Method for detecting sulfur element in household garbage and application

Abstract

The invention discloses a method for detecting a sulfur element in household garbage. The method comprises the following steps: S1, drying, grinding and sieving the household garbage; s2, weighing, adding the absorption liquid, combusting, cooling, transferring the absorption liquid into a volumetric flask, fixing the volume, and uniformly shaking to obtain a to-be-detected substance; and S3, detecting the to-be-detected substance by using an ion chromatograph. According to the present invention, the sampling amount of 1-10 g is adopted, such that the sampling amount is increased, the error influence caused by the non-uniformity of the garbage sample when the sampling amount is too low is reduced, the stability of the analysis result is improved, and the accuracy of the analysis result is high. By adopting the leacheate combination of the sodium carbonate solution and the sodium bicarbonate solution, the separation degree of sulfate ions, nitrate ions, chloride ions and fluorine ions can be increased, the detection accuracy is improved, and the detection reproducibility is optimized.

Description

Technical Field

[0001] The present invention relates to the field of testing or analyzing materials by means of determining the chemical or physical properties of the materials, and in particular to a method for detecting sulfur in domestic garbage and its application. Background Art

[0002] With the development of society and the increase in population, more and more domestic waste is generated. How to properly dispose of domestic waste is an environmental problem that needs to be solved urgently. Domestic waste contains a large amount of sulfur, and direct discharge will have adverse effects on the environment. Therefore, domestic waste can only be discharged after it is tested and qualified. However, the existing methods for detecting sulfur in domestic waste are inaccurate, the test results are unstable, and the repeatability is poor. Therefore, it is very important to develop a method for detecting the content of sulfur in domestic waste that is stable.

[0003] Chinese invention patent CN108680707B discloses a method for quantitative analysis of all components of fly ash, using an organic element analyzer to determine the percentage of organic elements in the first sample, and using an ion chromatograph to determine the percentage of Cl in the second sample, solving the problem of inaccurate and incomplete quantitative analysis of all components of fly ash. However, the sulfur content determined by the organic element analyzer is inaccurate, and the interference between the elements is large. Chinese invention patent CN114487225B discloses a method for determining the sulfur and chlorine content in fly ash, mixing fly ash with manganese oxide and anhydrous sodium carbonate, roasting at a specific temperature, and then extracting with water, converting all Cl and S in various forms in the fly ash into Cl - and SO 4 2- , and conduct the determination. It can quickly detect the chlorine and sulfur content in fly ash at the same time, with stable results and high accuracy. However, the pretreatment process is complicated and the processing time is long. Summary of the invention

[0004] In order to develop a method for detecting the content of sulfur in stable domestic waste, the first aspect of the present invention provides a method for detecting sulfur in domestic waste, comprising the following steps:

[0005] S1 dries, grinds and sieves the domestic waste;

[0006] S2 accurately weighs the sieved domestic waste, puts it into an oxygen bomb, adds absorption liquid, burns it, transfers the absorption liquid into a volumetric flask after cooling, fixes the volume, and shakes it to obtain the object to be tested;

[0007] S3: using an ion chromatograph to detect the substance to be tested prepared in step S2.

[0008] As an implementation manner, the drying temperature of step S1 is 100-110°C.

[0009] As an implementation manner, the drying temperature in step S1 is 105 °C.

[0010] As an implementation manner, the sieving in step S1 is through a 50 - 70 mesh sieve.

[0011] As an implementation manner, the sieving in step S1 is through a 60 mesh sieve.

[0012] As an implementation manner, the weight of the domestic waste accurately weighed in step S2 is 1 - 10 g.

[0013] The weight of the domestic waste in step S2 is weighed accurately to 0.0001 g.

[0014] The inventor found during the experiment that the sampling amount for detecting the sulfur content in traditional domestic waste is generally at the mg level. Due to the small sampling amount of the waste, uneven sampling is likely to cause unstable detection results. The inventor can improve the problems of uneven sampling and unstable detection results by increasing the sampling amount of domestic waste. The reason may be that after drying and crushing the domestic waste for sampling, the volume of the pretreated domestic waste can be reduced, the injection volume can be increased, and the mixing uniformity of the dried and crushed domestic waste is higher, which can make the sampling of domestic waste more uniform, thereby improving the subsequent detection stability.

[0015] As an implementation manner, in step S2, combustion is ignited by an oxygen bomb ignition device or an oxygen bomb calorimeter.

[0016] As an implementation manner, the absorbent liquid in step S2 is ultrapure water.

[0017] As an implementation manner, in step S2, the volume is fixed to 50 mL using ultrapure water.

[0018] As an implementation manner, the analyte obtained in step S2 is filtered with a disposable hydrophilic microfiltration membrane syringe filter before being detected by an ion chromatograph. The pore size of the disposable hydrophilic microfiltration membrane syringe filter is 0.3 - 0.5 μm.

[0019] As an implementation manner, the pore size of the disposable hydrophilic microfiltration membrane syringe filter is 0.45 μm.

[0020] As an implementation manner, the chromatographic column in the ion chromatograph is an anion chromatographic column, and the column temperature of the anion chromatographic column is 30 - 40 °C.

[0021] As an implementation manner, the anion chromatographic column is an SH - AC - 4 anion chromatographic column.

[0022] As an implementation manner, the column temperature of the anion chromatographic column is 35 °C.

