Cu(II) iyonlarının poli(2,5-dihidro-2,5-dimetoksifuran) üzerine adsopsiyonu

Abstract

Poly(2,5-dihydro-2,5-dimethoxyfuran), pDMHF, was obtained from thepolymerization of cis,trans-2,5-dihydro-2,5-dimethoxyfuran, DMHF, withSnCl4 in dioxane. The FT-IR spectroscopic characterizations showed the ringopening and formation of C=O, Oâ??H and â??C(O)â??OH groups in the structureof polymer. The observed decrease in the pH of the adsorption solutionsupported the presence of acidic groups in the structure of the resin also.The SEM analyses of the resins indicated a rough surface for the resins.The maximum adsorption of Cu2+ ions on pDMHF was found to takeplace at pH=5.0. It was calculated that for each adsorbed Cu2+ ionapproximately 3 H3O+ ion (ca. 3H3O+/Cu2+) was released to the solution.The adsorption capacity of pDMHF was intended to increase byfunctionalization with H2SO4, HNO3, NH3 and NaOH solutions with differentconcentrations. An increase in adsorption capacity, ca. 2.5-3.0 times, wasobserved for NaOH treatment. FT-IR analyses showed the increase in â??OHcontent and neutralization of carboxylic acid groups by NaOH treatment.During adsorption, NaOH/pDMHF did not change the pH of the adsorptionsolution. This supported the formation and neutralization of carboxylic acidgroups, also.The kinetic studies showed a second order adsorption mechanismwhich follows Langmuir isotherms with high correlations.The desorption properties of pDMHF was studied also. Maximumdesorption (ca. 20%) was obtained in 0.1 M EDTA solution. Studies with Cu2+and Cd2+ mixture (1:1) indicated 70% selectivity toward Cu2+ ions.Key Words : Poly(2,5-dihydro-2,5-dimethoxyfuran), Cationic polymerization,Adsorption, Heavy metal adsorption