A special column for dioxin purification that can replace traditional activated carbon columns at low cost and its application

Abstract

The invention discloses a special column for dioxin purification that can replace the traditional activated carbon column at low cost and its application, and belongs to the technical field of feed and agricultural product quality safety detection. It includes a column tube, a filler and the application of a special column in the dioxin purification process. A sieve plate, anhydrous sodium sulfate, a filler, anhydrous sodium sulfate and a sieve plate are arranged in the column tube from the liquid outlet end to the liquid inlet end of the column tube. The filler is a composite material of sulfur-doped carbon nitride and diatomaceous earth. The sulfur-doped carbon nitride and diatomaceous earth are mixed in a certain proportion, which can disperse the carbon nitride material to increase the contact area and weaken the non-polarity of the sulfur-doped carbon nitride, thereby achieving the purpose of adsorbing dioxins without dead adsorption, thereby achieving the purpose of purifying dioxins. The special column for dioxin purification of the invention is simple to prepare, has the same effect as imported activated carbon materials, has good stability, and is extremely low in cost, which greatly reduces the detection cost of dioxins and reduces the dependence on the import of foreign activated carbon.

Description

Technical Field

[0001] The invention belongs to the technical field of feed and agricultural product quality safety detection, and specifically relates to a special column for dioxin purification which can replace a traditional activated carbon column at low cost and application thereof. Background Art

[0002] Dioxins are complex, colorless, odorless, fat-soluble organic pollutants of polychlorinated planar aromatic hydrocarbons with strong carcinogenicity, reproductive toxicity, immunotoxicity, and endocrine toxicity. Among them, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is the most toxic pollutant known to mankind. Due to its high toxicity, long-term residual, accumulation and strong mobility, it can migrate over long distances around the world, pass through various links in the environment step by step, and eventually accumulate in the tissues and organs of animals and humans, and exist for a long time, posing a widespread, long-term, hidden and delayed threat to the health of organisms and humans, making it an environmental and food safety issue that has attracted international attention.

[0003] The conventional detection method for dioxins is high-resolution magnetic mass spectrometry. Since the content of dioxins in feed and agricultural products is complex and low, they need to be highly concentrated, so the purification requirements are strict. In the purification process, in addition to removing conventional impurities such as pigments, fats, and proteins, dioxins need to be separated from small molecular compounds such as polychlorinated biphenyls and polybrominated diphenyl ethers with similar structures to dioxins to achieve a higher degree of purification in order to achieve accurate trace quantification. At present, activated carbon columns are widely used at home and abroad to separate and purify similar compounds. Imported activated carbon-filled purification columns are expensive and have poor stability. Therefore, there is an urgent need to find a low-priced and highly stable purification column to replace the activated carbon column to reduce the detection cost of dioxins in feed and agricultural products. It has broad market promotion prospects in the dioxin detection market. Summary of the invention

[0004] The purpose of the present invention is to provide a special column for dioxin purification and its application, which can replace the traditional activated carbon column at low cost, in view of the existing problems.

[0005] The present invention is achieved through the following technical solutions:

[0006] A special column for dioxin purification that can replace traditional activated carbon columns at low cost, comprising a column tube, wherein a sieve plate, a packing layer and a sieve plate are arranged in sequence from the liquid outlet end of the column tube to the liquid inlet end of the main tube; the lower sieve plate and the upper sieve plate are respectively installed with interference fit on the inner wall of the column tube; and a liquid inlet is arranged at the top of the column tube.

[0007] Furthermore, the filler layer is composed of anhydrous sodium sulfate, sulfur-doped carbon nitride and diatomaceous earth composite filler, and anhydrous sodium sulfate.

[0008] Furthermore, the preparation ratio of sulfur-doped carbon nitride to diatomaceous earth in the sulfur-doped carbon nitride and diatomaceous earth composite filler is 23:77.

[0009] Furthermore, the preparation of the sulfur-doped carbon nitride is as follows: thiocyanate is placed in a crucible, covered with a lid to prevent volatilization, the temperature is raised to 550° C. in a muffle furnace, and then baked for 4 hours. After the temperature is cooled, the mixture is ground in a mortar.

