Studies On The ZrO₂ Supported Noble Metal Catalysts For Catalytic Wet Oxidation

Catalytic wet air oxidation (CWO) is an attractive method for waste waterwhich is too dilute to incinerate and too concentrated for biological treatment. Itcan be defined as the oxidation of organic and inorganic substances in an aqueoussolution or suspensionby means ofoxygen or air at elevated temperatures andpressures.Although many supports such as TiO₂, CeO₂ and Al₂O₃ have been thoroughlyinvestigated for catalytic wet oxidation (CWO), researches about noble metalsupported on ZrO₂ are seldom reported, due to lower activity of ZrO₂ comparedwith the supports mentioned above. ZrO₂ employed in the past CWO investigationis invariably low surface area prepared through conventional route.In these research works, high surface area ZrO₂ was briefly preparedthroughdigesting hydrous zirconia without adding surfactants. Low surface area ZrO2 wasalso prepared for comparison. Based on these two kinds of supports, Ru, Ptcatalysts showed effective activity to decompose phenol, acetic acid, ammoniaand actual industrial waste water. Especially, noble metal catalysts supported onhigh surface area ZrO₂ were remarkably more active and more stable than those ofsupported on low surface area ZrO₂.