Synthesis, characterization and Cr(VI) uptake studies of polypyrrole functionalized chitin

• PC was successfully prepared and used for the removal of Cr(VI) ions.
• pH of the working solution played vital role in the adsorption process.
• The Cr(VI) removal was mainly driven by electrostatic adsorption coupled reduction.
• Equilibrium data were well described by the pseudo-second-order model.
• The Cr(VI) removal process was spontaneous and endothermic in nature

The present study deals with the in situ synthesis of polypyrrole functionalized chitin (PC) and its application for the removal of Cr(VI) from aqueous solution. The prepared PC was characterized using FTIR, XRD, SEM-EDX and TGA techniques. The batch experiments were carried out to examine the adsorption of Cr(VI) ion onto PC as a function of pH, dosage, contact time and initial concentration.The Freundlich isotherm model was fitted well to the equilibrium data and the maximum adsorption capacity obtained by the Langmuir model was found to be 28.92–35.22 mg/g at 303–323 K. Thermodynamic data revealed the spontaneous and endothermic nature of the present sorption process. Kinetic data were well described by the pseudo-second-order model than the pseudo-first-order kinetic model. This study not only offered the simplest way to prepare PC, but also enhanced the sorption capacity of chitin for Cr(VI) removal.

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