Pharmaceutical and personal care products removal from drinking water by modified cellulose acetate membrane: Field testing

Abstract

To maximize the removal of charged pharmaceutical and personal care products (PPCPs), modified cellulose acetate (CA) nanofiltration (NF) membranes were developed by incorporating charged surface modifying macromolecules (CSMM) to increase their surface charge. The objective of this study was to evaluate their removal of trace levels of PPCPs at two water treatment plants. This new membrane and a commercial thin-film composite (TFC) NF membrane (Filmtec NF-270) were tested simultaneously in the field using two SEPA cells. The testing was conducted at the Britannia Water Treatment Plant (Ottawa, ON) and the Walkerton Clean Water Centre (Walkerton, ON). The challenge waters were filter effluents spiked with ppt and ppb levels of carbamazepine (CBZP), ibuprofen (IBUP) and sulfamethazine (SFMZ). The new experimental modified CA membrane achieved very good IBUP removals, good SFMZ removals and poor CBZP removals. The commercial TFC NF membrane (NF-270) had better removals and significantly higher fluxes than the modified CA membrane. The larger removals are not surprising given that the commercial membrane is the result of extensive development and optimization, while the modified CA membrane has undergone very limited optimization. The larger flux of the NF-270 membrane is also expected given that this is a TFC membrane, while the experimental modified membrane was prepared via a single casting step via the phase inversion technique which produces a thicker skin layer.