Method for recovering organic reagent in dioxin pretreatment process

Abstract

The invention discloses a method for recycling an organic reagent in a dioxin pretreatment process, and belongs to the technical field of waste liquid recycling treatment.The method for recycling the organic reagent in the dioxin pretreatment process is characterized in that the method comprises the following recycling steps that S1, a dispersing and purifying bag is added into organic reagent waste liquid to be shaken, and the organic reagent waste liquid is recycled; glass wool is plugged into a glass funnel, anhydrous magnesium sulfate is added, solid substances are filtered, the dispersing and purifying bag is composed of silica sulfate and Flory, the silica sulfate is prepared by activating column chromatography silica gel under the condition of 550 + / -5 DEG C and then mixing the activated column chromatography silica gel with concentrated sulfuric acid, and the Flory is obtained by activating under the condition of 550 + / -5 DEG C; s2, the filtrate obtained in the step S1 is subjected to two times of rotary evaporation, and then an organic reagent is collected, by means of the recovery method, 90% of consumption of methylbenzene and n-hexane can be reduced, and expenditure of a pretreatment reagent for dioxin detection can be remarkably reduced.

Description

Technical Field

[0001] The invention relates to the technical field of waste liquid recovery and treatment, in particular to a method for recovering organic reagents in a dioxin pretreatment process. Background Art

[0002] Dioxin is a general term for some chlorinated polynuclear aromatic compounds. When testing dioxins, it is necessary to go through two pre-treatment processes, extraction and purification. In the pre-treatment process, a large amount of n-hexane and toluene will be consumed. Depending on the extraction and purification methods, each sample is expected to consume 300-1000mL of n-hexane and 140-500mL of toluene. Different operation methods also consume different amounts of organic reagents. For example, in the extraction step, Soxhlet extraction consumes more organic reagents than ASE extraction, and in the purification step, the automatic purification scheme consumes more organic reagents than the manual purification scheme of hand-filled purification columns. However, no matter which scheme is chosen, it is impossible to avoid the consumption of a large amount of organic reagents and the generation of a large amount of waste liquid, which puts tremendous pressure on the laboratory reagent cost and waste liquid treatment cost, and has a greater negative impact on environmental protection.

[0003] After years of practice and improvement, the dioxin extraction and purification scheme has basically reached a better level in the selection and dosage of reagents, so there is little room for reducing the dosage, and the dosage of reagents will directly affect the test results. Therefore, the recycling of reagents is the best solution to reduce the cost of laboratory reagents. Therefore, it is urgent to establish a method for recovering toluene and n-hexane in dioxin pretreatment wastewater to solve the current cost and environmental protection problems. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention provides a method for recovering organic reagents in a dioxin pretreatment process, which can reduce the consumption of toluene and n-hexane by 90%, and can significantly reduce the expenses of dioxin detection pretreatment reagents. For a dioxin laboratory with an annual sample volume of 10,000 batches, it is estimated that the reagent cost expenses can be reduced by 300,000 to 1 million, and the waste liquid treatment cost can be reduced by 3,960 to 13,500 L. Under normal circumstances, if the dehydrating agent magnesium sulfate is recovered, while reducing the generation of 1 L of organic waste liquid, only 1.5 g of solid waste will be generated, which is relatively friendly to the environment.

[0005] The present invention provides a method for recovering organic reagents in a dioxin pretreatment process, which adopts the following technical scheme: A method for recovering organic reagents in a dioxin pretreatment process comprises the following recovery steps: S1. Add a dispersion purification package to the organic reagent waste liquid and shake it, insert glass wool into a glass funnel, add anhydrous magnesium sulfate, and filter the solid matter. The dispersion purification package is composed of sulfuric acid silica gel and Florisil. The sulfuric acid silica gel is prepared by activating column chromatography silica gel at 550±5°C and mixing it with concentrated sulfuric acid. The Florisil is obtained by activating it at 550±5°C. S2. The filtrate obtained in step S1 is subjected to rotary evaporation twice and then the organic reagent is collected.

[0006] In a preferred embodiment, the concentration of the dispersed purification package in the organic reagent waste liquid is 1.4-1.6 g / L.

[0007] In a preferred embodiment, the weight ratio of the sulfuric acid silica gel to Florisil is 1:(0.8-1.2).

[0008] In a preferred embodiment, the mass concentration of concentrated sulfuric acid in the sulfuric acid silica gel is 20-40wt%.

[0009] In a preferred embodiment, the mass concentration of concentrated sulfuric acid in the sulfuric acid silica gel is 30-40wt%.

