JPH03114544A - Hydrogen peroxide decomposition catalyst - Google Patents

Abstract

PURPOSE:To obtain a hydrogen peroxide decomposition catalyst which is stable for a long period and maintains high activity by roughening the surface of a hydrophobic support to carry a transition metal. CONSTITUTION:The surface of a hydrophobic support of a metal, glass, plastic, etc., is roughened by sand blast, brushing, chemical etching, etc. A solution containing a transition metal compound dissolved in water or an organic solvent is sprayed to the surface roughened support or the support is immersed in the solution so as to carry the transition metal compound. The transition metal is uniformly distributed on the surface of a catalyst prepared in this way and hard to peel off and drop from the support and the catalyst has a high activity and stability for a long period. The catalyst is preferably used for decomposition and removal of hydrogen peroxide in a sterilization solution after sterilization of contact lens with hydrogen peroxide.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a hydrogen peroxide decomposition catalyst, and more specifically, a catalyst suitable for decomposing residual hydrogen peroxide in a sterilizing solution after contact lens sterilization treatment. Related to hydrogen peroxide decomposition catalysts used in

[Prior Art - Problems to be Solved by the Invention] Hydrogen peroxide is used in a wide range of fields such as sterilization, disinfection, and bleaching, but depending on the application, it is necessary to decompose and remove hydrogen peroxide after use. is often required. For example, when hydrogen peroxide is used to sterilize contact lenses, it is necessary to substantially completely decompose the residual hydrogen peroxide in order to eliminate the effect on the eyes when wearing the contact lenses.

On the other hand, as a catalyst for decomposing and removing hydrogen peroxide, P t+
It is well known that compounds such as transition metals such as Ru, Rh, Ir+Cu, Mn, Fe and Cr and their oxides and hydroxides are effective. In addition, catalysts in which they are supported on a carrier such as alumina are already commercially available.

However, when commercially available catalysts supported on so-called hydrophilic carriers such as alumina and silica are used, these carriers are hydrophilic not only on the surface but also on the inside, so even after decomposing hydrogen peroxide, The problem is that the solution remains inside the catalyst carrier, which promotes the growth of bacteria, making it impractical for use in post-treatments such as contact lens sterilization.

As a means to overcome this drawback, platinum black was supported on a molded body of the hydrophobic plastic Noryl (trade name of a product manufactured by General Electric Company), and this was used to decompose a 3z hydrogen peroxide solution used for sterilizing contact lenses. A method of using this method is disclosed in Japanese Patent Publication No. 51-12633.

However, in this method, an ethanol solution of chloroplatinic acid is sprayed onto the surface of a smooth hydrophobic carrier, dried, and then the chloroplatinic acid is reduced with hydrogen to form platinum black. However, since the surface of the carrier is smooth, it is difficult to uniformly attach chloroplatinic acid to the carrier, and therefore the distribution of platinum black obtained after hydrogen reduction is also affected by segregation. It becomes a certain non-uniformity. For this reason, not only high decomposition activity cannot be obtained, but also the adhesion of the platinum black is insufficient, and the platinum black peels off and falls off with use, resulting in a gradual decrease in activity. Furthermore, since the plastic molded body that is the catalyst assembly occupies a considerable volume, there is a drawback that it is difficult to make the processing container more compact.

[Means for Solving the Problems] As a result of intensive studies to solve the problems of the prior art as described above, the present inventors found that when using a hydrophobic carrier with a roughened surface, The inventors have discovered that these problems can be solved by using a hydrophobic carrier whose surface has been treated to make it hydrophilic, and have completed the present invention. Specifically, the present invention provides a hydrogen peroxide decomposition catalyst characterized in that a transition metal is supported on a hydrophobic carrier having a rough surface, and a hydrogen peroxide decomposition catalyst characterized in that a transition metal is supported on a hydrophobic carrier having a rough surface that has been subjected to a hydrophilic treatment. This is a hydrogen peroxide decomposition catalyst characterized in that it supports a hydrogen peroxide decomposition catalyst.