[0010] Furthermore, the sulfur-doped carbon nitride and diatomaceous earth composite filler is prepared by mixing the prepared sulfur-doped carbon nitride and diatomaceous earth in a mass ratio of 27:73, and then placing them in a shaker for 2 hours to fully mix them.

[0011] Furthermore, the preparation of the special purification column: the purification column is installed with a sieve plate, 0.5g of anhydrous magnesium sulfate, 1g of a composite filler of sulfur-doped carbon nitride and diatomaceous earth, 0.5g of anhydrous magnesium sulfate, and a sieve plate in sequence from bottom to top.

[0012] The invention discloses an application of a special column for dioxin purification which can replace the traditional activated carbon column at low cost. The specific method is as follows: dioxin is extracted and degreased according to the national standard GB / T5009.205 "Determination of toxic equivalents of dioxins and their analogs in feed" and GB / T28643 "Determination of dioxins and dioxin-like polychlorinated biphenyls in feed by isotope dilution-high resolution gas chromatography / high resolution mass spectrometry", the degreased and purified solution is re-dissolved with 5 mL of n-hexane after rotary evaporation, the sulfur-doped carbon nitride purification column is activated with 20 mL of n-hexane, the degreased n-hexane re-solution is loaded on the column, and then 50 mL of n-hexane is used to elute dioxin-like polychlorinated biphenyls and other impurities, and then 80 mL of toluene is used to elute dioxin, the eluted solution is received, rotary evaporated, nitrogen blown, transferred to an inner liner tube, nitrogen blown to dryness, 15 ul of nonane and 5 ul of dioxin are added as internal standard, and the column is tested on a machine.

[0013] Carbon nitride has a unique graphite layered stacking structure and sp 2The hybridized π conjugated electron band structure can form a strong interaction force with the target molecule, such as hydrogen bonding, π-π stacking, electrostatic force, van der Waals force and hydrophobic force, which can ensure that it is an excellent adsorbent for adsorbing dioxins. Element doping modification can improve the adsorption and selectivity of carbon nitride by adjusting the electronic structure, surface site and relative specific surface area. By studying the effects of three types of carbon nitride, carbon nitride, sulfur-doped carbon nitride and phosphorus-doped carbon nitride in purifying dioxins, it was found that sulfur-doped carbon nitride has the best effect. By adding diatomaceous earth, sulfur-doped carbon nitride can be dispersed, its material contact area can be increased, and the non-polarity of sulfur-doped carbon nitride can be weakened, so as to achieve the purpose of adsorbing dioxins without dead adsorption, thereby achieving the purpose of purifying dioxins.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The present invention mixes sulfur-doped carbon nitride with diatomaceous earth in a certain proportion, which can disperse the carbon nitride material to increase the contact area, and at the same time weaken the non-polarity of sulfur-doped carbon nitride, so as to achieve the purpose of adsorbing dioxins without dead adsorption, thereby achieving the purpose of purifying dioxins; the application of the special column in the dioxin purification process refers to the process of purifying dioxins in feed and agricultural products in the actual operation process. The invented special column for dioxin purification is simple to prepare, has the same effect as imported activated carbon materials, has good stability, and is extremely low in cost, which greatly reduces the detection cost of dioxins and reduces the dependence on the import of foreign activated carbon.

[0016] 2. The special column filler for dioxin purification of the present invention is simple and easy to prepare, and is dozens of times cheaper than the traditional activated carbon purification column. It is suitable for large-scale promotion within the industry and has great practical significance.

