SORPTION PROPERTIES OF HYDROLYZED STARCH GRAFT COPOLYMERS IN THE REMOVAL OF CADMIUM (II) AND COPPER (II) IONS FROM AQUEOUS MEDIA

Authors: *Ekebafe L.O, Ogbeifun D.E, Okieimen F.E

DOI Info: N/A

ABSTRACT

Sorption properties of hydrolyzed starch graft poly (acrylic acid) and starch graft poly(acrylonitrile) copolymers as sorbents for the removal of Cd (II) and Cu(II) ions from aqueous solution in batch process were assessed. The copolymers were prepared using methods as reported in literature and were characterized in terms of morphology using scanning electron microscopy, confirmation of sorbents produced using Fourier transform infrared spectroscopy and thermal stability using thermogravimetric analysis. The effect of contact time, initial concentration and temperature were assessed to optimize the conditions for the sorption of the metal ions. The experimental data were subjected to analysis using the models; Langmuir, Freundlich, Temkin, Dubinin Radushkevich and Sips isotherm models. The Freundlich and the Sips isotherms confirmed the applicability of the models. The sorption capacity of the copolymers was found to be 118.61mg/g for starch graft poly (acrylic acid) and 115.83mg/g for starch graft poly (acrylonitrile). The sorption kinetics was assessed by Lagergren pseudo first order, pseudo second order, Elovich equation, Intraparticle diffusion and the liquid film diffusion models. The experimental data fitted very well with the Elovich equation and the Intraparticle kinetic models. The thermodynamic analysis showed that the sorption was a spontaneous and endothermic process. The results indicated that starch graft copolymers can be used as effective sorbents for Cd (II) and Cu (II) removal from aqueous media.

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