JPS6320090A - Water cleaning agent and its production - Google Patents

Abstract

PURPOSE:To maintain excellent sterilization performance for a long period of time by using a water cleaning agent prepd. by depositing a hardly soluble silver salt on a silica-alumina porous inorg. carrier in water. CONSTITUTION:An aq. silver nitrate soln. is added to the silica-alumina porous inorg. carrier (e.g., silica gel) and thereafter, a halogen compd. (e.g., salt water) is acted thereto to deposit the hardly soluble silver salt (e.g., AgCl) on the carrier at the time of depositing the silver salt onto said carrier. The water cleaning agent produced in such a manner has the excellent sterilization performance and is capable of maintaining the capacity for a long period of time. Since there are no exfoliation of the silver salt, the dissolution of the carrier, etc., the safe use of the treated water and the protection of the device are possible. Since the stable silica gel carrier is usable, the inexpensive provision of the water cleaning agent is feasible.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a water purifying agent for the purpose of sterilizing microorganisms and killing algae in water such as building cooling tower water and swimming pool water, and a method for producing the same.

<Prior Art> It is known that the presence of metal ions is effective in suppressing the proliferation of bacteria in stored water, which is known to be the cause of Legionnaires' Disease.

Among these, the presence of silver ions is the most effective, and is therefore used to sterilize cooling towers and kill algae.

When silver ions are used in stored water, what is required is that the concentration of silver ions in the water be moderately suppressed, and.

It is possible to supply silver ions over a long period of time.

Therefore, instead of putting silver compounds directly into the storage water,
Proposed structures include glass containing silver compounds in the form of particles, or activated carbon carrying silver (Special Publication No. 38666/1989), which is placed in water to gradually elute silver ions. and is also commercially available.

<Problems to be solved by the invention> However, the amorphous glass that is made into particles by impregnating it with a compound takes advantage of the property of the borosilicate glass itself to melt, so the melted glass is It has been pointed out that glass exists in water and that the glass is deposited somewhere in the circulation system. In addition, amorphous glass has the disadvantage that as melting progresses, the surface changes and the amount of silver eluted gradually decreases. Activated carbon with silver supported has a low affinity between the activated carbon and the silver compound, so the silver easily peels off from the activated carbon and cannot withstand long-term use (it maintains its performance for more than a month). That's a shame)! ! , has a point.

Means for Solving the Problems> Therefore, the present inventors focused on the adsorption ability of a silica-alumina porous inorganic carrier and developed a water purifying agent in which a grass-soluble silver salt is supported on the carrier. be.

The water purifying agent is produced by supporting a silver salt on a silica/alumina porous inorganic carrier, adding an aqueous silver nitrate solution to the carrier, and then applying a halogen compound or the like to support the silver salt as a sparingly soluble silver salt. be able to.

The soluble silver salts mentioned here are A, CQ, A g B r
, A[Xl, Ag2O, AgC2H502, AgBrO
3, Ag2CO3, Ag2Cr0,1. It is a silver salt with low solubility such as AgOH.

The silica-alumina porous inorganic carrier includes widely used silica gel, zeolite, perlite, etc., and has a porous structure.

Water purification agents that have silver salt supported on a silica/alumina porous inorganic carrier have different solubility depending on the type of halogen that combines with silver, and have the effect of keeping the silver concentration in water at a low required concentration. . During this moderate and long-term immersion in water, the silver present has a bactericidal effect.

<Example> The present invention will be explained in detail below with reference to Examples.

Approximately 100 ml of 5% silver nitrate aqueous solution in approximately 500 cc of silica gel
cc was added in a controlled manner until the entire amount was absorbed into the silica gel. In this case, the standard amount of silver nitrate is 5g,
In this case, the adsorption saturation point of silica gel is between 5 and 10 g. This was left to stand for about 1 hour to adsorb silver nitrate.

Next, 500 cc of 20% saline solution was poured into the silica gel and reacted. by this chemical reaction.

AgN0 a-+ AgCQ was obtained, and the entire reaction was completed in about 1 hour, and silver chloride was adsorbed on the silica gel. This was heated and dried in an oven at about 80° C. for 1 hour to obtain a water purifier. In the same manner, various water-soluble silver compounds as shown in Table 1 were supported.

Table 1 shows the solubility of each supported silver compound and the results of measuring the concentration of each compound contained in running water using atomic absorption spectrometry when 100 g of each water purifying agent was immersed in running water for 5 days. It shows.

As is clear from the results in Table 1 and above, the water purifying agent of the present invention
Moderate silver ions of ~50 ppb can be released into water over a long period of time.

Bactericidal effect test Next, the conventional amorphous glass containing Ag ions and the silica gel containing Ag ions according to the present invention were immersed in a poly bucket, and the bactericidal effect of the dissolved Ag ions was tested using water containing Escherichia coli.

The strain used was Eschericha Co11,
The medium used was an ordinary agar medium (manufactured by Nihon Pharmaceutical Aji).

IOR water was poured into two prepared buckets, and 6 g of the Ag ion-containing amorphous glass and silica gel were each placed in the buckets and immersed. lθ% or IQ once a day from a bucket
The water was discarded, new water was added in its place, and this operation was repeated for one week to obtain Ag ion elution test water.

Next, a bacterial solution of E. coli was prepared using 3 cc of physiological saline, divided into three equal parts, and three standard bacterial solutions of the same concentration were prepared in test tubes. 3 cc of the two types of Ag ion elution test waters were collected and added to each of the three test tubes, and 3 cc of sterile distilled water was added to the remaining test tube as a blank.

After 5 hours and 24 hours, the cells were collected from these test tubes on ice, poured into an agar medium, and cultured, and the number of bacteria was counted 24 hours later. The results are shown in Table 2.

As is clear from Table 2, the water purifying agent of the present invention has a much better killing +M effect than conventional products.

The main reason why silica gel and poorly water-soluble silver salts are used in the present invention is to have the ability to release silver ions into water for a long period of time, at least several months. In addition, the U.S. Public Health Service has set the Kichu silver ion concentration at 50 ppb or less for drinking water, and in case of an emergency, silver chloride-saturated water should be used for drinking to soften seawater. This is because the product of the present invention can also be used to purify drinking water, although toxicity is not much of a problem.

<Effects of the Invention> As detailed above, the water purifying agent of the present invention has excellent bactericidal performance,
Furthermore, this ability can be maintained over a long period of time.

Furthermore, since there is no peeling of the silver salt or dissolution of the carrier, the treated water can be used safely and the equipment can be protected. Since it is possible to use an inexpensive silica gel carrier, it has become possible to provide products at low cost.

In addition to water purification agents for cooling towers and swimming pools, it can also be used in various sterilizations for baths and industrial water, as an algaecide, as a rust preventive agent, as a sterilizer for machine tool cutting oil, and as a rust preventive agent.

that's all

Claims (1)

[Scope of Claims] 1. A water purifier comprising a silica-alumina porous inorganic carrier supporting a sparingly soluble silver salt. 2. A water purifying agent characterized in that when a silver salt is supported on a silica/alumina-based porous inorganic carrier, an aqueous silver nitrate solution is added to the carrier, and then a halogen compound or the like is applied to support the poorly soluble silver salt. Production method.