LAUSR

Groundwater contains high levels of dissolved ions, which pose health risks when consumed. This study proposes biochar production for fluoride (F ‒ ) removal from aqueous solutions using sustainable materials and functionalization processes.Biochar derived from coffee grounds carbonization at 500 °C was functionalized with hydrogen peroxide (H 2 O 2 ). Structural morphology analysis utilized SEM+EDS, BET, and BJH techniques, while XRD and FTIR analyses assessed surface chemistry. Effects of pH, dosage, and initial F ‒ concentration on adsorption were evaluated, along with kinetics and thermodynamics.H 2 O 2 increased acid functional groups on the surface without significantly altering surface area or pore volume. The highest adsorption capacity (0.179 mg g -1 ) and removal efficiency (25.5%) were at pH = 4. Kinetic studies highlighted the influence of initial F ‒ concentration on adsorption equilibrium time and capacity. Experimental data fitting to pseudo-second-order and Elovich models suggested chemical mechanisms predominance, with intraparticle diffusion as the rate-limiting step. Adsorption isotherm fitting to Langmuir and Freundlich models indicated physical and chemical processes combination. The highest adsorption capacity was recorded at 1.46 mg g ‒1 at 55 °C. Thermodynamic analysis revealed endothermic and non-spontaneous nature, potentially affecting F ‒ affinity towards the adsorbent.