Examples of the hydrophobic carrier used in the present invention include metals, glass, and plastics, but plastics are preferred because they can easily roughen the surface, and among them, plastic films (including plastic sheets) are preferred. ) is preferred.

Representative examples of hydrophobic plastics include polyethylene terephthalate, polycarbonate, acrylic resin, polystyrene, ABS resin, modified PPE resin, and polyolefin. Furthermore, compositions and copolymers with other resins can also be used as long as hydrophobicity is maintained.

These hydrophobic plastics may further contain additives.

In order to make the processing container more compact, it is preferable to roll the carrier inside the sterilization container and bring it into close contact with the inner surface of the container. It is preferable that

Although there are no particular limitations on the shape of these hydrophobic carriers, molded bodies such as spherical, cylindrical, and plate-like shapes are practically preferred.

Furthermore, in order to increase the contact area, these hydrophobic carriers are preferably wavy or provided with protrusions, holes, and the like.

The roughening of the hydrophobic carrier is carried out by conventional methods, and in practice, methods such as sandblasting, brushing, chemical etching, and solution etching after imprinting with calcium carbonate can be employed.

In practice, the degree of roughness is usually 0.05 μm or more, preferably 0.05 μm or more, when expressed as center line average roughness (Ra).
The range is from 0.05 to 50 μm, particularly preferably from 0.1 to 10
It is assumed to be in the μm range.

The degree of roughness is 0.05 μm in center line average roughness (Ra)
If it is less than 20%, the transition metal attached to the hydrophobic carrier becomes non-uniform, and the adhesion force decreases, making it easy to fall off or peel off.

In the present invention, the definition and measurement method of center line average roughness (Ra) are based on Japanese Industrial Standards (JIS) B 060.
11982.

In order to further improve the uniformity and adhesion of the supported metal, the surface of this roughened hydrophobic support is further subjected to a hydrophilic treatment.

The hydrophilization treatment method for the surface of a hydrophobic carrier varies depending on the type of carrier, and although it cannot be generally specified, for example, in the case of polyethylene terephthalate and polycarbonate, it is usually treated with an aqueous hydrazine solution, an aqueous hexanediamine solution, etc. are validly applied. Also,
A method of applying an acrylic anti-fog paint is also effectively applied.

Supporting of the transition metal component is carried out by a conventional method, for example, by dissolving the transition metal compound in water or an organic solvent such as ethanol or acetone and immersing a roughened hydrophobic support in this solution; A transition metal compound solution is applied to the roughened hydrophobic carrier by a method such as spraying this solution, and then the transition metal compound is supported by drying the solution.

The transition metal compounds used in this case are not particularly limited as long as they are soluble in water or organic solvents, but include halides,
In particular, chlorides are preferably used.

The supported metal compound is usually used after being converted into an elemental metal by hydrogen reduction, reduction with sodium borohydride, etc., but the transition metal compound can also be used as it is.

The catalyst of the present invention is suitably used to decompose residual hydrogen peroxide in a sterilizing solution after sterilizing contact lenses, and is also contained in wastewater discharged from metal etching factories and food factories. It is also suitably used to decompose hydrogen peroxide.

In addition, when used in this way, the decomposition temperature may be room temperature or normal temperature, but heating or cooling is not prohibited.

[Example] The effects of the present invention will be explained in more detail with reference to Examples.

Example 1 Modified PP with a diameter of 20 mm, a thickness of 5 mm, and an area of about 9 c + f
The surface of the disc-shaped molded body of E resin (Noryl) was roughened by sandblasting, and the degree of roughness Ra was 2.
．． A roughened carrier having a surface of 3 μm was obtained.

A chloroplatinic acid ethanol solution having a chloroplatinic acid concentration of 10 wtχ was applied to this, and after drying, hydrogen reduction was performed at 80°C to precipitate platinum black on the carrier surface to obtain a hydrogen peroxide decomposition catalyst.

The amount of platinum black supported on this hydrogen peroxide decomposition catalyst is 0.3 mg.
/ cJ, and the platinum black did not fall off even when touched with fingers.

