Catalyst for treating waste water, method for preparing the same and process for treating waste water

A method of preparing a catalyst for oxidizing and/or decomposing organic and/or inorganic oxidizable substances in waste water by wet oxidation with a use of a catalyst, comprising the steps of:

• 1) depositing first component on an activated carbon wherein the first component is at least one selected from the group consisting of Ti, Zr, Hf, Nb, Ta, Fe, Co, Mn, Al, Si, Ga, Ge, Sc, Y, La, Ce, Pr, Mg, Ca, Sr, Ba, In, Sn, Sb and Bi;
• and
• 2) depositing second component on the activated carbon wherein the second component is at least one selected from the group consisting of Pt, Pd, Rh, Ru, Ir and Au.

A method for oxidizing and/or decomposing organic and/or inorganic oxidizable substances in waste water by wet oxidation with a use of a catalyst, wherein

• the oxidizable substances are oxidized and/or decomposed with an oxygen containing gas in the presence of the catalyst under pressure such that said waste water retains the liquid phase thereof at temperature of 50 to less than 170° C. and the catalyst contains activated carbon;
• and
• an oxygen concentration in an exhaust gas is controlled in the range of 0 to 5 vol %.

A method for oxidizing and/or decomposing organic and/or inorganic oxidizable substances in waste water by wet oxidation with a use of a catalyst, wherein

• the oxidizable substances are oxidized and/or decomposed with an oxygen containing gas in the presence of a catalyst under pressure such that said waste water retains the liquid phase thereof at temperature of 50 to less than 170° C. and the catalyst contains activated carbon;
• and
• supplying a catalyst protection liquid which contains easily decomposable substances at the time of temperature rising when starting up a operation of the wet oxidation and/or at the time of temperature lowering when suspending the operation.