Flower‐Like Polyaniline‐Modified Yttrium Phosphate Nanocomposite: An Effective Adsorbent for Cr(VI) Removal via Adsorption–Reduction Mechanism

In this study, flower‐like polyaniline‐modified yttrium phosphate (PANI‐YPO 4 ) nanocomposites are investigated as a promising adsorbent for removing hexavalent chromium (Cr(VI)) from both wastewater as well as aqueous solutions. The PANI‐YPO 4 nanocomposite is synthesized using an in situ oxidative polymerization method followed by hydrothermal synthesis of yttrium phosphate. Morphological analysis by field emission scanning electron microscopy and transmission electron microscopy reveals a flower‐like structure of the nanocomposite. The PANI‐YPO 4 nanocomposite shows the highest removal percentage of 99.1% toward Cr(VI) in a wide pH range of 2–5, with a 0.4 g L −1 adsorbent dose, 10 ppm initial concentration, and a 60‐minute equilibrium time as compared to sole yttrium phosphate (53.7%) and polyaniline (69.8%). The Langmuir maximum adsorption capacity for Cr(VI) removal by PANI‐YPO 4 is 91.0 mg g −1 . Moreover, the nanocomposite shows successful regeneration and reuse for up to five cycles with 85% removal efficiency. The proposed adsorption mechanism involves the electrostatic interaction between Cr(VI) and the PANI‐YPO 4 nanocomposite, accompanied by the in situ chemical reduction of Cr(VI) to Cr(III). Additionally, the PANI‐YPO 4 nanocomposite exhibits an impressive adsorption efficiency of 99% for real chromium wastewater solutions. Thus, the PANI‐YPO 4 nanocomposite is a promising material for efficiently removing Cr(VI) from contaminated water sources, emphasizing its potential for future environmental remediation applications.