JP2008194590A - In situ purification method of polluted ground or polluted underground water utilizing fenton reaction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in situ purification method of a polluted ground or polluted underground water utilizing the Fenton reaction, which enables the purification of the polluted soil or the polluted underground water in situ over an extensive range. <P>SOLUTION: This in situ purification method of the polluted ground or the polluted underground water utilizes the Fenton reaction, and supplies a solution containing divalent ferrous ions and a hydrogen peroxide solution together with a water-soluble alcohol to the polluted ground or the polluted underground water fouled by an organic pollutant. Thus the purification of the polluted ground or the polluted underground water is performed at a source site. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for in situ purification of contaminated ground or contaminated groundwater using a Fenton reaction.

Conventionally, a technique for purifying contaminated ground or contaminated groundwater contaminated with organic pollutants (for example, organic halogen compounds, dioxins, oil, etc.) using the Fenton reaction is known (for example, Patent Document 1). -3 etc.) In this technology, a solution containing divalent iron ions and hydrogen peroxide water are supplied to contaminated ground or contaminated groundwater, and trivalent iron is reacted by the reaction between the divalent iron ions and hydrogen peroxide (Fenton reaction). In addition to producing ions and hydroxy radicals, the organic radicals are decomposed into carbon dioxide and detoxified by the hydroxy radicals.
JP-A-5-345189 JP 2000-197867 A JP 2000-210683 A

  However, the hydroxyl radical generated by the Fenton reaction reacts not only with organic pollutant compounds but also with other hydroxyl radicals rapidly, and the degradation performance of organic pollutants disappears in a very short time. Will cause severe foaming.

  Therefore, when purifying contaminated ground or contaminated groundwater in situ using the Fenton reaction, the following problems arise.

  First, when supplying hydrogen peroxide solution or the like to the contaminated ground or contaminated groundwater in the original position, intense foaming occurs, so that it becomes extremely difficult to supply the hydrogen peroxide solution or the like. In addition, even if hydrogen peroxide water or the like is supplied to the contaminated ground or contaminated groundwater in the original position, the decomposition performance of organic pollutants disappears before hydroxy radicals are sufficiently diffused into the contaminated ground or contaminated groundwater. Therefore, the purification target area of the contaminated ground or the contaminated groundwater becomes narrow.

  The present invention has been made in view of the above problems, and a method for in situ purification of contaminated ground or contaminated groundwater using a Fenton reaction capable of purifying contaminated soil or contaminated groundwater over a wide range in situ. The purpose is to provide.

  In order to solve the above problems, the present invention supplies a solution containing divalent iron ions and aqueous hydrogen peroxide together with water-soluble alcohol to contaminated ground or contaminated groundwater contaminated with organic pollutants, and This is an in-situ purification method for contaminated ground or contaminated groundwater using a Fenton reaction to purify the ground or the contaminated groundwater in situ.

  The water-soluble alcohol is not particularly limited, and examples thereof include ethanol, 1-propanol, 2-propanol, t-butanol, etc. Among them, ethanol, 1-propanol, and 2-propanol are preferable, and 2- More preferred is propanol.

  According to the present invention, it is possible to purify contaminated soil or contaminated groundwater over a wide range at the original position.

Hereinafter, the best mode for carrying out the present invention will be described.
The present invention is an in-situ purification method for contaminated ground or contaminated groundwater using the Fenton reaction, and a solution containing divalent iron ions and hydrogen peroxide water in contaminated ground or contaminated groundwater contaminated with organic pollutants. Is supplied with water-soluble alcohol to purify contaminated ground or contaminated groundwater in situ.

  That is, the present inventors can maintain the Fenton reaction by reacting a hydrogen peroxide solution with a solution containing divalent iron ions in the presence of a water-soluble alcohol. It has been found that the foaming generated in can be suppressed (see the confirmation test below). Further, the water-soluble alcohol is not particularly limited, but the present inventors preferably use ethanol, 1-propanol, or 2-propanol among the water-soluble alcohols (see FIGS. 1 to 3 below). In particular, it was found that 2-propanol is more preferable (see FIGS. 3 and 4 below). Then, the present inventors supply the solution containing divalent iron ions and the hydrogen peroxide solution together with the water-soluble alcohol to the contaminated ground or contaminated ground water in the original position, thereby bringing the contaminated ground or the contaminated ground water into the original position. Therefore, the present invention has been completed. Specifically, the present invention is implemented by any one of the following methods (1) to (6).