[0017] 3. The present invention has a good purification effect and can separate dioxins from impurities such as dioxin-like polychlorinated biphenyls to achieve the purpose of purification, thereby improving the accuracy of analysis and reducing the failure rate of the instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the purification column structure;

[0019] Figure 2 is the recovery rate of dioxins and dioxin-like PCBs after purification by three types of carbon nitride;

[0020] Figure 3 is the recovery rate of dioxins and dioxin-like PCBs after column passing;

[0021] Figure 4 This is a bar graph comparing the recovery rates of dioxins and dioxin-like PCBs after the samples pass through this purification column and the traditional purification column;

[0022] Figure 5 This is a chromatogram comparing the dioxin purification effects of sulfur-doped carbon nitride and traditional activated carbon;

[0023] Figure 6 This is a chromatogram comparing the purification effects of sulfur-doped carbon nitride and traditional activated carbon on dioxin-type polychlorinated biphenyls. DETAILED DESCRIPTION

[0024] 1. Common carbon nitride, sulfur-doped carbon nitride and phosphorus-doped carbon nitride were selected to investigate their adsorption, desorption and separation effects on dioxins and dioxin-like PCBs. According to the ratio of conventional activated carbon to diatomaceous earth of 9:41, the three carbon nitrides were dispersed and compounded, and the column was loaded as follows: 1g of compound filler was weighed and loaded into the column tube containing the sieve plate and 0.5g of anhydrous sodium sulfate at the bottom, and then 0.5g of anhydrous sodium sulfate and the sieve plate were added, and the column was pressed tightly, and 20mL of n-hexane was used for pre-activation, and the solution containing 27 dioxins and dioxin-like PCB isotope standards was passed through the purification column, and the dioxin-like PCBs were first eluted with 50mL of n-hexane, and then the dioxins were eluted with 80mL of toluene, and the two elution solvents were respectively taken. Rotary evaporation, nitrogen blowing, transfer to the inner liner tube, nitrogen blowing to dryness, 15ul of nonane and 5ul of the internal standard IS were added and re-dissolved on the machine. The evaluation was conducted based on the recovery rate range of 27 compounds specified in GB / T5009.205 "Determination of toxic equivalents of dioxins and their analogs in food".

[0025] The test results are shown in Table 1 and Figure 2 Among the three carbon nitrides, sulfur-doped carbon nitride has the best separation and recovery effect. Most dioxins and dioxin-like PCBs are separated. According to the internal standard recovery rate range required by the national standard, only 13 C 12 -2,3,7,8-TCDD, 13 C 12 -1,2,3,7,8-PeCDF, 13 C 12 -2,3,4,7,8-PeCDF, 13 C 12 The dioxins of the four small molecules -1,2,3,7,8-PeCDD did not meet the requirements, and could be further optimized by adjusting the proportion of the dispersant diatomaceous earth and the amount of elution solvent used.

[0026] Table 1 Recovery of dioxins and dioxin-like PCBs after purification by three types of carbon nitride

