Phosphate removal fromaqueous solution using a hybrid impregnated polymeric sorbent containing hydrated ferric oxide (HFO).

BACKGROUND: This study evaluated a polymeric ion exchanger impregnated with nanoparticles of hydrated ferric oxide as a selective sorbent for anionic P(V) species. The hybrid impregnated anion exchanger (HAIX) employed as sorbent combines the durability and mechanical strength of a polymeric weak base anion exchange resin with the high sorption affinity of hydrated ferric oxide towards P(V) species. RESULTS: The P(V) loading capacity of the sorbent at a pH simulating the expected conditions in treated wastewaters was 92±3mg P-PO₄ g^-1 in single component solutions. The sorption of P(V) is affected slightly by the common ions typically present in these effluents such as Cl^-, SO_{4 2-} and NO₃-, and a reduction of only 5% was observed (89±2mg P-PO₄ g^-1) in multicomponent solutions. The sorbent can be regenerated (95±3%) using 4% (w/w) sodium hydroxide solution. CONCLUSIONS: HAIX displays high selectivity for phosphate and small affinity for SO₄ ^2-, NO₃- and Cl^- ions, which provides excellent conditions for its application at pH values typical of secondary wastewater effluents. HAIX exhibits higher and competitive phosphate removal capacity compared with data reported in the literature for materials based on HFO and for adsorbents prepared by impregnation of HFO onto polymeric supports. [ABSTRACT FROM AUTHOR]