JP2531253B2 - Method for removing phenols and aromatic amines from aqueous solution - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for removing phenols and aromatic amines from an aqueous solution, and more particularly to a method for removing phenols and / or aromatic amines by peroxidase catalysis. The present invention relates to a method for removing hydrogen peroxide by reacting with hydrogen peroxide.

(Prior Art) In a method of removing phenols and aromatic amines contained in an aqueous solution, a method of reacting these substances with hydrogen peroxide as a peroxidase reaction catalyst to remove from the aqueous solution as an insoluble polymer. Is, for example, Science, Vol. 224, No. 4607, pages 259-261 (1983
Year). In this paper, especially the removal of phenol is examined in detail, and it is said that this method is effective in the concentration range of 0.01 to 5 g / phenol in the solution, and 98% of phenol in the aqueous solution can be removed. The amount of peroxidase required to remove phenol from an aqueous solution containing 1 g of phenol is 20,000 per aqueous solution.
Purpurogallin unit, hydrogen peroxide amount per aqueous solution
At 20 mmol, if the phenol concentration was increased or decreased by 0.01 to 5 g /, the required amount of peroxidase and hydrogen peroxide should be increased or decreased in proportion to the phenol concentration. For example, in the case of an aqueous solution with a phenol concentration of 5 g /, aqueous solution 1
Therefore, 100,000 purpurogallin units of peroxidase and 100 mmol of hydrogen peroxide are required for removal.

The results of studies on other phenols and aromatic amines such as aniline are shown in the Journal of Applied B chemistry.
iochemistry), Vol. 2, pp. 414-421 (1980). Further, instead of adding hydrogen peroxide itself to an aqueous solution, a method of adding an enzyme that produces hydrogen peroxide as a reaction product and its substrate together with peroxidase to an aqueous solution, such as glucose oxidase or alcohol oxidase, is also disclosed in This is disclosed in JP-A-59-213494.

(Problems to be Solved by the Invention) In such a method for removing phenols or aromatic amines from an aqueous solution, the problem is the removal cost, and a large proportion of them is a problem such as peroxidase. The cost of the enzyme. In particular, when an aqueous solution containing a high concentration of phenols and / or aromatic amines is targeted, the required amount of peroxidase increases and the removal cost becomes enormous, and the practical use of this method is economical. It was difficult in terms of sex.

(Means for Solving the Problems) (1) In a method of removing phenols and / or aromatic amines from aqueous solution by reacting with hydrogen peroxide by the catalytic action of peroxidase, boric acid and / or
Alternatively, a method for removing phenols and aromatic amines from an aqueous solution, characterized by adding borate, (2) Phenols and / or aromatic amines are converted to hydrogen peroxide from the aqueous solution by the catalytic action of peroxidase. A method for removing phenols and aromatic amines from an aqueous solution, characterized in that the reaction is carried out while keeping the hydrogen peroxide concentration in the aqueous solution at 10 mmol /% or less, (3) In a method for removing phenols and / or aromatic amines from an aqueous solution by catalytic action of peroxidase by reacting with hydrogen peroxide, the peroxidase activity in the aqueous solution is kept at 1,000 purpurogallin units or less per 1 And / or phenol from an aqueous solution characterized in that Method of removing the aromatic amines are,.

(Action) In the method of removing phenols and / or aromatic amines from aqueous solution by reacting with hydrogen peroxide by peroxidase catalysis, the catalytic activity of peroxidase is lost from the aqueous solution as the removal reaction proceeds. Was pointed out (Science magazine,
Vol. 224, No. 4607, pages 259-261 (1983)). It is thought that this is because the aromatic radical, which is an intermediate product of the removal reaction, binds to the active center of peroxidase and deactivates peroxidase.

However, according to the study by the inventors, the peroxidase activity in the aqueous solution decreases as the reaction proceeds,
It was revealed that the decrease amount of peroxidase activity and the decrease amount of peroxidase itself were almost proportional. From this, the loss of peroxidase activity is mainly due to the fact that the peroxidase is adsorbed to the polymerization product generated by the removal reaction and removed from the reaction solution, rather than being deactivated by physicochemical factors. it is conceivable that.

