Studies of adsorption thermodynamics and kinetics of Cr(III) and Ni(II) removal by polyacrylamide

• Main Authors: Mousavi Zavvar Hassan, Hosseinifar Abdorrahman, Jahed Vahdat
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2012-01-01
• Series: Journal of the Serbian Chemical Society
• Subjects: adsorption; polyacrylamide; Cr(III); Ni(II); kinetic
• Online Access: http://www.doiserbia.nb.rs/img/doi/0352-5139/2012/0352-51391100172M.pdf

Polyacrylamide (PAA), as an adsorbent was investigated for the removal of Ni(II) and Cr(III) metal ions from their synthesized aqueous solutions. The different variables affecting the adsorption capacity of the adsorbent such as contact time, pH of the sorption medium, metal ions concentration and temperature of the solution were investigated on a batch sorption basis. The adsorption equilibrium data fitted best with the Langmuir isotherm model. The maximum adsorption capacities found to be 84.03 and 32.67 mg g-1 of the polyacrylamide for Cr(III) and Ni(II), respectively. Three kinetic models including the pseudo-first-order, pseudo-second-order and intraparticle diffusion equations were selected to follow the adsorption process. Kinetic parameters such as rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was indicated that the adsorption of both ions onto polyacrylamide could be described by the pseudo-second-order kinetic model. Different thermodynamic parameters such as ΔH◦, ΔS◦ and ΔG◦ have also been evaluated and it has been found that the sorption was feasible, spontaneous and exothermic.