PEG promoted anti-fouling adsorptive membranes with excellent adsorption performance for removal of pharmaceuticals from water

Rapid and effective removal of pharmaceutical contaminants (PhCs) from water through adsorptive approach remains a huge challenge due to the multiple ionization sites and lipophilic property of most PhCs. Another issue for adsorptive media is the tough trade-off problem between adsorption enhancement and fouling-resistance. Adsorptive membranes have the advantages of convenient post-treatment and huge promise in removing PhCs compared with conventional adsorbents. Herein, two types of PEG-coupled ionic grafting adsorption membranes (NVFM-H-PEG and PPM-PMA-PEG) with outstanding adsorption and antifouling performance are developed for PhCs removal. The membranes obtained shows ultra-high water flux (up to ca. 45,000 L/(m2h) at a pressure drop of 15 cm water gravity) and outstanding protein repulsion. According to the Langmuir model, the adsorption capacity of NVFM-H-PEG toward ibuprofen (IBU) reaches at 81.3 mg/g at 45 celcius. The large negative & UDelta;G value (-22.0 kJ/mol) reveals the strong affinity of the positively charged NVFM-H-PEG to adsorb negative PhCs at environmental concentrations (10 & mu;g/L). A mechanism for the excellent adsorption performance of the mem-branes is proposed based on the synergy of hydrophobic interactions and electrostatic interaction. After ten adsorption/eluting cycles, no detectable decrease was observed in the removal efficiency (>96%) of IBU from the river contaminated with IBU. Furthermore, high removal efficiency (totally 90.8%) could be achieved from river water multi-contaminated with five PhCs using a complex of positively charged (NVFM-H-PEG) and negatively charged (PPM-PMA-PEG) membranes. This study provides a new design strategy for effective removing PhCs from contaminated water using adsorptive membrane technique.