Modification of polysulfone membrane used in the water filtration process to reduce biofouling

Polysulfone membranes (PSF) were modified with silver nanoparticles obtained by new synthesis (nAgNS), silver nanoparticles obtained commercially (nAgC), silver sulfadiazine (SP), dodecyltrimethylammonium bromide (DOTAB), benzalkonium chloride (CB) or sodium dodecylbenzene sulfonate (DBSS) to improve the efficiency of the water filtration process by reducing biofouling. All membranes had lower hydrophobicity compared with PSF. The zeta potentials of all membranes were negative at pH 7.0, except for CB 10%. In the agar diffusion test, E. coli was considered to be sensitive to the antimicrobial effect of the nAgNS 1%, 3%, 6%, 10% and DOTAB 10%, whereas S. aureus was sensitive to the nAgNS 1%, 3%, 6%, 10%, DOTAB 10%, CB 0.22%, 2% and 10%. The lowest adhesion of E. coli was found in the nAgNS 6% and 10%. In the evaluation of the loss of flow rate during filtration of the E. coli suspension and pure water, nAgNS showed higher flow rate values when compared with PSF. The nAgNS did not release quantities of silver (0.1 mg/l) above the amount considered safe by the World Health Organization. Membranes nAgNS 6% and 10% showed the best anti-biofouling characteristic.