Modification of Activated Carbon from Pomelo Peel and Its Adsorption Properties of Isoprene

Pomelo (Citrus maxima) peel was used to prepare activated carbon. Modified activated carbon was resulted by alkaline solution and by treatments with NaNO₂, KMnO₄, and (NH₄)₂S₂O₈. Experiment was carried out on different modified pomelo peel biochar to adsorb and recover isoprene from VOCs for the degradation of benzene pollutants. The results showed that the absorption process of isoprene by NaNO₂, KMnO₄, and (NH₄)₂S₂O₈ modified pomelo peel biochar followed a pseudo-second-order kinetics, indicating that the reaction rate was proportional to the square of reactant concentration. Thermodynamic experiments revealed significant conformity to the Langmuir model, while poor fitting with the Freundlich model, suggesting negligible reference value of 1/n parameter. The result indicated monolayer adsorption and uniform adsorption site energies. Among them, (NH₄)₂S₂O₈ modified pomelo peel biochar had the highest adsorption capacity for isoprene at 25℃, with a value of 3.93 mg/g.