The inventor has found that the adsorption of the peroxidase to the polymerization product as described above is suppressed by adding boric acid and / or borate to the aqueous solution. Due to the effect of suppressing the adsorption of boric acid and borate, the amount of peroxidase required for removing phenols and / or aromatic amines can be significantly reduced. In addition,
The borate may be any of orthoborate, diborate, metaborate, tetraborate, pentaborate, octaborate, hypoborate, and perborate. These borates generate borate ions after being dissolved in water, and borate ions are effective in suppressing adsorption.

In the removal method of the present invention, hydrogen peroxide is an essential chemical substance, but when the concentration of the substance to be removed is increased, the required amount of hydrogen peroxide is increased as described in the section of the prior art. If the amount is added at once to the aqueous solution, the hydrogen peroxide concentration in the aqueous solution will also increase. Hydrogen peroxide does not affect the activity of peroxidase at low concentrations, but when the concentration is higher than 10 mmol / mol, the action of impairing the activity of peroxidase becomes remarkable.

On the other hand, the concentration of hydrogen peroxide added to the aqueous solution decreases as the removal reaction progresses. Therefore, 10
After adding hydrogen peroxide to a concentration of mmol / or less, if hydrogen peroxide is gradually added to replenish the amount of hydrogen peroxide that has decreased with the progress of the removal reaction, a high concentration of Inactivation of peroxidase by contact with hydrogen peroxide can be minimized and the amount of peroxidase required for removal can be reduced.

As described above, when boric acid and / or borate is added to the aqueous solution, adsorption of peroxidase to the polymerization product is suppressed, but when boric acid and / or borate is not added, the removal reaction starts. At times, if the total amount of peroxidase necessary for the reaction is added to the aqueous solution, most of the added peroxidase is adsorbed on the polymerization product without contributing to the removal reaction. Therefore, when the method of adding peroxidase was examined, it was possible to minimize the adsorption of peroxidase on the polymer by gradually adding peroxidase to the aqueous solution so that the peroxidase activity in the aqueous solution was kept below 1,000 purpurogallin units per aqueous solution. It has been found that the amount of peroxidase required can be suppressed and the required amount of peroxidase can be reduced. Here, 1 purpurogallin unit is an active amount of peroxidase which produces 1 mg of purprogarin from pyrogallol in 20 seconds at pH 6 and 20 ° C.

Although the actions relating to the claims 1, 2 and 3 have been described above, if any two or three methods among these methods are used in combination, the peroxidase is used. The effect will be even greater in reducing the required amount.

(Example) Hereinafter, the Example of this invention is described.

The peroxidase used in the following examples was manufactured by Wako Pure Chemical Industries, Ltd., and its specific activity was 100 purpurogallin units / mg standard. The phenol concentration in the aqueous solution was measured by the industrial water test method, JIS K 0101.

Example 1 To a 0.1 M sodium tetraborate aqueous solution adjusted to pH 8.5, 1
Phenol was dissolved to 0 g /. After dissolving a predetermined amount of peroxidase in this phenol aqueous solution,
30% hydrogen peroxide solution was added to 0.12 M to start the removal reaction. After the removal reaction was carried out at room temperature for 2 hours, the polymerization product generated by the removal reaction was filtered off, and the phenol concentration in the filtered water was measured. FIG. 1 shows the relationship between the added amount of peroxidase and the removal rate of phenol. Here, the phenol removal rate is defined by the following equation.

Removal rate (%) = (phenol initial concentration-phenol concentration in filtered water) / phenol initial concentration x 100 As can be seen from Fig. 1, it is possible to obtain a removal rate of 90% or more with an aqueous phenol solution having an initial concentration of 10 g /. Required more than 100,000 purpurogallin units per oxidase per phenol aqueous solution.

As a control, 0.1M taps (TAPS, N-Tris (h
ydroxymethy l) methy l-1--3-aminopropanesulfon
ic acid) buffer solution was used to prepare a 10 g / phenol aqueous solution, and the same operation was performed. The amount of peroxidase required to obtain a removal rate of 90% or more was 150,000 purpurogallin units per 1 phenol aqueous solution. It was necessary to add hydrogen peroxide solution to 0.2M.

