Abstract
Treatment of discharges/effluents containing residual dyes has been a topic of interest for long. Adsorption is a widely accepted process for the treatment of industrial discharges containing dyes. The search for replacement of commonly used adsorbents - activated carbon - by locally available materials has gained importance. Adsorption of disperse yellow 22 (DY 22) using wood dust from local saw mills to treat effluents was studied and has given promising results. The operating parameters of adsorption process, initial solution pH, initial concentration, adsorbent dosage, adsorbate-adsorbent contact time influencing adsorption of DY 22 dye onto activated sawdust (ASD), were investigated. The optimum conditions were obtained by using response surface methodology (RSM). The batch adsorption experimental data were analysed by using Lageregan's pseudo-first-order and pseudo-second-order kinetic models and found that the adsorption of DY 22 onto ASD followed the pseudo-second-order kinetic model. The experimental data were fitted to Langmuir and Freundlich's isotherm models. The adsorption of DY 22 onto ASD was fitted satisfactorily with Langmuir's isotherm model with an adsorption capacity of 33.78 mg/g (R-2 = 0.99). Based on the experimental investigations, it is suggested that ASD is a potential effectual adsorbent for the removal of DY 22 from aqueous solution.