Facile one-pot strategy to fabricate polyurea-based palladium for flow-through catalytic reduction of harmful hexavalent chromium from water

Developing facile approaches for fabrication of supported metallic nanoparticle (NPs) catalysts, and nascent technologies for their efficient application are highly desired. Herein, one-pot approach is developed for anchoring of palladium (Pd) nanoparticles on porous polyurea (PPU). In this process, tolylene-2,4-diisocyanate was poured to a mixture of water, acetone and palladium acetate at a fixed rate. After that, NaBH4 was added to the reaction mixture to obtain Pd/PPU with highly porous morphology. The obtained hybrid composite Pd/PPU was characterized by NMR, BET, SEM, XRD, TEM, ICP-OES, and XPS techniques. The outcomes revealed the efficacious anchoring and uniform dispersion of Pd with average size of 7.81 nm onto PPU containing highly porous structure with surface area of 115.51 m(2)/g. A packed-bed reactor was designed by using Pd/PPU for flowthrough catalytic reduction of harmful hexavalent chromium (Cr(VI)) to benign trivalent (Cr(III)) with formic acid as reducer from water. A good permeation flux of 20,000 L/m(2)/h with > 99% of Cr(VI) reduction efficiency were obtained. Moreover, it was observed that Pd/PPU was a highly stable (>96% efficiency for 15 h used) catalyst for flow-through transformation of Cr(VI) to Cr(III). This report therefore proposes a facile approach for synthesis of PPU-based Pd, for continuous flow catalytic remediation of wastewaters, an emerging technology.