[0010] In a preferred embodiment, the column chromatography silica gel is activated at 550±5° C. for 12±0.5 h and then mixed with concentrated sulfuric acid.

[0011] In a preferred embodiment, the Florisil is obtained after being activated at 550±5° C. for 24±0.5 h.

[0012] In a preferred embodiment, the organic reagent waste liquid is toluene waste liquid or n-hexane waste liquid; the conditions for the first rotary evaporation of the toluene waste liquid are 60±2°C, 180-200hPa for 10-15min, and the conditions for the second rotary evaporation are 60±2°C, 180-220hPa, and the pressure is reduced to 100-120hPa within 2min.

[0013] In a preferred embodiment, the conditions for the first rotary evaporation of the n-hexane waste liquid are 60±2°C, 480-500hPa for 10±2min, and the conditions for the second rotary evaporation are 60±2°C, 480-500hPa, and the pressure is reduced to 300-330hPa within 5min.

[0014] In summary, the present invention has the following beneficial effects: When the method of the present application is used to recover organic reagents, the consumption of toluene and n-hexane can be reduced by 90%, and the expenses of dioxin pretreatment reagents can be significantly reduced. For a dioxin laboratory with an annual sample volume of 10,000 batches, it is estimated that the reagent cost can be reduced by 300,000 to 1 million. For a dioxin laboratory with an annual sample volume of 10,000 batches, it is estimated that the waste liquid treatment cost can be reduced by 3,960 to 13,500 L. In addition, the addition of a dispersed purification package can efficiently remove most impurities in toluene and n-hexane, so that no dioxin substances are detected after toluene and n-hexane are concentrated 10,000 times.

[0015] The present application can remove organic matter and moisture contained in the column chromatography silica gel and Floris earth after high-temperature purification of the column chromatography silica gel and Floris earth in the dispersion purification package, thereby improving the adsorption effect of impurities.

[0016] The sulfuric acid in sulfuric acid silica gel has a sulfonation effect, and the silica gel has an adsorption effect. When sulfuric acid and silica gel are used together, the organic impurities can be completely sulfonated and the adsorption of organic impurities by silica gel can be improved. However, when the content of sulfuric acid is relatively low, some organic impurities will not be completely sulfonated and cannot be adsorbed by silica gel. When the sulfuric acid content exceeds 40%, it is easy to cause carbonization of impurities, which will cause potential adverse effects. Moreover, the impurities after sulfonation need to be adsorbed by silica gel. The higher the sulfuric acid content means that the silica gel content is reduced at the same quality, and the dosage needs to be increased, which will affect the cost and solid waste. Therefore, when the mass concentration of sulfuric acid in sulfuric acid silica gel is in the range of 20-40%, it can effectively ensure the adsorption effect of silica gel on organic impurities, and at the same time, it can also make the recycling cost lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1-Figure 10 This is the detection spectrum of Example 1 of the present application.

[0018] Figure 11-Figure 20 It is the detection spectrum of comparative example 3 of the present application. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the examples. All reagents without manufacturer indicated are conventional reagent products that can be obtained commercially.

[0020] The relevant toluene waste liquid includes toluene extract (Soxhlet extraction and ASE extraction), about 60-350mL sample, and toluene eluate produced during the reverse elution of the activated carbon silica gel column, about 80-150mL sample. Because these two parts of toluene have been concentrated by rotary evaporation, most of the non-volatile impurities have been removed. The main impurities are water and volatile substances in the sample, and there may be a small amount of dioxins and dioxin internal standard substances.

