Phosphoric acid modified-Y zeolites: A novel, efficient and versatile ion exchanger

Abstract

Large pore HY zeolite was modified with phosphoric acid by wet method. The modified zeolite was converted to Na + form using aqueous NaHCO 3 solution . The Na + form of modified zeolite, represented as PNa 2Y, was characterized by XRD, BET surface area, SEM, and AAS techniques. The XRD analysis showed diffraction patterns same as that of parent HY zeolite, as a result there has been no structural degradation during modification. It was then tested for sorption of Cu 2+ ions from aqueous solution. The Cu 2+ content of the solution was analyzed by AAS. PNa 2-Y shows higher sorption capacity (≈40%) than the parent Na-Y (≈23%) zeolite, which is attributed to the double of amount Na + content in PNa 2-Y compared to the Na-Y zeolite. Equilibrium modeling data were found to fit more to the linear Langmuir model than the Freundlich model. The thermodynamic parameters such as change in free energy (Δ G°), enthalpy (Δ H°), and entropy (Δ S°), were also calculated. These parameters confirmed that the sorption of Cu 2+ is feasible, spontaneous and endothermic.