Hydrodehalogenation of Halogenated Organic Contaminants from Aqueous Sources by Pd Nanoparticles Dispersed in the Micropores of Pillared Clays Under Transfer Hydrogenation Condition

Abstract

Palladium nanoparticles dispersed in the micropores of the Al-pillared clay was prepared by chemical reduction of palladium chloride salt. The Al-pillared clay was prepared by insertion of [AlO4Al12(OH)24(H2O)12]7+ clusters into clay interlayer and subsequent thermal activation. The pillared clay supported system (Pd/Al–P) was characterized using XRD, IR, UV–Vis, SEM, TEM and sorptometric technique. The expansion of the interlayer space as a result of pillaring was noted for Pd/Al–P system from the XRD study. The TEM study of the supported system indicated well dispersion of the Pd species with particle size in the range of 5–30 nm. The supported Pd particles were used as an efficient heterogeneous catalyst for the hydrodehalogenation of halogenated organics under hydrogen transfer condition using hydrazine hydrate as hydrogen donating agent. The effect of various reaction parameters such as temperature, time, and nature of support, type of hydrogen transfer agents and functionality of substrate was studied in details. The catalytic study clearly indicated superior catalytic activity of the supported Pd system in presence of hydrazine hydrate as hydrogen donating agent. The Al-pillared clay as support influences the dispersion and catalytic activity of the supported Pd nanoparticles.