Integrating rod-shaped nickel molybdate@polypyrrole matrix for sustainable adsorptive removal of organic dye: Kinetics, isotherm, and thermodynamics study

Water pollution presents a significant global challenge that impacts the environment. The release of industrial effluents significantly contributes to this. Adsorption studies offer a sustainable and cost-effective solution to efficiently remove organic pollutants from water. The current study comprises a polypyrrole/nickel molybdate composite for the effective adsorption of organic dyes, such as methylene blue, from aqueous solutions. The catalyst has been comprehensively characterized using various techniques, including XRD, FE-SEM, FT-IR, HR-TEM, XPS, BET, TGA, zeta potential, and DLS analysis. Adsorption studies demonstrate up to 97% removal efficiency in 60 min. This study also evaluates the impact of various parameters, such as temperature, pH, dye concentration, and quantity of the catalyst, on the adsorption efficiency. The R2 value of 0.99 that is obtained in the kinetics study suggests the suitability of the adsorption process toward pseudo-second-order kinetics. The adsorption isotherm study reveals that the adsorption follows Freundlich's adsorption isotherm. The maximum adsorption capacity of the study is found to be 17.76 mg/g. Investigations into thermodynamic study give a increment H value of -19.21 J/mol K, indicating the exothermic behavior, and increment G of -6.95 KJ/mol, suggesting the spontaneity of the composite during the adsorption process. These results demonstrate the potential of the developed material as an effective adsorbent for removing organic dyes from water sources. Adsorptive removal of methylene blue dye using PPy/NiMoO4 composite.image