COMPARATIVE STUDY OF NATURAL AND CHEMICALLY MODIFIED ADSORBENTS FOR PHENOL REMOVAL

Abstract

The contamination of water resources by phenolic compounds represents a significant environmental and public health concern due to their toxicity, persistence, and resistance to conventional biological degradation. This study provides a comprehensive comparative evaluation of natural and chemically modified adsorbents for the removal of phenol from aqueous systems. Adsorption is identified as an efficient and economically viable technique compared to alternative treatment methods. Natural adsorbents derived from agricultural biomass and mineral sources exhibit moderate adsorption capacities, primarily due to the presence of functional groups such as hydroxyl and carboxyl. However, their performance is substantially enhanced through chemical modification techniques, including alkaline and acid activation, as well as surface functionalization. Modified adsorbents demonstrate improved surface area, pore structure, and active site availability, resulting in significantly higher adsorption capacities. Advanced materials, particularly nanostructured adsorbents, show exceptional performance with capacities exceeding 1600 mg/g. The study further explores adsorption mechanisms, distinguishing between physisorption and chemisorption, and evaluates the influence of key operational parameters such as pH, temperature, and contact time. Kinetic and isotherm analyses reveal that the adsorption process predominantly follows pseudo-second-order kinetics and is well described by the Langmuir model. Overall, chemically modified adsorbents offer a highly effective and sustainable solution for phenol removal in wastewater treatment applications.