Muhammad Ali Zulfikar, Henry Setiyanto, and Samitha Dewi Djajanti

pp. 309 - 316

Abstract

The sorption of lignosulfonate onto powdered eggshell under the influence of temperature has been studied. The rate
of adsorption onto eggshell was investigated under a variety of adsorbent dosages. The kinetic data from these investigations
were correlated to a number of adsorption models in an attempt to elucidate the mechanism of the adsorption processes.
Thermodynamic parameter data indicated that the lignosulfonate sorption process was non-spontaneous and endothermic
under the experimental conditions, with the Gibbs free energy (ΔG^o) in the range of 1.83-1.07 kJ mol^-1, enthalpy (ΔH^o) and
entropy (ΔS^o) of 5.66 kJ mol^-1 and 12.82 J mol^-1, respectively and the activation energy of 18.17 kJ mol^-1. The adsorption
mechanism was found to follow a pseudo-second-order model, with the kinetic constants in the range of 0.689–1.430 g mg^-1
min^-1. Both the intra-particle diffusion and Boyd kinetic models indicated that boundary layer/film diffusion was the main rate
determining step in lignosulfonate adsorption process.