Removal of the hazardous, volatile, and organic compound benzene from aqueous solution using phosphoric acid activated carbon from rice husk.

BACKGROUND: Benzene is one of the most hazardous organic pollutants in groundwater. The removal of benzene from water is very important from a health point of view and for environmental protection. In this study, benzene adsorption kinetics was investigated using phosphoric acid activated carbon, prepared from rice husk. RESULTS: An initial rapid uptake of benzene was observed and became almost constant after 40 minutes of contact. Kinetic data was analyzed using pseudo first order, pseudo second order, and Elovich equations. Kinetic data was well fitted to pseudo-second order models (R(2) = 0.98), indicating chemisorption. Results from intraparticle diffusion and Boyed models indicate that particle diffusion is the most probable operating mechanism and does not control the kinetics of benzene sorption. A comparative study on the benzene adsorption revealed that the rice husk carbon (RHC) had better benzene adsorption capacity (365 mg/g) as compared to other adsorbents. CONCLUSIONS: In conclusion, we have demonstrated that rice husk carbons are efficient benzene adsorbents and that they possess a good potential for benzene removal in wastewater treatment. Graphical AbstractPhosphoric acid activated carbon from rice husk and benzene adsorption mechanism.