their mechanical strength and chemical stability. However, PSU membranes face limitations such as inadequate salt rejection, susceptibility to fouling, and suboptimal permeability, which collectively hinder desalination performance. To avoid these limitations, researchers have modified PSU membranes through nanoparticles and nanocomposite incorporation. These modifications demonstrated promising results in enhancing salt rejection and antifouling properties. This study aimed to enhance PSU membrane performance by incorporating silica (Si) nanoparticles and silicon-silver (Si-Ag) nanocomposites. The Si-Ag nanocomposites were synthesized using citrus peels as a sustainable, green synthesis method to minimize chemical usage. The membranes were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). Antimicrobial and quartz crystal microbalance (QCM) examinations were conducted to determine the desalination efficacy of the membranes. XRD analysis revealed broad peaks associated with PSU and Si in both membrane types. Raman spectroscopy confirmed Si nanoparticles with a characteristic peak at ۴۱۰-۴۲۰ cm⁻¹, while a shift to ۴۷۷ cm⁻¹ was observed in the Si-Ag nanocomposite, indicating successful Ag incorporation. EDX analysis confirmed the presence of Si, S, C, and O in both membranes and Ag in the PSU-Si-Ag membrane. QCM results showed that the PSU-Si-Ag membrane demonstrated a good balance between water flux and salt rejection. It could be concluded that PSU-Si-Ag membrane possesses antimicrobial, optimal salt rejection, and antifouling characteristics which enhance the desalination efficacy. Antimicrobial testing revealed that the PSU-Si-Ag exhibited a larger inhibition zone, and lower MIC, and MBC values, indicating better antimicrobial activity compared to the PSU-Si membrane.

کلیدواژه ها:

Polysulfone membrane ، Nanocomposite ، Water desalination ، Silver Nanocomposite ، Silica nanoparticles ، Metal-Organic Framework