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Simultaneous nutrients (N,P) removal by using a hybrid inorganic sorbent impregnated with hydrated manganese oxide

Abstract:

A natural clinoptilolite zeolite (Z-N) and its hybrid form (Z-Mn) prepared by impregnation with hydrated manganese oxide have been evaluated for the simultaneous removal of ammonium and phosphate. The ammonium sorption capacity reported by Z-Mn was 23 ± 2 mg N-NH4+/g; while the phosphate uptake reached 5.6 ± 0.2 mg P-PO43-/g at pH 7.5. Both ammonium and phosphate uptake were slightly influenced coexisting ions commonly found in treated wastewater effluents. The Mn(II) activated zeolite (Z-Mn) improved the phosphate uptake capacity, in the pH range 7-9, by formation of surface complexes of P(V) anions with the precipitated Mn(II) hydrated oxide or by formation of mineral phases as Mn(II)-NH4-PO4 (e.g., (NH4MnPO4·H2O)) which was detected by XRD analysis. The soil bio-availability test of loaded impregnated zeolites reported higher ammonium than phosphate bio-availability. The desorption of ammonium and phosphate from the loaded manganese impregnated zeolites using 40 gL-1 NaOH solution in dynamic experiments reported higher recoveries and concentration factors of ammonium than phosphate.