Kinetics and Thermodynamics of Sodium Alginate/Hydroxyapatite Composite Adsorption Fiber for Cd(II) Adsorping

In this study, kinetics and thermodynamics of sodium alginate/ hydroxyapatite composite adsorption fiber for adsorping Cd () were studied. The morphology and structure were characterized by SEM and IR, and the effects of pH value and bath ratio on Cd () adsorption were discussed. The model of adsorption kinetics and thermodynamics were simulated, and the parameters were calculated. The results showed that the sodium alginate/hydroxyapatite composite adsorption fiber possessed good adsorption ability towards Cd (). The optimum adsorption was found at the pH value of 6-7. High removal percent of more than 90% at low concentration and high concentration of Cd () was obtained at the bath ratio of 1:100 and 1:1000, respectively. The adsorption kinetics and thermodynamics studies showed that the pseudo-second-order model and Freundlich isotherm described the adsorption behaviors well. The thermodynamic parameters indicated that the adsorption of Cd () onto sodium alginate/hydroxyapatite composite adsorption fiber was physical and chemical sorption, endothermic in nature.