The production and consequently the consumption of the pulp of the fruit of the palm tree Bactris guineensis occurs extensively in Colombia. The majority of the fruit is formed by waste (peel and core), producing high residual biomass. Thus, it is necessary to find a practical utilization of these peels, making the production and consumption of the fruit of the palm tree Bactris guineensis highly sustainable. This study produced activated biochar chemically activated using ZnCl2 and utilized it as an effective adsorbent. The high micropollutant uptake is because of the high porosity and good specific surface area (SBET = 625 m2 g−1). Under basic conditions, propranolol adsorption was favored for an adsorbent dosage of 0.7 g/L. The adsorbent showed fast kinetics, with the equilibrium influenced by the concentration. Avrami's model showed a satisfactory fit having a t0.95 ranging from 47.8 to 179.3 min. Equilibrium data were best adjusted to the Liu isotherm model. The values of Qmax increased with the temperature, reaching up to 161.3 mg g−1 (45 °C). The thermodynamic data showed ΔG° < 0 for 298–328 K (adsorption process favorable) ΔH°= + 7.403 kJ mol−1 (endothermic; magnitude compatible with physical adsorption), and ΔS°= +115.2 J K−1 mol−1 (releases of water molecules of the adsorbate before it being adsorbed in the carbon surface). The biochar chemically activated with ZnCl2, produced from the leftover peels of Colombian palm fruits, is therefore inferred to be a promising option as an adsorbent for the treatment of effluents containing the medication propranolol hydrochloride.