[0027] Compound internal standard Recovery rate range required by national standards (%) Carbon Nitride Phosphorus-doped carbon nitride Sulfur-doped carbon nitride <![CDATA[ 13 C 12 -2,3,7,8-TCDF]]> 24～169 0 0 73 <![CDATA[ 13 C 12 -2,3,7,8-TCDD]]> 25～164 1 0 6 <![CDATA[ 13 C 12 -1,2,3,7,8-PeCDF]]> 24～185 1 0 13 <![CDATA[ 13 C 12 -2,3,4,7,8-PeCDF]]> 21～178 1 0 0 <![CDATA[ 13 C 12 -1,2,3,7,8-PeCDD]]> 25～181 1 0 0 <![CDATA[ 13 C 12 -1,2,3,4,7,8-HxCDF]]> 26～152 6 0 94 <![CDATA[ 13 C 12 -1,2,3,6,7,8-HxCDF]]> 26～123 5 0 76 <![CDATA[ 13 C 12 -2,3,4,6,8,9-HxCDF]]> 28～136 2 0 72 <![CDATA[ 13 C 12 -1,2,3,7,8,9-HxCDF]]> 29～147 5 0 88 <![CDATA[ 13 C 12 -1,2,3,4,7,8-HxCDD]]> 32～141 1 0 91 <![CDATA[ 13 C 12 -1,2,3,6,7,8-HxCDD]]> 28～130 80 80 96 <![CDATA[ 13 C 12 -1,2,3,4,6,7,8-HpCDF]]> 28～143 3 0 96 <![CDATA[ 13 C 12 -1,2,3,4,7,8,9-HpCDF]]> 26～138 100 1 137 <![CDATA[ 13 C 12 -1,2,3,4,6,7,8-HpCDD]]> 23～140 11 0 111 <![CDATA[ 13 C 12 -OCDD]]> 17～157 165 6 173 <![CDATA[ 13 C 12 -3,4,4',5-TePCB(81L)]]> 25～150 37 46 25 <![CDATA[ 13 C 12 -3,3',4,4'-TePCB(77L)]]> 25～150 44 48 28 <![CDATA[ 13 C 12 -2,3,3',4,4'-PePCB(105L)]]> 25～150 65 68 57 <![CDATA[ 13 C 12 -2,3,4,4',5-PePCB(114L)]]> 25～150 54 62 39 <![CDATA[ 13 C 12 -2,3',4,4',5-PePCB(118L)]]> 25～150 54 59 38 <![CDATA[ 13 C 12 -2',3,4,4',5-PePCB(123L)]]> 25～150 53 61 39 <![CDATA[ 13 C 12 -3,3',4,4',5-PePCB(126L)]]> 25～150 77 73 62 <![CDATA[ 13 C 12 -2,3,3',4,4',5-HxPCB(156L)]]> 25～150 86 73 70 <![CDATA[ 13 C 12 -2,3,3',4,4',5'-HxPCB(157L)]]> 25～150 78 75 76 <![CDATA[ 13 C 12 -2.3',4.4',5.5'-HxPCB(167L)]]> 25～150 73 75 68 <![CDATA[ 13 C 12 -3,3',4,4',5,5'-HxPCB(169L)]]> 25～150 73 68 72 <![CDATA[ 13 C 12 -2,3,3',4,4',5,5'-HpPCB(189L)]]> 25～150 78 74 71

[0028] 2. According to the previous results, the ratio of sulfur-doped carbon nitride to diatomite was improved. Since the recovery rate of the first four small molecules was low, it was considered that the content of sulfur-doped carbon nitride was small and the adsorption performance was weak, resulting in the previous not being adsorbed on the filler. Therefore, the ratio of sulfur-doped carbon nitride was increased. The experiment was carried out according to the mass ratio of sulfur-doped carbon nitride to diatomite of 23:77 and 27:73, and compared with the previous 18:82. The results are shown in Table 2 and Figure 3 The results showed that the separation effect and recovery rate were best when the mass ratio of sulfur-doped carbon nitride to diatomite was 27:73, and the recovery rate of each compound was within the internal standard recovery rate range required by the national standard. Finally, the mass ratio of sulfur-doped carbon nitride to diatomite was 27:73.

[0029] Table 2 shows the recovery rates of dioxins and dioxin-like PCBs after column flow.

[0030]

[0031] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0032] 1. Embodiment:

[0033] Screening of purification column packing

[0034] Common carbon nitride, sulfur-doped carbon nitride and phosphorus-doped carbon nitride were selected, and the conventional dioxin purification materials activated carbon and diatomaceous earth were mixed in a ratio of 18:82. Then 1g was weighed and loaded into the solid phase extraction empty tube with a sieve plate and 0.5g anhydrous sodium sulfate at the bottom, and 0.5g anhydrous sodium sulfate and sieve plate were loaded into the upper layer to make three dioxin purification columns. The purification column was activated with 20mL n-hexane in advance, and the purified liquid containing dioxins and dioxin-like PCBs after degreasing was loaded. The dioxin-like PCBs were eluted with 50mL n-hexane first, and then the dioxins were eluted with 80mL toluene. The two elution solvents were taken separately. Rotary evaporation, nitrogen blowing, transfer to the inner liner tube, nitrogen blowing to dryness, 15ul nonane and 5ul internal standard IS were added to dissolve and load on the machine. The recovery rate of 27 compounds was used as the evaluation basis for purification fillers.