[0021] Example 1

[0022] A method for recovering organic reagents in a dioxin pretreatment process, wherein toluene produced in the pretreatment step is recovered according to the following steps: S1. Combine the toluene waste liquid. If there are obvious water droplets on the bottom or wall of the container, add enough anhydrous magnesium sulfate, shake appropriately until there are no obvious water droplets, put a small amount of glass wool in the glass funnel, add 5g of anhydrous magnesium sulfate, and filter out the solid matter used; S2. Add 6 g of a dispersion purification package to 4 L of toluene waste liquid and shake thoroughly for 15 min. Put a small amount of glass wool in a glass funnel, add 5 g of anhydrous magnesium sulfate, and filter all solid substances. The dispersion purification package is composed of sulfuric acid silica gel and Florisil in a weight ratio of 1:1. The sulfuric acid silica gel is prepared by activating column chromatography silica gel at 550±5°C for 12 h and then mixing with concentrated sulfuric acid. The mass concentration of sulfuric acid in the sulfuric acid silica gel is 20 wt %. Florisil is obtained after being activated at 550±5°C for 24 h. S3, adding the filtrate obtained in step S1 into a round-bottom bottle, performing the first rotary evaporation at 60°C and 180hPa for 10 minutes to remove volatile impurities. Be careful not to boil obviously during the rotary evaporation, discard the liquid in the collection bottle, and replace the collection bottle; S4. Starting from 60℃ and 180hPa, gradually reduce the pressure to 100hPa within 2min and perform the second rotary evaporation for 35min to evaporate about 97% of the liquid. Be careful not to boil obviously during the rotary evaporation to avoid evaporation of the liquid. The liquid remaining in the round-bottom flask contains most of the non-volatile impurities, including dioxins and their corresponding internal standard substances and a small amount of toluene. The liquid remaining in the round-bottom flask is discarded, and the final product obtained in the collection bottle is toluene. Take 100mL of the final product, concentrate it to 10μL and analyze it on the machine. No dioxin and its internal standard peak appear, that is, the toluene obtained in the collection bottle is a qualified product. Transfer it to a clean brown glass bottle for storage. The test results are as follows: Figure 1-Figure 10 As shown, the specific substances in the spectrum are as follows:

[0023] Example 2

[0024] A method for recovering organic reagents in a dioxin pretreatment process, wherein toluene produced in the pretreatment step is recovered according to the following steps: S1. Combine the toluene waste liquid. If there are obvious water droplets on the bottom or wall of the container, add enough anhydrous magnesium sulfate, shake appropriately until there are no obvious water droplets, put a small amount of glass wool in the glass funnel, add 5g of anhydrous magnesium sulfate, and filter out the solid matter used; S2. Add 5.6 g of a dispersion purification package to 4 L of toluene waste liquid and shake thoroughly for 15 min. Put a small amount of glass wool in a glass funnel and add 5 g of anhydrous magnesium sulfate to filter out all solid matter. The dispersion purification package is composed of sulfuric acid silica gel and Florisil in a weight ratio of 1:1. The sulfuric acid silica gel is prepared by activating column chromatography silica gel at 550±5°C for 11.5 h and then mixing with concentrated sulfuric acid. The mass concentration of sulfuric acid in the sulfuric acid silica gel is 20 wt %. Florisil is obtained after being activated at 550±5°C for 24.5 h. S3, adding the filtrate obtained in step S1 into a round-bottom bottle, performing the first rotary evaporation at 60°C and 200 hPa for 15 min to remove volatile impurities. During the rotary evaporation, it is important not to cause obvious boiling, discard the liquid in the collection bottle, and replace the collection bottle; S4. Starting from 60°C and 200 hPa, the pressure was gradually reduced to 120 hPa within 2 minutes for a second rotary evaporation for 35 minutes to evaporate about 97% of the liquid. During the rotary evaporation, it was noted that no obvious boiling should occur to avoid evaporation of the liquid. The liquid remaining in the round-bottom flask contained most of the non-volatile impurities, including dioxins and their corresponding internal standard substances and a small amount of toluene. The liquid remaining in the round-bottom flask was discarded, and the final product obtained in the collecting bottle was toluene. 100 mL of the final product was taken, concentrated to 10 μL, and then analyzed on a computer. No dioxin and its internal standard peak appeared, that is, the toluene obtained in the collecting bottle was a qualified product. It was transferred to a clean brown glass bottle for storage. The test result was roughly the same as the spectrum in Example 1.

