For the purification of water with small contents of 1,4-
chlorophenol (10 ppm), a two-stage regeneration technology of
adsorbent catalysts has recently been proposed [18] which includes
(1) hydrodechlorination of the adsorbed compound and (2) lowtemperature
oxidation. The stage of hydrodechlorination allowed
the oxidation temperature to be decreased to 250 ◦C with a reduction
of the aggressive action of HCl and Cl2. This allowed the
Pd-containing catalysts to be supported onto activated carbons
modified by oxides of iron, chromium and copper which act as
efficient oxidation catalysts. A drawback of this technology is
the low activity of the adsorbent catalysts in spite of their high
content of palladium (2.5–8 wt.%). Thus, complete conversion of
1,4-chlorophenol in the gas-phase dechlorination at 200 ◦C by
molecular hydrogen was achieved only after 9 h of the reaction.
The authors show that at low temperatures (52 ◦C) liquid-phase
hydrodechlorination is less efficient even in the presence of a strong
reducing agent (N2H4)H2SO4 because of the long time of the reaction
(30 h)