Kinetics and Thermodynamics of Cd( II) Sorption onto Sodium Alginate/Poly(vinyl alcohol)/Hydroxyapatite Composite Fiber

摘要

In this paper, the sodium alginate(SA)/poly(vinylalcohol)(PVA)/hydroxyapatite(HAp) fiber was prepared via solution spinning. The adsorption properties of SA/PVA/HAp composite fiber were studied, and the adsorption kinetics and isotherms were investigated. The experimental results showed that the adsorption process was fast, in which half-equilibrium and equilibrium was obtained in 5 and 30 minutes, respectively. The pseudo-second-order kinetic model provided a better correlation of the experimental results. Both of Langmuir isotherm and Freundlich isotherm could describe the adsorption behavior of SA/PVA/HAp composite fiber towards cadmium. The positive AH° value and increased absolute value of the AG° with temperature indicate that high temperature is good to the adsorption process.