Trioctylphosphine oxide (TOPO) was immobilized in polypropylene hollow fiber membranes for removal of phenol from wastewater. Scanning electron microscopy showed white deposits of TOPO dispersed non-uniformly within the resulting extractant-impregnated hollow fiber membranes (EIHFM). The EIHEMs manifested high adsorption capacity and mass transfer rates, with adsorption equilibrium attained within 10-30 min of operation. Experimental equilibrium adsorption capacities with a feed of 1000 mg/L phenol were 32, 42, 52 and 57 mg/g at 50, 100, 200 and 400 g/L TOPO, respectively. During repeated operation with 1000 mg/L phenol, the adsorption capacities of the EIHEMs remained stable at 32.2 +/- 1.3 and 52.3 +/- 0.9 mg/g for 10 subsequent runs at TOPO concentrations of 50 and 100 g/L, respectively. The EIHEMs, when used as adsorbents in a two phase partitioning bioreactor, alleviated substrate inhibition on Pseudomonas putida by rapidly adsorbing phenol to sub-inhibitory levels. Biodegradation of 1000 and 2000 mg/L phenol was completed within 26 and 36 h, respectively. These results suggest that the EIHFM is a promising technology for solventless extraction of aromatic compounds in wastewater treatment. (C) 2013 Elsevier B.V. All rights reserved.
