AbstractActivated carbon derived from biomass waste, namely palm shell, was evaluated as a potential adsorbent for the removal of Reactive Black 5 dye (RB5) from an aqueous solution. This work focused on the equilibrium isotherms and the kinetics of the adsorption process. Batch adsorption tests were conducted to determine the effects of various parameters, such as contact time, RB5 concentration, adsorbent dose, temperature, and initial solution pH, on the treatment performance. The adsorption capacity of the adsorbent used in the study was higher in an acidic medium. The Langmuir model provided the best fit for the obtained equilibrium isotherm data, while the adsorption kinetics was best represented by the pseudo-first-order model. RB5 adsorption was endothermic in nature, with an activation energy of 12.6 kJ/mol. The maximum adsorption capacity of the adsorbent was 25.1 mg/g at pH 2. Palm shell-based activated carbon is shown to have great potential in the adsorption of RB5 from aqueous solution.