[0035] Depend on Figure 2 It can be seen that the sulfur-doped carbon nitride has the best separation effect and the highest recovery rate among the three carbon nitrides tested, but there are still some 13 C 12 -2,3,7,8-TCDD, 13 C 12 -1,2,3,7,8-PeCDF, 13 C12 -2,3,4,7,8-PeCDF, 13 C 12 The dioxins of the four small molecules -1,2,3,7,8-PeCDD did not meet the requirements, and could be further optimized by adjusting the proportion of the dispersant diatomaceous earth and the amount of elution solvent used.

[0036] Compounding of purification fillers

[0037] The present invention finds that different proportions of diatomite can affect the adsorption performance of sulfur-doped carbon nitride, and by adjusting the proportion of diatomite, a more perfect purification effect and recovery effect can be achieved. Therefore, sulfur-doped carbon nitride and diatomite are compounded as the filler of the dioxin purification column.

[0038] Example 1: Raw materials and preparation of dioxin purification separation column

[0039] raw material:

[0040] Thiocyanate: Sinopharm Chemical Reagent Co., Ltd.

[0041] Sulfur-doped carbon nitride: prepared by thiocyanate, the preparation method is described above.

[0042] Diatomaceous earth: purchased from Sinopharm Chemical Reagent Co., Ltd.

[0043] Column tube: capacity 10ml, inner diameter 1cm, length 20cm,

[0044] Screen plate: polyethylene screen plate with a pore size of 10 μm;

[0045] Filler: prepared by mixing diatomaceous earth with a particle size of 100 to 400 meshes and sulfur-doped carbon nitride.

[0046] (2) Preparation:

[0047] Sulfur-doped carbon nitride and diatomaceous earth are prepared in a mass ratio of 27:73, and then placed in a shaker for 2 hours to fully mix. The purification column is installed from bottom to top in sequence with a sieve plate, 0.5g of anhydrous magnesium sulfate, 1g of a composite filler of sulfur-doped carbon nitride and diatomaceous earth, 0.5g of anhydrous magnesium sulfate, and a sieve plate, wherein the upper sieve plate and the lower sieve plate are installed with an interference fit with the column tube and pressed tightly.

[0048] Example 2: Raw materials and preparation of dioxin purification separation column

[0049] (1) Raw materials: the same as in Example 1

[0050] (2) Preparation:

[0051] Sulfur-doped carbon nitride and diatomaceous earth are prepared in a mass ratio of 23:77, and then placed in a shaker for 2 hours to fully mix. The purification column is sequentially installed with sieve plates, 0.5g anhydrous magnesium sulfate, 1g of a composite filler of sulfur-doped carbon nitride and diatomaceous earth, 0.5g anhydrous magnesium sulfate, and sieve plates from bottom to top, wherein the upper sieve plate and the lower sieve plate are installed with interference fit with the column tube and pressed tightly.

[0052] Example 3: Raw materials and preparation of dioxin purification separation column

[0053] (1) Raw materials: the same as in Example 1

[0054] (2) Preparation: Sulfur-doped carbon nitride and diatomaceous earth are prepared in a mass ratio of 18:82, and then placed in a shaker for 2 hours to fully mix. The purification column is sequentially installed with a sieve plate, 0.5 g of anhydrous magnesium sulfate, 1 g of a composite filler of sulfur-doped carbon nitride and diatomaceous earth, 0.5 g of anhydrous magnesium sulfate, and a sieve plate from bottom to top, wherein the upper sieve plate and the lower sieve plate are installed with an interference fit with the column tube and pressed tightly.

[0055] By comparing the purification columns prepared in Examples 1 to 3, it is found that the purification column prepared in Example 3 has the best effect. It can be seen that the dioxin purification column filled with fillers prepared by combining sulfur-doped carbon nitride and diatomaceous earth in a ratio of 27:73 can achieve better purification and separation effects.

