Abstract: 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 (H2O2). 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.H2O2 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.