This disk-shaped hydrogen peroxide decomposition catalyst is used in a soft contact lens sterilization container with lens holder (capacity 1120
mβ), and in this sterilized container, add 10.9wtL of NaCl as an isotonic agent and Na, llP as a pH adjuster.
A hydrogen peroxide decomposition test was performed by injecting 10 ml of a 3 wt χ hydrogen peroxide aqueous solution containing 0.09 wt % of a mixture of O4 and NaH2PO.

The time required for the concentration of hydrogen peroxide in the boiling solution to drop to 1100 pp was 3.2 hours, and this remained unchanged even after the decomposition test was repeated 100 times.

Example 2 One side of a polyethylene terephthalate film measuring 36 mm x 9 mm, 0.1 mm thick, and 9.4 cffl on one side was roughened by sandblasting, and the roughened carrier had a surface with a roughness level Ra of 3.4 μm. I got it.

Furthermore, this roughened carrier was immersed in an aqueous hydrazine solution of 30wtχ at 80°C for 30 minutes to make the surface of the roughened carrier hydrophilic.

A chloroplatinic acid ethanol solution with a concentration of 10 wtχ is applied to the surface of the roughened carrier whose surface has been made hydrophilic, and after drying, hydrogen reduction is performed at 80°C to coat the surface of the carrier with platinum black. was precipitated to obtain a hydrogen peroxide decomposition catalyst.

The amount of platinum black supported on this hydrogen peroxide decomposition catalyst is 0.24 mg.
/c+fl, and this hydrogen peroxide catalyst maintained flexibility, and furthermore, it was observed that precipitated platinum black was uniformly attached to the film surface.

This hydrogen peroxide decomposition catalyst was placed in a soft contact lens sterilization container (capacity 18 mβ) equipped with a lens holder so that the transition metal-supporting surface was on the inside and closely contacted the inner peripheral surface of the sterilization container, and the sterilization container was then isostatically NaCl as a oxidizing agent
0.9 wt
A hydrogen peroxide decomposition test was conducted by injecting 10 ml of wtX hydrogen peroxide aqueous solution.

The time required for the concentration of hydrogen peroxide to drop to 1100 pp was 262 hours, and this remained unchanged even after repeating the decomposition test 100 times.

At this time, by using a film-like carrier for the hydrogen peroxide decomposition catalyst, the volume of the catalyst was significantly reduced, so the sterilization container could be made more compact.

In addition, this hydrogen peroxide decomposition catalyst has flexibility and elasticity, and when it is set in a sterilization container, its flexibility and elasticity allow it to adhere tightly to the inner surface of the container, and it is also extremely easy to attach and detach. .

Comparative Example 1 The same procedure as in Example 1 was carried out except that the surface of the carrier was not roughened and was used as it was.

The amount of platinum black supported on the obtained hydrogen peroxide decomposition catalyst was 0.3■
/cffl, but the supported state was non-uniform, and the platinum black easily peeled off and fell off even when touched lightly with fingers.

The time required for the concentration of hydrogen peroxide to reach 1100pp was 4.8 hours the first time, but the activity gradually decreased and the concentration reached 100pp.
At the second time, the time had decreased to 6.3 hours.

[Effects of the Invention] The hydrogen peroxide decomposition catalyst of the present invention has a supported transition metal component uniformly distributed on the surface of the carrier, less peeling and falling off of the transition metal component from the carrier, and high activity over a long period of time. is maintained, so it can be used stably for a long period of time. Furthermore, since the inside of the carrier is hydrophobic, the solution after decomposition will not remain inside the carrier and seedlings will not propagate. Therefore, the hydrogen peroxide decomposition catalyst of the present invention is suitably used for decomposing and removing hydrogen peroxide in a sterilizing solution after contact lenses are sterilized with hydrogen peroxide. It can also be suitably used for processing in liquid.

Claims (1)

[Scope of Claims] 1. A hydrogen peroxide decomposition catalyst characterized by having a transition metal supported on a hydrophobic carrier having a rough surface. 2. A hydrogen peroxide decomposition catalyst characterized in that a transition metal is supported on the surface of a hydrophobic carrier having a rough surface treated to make the surface hydrophilic.