[0056] 2. Comparative ratio:

[0057] Price Comparison

[0058] Material Cost of purifying one sample / yuan Purification effect Activated carbon About 80 yuan Unstable Sulfur-doped carbon nitride About 1 yuan Stablize

[0059] 3. Application column: The dioxin purification separation column prepared in Example 1 was used to purify crab samples.

[0060] (1) Accurately weigh 5 g of freeze-dried feed or agricultural products into the ASE extraction cell, add 10 uL of LCS internal standard, and extract three times with n-hexane and dichloromethane solvent (1:1).

[0061] (2) The extract is evaporated and then redissolved in n-hexane and passed through a composite silica gel column for preliminary degreasing and purification. The column is made of a glass column with an inner diameter of 300 mm × 15 mm and a stopper plate. 1 g of active silica gel, 4 g of alkaline silica gel, 1 g of active silica gel, 4 g of low-quality acidic silica gel, 4 g of high-quality acidic silica gel, 2 g of active silica gel, and 2 cm of anhydrous sodium sulfate are added from bottom to top; 80 ml of n-hexane is added for elution; when the eluent is about 1 to 2 mm away from the filler, the above-mentioned concentrated solution is added, and the degreasing flask is rinsed 3 times with 2 to 3 ml of n-hexane each time, and then eluted with 100 ml of n-hexane. A 250 ml flat-bottom flask is used to receive the concentrated solution and the eluent; the eluent is concentrated to 3 to 5 ml by a rotary evaporator for later use.

[0062] (3) The carbon nitride column prepared in Example 1 was activated with 20 mL of n-hexane, and the above solution was loaded. First, 50 mL of n-hexane was used to elute the dioxin-type PCBs, and then 80 mL of toluene was used to elute the dioxins. The two elution solvents were collected separately. Rotary evaporation, nitrogen blowing, transfer to the inner liner tube, nitrogen blowing to dryness, 15 ul of nonane and 5 ul of internal standard IS were added to re-dissolve and load on the machine.

[0063] The purification effect of the dioxin purification separation column prepared by sulfur-doped carbon nitride on the actual sample is shown in Figure 5 and Figure 6 As shown in the figure, the purification column prepared by the present invention is superior to the traditional activated carbon column and can purify the separated dioxins.

[0064] Figure 5 Middle: 1, 13 C 12 -2,3,7,8-TCDF; 2, 13 C 12 -2,3,4-TCDD; 3, 13 C 12 -2,3,7,8-TCDF; 4, 13 C 12 -1,2,3,7,8-PeCDF; 5, 13 C 12 -2,3,4,7,8-PeCDF;6, 13 C 12 -1,2,3,7,8-PeCDD;7, 13 C 12 -1,2,3,4,7,8-HxCDF;8, 13 C 12 -1,2,3,6,7,8-HxCDF;9, 13 C 12 -2,3,4,6,7,8-HxCDF; 10, 13 C 12 -1,2,3,7,8,9-HxCDF; 11, 13 C 12 -1,2,3,4,7,8-HxCDD; 12, 13 C 12 -1,2,3,6,7,8-HxCDD;13, 13 C 12 -1,2,3,7,8,9-HxCDD;14, 13 C 12 -1,2,3,4,6,7,8-HpCDF; 15, 13 C 12 -1,2,3,4,7,8,9-HpCDF; 16,13 C 12 -1,2,3,4,6,7,8-HpCDD.

[0065] Figure 6 Middle: 1, 13 C 12 -3,4,4,5-TePCB; 2, 13 C 12 -3,3,4,4-TePCB;3, 13 C 12 -2,3,4,4,5-HxPCB; 4, 13 C 12 -2,3,4,4,5-PePCB; 5, 13 C 12 -2,3,4,4,5-PePCB;6, 13 C 12 -2,3,4,4,5-PePCB;7, 13 C 12 -3,3,4,4,5-PePCB;8, 13 C 12 -2,2,4,4,6,6-HxPCB; 9, 13 C 12 -2,3,3,4,4,5-HxPCB; 10, 13 C 12 -2,3,4,4,5,5,-HxPCB;11, 13 C 12 -3,3,4,4,5,5-HxPCB; 12, 13 C 12 -2,3,3,4,4,5,5-HpPCB.

