Aqueous-phase hydrodechlorination of chlorophenols with pillared clays-supported Pt, Pd and Rh catalysts

Pt, Pd and Rh catalysts supported on pillared clays have been prepared and tested in the hydrodechlorination (HDC) of chlorophenols with H-2. Different catalyst reduction temperatures, metal loadings and reaction temperatures were tested. Pd and Rh catalysts showed the highest activity with 4-chlorophenol as target compound allowing complete dechlorination at mild operating conditions (25 degrees C and atmospheric pressure) with negligible metal leaching. The kinetics of 4-CP hydrodechlorination with these catalysts has been analyzed from the corresponding proposed pathways. The stability of the catalysts was checked in long-term experiments being the most stable those of Pd and Rh with no more of 5% activity loss after 300 h on stream. Other chlorophenols (2-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol) were also tested as target pollutants with the Rh catalyst yielding complete conversion in all cases. Chlorinated compounds were not found as final products. (C) 2013 Elsevier B.V. All rights reserved.