Bauhinia monandra derived mesoporous activated carbon for the efficient adsorptive removal of phenol from wastewater

The quality evaluation of the activated carbon made from agricultural waste is investigated in the adsorption of phenol. Adsorbent was prepared through the activation of orthophosphoric acid, producing a structure that is porous with a surface area of 1090 m²/g. Elemental composition analysis confirmed that the carbon composition is 78.23%. X-ray photoelectron spectroscopy (XPS) and other characterizations were conducted to study the structural, chemical and thermal performance metrics. The results from the Boehm titration were aligned with the point of zero charge. Response Surface Methodology was used to optimize adsorption parameters. The adsorption outcomes demonstrated the effectiveness of phenolic removal, with the Langmuir isotherm under optimal conditions exhibiting a maximum adsorption capacity of 185.93 mg/g. The study on the kinetics of adsorption showed that they closely matched the second-order pseudo model (R² > 0.98). Thermodynamic studies indicate that adsorption occurs spontaneously, as evidenced by negative ΔG° values. This further validates its exothermic nature and decreases randomness at the solid–liquid interface, as indicated by negative ΔH° and ΔS° values. The adsorbent regeneration and spiking studies were methodically examined. Activation energy and isosteric heat of adsorption were assessed. The adsorption mechanism is discussed thoroughly. These results highlight the effectiveness of activated carbon as a practical adsorbent for treating wastewater.