Modification of a natural zeolite with Fe(III) for simultaneous phosphate and ammonium removal from aqueous solutions

Abstract

AbstractBACKGROUNDThe incorporation of Fe(III) was performed in a natural clinoptilolite (Z‐N) for simultaneous phosphate and ammonium removal.RESULTSThe existence of hydroxyl groups (≅Fe‐OH) in the iron zeolite (Z‐Fe) enhances the phosphate uptake from 0.6 ± 0.1 mg‐P g−1 in Z‐N to 3.4 ± 0.2 mg‐P g−1 in Z‐Fe. However, the ammonium sorption capacity slightly decreases from 33 ± 2 mg‐N g−1 in Z‐N to 27 ± 2 mg‐N g−1 in Z‐Fe. The equilibrium and kinetics sorption were well explained by the Langmuir isotherm and the intraparticle diffusion model, respectively.CONCLUSIONSBoth the phosphate and ammonium uptake were slightly affected by the coexistence of competing ions. The phosphate sorption capacity of iron zeolite was decreased in the regeneration cycles. Desorption using a 1 mol L−1 NaOH solution under dynamic conditions provided higher enrichment factors for ammonium than phosphate. © 2015 Society of Chemical Industry