Comparison of physical- and chemical-activated Jatropha curcas husk carbon as an adsorbent for the adsorption of Reactive Red 2 from aqueous solution

Abstract

An abundant lignocellulosic agricultural waste of jatropha husk was used to prepare jatropha husk carbon (JHC) and zinc chloride–activated jatropha husk carbon (ZAJHC) as an adsorbent for the removal of Reactive Red 2 (RR2) from water. Batch mode adsorption experiments were carried out and the parameters investigated include agitation time, dye concentration, adsorbent dose, pH and temperature. Adsorption equilibrium data were analyzed using Langmuir, Freundlich, and Dubinin– Radushkevich isotherm models for RR2 concentrations of 20–100 mg L−1. Langmuir adsorption capacity was found to be 12.5 mg g−1 for JHC and 100 mg g−1 for ZAJHC. The kinetic data are following closely the pseudo-second-order kinetic model. Acidic pH was favorable for the adsorption of RR2. The pH effect and desorption studies suggest that the ion-exchange mechanism might be the major mode of the adsorption process. Significance of this study provides the ZAJHC sample that shows excellent adsorbent toward the removal of RR2 from wastewater.