Development and characterisation of novel hybrid materials of modified ZnO-SiO2 and polyaniline for adsorption of organic dyes.

Polyaniline (PAni)–coated ZnO–SiO₂–based hybrid material was prepared successfully with the in-situ polymerisation method and the product was subsequently analysed using XPS, XRD, TEM, UV-vis, TGA, FTIR and BET. The optical band gap calculated from the Tauc plot was found to be 2.89 eV. Moreover, this work reports an extensive study of the effect of the SiO₂ on the electrochemical performance of hybrid material based on ZnO and PAni employing cyclic voltammetry. Furthermore, to evaluate the adsorption of methylene blue (MB), the parameters for the effectiveness of the adsorption process, including pH value, concentration and temperature, were investigated. The results indicated that the maximum adsorption of MB on the produced hybrid material occurred at pH 6.8 with a capacity reaching 71.2 mg.g⁻¹. The thermodynamic studies indicate that the adsorption of MB on this adsorbent is spontaneous and endothermic in nature. Furthermore, PAni@ZnO–SiO₂ is attractive for treating the effluents containing dyes due to its recyclability and high removal capacity. [ABSTRACT FROM AUTHOR]