Adsorptive Removal of Uranium from Water by Sulfonated Phenol-Formaldehyde Resin

摘要

Adsorption characteristics of a sulfonated phenol-formaldehyde resin (SPR) have been studied for U removal from aqueous solution by means of batch method. Adsorption experiments have been carried out as a function of contact time, solution/adsorbent ratio, particle size and pH. Adsorption isotherm has been evaluated by changing adsorbent dosage in the range of 0.04-80 g/L at an initial uranyl nitrate concentration of 0.05 mol/L. The enormous adsorption capacity of 0.29 mol/g estimated from the plateau region of the S shaped isotherm is well comparable the Langmuir capacity of 0.31 mol/g. Equilibrium data are also adequately well described by the Freundlich and the Dubinin-Radushkevich (D-R) isotherm equations. The parameters of the isotherms and pH dependency of distribution coefficients (K-D) indicate that polymeric uranyl chains form on bidentate surface complex as a result of solute-solute interactions on the adsorbent surface. Both desorption and elution studies show that uranyl chains are irreversibly bounded on the SPR. Kinetic curves having a fast initial part followed by a slower process well fit both McKay model based on two-resistance diffusion and Nernst-Plank model with single diffusion coefficient.