Abstract
This study demonstrates the effective production of biochar (EWB) from eucalyptus wood waste as a novel, sustainable adsorbent for Arsenic (As(V)) removal from wastewater. EWB achieved over 95% removal efficiency under optimal conditions: initial As(V) concentration of 40 ppm, contact time of 120 min, temperature of 60 °C, adsorbent dose of 0.80 g, and pH 6. Characterisation by SEM, FT-IR, and surface area analysis revealed functional groups and a porous structure conducive to adsorption. To study adsorption, the pseudo-first-order, pseudo-second-order, Langmuir, Freundlich, Temkin, Jovanovich, and Harkins-Jura isotherms were analysed. Kinetic studies revealed that the process followed a pseudo-first-order model, while the equilibrium data fitted the Langmuir isotherm, indicating monolayer adsorption. Thermodynamic parameters (ΔS°, ΔG°, ΔH°) confirmed that the adsorption was spontaneous and endothermic. EWB offers a cost-effective and environmentally friendly alternative with potential for treating industrial arsenic wastewater.