Adsorption of acrylonitrile from aqueous solution using bagasse fly ash

The adsorption of acrylonitrile (AN) by bagasse fly ash was studied at the temperature of 303 K with different initial concentrations of AN (50, 100, 200, and 500 mg/l). Removal and the effect of initial pH, adsorbent dosage (m), and contact time (t) on the kinetics of the sorption process were also studied. Optimum conditions for AN removal were found to be m ≈ 4 g/l of solution and the equilibrium time ≈5 h. Three kinetic models viz. the pseudo-first-order, pseudo-second-order and Intra-particle diffusion models were tested to study the dynamics of the AN-BFA system. Results show that the adsorption process was best represented by the pseudo second-order equation. It was also observed that the isosteric heat of adsorption is high at very low coverage and decreases steadily with an increase in qe indicating that BFA has energetically heterogeneous surfaces. The spent BFA loaded with AN can be disposed off in the boilers/incinerators, or can be used for the production of fuel-briquettes, so as to utilize the energy of the BFA and AN.