[0066] The above embodiments describe the implementation methods of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The above description is only a preferred feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent structural changes made by using the contents of the present invention and the drawings are included in the scope of rights of the present invention.

Claims

1. A special column for dioxin purification that can replace the traditional activated carbon column at low cost, including a column tube, characterized in that: The column tube is provided with a sieve plate, a packing layer, and a sieve plate in sequence from the liquid outlet of the column tube to the liquid inlet of the main tube; the lower sieve plate and the upper sieve plate are respectively installed with interference fit with the inner wall of the column tube; the top of the column tube is provided with a liquid inlet; the packing layer is composed of anhydrous sodium sulfate, sulfur-doped carbon nitride and diatomaceous earth composite filler, and anhydrous sodium sulfate; The sulfur-doped carbon nitride is mixed with diatomaceous earth in a certain proportion, the carbon nitride material is dispersed to increase the contact area, and the non-polarity of the sulfur-doped carbon nitride is weakened, so as to achieve the effect of adsorbing dioxins without dead adsorption, thereby achieving the purpose of purifying and separating dioxins and dioxin-like polychlorinated biphenyls.

2. According to claim 1, a special column for dioxin purification that can replace the traditional activated carbon column at low cost, characterized in that: The preparation ratio of sulfur-doped carbon nitride to diatomaceous earth in the sulfur-doped carbon nitride and diatomaceous earth composite filler is 18-27:82-73.

3. According to claim 2, a special column for dioxin purification that can replace the traditional activated carbon column at low cost, characterized in that: The preparation of the sulfur-doped carbon nitride is as follows: thiocyanate is placed in a crucible, a lid is put on the crucible to prevent volatilization, the temperature is raised to 550° C. in a muffle furnace, and then the baking is continued for 4 hours. After the temperature is cooled, the carbon nitride is ground in a mortar.

4. According to claim 3, a special column for dioxin purification that can replace the traditional activated carbon column at low cost, characterized in that: Preparation of the sulfur-doped carbon nitride and diatomaceous earth composite filler: The prepared sulfur-doped carbon nitride and diatomaceous earth are configured in a mass ratio of 27:73, and then placed in a shaker for 2 hours to be fully mixed.

5. According to claim 4, a special column for dioxin purification that can replace the traditional activated carbon column at low cost, characterized in that: Preparation of the special purification column: The purification column is sequentially installed with a sieve plate, 0.5 g of anhydrous magnesium sulfate, 1 g of a composite filler of sulfur-doped carbon nitride and diatomaceous earth, 0.5 g of anhydrous magnesium sulfate, and a sieve plate from bottom to top.

6. A special column for dioxin purification that can replace the traditional activated carbon column at low cost, characterized in that: Prepared according to any one of claims 1 to 5.

7. An application of a special column for dioxin purification as a low-cost alternative to traditional activated carbon columns, characterized in that: The specific method is as follows: dioxins are extracted and degreased according to the national standard GB / T5009.205 "Determination of toxic equivalents of dioxins and their analogs in feed" and GB / T28643 "Determination of dioxins and dioxin-like polychlorinated biphenyls in feed by isotope dilution-high resolution gas chromatography / high resolution mass spectrometry". The degreased and purified solution is re-dissolved with 5 mL of n-hexane after rotary evaporation, and a sulfur-doped carbon nitride purification column is activated with 20 mL of n-hexane. The degreased n-hexane re-solution is loaded onto the column, and then 50 mL of n-hexane is used to elute dioxin-like polychlorinated biphenyls and other impurities, and then 80 mL of toluene is used to elute dioxins. The eluted solution is received, rotary evaporated, nitrogen blown, transferred to an inner liner tube, nitrogen blown to dryness, 15 ul of nonane and 5 ul of dioxin are added as internal standard, and then tested on a machine.

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