Method for efficiently degrading chloroneb by Fe / Na2SO3 mechanical abrasive

Abstract

The present invention provides a method for efficiently degrading chlorthal-dimethyl by using an Fe / Na2SO3 mechanical abrasive, and the method is as follows: iron powder, Na2SO3 and chlorthal-dimethyl are added into a planetary ball mill together, and ball milling is carried out at a rotation speed of 450 rpm - 600 rpm for 40 min - 100 min in an air atmosphere. The abrasive combination of Fe / Na2SO3 can achieve a degradation rate of more than 90% for chlorthal-dimethyl and a dechlorination rate of more than 76% for chlorthal-dimethyl within 40 min, and this grinding efficiency is of great significance for the treatment of chlorthal-dimethyl in industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanochemical treatment of environmental pollutants, and specifically relates to a new abrasive combination Fe / Na2SO3 for mechanical grinding degradation of chloroneb. Background Art

[0002] Chlorinated organic compounds refer to refractory chlorinated hydrocarbon or aromatic organic compounds. They can be used as important industrial raw materials, organic solvents and intermediates, and are widely used in industries such as chemical engineering, medicine, pesticides, and leather making. Many chlorinated organic pollutants have obvious "carcinogenic, teratogenic and mutagenic effects", and will seriously pollute the atmosphere, soil, groundwater and surface water. In addition, due to the high volatility and fat solubility of many chlorinated organic pollutants, they are easily absorbed by the skin, mucous membranes, etc., causing serious damage to the health of animals and even humans. Therefore, they are listed as priority control pollutants by the US Environmental Protection Agency (EPA).

[0003] Chloroneb is a kind of highly efficient chlorinated pesticide, which is particularly effective in controlling damping-off of crops such as cotton, tobacco, pepper, and tomato, and also has significant control effects on tobacco stem rot, cucumber root rot, cotton red rot, etc. However, due to its strong biological toxicity, relevant research shows that after chloroneb enters the animal body, 2,5-dichloro-4-methoxyphenol can be detected in urine, existing in free and conjugated forms. When it enters the plant body, three metabolites, namely 2,5-dichloro-4-methoxyphenol, 2,5-dichlorohydroquinone, and 2,5-dichlorobenzoquinone, are detected in the plant tissue. Since it is difficult to completely degrade into non-toxic and harmless products in the organism, various methods are needed to limit and treat it. In Japan, there are strict restrictions on the residues of chloroneb in edible pork and beef, and there are also corresponding restrictions on its content in groundwater.

[0004] For the treatment methods of chloroneb, there are few studies at home and abroad. In the field of mechanochemistry, the abrasive combination Fe / Na2SO3 has not been studied and applied. Summary of the Invention

[0005] The purpose of the present invention is to provide a new abrasive combination Fe / Na2SO3 for mechanical grinding degradation of chloroneb.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for degrading chloroneb with Fe / Na2SO3 mechanical abrasive, and the method is as follows: Add iron powder, Na2SO3 and chloroneb into a planetary ball mill together, and under an air atmosphere, carry out ball milling at a rotation speed of 450 rpm - 600 rpm (preferably 600 rpm) for 40 min - 100 min (preferably 100 min); the mass of the iron powder is 60% - 90% (preferably 60% - 70%, particularly preferably 66.6%) of the total mass of the iron powder and Na2SO3; the mass ratio of the total mass of the iron powder and Na2SO3 to the mass of chloroneb is 15 - 25:1 (preferably 20:1); the ball-to-material ratio of the ball milling is 50 - 80:1 (preferably 50:1).

[0008] Among them, in the ball-to-material ratio, the "material" is the total mass of iron powder, Na2SO3 and chloroneb.

[0009] Furthermore, the present invention particularly recommends the method as follows: Add iron powder, Na2SO3 and chloroneb into a planetary ball mill together, and under an air atmosphere, carry out ball milling at a rotation speed of 600 rpm for 100 min; the mass of the iron powder is 66.6% of the total mass of the iron powder and Na2SO3; the mass ratio of the total mass of the iron powder and Na2SO3 to the mass of chloroneb is 20:1; the ball-to-material ratio of the ball milling is 50:1.

[0010] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in: The present invention provides a method for efficiently degrading chloroneb with Fe / Na2SO3 mechanical abrasive, and currently there is no research on the grinding and degradation of chloroneb by Fe / Na2SO3 in the field of mechanochemistry. Experiments have found that this abrasive combination of Fe / Na2SO3 can achieve a degradation rate of more than 90% for chloroneb and a dechlorination rate of more than 76% for chloroneb within 40 min, and this grinding efficiency is of great significance for the treatment of chloroneb in industry. Description of the Drawings

[0011] The following further elaborates on the specific embodiments of the present invention in conjunction with the drawings.