Example 2 0.01M, 0.02M, 0.05M, 0.07 using 0.1M taps aqueous solution
Sodium tetraborate solutions having respective concentrations of 5M, 0.1M, and 0.15M were prepared, pH was adjusted to 8.5, and then phenol was dissolved to 10 g /. After dissolving peroxidase in these solutions to 100,000 purpurogallin units /
30% hydrogen peroxide solution was added to 0.12 M to start the removal reaction. After the removal reaction was carried out at room temperature for 2 hours, the polymerization product generated by the removal reaction was filtered off, and the phenol concentration in the filtered water was measured. FIG. 3 shows the relationship between the sodium tetraborate concentration and the phenol removal rate. From this figure, it was found that the sodium tetraborate concentration needs to be 0.1 M or more.

Example 3 Peroxidase was added to a phenol aqueous solution at a concentration of 100,000 purpurogallin units / by using a phenol aqueous solution prepared by dissolving phenol at 10 g / in a 0.4 M boric acid aqueous solution adjusted to pH 8.5. Later, 0.
A 30% hydrogen peroxide solution was added to 12 M to start the removal reaction. After the removal reaction was carried out at room temperature for 2 hours, the polymer generated from the removal reaction was filtered off and the phenol concentration in the filtered water was measured.
It was 91%.

Example 4 A 10 g / phenol aqueous solution was prepared using 0.1 M taps buffer, and then a solution 1 containing 100,000 purpurogallin units / peroxidase was added,
The following operations were performed. That is, 30% hydrogen peroxide solution was added so as to meet the conditions shown in Table 1, and the removal reaction was performed after the removal reaction was performed at room temperature for 2 hours from the last addition of the hydrogen peroxide solution. The polymerized product was filtered off, and the phenol concentration in the filtered water was measured.

Table 2 shows the phenol removal rate for each hydrogen peroxide solution addition condition in Table 1.

Table 2. Phenol removal rate Hydrogen peroxide water addition conditions Phenol removal rate (%) A 82 B 83 C 64 D 55 Example 5 0.1 M sodium tetraborate aqueous solution adjusted to pH 8.5
Phenol was dissolved to 0 g /. After dissolving 5,000 purpurogallin units of this aqueous phenol solution 1 peroxidase, 0.1 ml of 30% hydrogen peroxide solution was added every 30 seconds. Immediately after the hydrogen peroxide solution was added, the hydrogen peroxide concentration in the phenol aqueous solution reached 0.98 mM, and the peroxidase reaction occurred until the next hydrogen peroxide solution was added (after 30 seconds).
It became less than 1uM. FIG. 2 shows the change over time in the phenol concentration in the phenol aqueous solution. As shown in the figure, the phenol concentration was 20 minutes after 60 minutes from the start of the reaction.
It became 0 mg /, and the phenol removal rate became 98%. The total amount of hydrogen peroxide added during that time was about 0.21 mol.

Example 6 To a 0.1 M sodium tetraborate aqueous solution adjusted to pH 8.5, 1
After dissolving phenol to 0 g /, 30% in aqueous solution 1 prepared by dissolving a predetermined amount of peroxidase.
Hydrogen peroxide water was added at a rate of 0.2 ml per minute to carry out a removal reaction. After 60 minutes from the start of the addition of the hydrogen peroxide solution, the polymerization product generated by the removal reaction was filtered off and the phenol concentration in the filtered water was measured. The amount of peroxidase required to obtain a removal rate of 95% or more was 3,000 purpurogallin units per 1 phenol aqueous solution.

Example 7 30% hydrogen peroxide solution was added to 10 g / phenol aqueous solution 1 prepared using 0.1 M taps buffer solution so that the hydrogen peroxide concentration in the phenol aqueous solution would be 0.2 M. 0.05 ml of a peroxidase solution (peroxidase dissolved in 0.1 M potassium phosphate buffer at 50 mg / ml) was added to this solution to start the removal reaction. After addition of the peroxidase solution, the same amount of peroxidase solution was added again after the decrease of the phenol concentration in the filtered water had stopped. The above operation was repeated until the total amount of peroxidase added reached 80,000 purpurogallin units per 1 phenol aqueous solution. The same operation was performed for each case of the added amounts of peroxidase of 0.1 ml, 0.2 ml, 0.3 ml, and 0.4 ml. The phenol removal rate at the end of the operation is shown in Table 3.

