Fabrication and characterization of polysulfone/modified nanocarbon black composite antifouling ultrafiltration membranes

Membrane fouling in membrane filtration technology is the major obstacle in maximizing its efficiency leading to short membrane lifetime and high operating cost. Here we reported that the use of oxidized nanocarbon black (ONC) in the preparation of composite ultrafiltration membrane, suppresses the fouling together with improved hydrophilicity and water permeate flux. Nanocarbon black (NC) was oxidized using ammonium persulfate, while morphology, nature and extent of oxidized groups were determined through scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and ion exchange capacity (IEC) measurement. The dispersion of the ONC was stable in organic solvent (NMP) and in DI water even after 6 months. Oxidized nanocarbon black was incorporated in polysulfone matrix to prepare nanocomposite membranes (CNC) through phase inversion method. The influence of ONC on surface morphology, surface chemical composition, hydrophilicity, mechanical strength, surface negative charge, porosity, ultrafiltration and antifouling characteristics were evaluated. The results showed that inclusion of 1.0 wt% ONC enhance water permeate flux from 188.5 to 307 L m(-2) h(-1), protein rejection up to 97.6%, highest flux recovery ratio of 89.4% after three cycle permeation and lowest irreversible fouling of 10.5%. Considering relatively low cost, excellent antifouling properties and mechanical strength of CNC membranes, make it potential candidate as antifouling membrane for water purification.