JPS59115745A - Catalyst for wet oxydation treatment - Google Patents

Abstract

PURPOSE:To give an excellent catalytic activity to a catalyst by using Ru, Rh, Pd, Ir, Pt, Au and the water-soluble or hardly soluble compds. of the above- mentioned metals as effective components, and using TiO2 having anatase type crystal and rutile type crystal as carrying catalyst in a specified composition ratio as a carrier. CONSTITUTION:A catalyst for wet oxidation treatment to be used for decomposing COD components, ammonia etc. in waste water is composed of one or >=2 kinds among Ru, Rh, Pd, Ir, Pt, Au and the water-soluble or hardly soluble compds. of the above-mentioned metals as effective components. TiO2 composed of 1pt.wt. anatase type crystals and 0.1-6pts.wt. rutile type crystals as the carrying catalyst is used as a carrier. The amt. of effective components of the catalyst is regulated to 0.05-25wt% (especially 0.5-3wt%) of the carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supported catalyst used in wet oxidation treatment of wastewater.

Various methods have been proposed for the treatment of wastewater containing chemical oxygen demand substances (hereinafter referred to as COD components), suspended solids, and in some cases even ammonia. As a result of many years of research into the treatment of such wastewater, the present inventors have determined that the type of catalyst metal, the concentration and supply amount of oxygen used in wet oxidation, the p"b of the wastewater to be treated and the p during the wet oxidation reaction.
It has been discovered that H reduction has a significant effect on processing efficiency, corrosion of equipment used, and catalyst life, and a patent application has already been filed based on these findings (Japanese Patent Application No. 1983)
1-95507, Japanese Patent Application No. 52-110257, Japanese Patent Application No. 56-165168, etc.). As a result of continuing various studies to further improve the excellent effects of these earlier methods, especially the high treatment efficiency, the present inventor discovered that treatment efficiency is affected not only by the catalyst metal but also by the type of support. Even for the same type of carrier, the wastewater treatment efficiency, the durability and activity of the catalyst, the degree of activity recovery after regeneration treatment of the catalyst used, etc. may vary greatly due to differences in the manufacturing method of the carrier, differences in crystal structure, etc. etc. were found. In particular, in wet oxidation catalysts that use 10,000 ml of blue gold such as Ru as a catalytically active component and titanium oxide (hereinafter referred to as TlO2) as a carrier, the knowledge of catalysts in other fields that use TlO2 as a carrier should be applied as is. It turned out that it was not possible. The present invention was completed based on the results of elucidating the above-mentioned specificity of TlO2 as a carrier in a wet oxidation catalyst.

That is, the present invention provides Ru, ■h, Pd, Ir, Pt and A
u and one or more of these metal compounds that are insoluble or sparingly soluble in water are used as catalytic active ingredients, and the composition ratio of anatase type crystals and rutile type crystals of the supported catalyst is 1 part by weight of the former to 0.5 parts by weight of the latter. The present invention relates to a catalyst for wet oxidation treatment of wastewater that uses 1 to 6.0 parts by weight of titanium oxide as a carrier.

In the present invention, the anatase type crystal structure portion of the TlO2 carrier in the catalyst is 1 part by weight, and the rutile type crystal structure portion is 0.1 to 6.0 parts by weight. 0 rutile crystals
．． If it is less than 11 parts or more than 6.0 parts, the ammonia decomposition rate and COD during wet oxidation treatment
There are one or more drawbacks, such as low decomposition rate, poor catalyst durability and catalyst strength, and insufficient activity recovery after regeneration treatment. If the ratio of rutile type crystals is 0.2 to 2.01 parts by weight per 1 part by weight of anatase type crystals, the decomposition rate of ammonia and COD components will be particularly high, so the composition ratio of both should be within this range. It is more preferable to do so.

In the catalyst of the present invention, the scattering of the catalytic IA# active ingredient is about 005 to 25 inches (as a metal) of the weight of the carrier, and 0
．． 5-a, OS is more preferable 0 The catalyst of the present invention heats the wastewater to about 100 to 370°C and maintains the wastewater at a pressure that maintains the liquid phase, while reducing COD in the wastewater in the presence of oxygen. It is particularly suitable as a catalyst for wet oxidation treatment of wastewater to decompose components and/or suspended solids and/or ammonia.

Example 1-10 A TlO2-supported catalyst (with a weight composition ratio of anatase type crystal structure part and rutile type crystal structure part as shown in Table 1)
A cylindrical reaction tower was filled with a spherical catalyst with a diameter of 4 mm, and wet oxidation treatment of wastewater was performed.

Gas liquid (0(l Deoo) generated in a coke oven
oppm, total ammonia It 3000 ppm, p
H9.5) was supplied to the bottom of the cylindrical reaction tower at a space velocity of 2.01/hr (based on the empty column). The lR stirring rate of the liquid is 3 Q
fan/m2h T, and the pH of the treated water is approximately 7.
．． A caustic soda solution was continuously supplied into the reaction tower so that the concentration of sodium hydroxide was 0. On the other hand, air was supplied to the lower part of the reaction tower at a space velocity of 1001/hr (empty column reference, standard state conversion W).

The temperature inside the reaction tower is 250°C, and the pressure cuff is 0 kg/c-・
GK was maintained, and the gas-liquid mixed phase after wet oxidation was sequentially extracted from the upper part of the reaction tower, and after indirect cooling, was led to a gas-liquid separator.

From the absolute amount of each residual component in the separated gas phase and liquid phase, N
Table 1 shows the results of determining the removal rates of H3 and COD components. The values shown in Table 1 are 100% after the start of the wet oxidation reaction.
This is the result after hours.

Comparative Examples 1 to 4 Examples 1 to 4 except that a catalyst in which a catalytically active component was supported on a TlO2 carrier in which the weight composition ratio of the anatase type crystal structure part and the rutile type crystal structure part was the same as shown in Table 2 was used.
Wet oxidation treatment of wastewater was carried out in the same manner as in Example 10.

The results were as shown in Table 2. NH3 decomposition rate and C
It is clear that the OD decomposition rate is inferior to Examples 1 to 1O.

Table 2 (that's all) Agent: Patent Attorney Eiji Sanae

Claims (1)

[Claims] ■ Ruthenium, rhodium, palladium, iridium,
Platinum, gold, and one or more of water-insoluble or sparingly soluble compounds of these metals are used as catalytic active ingredients, and the composition ratio of anatase type crystals and rutile type crystals of the supported catalyst is 1 for the former.
A catalyst for wet oxidation treatment of wastewater, which uses titanium oxide as a carrier in an amount of 0.1 to 6.0 parts by weight based on the heavy part.