Abstract

The effect of biofouling control measures, based on iron nanoparticle (FeNP) coating for RO membranes, was determined using accelerated biofouling experiments on a commercial polyamide. The zeta potential, XRD, roughness, contact angle, permeance and flux were determined for coated and uncoated membranes. Feed water was obtained from the Sea of Cortez, Mexico, which was pretreated, sterilized and inoculated with a high concentration (109 CFU ml -1) of bacteria found naturally in the Sea of Cortez. In order to evaluate the anti-biofouling effect, the total organic carbon, total cell count and optical density were determined for the biofilm cake layer. The FeNP coating resulted in a significant reduction (32%) in the membrane permeance for pure water. Nonetheless, after the biofouling test the coated membranes showed 90% less biofilm cake layer, 67% lower total cell count and a 42% reduction in optical density. This highlights the biocide effect of the FeNPs, which could have a practical and important application in sea water desalination. Due to the easy synthesis of FeNPs, they have the potential to extend the useful life of RO membranes without significantly increasing membrane production costs, thus decreasing the total water cost.