  (1) A solution containing divalent iron ions and a water-soluble alcohol are mixed in advance, and the mixture is supplied to the contaminated ground or contaminated groundwater. Further, hydrogen peroxide is added to the contaminated ground or contaminated groundwater. Supply. (2) Alternatively, hydrogen peroxide solution and water-soluble alcohol are mixed in advance, and the mixture is supplied to the contaminated ground or contaminated groundwater, and a solution containing divalent iron ions is further added to the contaminated ground or contaminated groundwater. It is good also as supplying to. (3) In addition, a solution containing divalent iron ions and a water-soluble alcohol are mixed in advance, while a hydrogen peroxide solution and a water-soluble alcohol are mixed in advance, and the mixture is contaminated ground or contaminated. It is good also as supplying to groundwater simultaneously or sequentially. (4) Alternatively, a solution containing divalent iron ions and a hydrogen peroxide solution may be added to water-soluble alcohol and mixed in advance, and the mixture may be supplied to contaminated ground or contaminated groundwater. (5) A solution containing divalent iron ions, a hydrogen peroxide solution, and a water-soluble alcohol may be simultaneously added to the contaminated ground or the contaminated groundwater. (6) In addition, water-soluble alcohol is supplied to the contaminated ground or contaminated groundwater, and a solution containing divalent iron ions and hydrogen peroxide water are simultaneously or sequentially added to the contaminated ground or contaminated groundwater. It is good also as adding.

  Next, confirmation tests 1 and 2 of the present invention will be described with reference to FIGS.

<Confirmation test 1>
1 to 3 are graphs showing a confirmation test 1 of the present invention.
In this confirmation test, contaminated soil (sand) contaminated with TCE (trichloroethylene), which is an organic halogen compound, is used in the presence of various water-soluble alcohols (ethanol, 1-propanol, 2-propanol). It was confirmed that by reacting a solution containing divalent iron ions (sulfuric acid first solution) with hydrogen peroxide solution, the Fenton reaction is continued and the decomposition of TCE is promoted. Specifically, this confirmation test was conducted as follows. At that time, it was observed whether or not foaming was suppressed.

First, 1 g of sand was collected in a 40 ml vial with a sealing stopper, and 10 μL of TCE stock solution was added to the vial, and the vial was immediately sealed and stirred. Next, the vial bottle was opened, and 200 μL of FeSO ₄ .7H ₂ O solution (0.1 M) was added to the vial bottle, and a predetermined concentration (0.03%, 0.17%, 0.3%) was added. 200 μL each of water-soluble alcohol adjusted to 1.7%, 3.3%, and 19.7%) was added, and the vial was sealed and stirred. Then, the vial bottle was opened, 200 μL of 10% hydrogen peroxide solution was added to the vial bottle, and the vial bottle was immediately sealed and stirred, and allowed to stand at room temperature for 16 hours. Thereafter, sand was taken out from the vial, residual TCE contained in the sand was extracted into methanol, and further TCE contained in the methanol was extracted into decane. And TCE contained in this decane was quantified by GCMS (HP5863). The quantitative results are shown in FIGS. Each figure is a graph showing TCE quantification results when ethanol (FIG. 1), 1-propanol (FIG. 2), and 2-propanol (FIG. 3) are used as the water-soluble alcohol. In this confirmation test, a solution obtained by reacting a solution containing divalent iron ions (sulfuric acid first solution) and hydrogen peroxide solution in the absence of water-soluble alcohol was used as a comparative control. Used as a comparative control a solution in which 200 μL of water was added instead of 200 μL of water-soluble alcohol (no addition of water-soluble alcohol).

  As shown in FIG. 1, when ethanol is used as the water-soluble alcohol, by adding 3.3% ethanol, compared to the case of the normal Fenton reaction (when no water-soluble alcohol is added), A 30% TCE decomposition promoting effect was observed. A significant TCE degradation promoting effect was observed only when 3.3% ethanol was added, and when 19.7% ethanol was added, a TCE degradation inhibitory effect was observed. In addition, when ethanol was added, mild foaming was observed at any concentration compared to the normal Fenton reaction.

  In addition, as shown in FIG. 2, when 1-propanol is used as the water-soluble alcohol, the addition of 0.3% and 1.7% of 1-propanol makes it possible to compare with the normal Fenton reaction. 25% to 28% of TCE decomposition promoting effect was observed. A significant effect was observed only when 0.3% and 1.7% 1-propanol was added, and when 19.7% 1-propanol was added, inhibition of TCE degradation was observed. The effect was recognized. In addition, when 1-propanol was added, milder foaming was observed at any concentration compared to the normal Fenton reaction.

