In the present study, the activated carbon was prepared by chemically activating polymer waste under the influence of potassium hydroxide (KOH). The pore properties including the Brunauer-Emmett-Teller (BET) surface area, the volume of the pore, its size distribution, and average diameter were also characterized herein. The present study also evaluated the ability of the activated carbon to remove naproxen sodium, tannic acid, and caffeine from aqueous solutions through a process of adsorption. The equilibrium isotherms employed for the adsorption of drug organics onto the activated carbon were measured experimentally. The obtained results were analyzed by employing the Redlich-Peterson, Dubinin-Redushkevich, Temkin, Frumkin, Halsey, and Henderson equations by using a linearized correlation coefficient and statistically at varied temperatures. The models and the isotherm constants were evaluated based on the changes in the temperature. Among all, the Redlich-Peterson equation was determined to best represent the equilibrium data for the adsorption of naproxen sodium, and caffeine onto the activated carbon.