From the following results, by keeping the peroxidase activity in the aqueous phenol solution at 1,000 purpurogallin units / or less, the total amount of peroxidase added was 80,000 purpurogallin units / 10 g / 90% from the aqueous phenol solution.
It was found that the above phenol can be removed.

Example 8 50 mg of peroxidase in 0.1M potassium phosphate buffer
The peroxidase solution prepared by dissolving it to 10 ml / phenol solution (0.1M taps buffer, pH
(Prepared using 8.5) 1) was added at 5 m / h.
At the same time, 0.1 ml of 30% hydrogen peroxide solution was added to the phenol aqueous solution every 1 minute. The peroxidase activity in the aqueous phenol solution was maintained at about 500 purpurogallin units / unit during the progress of the removal reaction. After the above operation was continued for 2 hours, the phenol concentration in the filtered water obtained by filtering off the polymerization product generated by the reaction was measured, and it was found that the phenol concentration was reduced to 0.2 g /. The total amount of peroxidase solution added to the aqueous phenol solution was 10 ml, which corresponds to a peroxidase activity of 50,000 purpurogallin units.

Example 9 To a 0.1 M sodium tetraborate aqueous solution adjusted to pH 8.5, 1
Peroxidase solution prepared by dissolving peroxidase in 0.1M potassium phosphate buffer solution at 50 mg / ml in phenol aqueous solution 1 prepared by dissolving phenol at 0 g / hour using a peristaltic pump. Continuously added at a rate of 0.1 ml. 30% hydrogen peroxide solution was also added at a rate of 0.1 ml / min using a peristaltic pump. A removal reaction was performed. 120 minutes after the start of hydrogen peroxide solution addition, the polymerization product generated by the removal reaction was filtered off,
The phenol concentration in the filtered water was measured. The total amount of peroxidase added was 1,000 purpurogallin units and the total amount of hydrogen peroxide solution added was 108 mmol.
It was 3%.

Although the examples in which the method of the present invention is applied to the phenol aqueous solution have been described above, the fact that the method of the present invention can be applied to phenols other than phenol or aromatic amines is that peroxidase uses these substance groups as reaction substrates. It can be easily inferred from obtaining.

(Effects of the Invention) As described above, according to the method of the present invention, the amount of peroxidase used as a catalyst when removing phenols and the like from an aqueous solution can be made smaller than in the conventional case. Therefore, the cost required for removal is reduced, which is very advantageous in practical use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the relationship between the amount of added peroxidase in a phenol aqueous solution and the phenol removal rate, FIG. 2 is a diagram showing changes in the phenol concentration in a phenol aqueous solution over time, and FIG. It is a figure which shows the relationship between the sodium tetraborate concentration in a phenol aqueous solution, and a phenol removal rate.

Claims (5)

(57) [Claims] 1. A method for removing phenols and / or aromatic amines from an aqueous solution by reacting with hydrogen peroxide by the catalytic action of peroxidase, wherein boric acid and / or borate is added. A method for removing phenols and aromatic amines from an aqueous solution. 2. A method for removing phenols and / or aromatic amines from an aqueous solution by reacting with hydrogen peroxide by the catalytic action of peroxidase, wherein the hydrogen peroxide concentration in the aqueous solution is always kept at 10 mmol / l or less. A method for removing phenols and / or aromatic amines from an aqueous solution, which is characterized in that the reaction is carried out. 3. A method for removing phenols and / or aromatic amines from an aqueous solution by the catalytic action of peroxidase by reacting with hydrogen peroxide, so that the peroxidase activity in the aqueous solution is always maintained at 1,000 purpurogallin units or less per liter of the aqueous solution. A method for removing phenols and / or aromatic amines from an aqueous solution, which is characterized by reacting while performing 4. The concentration of hydrogen peroxide in the aqueous solution is always 10 mmol / l.
The removal method according to claim 1, wherein the reaction is carried out while maintaining the following. 5. The removal method according to claim 1, 2, or 4, wherein the peroxidase activity in the aqueous solution is allowed to react while keeping the aqueous solution at 1,000 purpurogallin units or less per liter.