[0012] Figure 1 For the degradation effect of chloroneb under different oxidant combinations in Example 1;

[0013] Figure 2 For the dechlorination effect of chloroneb under different oxidant combinations in Example 1;

[0014] Figure 3 For the degradation effect of chloroneb under different reductant combinations in Example 1;

[0015] Figure 4 For the dechlorination effect of chloroneb under different reductant combinations in Example 1;

[0016] Figure 5 Effect of mass fraction of Fe in Fe / Na2SO3 on the dechlorination effect of dimethachlor

[0017] Figure 6 Effect of different ball - material ratios on the dechlorination effect of dimethachlor

[0018] Figure 7 Effect of different material ratios on the dechlorination effect of dimethachlor Specific embodiments

[0019] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0020] In the following embodiments, the experimental steps for detecting the degradation rate and dechlorination rate of dimethachlor are as follows:

[0021] (1) Degradation rate: Weigh 0.05 g of the ground mixture sample into a 10 - mL centrifuge tube, add 10 mL of n - hexane to extract dimethachlor in the sample. First, ultrasonically treat for 20 min, then oscillate at low frequency with a vortex mixer for 10 min, then place it in a centrifuge and centrifuge at 8000 rpm for 1 min. Then take 1 mL of the supernatant and dilute it 10 times. Finally, after filtering through a 0.22 - um membrane, inject it into a high - performance gas chromatograph for detection and analysis.

[0022] (2) Dechlorination rate: Weigh 0.05 g of the ground mixed sample into a 10 - mL centrifuge tube, add 3 mL of dilute nitric acid (5%), and ultrasonically treat at 60 °C for 20 min. Then add ultrapure water to make the volume up to 10 mL. Place the centrifuge tube in a centrifuge and centrifuge at 8000 rpm for 1 min. Take 1 mL of the supernatant and dilute it to 10 times. Finally, after filtering through a 0.22 - um filter membrane, inject it into an ion chromatograph for detection and analysis.

[0023] Example 1. Degradation and dechlorination effects of dimethachlor under different grinding agent combinations

[0024] The grinding agent combinations of Fe / Na2SO3, Fe / PDS, and Fe / PMS are all carried out under the conditions of 145 g of stainless - steel grinding balls, dimethachlor content of 0.138 g, and a ball - mill rotation speed of 600 rpm in air. The Fe content in each group is 1.841 g, and the contents of Na2SO3, PDS, and PMS are all 0.921 g.

[0025] The abrasive combinations of Fe / Na2SO3, Zn / Na2SO3, Al / Na2SO3, and Mg / Na2SO3 were all carried out under the conditions of 145 g of stainless steel grinding balls, 0.138 g of dichlone content, and a ball mill rotation speed of 300 rpm in air. The contents of Fe, Zn, Al, and Mg in each group were all 1.841 g, and the content of Na2SO3 was 0.921 g. The ground samples were weighed at regular intervals, and after pretreatment, they were respectively injected into a high-performance gas chromatograph and an ion chromatograph for detection and analysis, and the degradation rate and dechlorination rate were calculated.

[0026] The results are as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown. We found that Fe / Na2SO3 can operate at a maximum rotation speed of 600 rpm, with a degradation rate of up to 98% and a dechlorination rate of up to 97%.

[0027] In addition, during the experiment, we further increased the rotation speed and found that the three active metals Zn, Al, and Mg burned violently at a rotation speed of 400 rpm, resulting in the termination of the reaction. Under the condition of 400 rpm, the degradation and dechlorination of dichlone by the Fe / Na2SO3 combination can reach about 70%. Therefore, we believe that the Fe / Na2SO3 combination can achieve a more ideal effect on the degradation and dechlorination of dichlone under high rotation speed conditions, and the subsequent experiments were continued.

[0028] Example 2. Influence of the mass fraction of Fe in Fe / Na2SO3 on the dechlorination effect of dichlone

[0029] The Fe contents were 0%, 10%, 20%, 30%, 50%, 66.6%, 80%, 90%, and 100%, that is, 0 g, 0.276 g, 0.552 g, 0.828 g, 1.38 g, 1.838 g, 2.208 g, 2.484 g, and 2.76 g, and the corresponding Na2SO3 contents were 2.76 g, 2.484 g, 2.208 g, 1.932 g, 1.38 g, 0.922 g, 0.552 g, 0.276 g, and 0 g. The other conditions were: 145 g of stainless steel grinding balls, 0.138 g of dichlone content, a ball mill rotation speed of 600 rpm, and the ball mill atmosphere was air.

