Development of the Sb₄O₅Cl₂@NbSe₂ Composite: The Impact of 2H-NbSe₂ Nanoparticles on Sb₄O₅Cl₂ and Their Application for the Removal of Cr(VI)/Fe(III) and Methyl Orange from Wastewater

A potential adsorbent, Sb₄O₅Cl₂@NbSe₂ composite, was generated from the Sb₄O₅Cl₂ photocatalyst and 5 wt % layered 2H-NbSe₂ nanoparticles for the highly effective removal of Cr(VI) and Fe(III) ions and methyl orange (MO) from aqueous solution, and a comparison was drawn against the precursors. Sb₄O₅Cl₂ crystallites and NbSe₂ nanoparticles were synthesized hydrothermally, and the composite was prepared by the incipient wetness impregnation technique. The crystal structure of Sb₄O₅Cl₂ was determined by single-crystal X-ray diffraction (SCXRD) data. Powder X-ray diffraction (PXRD) study revealed the 2H phase of NbSe₂ nanoparticles. Field emission scanning electron microscopy (FESEM) analysis confirmed the formation of the spherical-shaped NbSe₂ nanoparticles from rod-shaped bulk 2H-NbSe₂. Morphological changes from the hexagonal to irregular prismatic shape were found upon the formation of the Sb₄O₅Cl₂@NbSe₂ composite compared to pure Sb₄O₅Cl₂. Negative ζ-potential values indicated that electrostatic interactions were the predominant factor for the adsorption process. Sb₄O₅Cl₂@NbSe₂ provided removal efficiencies of 99% for MO in 6 h, 96.52% for Cr(VI) within 2.5 h, and 92.43% for Fe(III) within 4 h of 10 mg/L initial concentration. The maximum adsorption capacities of the composite for MO, Fe(III), and Cr(VI) were found to be 66.56, 131.48, and 122.30 mg/g, respectively, as calculated using the Langmuir isotherm equation.