In this research, thin-film composite (TFC) membranes were used for separating metronidazole antibiotic from effluents. In order to enhance the metronidazole separation performance, thin-film nanocomposite (TFNC) membranes containing copper sulfide nanoparticles as well as modified thin-film nanocomposite (MFTNC) membranes containing copper sulfide nanoparticles coated with acrylic acid were employed. The spherical morphology of CuS nanoparticles along with the acrylic acid chains coated on their surface was confirmed through TEM, scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS) analysis. The crystalline size of nanoparticles was obtained as 29 nm according to XRD. The effect of nanoparticles on chemical functional groups and membrane elemental analysis was investigated by FTIR and CHNS analysis. The structural comparison of TFC, TFNC, and MTFC membranes indicated that the degree of grafting (DG) of the composite thin-film was 17.2, 27.2, and 46.1%, respectively. The structural modification caused the contact angle of TFC, TFNC, and MTFNC to diminish by 47, 34, and 21 , and their porosity to rise by 37, 67, and 53%, respectively. Improvement of porosity and surface hydrophilicity resulted in flux recovery of 87, 100, and 100% in metronidazole filtration by TFC, TFNC, and MTFNC membranes respectively. AFM analysis reported lower roughness of TFNC and MTFNC compared to TFC roughness, obtained in response to less fouling for TFNC and MTFNC over TFC. The size of pores of TFC, TFNC, and MTFNC membranes was measured as 26.5, 16.8, and 14.5 nm respectively, bringing about metronidazole separations of 86.3%, 87.5%, and 98.3%, respectively.
