Removal of hormones by NF
Selected nanofiltration (NF) and ultrafiltration (UF) membranes were tested for the removal of the natural hormone, 17 -estradiol (E2) using a lab-scale cross-flow filtration apparatus housing flat sheet membrane coupons. The primary focus of this study was to understand adsorption and desorption characteristics of E2 at different water quality and operating conditions. The NF membranes showed a significant level of adsorption of E2 during the initial stage of filtration. The adsorbed E2 was easily desorbed when the feed solution was replaced with Milli-Q water. UF membranes showed much lower rejection than NF membranes, but did show a significant level of adsorption during the initial time period. On-going and future research will explore whether the results obtained at a high feed concentration are applicable to lower feed concentrations typical of those found in water treatment plants. The effect of natural organic matter (NOM) fouling of the membranes will also be considered.