Modified polyacrylamide nanofiber membrane for efficient nitrate removal from landfill leachate

This study investigates the modification of polyacrylamide (PAM) nanofibers with silver nanoparticles (Ag) and green tea (GT) extract to enhance nitrate removal from landfill leachate collected in Kermanshah, Iran. GT extract was used to synthesize Ag nanoparticles, and 1 wt% of the resulting nanomaterials was added to an 11.7 wt% PAM solution before electrospinning. The fabricated membranes were characterized using scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and Fourier-transform infrared spectroscopy (FTIR). Their hydrophilicity, water flux, and fouling resistance were also evaluated. Nitrate removal performance was optimized under varying flow rates, pH levels, and pressures using a design of experiments (DOE) approach. The PAM/Ag@GT membrane demonstrated enhanced properties, including reduced fiber diameter, increased porosity (from 26.2 to 58.6%), improved hydrophilicity, and decreased turbidity (from 32 to 3 NTU). Nitrate removal efficiency increased from 32 to 73.25%, with a leachate flux of 1850 L/m²·h and a flux recovery ratio of 84.45%. Additionally, the PAM/Ag@GT membrane exhibited superior tensile strength and elongation compared to unmodified PAM. Under optimal conditions (0.2 bar pressure, pH 7, and a flow rate of 120 L/h), the PAM/Ag@GT membrane demonstrated efficient nitrate removal, enhanced overall performance, and promising potential for sustainable wastewater treatment applications.