Effective remediation of chromium via catalytic conversion of Cr(VI)

Abstract

Development of new materials for the conversion of toxic metals is one of the rapidly growing research areas. Polyureas are a class of materials that have been widely used in various industrial applications, including adhesives, plastics, and paints. In this work, we report the fabrication of polyurea via the coprecipitation of diamines in the presence of diisocyanates. PXRD, SEM, solid-state NMR, and FT-IR studies are used to characterize polyureas. The obtained polyurea was characterized using PXRD, SEM, and solid-state NMR (¹³C CP) and FT-IR. Later, palladium nanoparticles (Pd NPs) entrapped in polyureas (Pd@PU) were prepared with a low palladium content and characterized using ICP-MS, PXRD, DLS, FT-IR, and TGA. Furthermore, this highly stable material has been utilized in the conversion of hazardous chemicals, such as Cr⁶⁺ reduction under heterogeneous conditions. The chromium oxide (Cr₂O₃) collected as green compound, which was confirmed by PXRD. The kinetic evaluation studies further indicate that it follows first-order kinetics with a rate constant (k) of 7.9 × 10⁻² min^-1.