The kinetics and mechanism of methylene blue (MB) adsorption onto activated carbon fibers (ACFs) have been studied. The effects of various experimental parameters, such as the initial MB concentration and the ACF mass...The kinetics and mechanism of methylene blue (MB) adsorption onto activated carbon fibers (ACFs) have been studied. The effects of various experimental parameters, such as the initial MB concentration and the ACF mass, on the adsorption rate were investigated. Equilibrium data were fit well by a Freundlich isotherm equation. Adsorption measurements show that the process is very fast. The adsorption data were modeled using first- and second-order kinetic equations and intra–particle diffusion models. It was found that the first-order kinetic equation could best describe the adsorption kinetics. The adsorption process was found to be complex and controlled by both surface and pore diffusion with surface diffusion at the earlier stages, followed by pore diffusion at the later stages. The thermodynamic parameters △G0, △S0 and △H0, have been calculated. The thermodynamics of the MB-ACF system indicate that the adsorption process is spontaneous.展开更多
基金Projects 20676110 supported by the National Natural Science Foundation of China20070421103 by the China Postdoctoral Science Foundation+1 种基金2006CB202202 by the National Basic Research Program of China06jk244 by the Special Fund of Shaanxi Education Department
文摘The kinetics and mechanism of methylene blue (MB) adsorption onto activated carbon fibers (ACFs) have been studied. The effects of various experimental parameters, such as the initial MB concentration and the ACF mass, on the adsorption rate were investigated. Equilibrium data were fit well by a Freundlich isotherm equation. Adsorption measurements show that the process is very fast. The adsorption data were modeled using first- and second-order kinetic equations and intra–particle diffusion models. It was found that the first-order kinetic equation could best describe the adsorption kinetics. The adsorption process was found to be complex and controlled by both surface and pore diffusion with surface diffusion at the earlier stages, followed by pore diffusion at the later stages. The thermodynamic parameters △G0, △S0 and △H0, have been calculated. The thermodynamics of the MB-ACF system indicate that the adsorption process is spontaneous.
