Adsorption of Butylparaben and Methylene Blue from Aqueous Solution Using Activated Carbon Derived from Oak Bark

This study presents the production of activated carbon through the direct physical activation of oak bark using carbon (IV) oxide. The activation process was conducted at three distinct temperatures of 700 °C, 800 °C, and 900 °C. The activation time was 60 min. A comprehensive series of analytical procedures was performed on the resultant adsorbents. These included elemental analysis, determination of textural parameters, Boehm titration, pH determination of aqueous extracts, pH_pzC0, assessment of ash content, and elemental and XPS analysis. Subsequently, adsorption tests for butyl paraben and methylene blue were carried out on the materials obtained. The total surface area of the sorbents ranged from 247 m²/g to 696 m²/g. The acid-based properties of the samples tested were examined, and the results indicated that the sorbents exhibited a distinct alkaline surface character. The sorption capacities of the tested samples for butylparaben ranged between 20 and 154 mg/g, while the capacities for methylene blue varied between 13 and 224 mg/g. The constants of the Langmuir and Freundlich models were determined for each of the impurities, as well as the thermodynamic parameters. The present study investigates the influence of contact time between adsorbent and adsorbate, in addition to the kinetics of the adsorption processes. The activated carbon samples obtained demonstrated satisfactory sorption capacities, with the material obtained at 900 °C exhibiting the best sorption capacities.