JPS5918365B2 - Red tide treatment agent and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a red tide treatment agent whose raw materials are easily available and which has a low risk of secondary pollution, and a method for producing the same.

In recent years, in Japan's territorial waters, inland tidal marshes, rivers, etc., wastewater from factories, domestic wastewater, agricultural wastewater, stockpiling or fisheries-related wastewater (such as flagellates and diatoms, which are said to be caused by water eutrophication) has been detected. The damage caused by the abnormal occurrence of floating organisms, or so-called red tide, has become a hot topic in various places, and once red tide occurs, there is little that can be done, but when it occurs near a fish farming area, it is said to move the fish farming area away from the red tide area. However, since it has recently become clear that aluminum ions are extremely effective in eradicating red tide, natural minerals or chemical agents have gained attention as red tide treatment agents. It became so.

However, as natural minerals, Aomori, Yamagata, Fukushima, Niigata,
Among the montmorillonites produced in wide areas such as Toyama, Shimane, Fukuoka, and Kagoshima, which can be said to be nationwide, the one from Kagoshima releases the most aluminum ions in water (substituted aluminum is 1 to 2 me/100? It is said to have the highest value among natural minerals), but this is extremely high, with a red tide of 15 per 1,771" of water surface.
It is necessary to spray 0 to 500g, and the amount of spraying is large.
There are concerns about the occurrence of secondary pollution due to the contamination of fish reefs by the sludge after settling, and the amount of spraying is small (less than one tenth).
0me/100? It is requested that the requirements be strong (or higher).

In addition, especially in Japan, many natural minerals have small-scale mines and are locally produced in limited quantities, making it extremely difficult to stably supply large quantities of the same composition over a long period of time. Therefore, montmorillonite from Kagoshima is no exception (there is a strong need for a stable supply of resources).

Although it is known that aluminum salts such as aluminum sulfate and aluminum chloride, which are chemical agents, have the effect of killing red tide against these natural minerals,
Neither natural minerals nor chemical agents can be said to be preferable red tide treatment agents, as they may also kill fish and shellfish and cannot be used except in special areas where marine resources do not exist. .

This invention has been made in view of the current situation, and includes a red tide treatment agent consisting of an aluminum-type clay mineral with a substitutable aluminum content of 20 me/1001 or more, and a porous clay mineral with a large base substitution capacity. The present invention provides a method for producing a red tide treatment agent, which comprises treating minerals with an aqueous hydrochloric acid solution, washing with water, and drying.

The details are described below. First, typical clay minerals that are porous and have a large base substitution capacity (20 me/100 P or more) are used in various agricultural and industrial fields as soil conditioners, catalyst carriers, binders, adsorbent, filtration agent,
Examples of ion exchange agents include montmorillonite, pennite, zeolite, etc., which are widely used.

These minerals vary considerably in composition in their naturally occurring state.

Therefore, by treating these minerals with an aqueous solution of hydrochloric acid, the hydrochloric acid that penetrates deeply into the porous region drives out the substituting salts (calcium salts, magnesium salts, etc.) and replaces them with substitutable hydrogen, which in turn in turn turns into substitutable aluminum. By utilizing the property of changing to
The aluminum-type clay powder is made to easily release aluminum ions with a value of e/100P or higher (such values are not found in natural products).

In addition, when treating clay minerals, which have a large base substitution capacity and are porous, with hydrochloric acid, clay minerals in fine powder form may undergo sedimentation, filtration, dehydration, etc. in the water washing process after the hydrochloric acid treatment. Since the operation becomes difficult, it is convenient to size the particles in advance to about 5 to 10 mrn.

In addition, the hydrochloric acid concentration of the hydrochloric acid aqueous solution is at or around 1N (
For example, the ratio of hydrochloric acid to 1 liter of water is 0.8 to 1.2 equivalents), and the amount of hydrochloric acid aqueous solution used is 1.5 to 2.0 equivalents per liter of displacing salts that hydrochloric acid drives out of the clay mineral.
It is desirable that the amount is 0 times equivalent.

This is because increasing the amount of hydrochloric acid far beyond the above limit will destroy the structure of clay minerals, while decreasing the amount of hydrochloric acid below the above limit will reduce the effect of hydrochloric acid treatment. This is because it cannot be expressed.

Such hydrochloric acid treatment is carried out at around room temperature (at high temperature).
The more the hydrochloric acid reacts, the more intense the reactivity of the hydrochloric acid becomes than necessary, and the risk of tissue destruction is high (which is undesirable). This is done while immersed in an aqueous solution.

In this way, hydrochloric acid can replace approximately 70 to 80% of the substitutable salts in the clay mineral to substitutable aluminum in about 4 hours.

After completing the hydrochloric acid treatment, the process moves to a water washing process.

There is no problem with washing with water by any of the commonly used methods such as decanting or filtration, but it is better to avoid using hot water to prevent tissue destruction of clay minerals, and avoid emitting chlorine ions ( Finish washing with water at this point.

The clay mineral that has been treated with hydrochloric acid and washed with water is then dried.

At this time, there is no need to particularly limit the drying method, but care must be taken to ensure that the drying temperature does not exceed 90° C. in order to prevent tissue destruction of the clay mineral.

After drying, some of the particles solidify into lumps, so they are crushed into powder with a particle size of 2 mm or less.

By doing so, it is possible to uniformly spray the water surface, and the surface area is also increased, so that the displaceable aluminum ions can be efficiently (eluted).

Note that although the clay mineral can be used as it is in a wet state without being dried, it is preferable to dry it in terms of transportation.

As is clear from the above, according to the present invention, it is possible to stably supply semi-permanently a substance that elutes a larger amount of substitutable aluminum ions than conventional natural minerals. It can be said that the significance of this is extremely large.

Examples are shown below.

Example Among the commercially available montmorillonites, the cheapest and most easily available one (origin unknown) was selected and treated with a 1N hydrochloric acid aqueous solution (room temperature) for 2 and 4 hours to obtain a pH 1 water-soluble montmorillonite. The salts, substitutable salts, and base substitution capacities were determined, and the results are summarized in Table 1.

As is clear from the results in Table 1, about 33% of the substitutable salts were converted to substitutable aluminum after 2 hours of acid treatment, and about 7% of the substitutable salts after 4 hours of acid treatment were converted to substitutable aluminum.
2% is replaced with substituted aluminum27.
8me/100? An extremely high value was obtained.

Substances with a large amount of substituted aluminum have not yet been found in natural products, and even the highest value known so far is only about 1 to 2 me/1001, as described above.

Therefore, the red tide treatment agent according to the present invention can reduce the concentration of replaceable aluminum by adjusting the acid treatment time.
Since it can be adjusted to 0me/1001 or more, it is extremely easy to reduce the amount to less than one tenth, even if it has the same effect as Kagoshima montmorillonite, which is effective in eradicating red tide. Secondary pollution due to subsequent sludge formation is also far more likely to occur.

Claims (1)

[Claims] 1. Substitutable aluminum is 20me/100? A red tide treatment agent made of the above aluminum-type clay mineral powder. 2. A method for producing a red tide treatment agent, which comprises treating a porous clay mineral with a large base substitution capacity with an aqueous hydrochloric acid solution, washing with water, and drying.