Adsorption behavior and mechanism of atrazine on biochar obtained from the peanut shell

Abstract

A series of peanut shell (PS) based biochar were prepared by the direct pyrolysis (BPS) and subse-quent hydrothermal treatment procedures with water (HPS) and potassium carbonate (K2 CO3 ) (KPS). The obtained PS-based biochars were applied as the effective adsorbents to remove atrazine (ATZ) in aqueous solution. The characterization analysis demonstrated that the PS-based biochar treated with KPS had large specific surface area (335.27 m2 g–1), abundant pore structure and surface functional groups. The results show that 98% of ATZ removal efficiency within 3 h was achieved in the KPS-adsorption process and the maximal adsorption (Qm ) of ATZ adsorption was 11.78 mg g–1. Besides, the effects of dosage, initial concentration, and solution pH on ATZ adsorption were sys-tematically evaluated. Moreover, the regeneration ability of KPS was evaluated through cycle trial. Furthermore, the isotherms, kinetics and thermodynamic of the PS-based biochar on ATZ adsorp-tion were also explored. The results demonstrated that the ATZ adsorption followed the pseudo-second-order kinetics model, and the Freundlich isotherm model was able to adequately describe the adsorption on ATZ. In conclusion, the PS-based biochar modified by K2 CO3 hydrothermal treatment can be used as an efficient adsorbent for the removal of ATZ from wastewater.