High flux microfiltration membranes with silver nanoparticles for water disinfection

Biofouling has a negative impact on the membrane water treatment since it reduces permeability, increases energy costs, and decreases the lifetime of the membranes. To minimize biofouling microfiltration (MF), polyethersulfone (PES) membranes were prepared by phase inversion method, and silver nanoparticles (AgNps) were synthesized by chemical reduction and incorporated into these MF membranes. Membranes with different pore size and porosity were selected and the presence of silver in the transversal section was confirmed. The antibacterial properties were analyzed against Pseudomonas fluorescens by the inhibition zone method after 24 and 96h of incubation and also by the bacterial count method. It was observed an inhibition ring of 20–30% of the sample diameter only around the membranes containing AgNps, indicating the suppression of micro-organism activity nearby the membrane. The permeate was analyzed using Colilert methodology to count the total number of coliforms. The coliform retention was 99.9 and 99.999% for membranes without and with AgNps, respectively. These results confirm the bactericide properties of the PES–AgNps membranes and their great potential in application for water treatment.