Kinetic and Equilibrium Studies of Liquid-Phase Adsorption of Phosphate on Modified Sugarcane Bagasse

Phosphate removal from aqueous solutions was investigated using chemically modified sugarcane bagasse. The modified sugarcane bagasse (MSBG) is an agricultural by-product adsorbent with anion exchange functionality MSBG and raw sugarcane bagasse (SBG) were characterized by elemental analysis, zeta-potential analysis surface-area determination, and SEM. Adsorption kinetics and the equilibrium of phosphate between aqueous solutions and MSBG were studied. The adsorption capacity of MSBG was 21.3 mg center dot g(-1) at natural pH when 50 mg L-1 of phosphate solution was adsorbed by 0.100 g of sorbent. The kinetic data was fitted using a pseudo-first-order equation and a pseudo-second-order equation. Among the kinetic model studies, the pseudo-second-order equation was the best-fit model for describing the adsorption process. Equilibrium data were modeled using the Langmuir and the Freundlich isotherms. The Langmuir isotherm model fits much better than the Freundlich model. The desorption study indicated that the sorbent could be recovered in 0.05 M NaOH solution within 30 min. DOI: 10.1061/(ASCE)EE.1943-7870.0000408. (C) 2012 American Society of Civil Engineers.