Cobalt oxide doped polyaniline composites for methyl orange adsorption: Optimization through response surface methodology

In this study, Cobalt Oxide (Co₃O₄) cube-doped polyaniline (PANI) composites were successfully synthesized through an in-situ oxidative polymerization process, with the primary objective of effectively eliminating Methyl Orange (MO) from aqueous solutions. The model dye MO was employed to assess the adsorption efficiencies of both PANI homopolymer and Co₃O₄ cube-doped composites. The results unequivocally reveal that the composites containing Co₃O₄ cubes exhibit significantly higher adsorption efficiency compared to undoped PANI. The adsorption kinetics adhere to a pseudo-second-order reaction, highlighting the exceptional effectiveness of these composites in MO adsorption. Furthermore, Response Surface Methodology (RSM) was employed to optimize the critical process parameters for MO removal. Utilizing a quadratic model generated by RSM, the study systematically explored the interplay between several key factors, namely initial pH, contact time, concentration, and temperature, and their impact on the removal rate of MO. Through a comprehensive analysis of the RSM model and experimental results, the optimal conditions for MO removal were identified, achieving a maximum adsorption capacity of 109.97 mg g⁻¹ with a Co₃O₄ loading of 4 wt%. This study underscores the superior adsorption efficiency of Co₃O₄ cube-doped PANI composites in the removal of MO from aqueous solutions. Additionally, the incorporation of RSM has yielded valuable insights into process optimization, elucidating the intricate relationship between experimental factors and the rate of MO removal. These compelling findings carry profound practical implications, offering a promising avenue for the development of efficient water treatment processes and environmental remediation techniques and possibilities for addressing water pollution challenges.