Abstract

The effect of the incorporation of copper nanoparticles (Cu and CuO) and Cu-(m-phenylenediamine) (Cu-mPD) oligomer complex into thin-film composite reverse osmosis (TFC-RO) membrane on their anti-biofouling and desalinization performance have been studied. Modified membranes by incorporating Cu and CuO nanoparticles during the interfacial polymerization process were obtained. Moreover, in situ formation of an (Cu-mPD) oligomer complex from copper chloride during the interfacial polymerization process was also successfully employed. Membranes were characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy, and contact angle measurements. Anti-biofouling properties were studied using a colony-forming unit (CFU) test in Escherichia coli as a model. Furthermore, an anti-adhesion test was developed using fluorescence microscopy. Membrane performance using a cross-flow cell was evaluated, and copper ion release test in long operation times were carried out. Characterization techniques allowed to confirm the formation of the polyamide active layer, the presence of incorporated copper nanoparticles and the in situ formation of the Cu-mPD oligomer complex. Modified membranes showed a slight decrease in hydrophilicity and higher surface roughness. However, an excellent anti-adhesion and bactericidal effect were observed in all cases, being more effective to Cu nanoparticles and (Cu-mPD) oligomer complex with respect to CuO nanoparticles. The anti-biofouling effect is attributed to the copper toxicity mainly due to the release of copper ions, whose release rates were higher in these two cases in comparison with CuO. Finally, the desalination performance of all modified membranes showed an important salt rejection (>98%) with stable water flux (about 30 L.m-2.h-1). In conclusion, the incorporation of copper into TFC-RO membranes during the interfacial polymerization process is a potential alternative method to improve the anti-biofouling capacities without impairing the performance of the membrane