Removal of 4-Picoline from Aqueous Solution by Adsorption onto Bagasse Fly Ash and Rice Husk Ash: Equilibrium, Thermodynamic, and Desorption Study

Abstract

This paper deals with the adsorption of 4-picoline (4Pi) from aqueous solutions onto bagasse fly ash (BFA) and rice husk ash (RHA) as adsorbents. We discuss the effect of several parameters, such as initial pH, adsorbent dose, contact time, initial concentration, and temperature, on the batch adsorption. We collected equilibrium sorption isotherm data, which could be well-represented by the Redlich-Peterson, Toth, and Radke-Prausnitz isotherm equations. The maximum removal of 4Pi was found to be 46% and 96% by BFA, and 55% and 95% by RHA for lower (50 mg/L) and higher (600 mg/L) concentration of 4Pi, respectively, with sorbent dosages of 5 g/L for BFA and 20 g/L for RHA. Adsorption was found to be very fast, and about 72–90% of 4Pi removal was achieved in the initial 5 min of contact time. We found the sorption of 4Pi on BFA and RHA to be endothermic in nature. The spent adsorbents can be dried and used as a cofuel in boiler furnaces/incinerators.