A novel composite adsorbent material, chitosan/activated carbon composite (CS-AC), was synthesized using a solution blending method for use in wastewater treatment. The structure and physicochemical properties of the composite adsorbent material confirmed its formation. The surface morphology of the composite showed a porous structure, which is suitable for adsorption. The elemental composition showed the presence of C, O, and N uniformly distributed within the composite structure. The crystal structure showed the semi-crystalline structure of chitosan and the amorphous structure of activated carbon. The functional group showed the presence of –OH, –NH₂, and –CO functional groups, which are responsible for metal ion adsorption. The composite adsorbent showed a high surface area of 283.87 to 312.76 m² g⁻¹, indicating a well-developed structure for adsorption. The thermal stability of the 40% composite after adsorption showed a low loss of 35% or less than 600 °C. In batch adsorption tests, high removal rates were achieved for Pb(II), COD, and BOD. Optimal adsorption conditions were achieved at 100-150 min contact time, 70-90 °C temperature, and 0.8-1.2 g adsorbent dosage, at which removal rates were higher than 99% for Pb(II) and 95% for COD and BOD. The adsorption capacity was found to increase with increasing adsorbent dosage and temperature, indicating improved adsorption interactions. The isotherm data were well correlated with the Langmuir isotherm equation, suggesting that the monolayer adsorption capacity was in the range of 85-120 mg g⁻¹. It was identified in this study that the composite of CS-AC with 40% AC loading has the fastest adsorption rate, highest adsorption capacity, and highest reusability, thus emphasizing the importance of AC loading in improving wastewater treatment performance. The pseudo-second-order kinetic equation was used to describe the adsorption kinetics, suggesting that chemisorption is the rate-controlling mechanism. Thermodynamic studies showed that the adsorption process is spontaneous and endothermic. The optimized CS-40%AC composite demonstrated good reusability, retaining over 78% of its initial Pb(II) removal efficiency after five consecutive cycles, suggesting that it is stable, reusable, and has potential as an eco-friendly adsorbent in advanced wastewater treatment.
Baba et al. (Fri,) studied this question.