Kinetic, isotherm and mechanism in paraquat removal by adsorption process using corn cob biochar produced from different pyrolysis conditions

Abstract

This work studied the isotherm, kinetic and mechanism of Paraquat adsorption in aqueous solution by using corn cob biochar produced from different pyrolysis temperatures and times. The kinetic and isotherm data was fitted by the Pseudo-second-order and Langmuir models. These results showed that the adsorption capacity decreased with increasing pyrolysis temperatures during 6 hours in the order 200, 300, 400, 500, 600 °C and decreasing pyrolysis time in the order 2, 3, 4, 5, 6 hours, respectively at 200 °C. The mechanisms possibly contributed to hydrogen bonding and pore filling while π-π interaction was minor contributor in the adsorption process. Therefore, the corn cob biochar can become an alternative and promising adsorbent for Paraquat removal from an aqueous solution.