Investigation of biochar from Cedrella fissilis applied to the adsorption of atrazine herbicide from an aqueous medium

Abstract

Biochar was produced from the sawdust of the wood forest species Cedrella fissilis and later used as an adsorbent to remove atrazine herbicide from aqueous media. Biochar showed high thermal stability, an amorphous structure, and a highly irregular surface, mainly composed of carbon-containing bonds. The isothermal curves confirmed that the increase in temperature favored the adsorption of the herbicide. The Langmuir model best suited the experimental equilibrium data, with the maximum adsorption capacity of 7.68 mg g-1 at 328 K. The thermodynamic parameters confirmed a spontaneous process of an endothermic nature governed by physical interactions (interactions of van der Waals and hydrogen bonds). Kinetic studies showed that equilibrium was reached within 180 min. The linear driving force model (LDF) showed good statistical adjustment to the experimental data, where it was observed that the diffusion coefficient increased with the concentration of adsorbate. Biochar can be reused in up to three cycles. Finally, the adsorbent showed good efficiency in real water samples from rivers contaminated with atrazine, with 76.58% and 71.29% removal.