Adsorption of Ni(SO4) on Malaysian rubber-wood ash

The possible use of wood ash as an adsorbent of nickel sulphate from dilute solutions and the effect of operating parameters were investigated in this study. The rate constants of adsorption were determined at different conce ntrations and temperatures. The applicability of the first-order reversible equation and an empirical kinetic model were tested to understand the kine tics of nickel sulphate removal at different concentrations. Pore diffusion was found as the rate-controlling step. The Langmuir and Freundlich isothe rms were applied to find out the adsorption parameters. The activation ener gy of adsorption was -11.54 kJ mol(-1). The value of the enthalpy change wa s Delta H = -10.35 kcal mol(-1). (C) 1999 Elsevier Science Ltd. All rights reserved.