Synthesis of Polypyrrole/Nano-silica Nanocomposite and Its Use for Removal of Reactive Dye from Aqueous Media: Adsorption Isotherm, Kinetic and Thermodynamic Studies

In this study, nano-silica particles were synthesized from tertraethylorthosilicate (TEOS) precursor and then, together with polypyrrole polymer, a nanocomposite was prepared and used for removal of reactive red 198. Scanning electron microscope (SEM) was applied to determine the superficial morphology, Transmission electron microscope (TEM) to measure the synthesized nano-silica particles and finally, the Fourier transform infra-red spectroscopy (FTIR) to confirm and functionalize the nano-silica particles together with polypyrrole polymer. Parameters affecting the removal of RR 198 such as pH, the amount of adsorbent, dye concentration, temperature, and contact time were investigated and optimized. Uv-vis spectrophotometer was used to determine the concentration of dye in the solution. The Langmuir and Freundlich adsorption isotherm models were applied for determine the adsorption isotherm equation and the presented results show very good agreement with Langmuir adsorption isotherm with high adsorption capacity of 312.5 mg/g. In addition, pseudo-second order kinetic equation was best fitted for adsorption kinetic model. The Gibbs free energy and enthalpy data verified its spontaneous and endothermic nature.