Utilization of Sawdust-Based Materials as Adsorbent for Wastewater Treatment

Abstract

Sawdust, a very low-cost material, has been utilized as adsorbent material for the removal of Zn(II) ions from aqueous solutions after treatment with citric acid. Three levels of esterified sawdust were prepared via reaction of sawdust with citric acid at elevated temperature. The esterified samples were characterized by estimating the carboxyl content expressed as m.eq.–COOH/100 g sample. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent concentration, extent of modification, and adsorbate concentration on the adsorption capacity of Zn(II) ions onto esterified sawdust. Langmuir and Freundlich models were applied in the adsorption studies. The adsorption capacity, qe (mg/g), of Zn(II) on esterified sawdust increases by increasing the extent of esterification, expressed as m.eq. –COOH/100 g sample. Maximum values of adsorption capacity, Qmax, are 0 and 270.27 mg/g on native and esterified sawdust, respectively. The equilibrium data were better fitted by the Freundlich adsorption model than the Langmuir model.