[0025] Example 3

[0026] A method for recovering organic reagents in a dioxin pretreatment process, wherein toluene produced in the pretreatment step is recovered according to the following steps: S1. Combine the toluene waste liquid. If there are obvious water droplets on the bottom or wall of the container, add enough anhydrous magnesium sulfate, shake appropriately until there are no obvious water droplets, put a small amount of glass wool in the glass funnel, add 5g of anhydrous magnesium sulfate, and filter out the solid matter used; S2. Add 6.4 g of a dispersion purification package to 4 L of toluene waste liquid and shake thoroughly for 15 min. Put a small amount of glass wool in a glass funnel, add 5 g of anhydrous magnesium sulfate, and filter all solid substances. The dispersion purification package is composed of sulfuric acid silica gel and Florisil in a weight ratio of 1:1. The sulfuric acid silica gel is prepared by activating column chromatography silica gel at 550±5°C for 12.5 h and then mixing with concentrated sulfuric acid. The mass concentration of sulfuric acid in the sulfuric acid silica gel is 20 wt %. Florisil is obtained after being activated at 550±5°C for 23.5 h. S3, adding the filtrate obtained in step S1 into a round-bottom bottle, performing the first rotary evaporation at 60°C and 200 hPa for 15 min to remove volatile impurities. During the rotary evaporation, it is important not to cause obvious boiling, discard the liquid in the collection bottle, and replace the collection bottle; S4. Starting from 60°C and 200 hPa, the pressure was gradually reduced to 120 hPa within 2 minutes for a second rotary evaporation for 35 minutes to evaporate about 97% of the liquid. During the rotary evaporation, it was noted that no obvious boiling should occur to avoid evaporation of the liquid. The liquid remaining in the round-bottom flask contained most of the non-volatile impurities, including dioxins and their corresponding internal standard substances and a small amount of toluene. The liquid remaining in the round-bottom flask was discarded, and the final product obtained in the collecting bottle was toluene. 100 mL of the final product was taken, concentrated to 10 μL, and then analyzed on a computer. No dioxin and its internal standard peak appeared, that is, the toluene obtained in the collecting bottle was a qualified product. It was transferred to a clean brown glass bottle for storage. The test result was roughly the same as the spectrum in Example 1.

[0027] Example 4

[0028] A method for recovering organic reagents in a dioxin pretreatment process, which is different from Example 1 in that the mass concentration of sulfuric acid in the sulfuric acid silica gel is 30%, and the rest is the same as Example 1. After detection, no dioxin and its internal standard peak appear, and the detection result is substantially the same as the spectrum in Example 1.

[0029] Example 5

[0030] A method for recovering organic reagents in a dioxin pretreatment process, which is different from Example 1 in that the mass concentration of sulfuric acid in the sulfuric acid silica gel is 40%, and the rest is the same as Example 1. After detection, no dioxin and its internal standard peak appear, and the detection result is substantially the same as the spectrum in Example 1.

[0031] Example 6

[0032] A method for recovering organic reagents in a dioxin pretreatment process is different from Example 1 in that the weight ratio of sulfuric acid silica gel to Florisil is 1:0.8, and the rest is the same as Example 1. After detection, no dioxin and its internal standard peak appear, and the detection result is substantially the same as the spectrum in Example 1.

[0033] Example 7

[0034] A method for recovering organic reagents in a dioxin pretreatment process is different from Example 1 in that the weight ratio of sulfuric acid silica gel to Florisil is 1:1.2, and the rest is the same as Example 1. After detection, no dioxin and its internal standard peak appear, and the detection result is substantially the same as the spectrum in Example 1.

[0035] The recovery of the n-hexane waste liquid produced in the purification step is the same as the recovery method of toluene, which is illustrated by the following example.

[0036] The n-hexane waste liquid generated in the purification step (including the n-hexane used for purification column activation and elution) of about 200-1000 mL sample is recovered using the following steps.

[0037] Example 8

[0038] A method for recovering organic reagents in a dioxin pretreatment process comprises the following steps: S1. Combine the n-hexane waste liquids produced multiple times, add 5.6g of a dispersion purification package to 4L of n-hexane waste liquid, and shake thoroughly for 15min. Put a small amount of glass wool in a glass funnel, add 5g of anhydrous magnesium sulfate, and filter all solid substances. The dispersion purification package is composed of sulfuric acid silica gel and Florisil in a weight ratio of 1:1. The sulfuric acid silica gel is prepared by activating column chromatography silica gel at 550±5℃ for 12h and then mixing with concentrated sulfuric acid. The mass concentration of sulfuric acid in the sulfuric acid silica gel is 20wt%, and Florisil is obtained after being activated at 550±5℃ for 24h. S2, adding the filtrate obtained in step S1 into a round-bottom bottle, performing the first rotary evaporation at 60°C and 480hPa for 10 minutes to remove volatile impurities. During the rotary evaporation, it is important not to cause obvious boiling, discard the liquid in the collection bottle, and replace the collection bottle; S3. Starting from 60°C and 480hPa, the pressure was gradually reduced to 300hPa within 5min for a second rotary evaporation for 35min, evaporating about 97% of the liquid. During the rotary evaporation, it was noted that no obvious boiling occurred to avoid evaporation of the liquid. The liquid remaining in the round-bottom flask contained most of the non-volatile impurities, including dioxins and their corresponding internal standard substances and a small amount of n-hexane. The liquid remaining in the round-bottom flask was discarded, and the final product obtained in the collecting bottle was n-hexane. 100mL of the final product was taken, concentrated to 10μL, and then analyzed on a computer. No dioxin and its internal standard peak appeared, that is, the n-hexane obtained in the collecting bottle was a qualified product. It was transferred to a clean brown glass bottle for storage. The test result was roughly the same as the spectrum in Example 1.

