Hydrodechlorination and complete degradation of chlorinated compounds with the coupled action of Pd/SiO2 and Fe/SiO2 catalysts: Towards industrial catalyst synthesis conditions

Abstract

In this study, Pd/SiO2 and Fe/SiO2 catalysts have been synthesized by the cogelation process for hydrodechlorination applications. Different synthesis conditions were tested to approach the industrial conditions using industrial grade reactants and ambient air drying. The influence of these changes has been studied on the texture and the catalytic activity of the catalysts. The resulting materials are composed of metallic (Pd catalysts) or metallic oxide (Fe catalysts) nanoparticles highly dispersed in porous silica. The catalysts present a high specific surface area (between 250 and 500 m2/g) with a large pore size range between micro-, meso- and macropores. The modifications of the synthesis conditions give catalysts with similar textural properties compared to lab-scale catalysts. The catalytic activity of the binary catalysts have been evaluated on the hydrodechlorination of the 2,4,6-trichlorophenol (TCP) in water. Results show that Pd/SiO2 catalysts are able to dechlorinate the TCP and that Fe/SiO2 materials are able to degrade the resulting phenol. So this process allows a complete degradation of TCP. Industrial conditions catalysts show also similar catalytic results compared to lab-scale catalysts for the hydrodechlorination of the 2,4,6-trichlorophenol (TCP) in water.