Zn2+ Ion Adsorption from Aqueous Solution Using Montmorillonite Clay Impregnated with Tri-n-octylamine

Montmorillonite (Mt) clay was used to remove zinc (Zn2+) ion from the aqueous solution. This clay material was modified (Mt-TOA) by impregnating trin-octylamine (TOA), a tertiary amine. The experiments on equilibrium and kinetics were done to analyze the effect of adsorbent amount (w, 0.05 to 0.3 g for Mt, 0.01 to 0.06 g for Mt-TOA), initial Zn2+ ion concentration (C-0, 15 mg.L-1 to 35 mg.L-1), pH (1 to 9), and contact time (t, 0 to 100 min) on the efficacy of both adsorbents. With a greater amount of adsorbent, the intake capacity of Mt and Mt-TOA for Zn2+ ion removal was found to lower but there was an increase in the separation efficiency. The optimum amount of Mt and Mt-TOA was found to be 0.1 and 0.01 g, respectively. The pH of the aqueous solution could be maintained at 7 to achieve a better adsorption of Zn2+ ion. In the kinetic experiments, after 90 min, the separation efficiency of Zn2+ ion from aqueous solution reached to a value of 86.68% with Mt (0.1 g) and 84.56% with Mt-TOA (0.01 g). Modeling of the equilibrium and kinetic data were done by using the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, and by using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, respectively, and the best fitted model is presented.