[0039] Comparative Example 1 A method for recovering organic reagents in a dioxin pretreatment process is different from Example 1 in that an equal amount of diatomaceous earth is used in a dispersion purification package instead of Florisil earth, and the rest is the same as Example 1. After the toluene obtained is tested, interference peaks appear in the spectrum, which are confirmed to be dioxins and their internal standard peaks, and polychlorinated biphenyls.

[0040] Comparative Example 2 A method for recovering organic reagents in a dioxin pretreatment process, which is different from Example 1 in that an equal amount of silver nitrate silica gel is used in a dispersion purification package instead of sulfuric acid silica gel, wherein the concentration of silver nitrate in the silver nitrate silica gel is 20wt%, and the rest is the same as Example 1. After the toluene obtained is tested, interference peaks appear in the spectrum, which are confirmed to be polycyclic aromatic hydrocarbons.

[0041] Comparative Example 3 A method for recovering organic reagents in a dioxin pretreatment process, which is different from Example 1 in that the dispersion purification package is composed of silver nitrate silica gel and diatomaceous earth in a weight ratio of 1:1, the concentration of silver nitrate in the silver nitrate silica gel is 20wt%, and the rest is the same as Example 1. After the toluene obtained is tested, interference peaks appear in the spectrum, which are confirmed to be polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dioxins and their internal standards. The test results are as follows Figure 11-Figure 20 shown.

[0042] Comparative Example 4 A method for recovering organic reagents in a dioxin pretreatment process, which is different from Example 1 in that the mass concentration of sulfuric acid in the sulfuric acid silica gel is 15wt%, and the rest is the same as Example 1. After the toluene obtained is tested, interference peaks appear in the spectrum, which are confirmed to be polycyclic aromatic hydrocarbons.

[0043] Comparative Example 5 A method for recovering organic reagents in a dioxin pretreatment process, which is different from Example 1 in that the mass concentration of sulfuric acid in the sulfuric acid silica gel is 45wt%, and the rest is the same as Example 1. After the toluene obtained is tested, more impurity peaks appear in the spectrum.

[0044] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for recovering organic reagents in a dioxin pretreatment process, characterized in that: The recycling steps include: S1. Add a dispersion purification package to the organic reagent waste liquid and shake it, insert glass wool into a glass funnel, add anhydrous magnesium sulfate, and filter the solid matter. The dispersion purification package is composed of sulfuric acid silica gel and Florisil. The sulfuric acid silica gel is prepared by activating column chromatography silica gel at 550±5°C and mixing it with concentrated sulfuric acid. The Florisil is obtained by activating it at 550±5°C. S2. The filtrate obtained in step S1 is subjected to rotary evaporation twice and then the organic reagent is collected.

2. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The concentration of the dispersed purification package in the organic reagent waste liquid is 1.4-1.6 g / L.

3. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The weight ratio of the sulfate silica gel to Floris earth is 1:(0.8-1.2).

4. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The mass concentration of concentrated sulfuric acid in the sulfuric acid silica gel is 20-40wt%.

5. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The mass concentration of concentrated sulfuric acid in the sulfuric acid silica gel is 30-40wt%.

6. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The column chromatography silica gel is activated at 550±5° C. for 12±0.5 hours and then mixed with concentrated sulfuric acid.

7. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The Florisil is obtained after being activated at 550±5° C. for 24±0.5 h.

8. The method for recovering organic reagents in a dioxin pretreatment process according to claim 1, characterized in that: The organic reagent waste liquid is toluene waste liquid or n-hexane waste liquid; the conditions for the first rotary evaporation of the toluene waste liquid are 60±2°C, 180-200hPa for 10-15min, and the conditions for the second rotary evaporation are 60±2°C, 180-220hPa, and the pressure is reduced to 100-120hPa within 2min.

9. The method for recovering organic reagents in a dioxin pretreatment process according to claim 8, characterized in that: The conditions for the first rotary evaporation of the n-hexane waste liquid are 60±2°C, 480-500hPa for 10±2min, and the conditions for the second rotary evaporation are 60±2°C, 480-500hPa, and the pressure is reduced to 300-330hPa within 5min.

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