[0030] The results are as Figure 5 shown. The data indicate that when the Fe content is 66.6%, the mechanical grinding dechlorination effect of the system on dichlone is the best.

[0031] Example 3. Influence of different ball-to-material ratios on the dechlorination effect of dichlone

[0032] Under the conditions of ball-to-material ratios of 20:1, 35:1, 50:1, 65:1, and 80:1 for grinding, when the ball-to-material ratio is 20:1, the amounts of Fe, Na2SO3, and dimethachlor are 4.603 g, 2.302 g, and 0.345 g respectively; when the ball-to-material ratio is 35:1, the amounts of Fe, Na2SO3, and dimethachlor are 2.630 g, 1.315 g, and 0.197 g respectively; when the ball-to-material ratio is 50:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.841 g, 0.921 g, and 0.138 g respectively; when the ball-to-material ratio is 65:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.416 g, 0.708 g, and 0.106 g respectively; when the ball-to-material ratio is 80:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.151 g, 0.575 g, and 0.086 g respectively. The remaining conditions are as follows: 145 g of stainless steel grinding balls, the rotational speed of the ball mill is 600 rpm, and the atmosphere in the ball mill is air.

[0033] The results are as Figure 6 shown. The data indicate that when the ball-to-material ratio is 50:1, the mechanical grinding dechlorination effect of the system on dimethachlor is the best.

[0034] Example 4. Influence of different material ratios on the dechlorination effect of dimethachlor

[0035] Under the conditions of material ratios of 10:1, 15:1, 20:1, 25:1, and 30:1 for grinding, when the material ratio is 10:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.758 g, 0.879 g, and 0.264 g respectively; when the material ratio is 15:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.813 g, 0.906 g, and 0.181 g respectively; when the material ratio is 20:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.841 g, 0.921 g, and 0.138 g respectively; when the material ratio is 25:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.859 g, 0.929 g, and 0.112 g respectively; when the material ratio is 30:1, the amounts of Fe, Na2SO3, and dimethachlor are 1.871 g, 0.936 g, and 0.094 g respectively. The remaining conditions are as follows: 145 g of stainless steel grinding balls, the rotational speed of the ball mill is 600 rpm, and the atmosphere in the ball mill is air.

[0036] The results are as Figure 7 shown. The data indicate that when the material ratio is 20:1, the mechanical grinding dechlorination effect of the system on dimethachlor is the best.

[0037] Finally, it should also be noted that the above are only several specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and there can be many variations. All variations that can be directly derived or associated by those of ordinary skill in the art from the content disclosed in the present invention should be considered within the protection scope of the present invention.

Claims

1. A method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive, characterized in that The method is as follows: Add iron powder, Na2SO3 and dimethachlor into a planetary ball mill, and carry out ball milling for 40 min - 100 min at a rotation speed of 450 rpm - 600 rpm in an air atmosphere; the mass of the iron powder is 60% - 90% of the total mass of the iron powder and Na2SO3; the mass ratio of the total mass of the iron powder and Na2SO3 to the mass of dimethachlor is 15 - 25:1; the ball-to-material ratio of the ball milling is 50 - 80:

1.

2. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 1, characterized in that: The rotation speed of the ball milling is 600 rpm.

3. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 1, characterized in that: The time of the ball milling is 100 min.

4. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 1, characterized in that: The mass of the iron powder is 60% - 70% of the total mass of the iron powder and Na2SO3.

5. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 4, characterized in that: The mass of the iron powder is 66.6% of the total mass of the iron powder and Na2SO3.

6. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 1, characterized in that: The mass ratio of the total mass of the iron powder and Na2SO3 to the mass of dimethachlor is 20:

1.

7. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 1, characterized in that: The ball-to-material ratio of the ball milling is 50:

1.

8. The method for degrading chloroneb by using Fe / Na2SO3 mechanical abrasive according to claim 1, characterized in that The method is as follows: Add iron powder, Na2SO3 and dimethachlor into a planetary ball mill, and carry out ball milling for 100 min at a rotation speed of 600 rpm in an air atmosphere; the mass of the iron powder is 66.6% of the total mass of the iron powder and Na2SO3; the mass ratio of the total mass of the iron powder and Na2SO3 to the mass of dimethachlor is 20:1; the ball-to-material ratio of the ball milling is 50:1.

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