Chemical Engineering Journal, Vol.319, 240-247, 2017
Mixed metal oxide coated polymer beads for enhanced phosphorus removal from membrane bioreactor effluents
Membrane bioreactors are effective and attractive for wastewater reclamation and reuse, but phosphorus polishing is required to meet more stringent environmental regulations. Mixed metal oxide coated beads compdsed of Fe-Ti bimetal oxides on a sulfonated polymer were fabricated, characterized, and tested for phosphorus removal from membrane bioreactor effluents. Ti doping substantially enhanced the adsorption rate and capacity of the coated beads, possibly due to more positively charged surfaces. The mixed metal oxide coated beads were highly selective to phosphate ions (selectivity factor >25) against background ions (e.g., Cl- , NO3-, and SO42-), although they were less selective against bicarbonate and organics. Regenerated beads showed greater adsorption performance than the virgin ones. Ca binding to mixed metal oxide layers was responsible for enhanced phosphorus sorption, presumably resulting from the formation of calcium phosphate. The phosphorus recovery from the exhausted column adsorber was successful with alkaline solution (e.g., >90% P was recovered at a NaOH load of 0.2 eq/L bed. Using mixed metal oxide chemically anchored on polymer beads for phosphorus sorption would be a promising complement to biological phosphorus removal. (C) 2017 Elsevier B.V. All rights reserved.