Removal of Bisphenol A and 17β-Estradiol in Carbon Nanotube-UF Membrane System for Drinking Water Treatment

摘要

Retention and adsorption of endocrine disrupting compounds such as bisphenol Arn(BPA) and 17β-estradiol (E2) was examined using a commercially availablernultrafiltration (UF) membrane. A stirred cell operated in a batch dead-end stirred-cell wasrnemployed to study solute retention and the membrane flux of solutions in the absence andrnpresence of natural organic matter (NOM) and single-walled carbon nanotubes (CNTs)rnunder different pH conditions. Both batch adsorption and stirred-cell filtrationrnexperiments indicated that adsorption is an important mechanism for the retention ofrnhydrophobic compounds and is related to the octanol-water partition coefficient. Thernresults also indicated that BPA and E2 transport is influenced by NOM because it foulsrnthe membrane by causing pore blockage and cake/gel formation. The percentagernretention of BPA/E2 during the UF filtration in the absence and presence of NOM andrnCNTs (at pH 7.5 and cumulative permeate volume of 500 mL) were 20.2/10.3rn(membrane only), 8.6/6.3 (NOM), 77.6/95.2 (CNTs), and 62.8/80.6 (NOM+CNTs).rnAlthough retention and adsorption showed similar relationships at pH 4 and 7.5, their raterndecreased at pH 11.