Synthesis and characterization of PANI-ZrWPO₄ nanocomposite: adsorption-reduction efficiency and regeneration...

A novel polyaniline zirconium tungstophosphate (PANI-ZrWPO₄) nanocomposite was successfully synthesized through an in situ oxidative polymerization reaction followed by a microwave irradiation process. The synthesized nanocomposite was characterized by using FESEM, EDX, TEM, XRD, FTIR, Raman, TGA-DTA, XPS, and N₂ adsorption-desorption analysis and chemical analysis to know about the formation of material. The results of the FTIR and Raman spectra confirmed that the conducting PANI polymer interacted with ZrWPO₄ to form the PANI-ZrWPO₄ nanocomposite. The XRD data showed that the composite had a crystalline nature. The TEM and FESEM images revealed that polyaniline had formed on the exterior of the PANI-ZrWPO₄ nanocomposite. Further investigation was done on the efficiency of the PANI-ZrWPO₄ nanocomposite as an adsorbent for Cr(VI) removal through batch adsorption experiments. The maximum Langmuir adsorption capacity of PANI-ZrWPO₄ was found to be 71.4 mg g^-1. The removal of Cr(VI) was optimized with the six variables namely adsorbent dose, initial concentration, Time, pH, Temperature, and stirring rate using the Box-Behnken design (BBD) model. The XPS spectra confirmed simultaneously adsorption reduction occurs Cr(VI) to Cr(III) through in situ chemical reduction. Moreover, the regeneration efficiency of PANI-ZrWPO₄ was studied, and it was found to be able to remove around 80% of Cr(VI) even after five cycles, demonstrating its potential as an effective and reusable adsorbent.