Amidoximation of Cyano Group for Chelating Ion Exchange of Some Heavy Metal Ions

What is it about?

Ion exchange behavior of some heavy metal ions, Pb2+, Ni2+ and Cd2+, onto amidoximated polyacrylonitrile based Ce(IV) phosphate was investigated. Polyacrylonitrile based Ce(IV) phosphate was prepared and followed by functionalization of the cyano group to amidoxime group with hydroxylamine. The amidoximated resin was characterized using FT-IR and SEM. Removal of Pb2+, Ni2+ and Cd2+ ions from aqueous solution was examined by studying some factors using batch technique such as effect of pH, contact time, initial metal ion concentration and temperature. Some kinetic and isotherm models had been applied. The calculated amount sorbed values in case of pseudo-second-order are more closer to the experimental data than that of pseudo-first-order model, and with a correlation coefficients R2 >0.99. Therefore, the sorption of the three metal ions can be approximated more favorably by the pseudo-second-order model. The sorption process obeys Freundlich isotherm model. The sorption has endothermic nature which is indicated by the positive value of the enthalpy change, ΔH, the high positive values of the entropy change, ΔS, show the increased randomness at the solid/solution interface. The obtained negative values of free energy change, ΔG, indicating the feasibility and the spontaneous nature of the sorption process.

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Why is it important?

Amidoximated polyacrylonitrile based Ce(IV) phosphate was prepared as a new ion exchanger which did not used before in existing literature. It is characterized by high capacity, compared to other materials in literature, it was used for studying the possibility of separation of some heavy metal ions from wastewater to overcome the difficulties facing the wastewater treatment process. The scientific impact of the work is the protection of human and environment from hazardous materials.