  As shown in FIG. 3, when 2-propanol is used as the water-soluble alcohol, 1.7%, 3.3%, and 19.7% of 2-propanol are added to obtain normal Fenton. Compared to the reaction, a TCE decomposition promoting effect of 20% to 40% was observed. In addition, when 2-propanol was added, only slight foaming was observed at any concentration compared to the normal Fenton reaction.

  As described above, by adding various water-soluble alcohols, an effect of promoting TCE decomposition was recognized as compared with the case of normal Fenton reaction, and foaming generated during the Fenton reaction was sufficiently suppressed. . This is because rapid reaction in the Fenton reaction is caused by reacting a solution containing divalent iron ions (sulfuric acid first solution) with hydrogen peroxide in the presence of a water-soluble alcohol adjusted to a predetermined concentration. This suggests that the reaction can be relaxed and the Fenton reaction can be sustained. The above has been clarified by the graph shown in FIG. In addition, when purifying contaminated ground or contaminated groundwater in situ, the water-soluble alcohol is preferably 2-propanol having the widest applicable concentration range.

<Confirmation test 2>
FIG. 4 is a graph showing a confirmation test 2 of the present invention.
In this confirmation test, contaminated soil contaminated with organohalogen compound PCE (tetrachloroethylene) (hereinafter referred to as “locally contaminated soil”) in the presence of 2-propanol, which is a water-soluble alcohol, is charged with divalent iron ions. It has been confirmed that the rapid reaction in the Fenton reaction is mitigated by the reaction of the solution containing hydrogen (sulfuric acid first solution) with hydrogen peroxide solution, and the Fenton reaction continues.

  Specifically, this confirmation test was conducted as follows. Further, as in Confirmation Test 1, it was observed whether foaming was suppressed.

First, 10 g of contaminated soil was collected into a 40 ml vial with a sealing stopper, and 2.5 ml of FeSO ₄ solution (5 mM) was added to this vial, and 0.25 ml of 5% 2-propanol was added. The vial was sealed and stirred. Then, the vial bottle was opened, 2.5 ml of 10% hydrogen peroxide solution was added to the vial bottle, and the vial bottle was immediately sealed, stirred and allowed to stand at room temperature. After standing, the residual PCE after 0.5 hours, 3 hours, 6 hours, 24 hours and 48 hours were measured by GCMS, respectively. The measurement results are shown in FIG. In this confirmation test, a comparative control was added with no water-soluble alcohol added.

  As shown in FIG. 4, when no water-soluble alcohol was added, the PCE concentration rapidly decreased in 0.5 to 3 hours, and thereafter the PCE concentration showed a substantially constant value. This suggests that in the case of a normal Fenton reaction, the decomposition of PCE proceeds rapidly, and then the decomposition of PCE stops. On the other hand, in the case where 2-propanol which is a water-soluble alcohol is not added, the progress of the PCE decomposition reaction after 24 hours has been moderated to about 50%. Continued until time. In addition, the density | concentration of PCE after 48-hour progress showed the substantially same value with the case where 2-propanol is not added, and the case where 2-propanol is added. In addition, in this confirmation test, as in Confirmation Test 1, when 2-propanol was added, foaming was sufficiently suppressed as compared with the normal Fenton reaction, and only slight foaming was observed. There wasn't.

  As described above, a rapid reaction in the Fenton reaction is caused by reacting a solution containing divalent iron ions (sulfuric acid first solution) with hydrogen peroxide in the presence of 2-propanol which is a water-soluble alcohol. It was revealed that the Fenton reaction can be sustained by relaxing Therefore, by supplying a solution containing divalent iron ions and aqueous hydrogen peroxide together with water-soluble alcohol to the contaminated ground or contaminated groundwater in the original position, the contaminated ground or contaminated groundwater is spread over a wide area in the original position. It becomes possible to purify.

It is a graph which shows the result of the confirmation test 1 (ethanol use) of this invention. It is a graph which shows the result of the confirmation test 1 (1-propanol use) of this invention. It is a graph which shows the result of the confirmation test 1 (2-propanol use) of this invention. It is a graph which shows the result of the confirmation test 2 of this invention.

Claims (2)

  A solution containing divalent iron ions and hydrogen peroxide solution are supplied together with water-soluble alcohol to contaminated ground or groundwater contaminated with organic pollutants, and the contaminated ground or the contaminated groundwater is purified in situ. In-situ purification method for contaminated ground or contaminated groundwater using Fenton reaction. In claim 1,
The water-soluble alcohol is any one of ethanol, 1-propanol, and 2-propanol. A method for in situ purification of contaminated ground or contaminated groundwater using a Fenton reaction.

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