[0023] As an implementation manner, the eluent in the ion chromatograph is a carbonate eluent, and the carbonate eluent includes at least one of a sodium carbonate solution and a sodium bicarbonate solution.

[0024] As an implementation manner, the carbonate eluent is a combination of an aqueous sodium carbonate solution and an aqueous sodium bicarbonate solution.

[0025] As an implementation manner, the molar concentration of the sodium carbonate solution in the eluent is 1 - 5 mol / L; the molar concentration of the sodium bicarbonate solution in the eluent is 5 - 15 mmol / L.

[0026] As an implementation manner, the molar concentration of the sodium carbonate solution in the eluent is 2 mol / L; the molar concentration of the sodium bicarbonate solution in the eluent is 10 mmol / L.

[0027] The inventors found during the experiment that using a combination of a sodium carbonate solution and a sodium bicarbonate solution as the eluent can increase the separation degree of sulfate ions from nitrate ions, chloride ions, and fluoride ions, improve the detection accuracy, and optimize the detection reproducibility. The possible reason is speculated to be: the high - concentration sodium carbonate undergoes ion exchange with sulfate ions, prolonging the number of ion exchange times, so that the elution time of sulfate ions is much higher than that of nitrate ions, chloride ions, and fluoride ions, thus obtaining a sulfate ion peak with fewer impurity peaks and clear separation, improving the detection accuracy and optimizing the detection reproducibility.

[0028] As an implementation manner, the flow rate of the eluent is 1 - 3 mL / min.

[0029] As an implementation manner, the flow rate of the eluent is 1.5 mL / min.

[0030] As an implementation manner, the detector in the ion chromatograph is a suppressed conductivity detector, and the current of the suppressed conductivity detector is 60 - 80 mA.

[0031] As an implementation manner, the suppressed conductivity detector is a continuous self - recycling regenerative suppressor.

[0032] As an implementation manner, the current of the suppressed conductivity detector is 65 mA.

[0033] During the experiment, the inventor found that by using a suppressed conductivity detector and setting the parameter to 65 mA, the background conductivity of the mobile phase can be reduced, and the selectivity and sensitivity of the detection can be improved. The possible reason is speculated as follows: The mobile phase of the present invention is a sodium carbonate solution. After the sodium carbonate solution conducts electricity, the ion concentration is relatively high, resulting in an unclear detection result of the current change of the detection target. By using a suppressed conductivity detector and setting the current parameter to 65 mA, the high-concentration electrolyte in the eluent can be converted into a low-conductivity component, and at the same time, the detection target is converted into a strong electrolytic form, increasing the conductivity signal of the detection target. Therefore, the background conductivity of the mobile phase is reduced, and the selectivity and sensitivity of the detection are improved.

[0034] As an embodiment, the injection volume of the ion chromatograph is 20 - 30 μL; as an embodiment, the injection volume of the ion chromatograph is 25 μL.

[0035] Standard solutions with concentrations of 0 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, and 40 mg / L were prepared using a sulfonamide standard, and the regression equation for sulfur was obtained: Y = 2.771e+006 + 6.455e+006X, r = 0.999450.

[0036] As an embodiment, the test sample is domestic waste. According to the chromatogram, the abscissa is the mass concentration of the ions, and the ordinate is the peak area (or peak height). The calculation formula for the result is as follows:

[0037]

[0038] In the formula: c: the mass concentration of anions in the sample (i.e., the mass concentration of sulfur), mg / kg;

[0039] h: the peak area (or peak height) of anions in the sample;

[0040] h 0 : the peak area (or peak height) of anions in the blank sample (ultrapure water);

[0041] a: the intercept of the regression equation;

[0042] b: the slope of the regression equation;

[0043] V: the constant volume, mL;

[0044] m: the sampling mass of the sample, g;

[0045] f: the dilution factor of the sample.

[0046] The second aspect of the present invention provides an application of a method for detecting sulfur in domestic waste, which is applied to the detection of domestic waste.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) For the method for detecting sulfur element in domestic waste of the present invention, a sampling amount of 1 - 10 g is adopted, which increases the sampling weight, reduces the error influence caused by the non-uniformity of the waste sample itself when the sampling amount is too low, improves the stability of the analysis result, and the analysis result has high accuracy.

[0049] (2) For the method for detecting sulfur element in domestic waste of the present invention, a suppressed conductivity detector is adopted, and the set current parameter is 65 mA, which reduces the background conductivity of the mobile phase and improves the selectivity and sensitivity of the detection.

[0050] (3) For the method for detecting sulfur element in domestic waste of the present invention, an eluent combination of sodium carbonate solution and sodium bicarbonate solution is adopted, which can increase the separation degree of sulfate ions from nitrate ions, chloride ions, and fluoride ions, improve the accuracy of the detection, and optimize the reproducibility of the detection.

[0051] (4) For the method for detecting sulfur element in domestic waste of the present invention, a linear relationship exists in the range of 0 - 40 mg / L, and the calculated content of sulfur element has good repeatability, small deviation, and the accuracy and repeatability meet the experimental requirements.

[0052] (5) For the method for detecting sulfur element in domestic waste of the present invention, the pretreatment operation is convenient and fast, the process takes less time, and the analysis efficiency of the sample is improved. Description of the Drawings

[0053] Figure 1 It is the ion chromatogram of the standard product sulfanilamide detected in Example 1;

[0054] Figure 2 It is the ion chromatogram of the domestic waste detected in Example 2. Detailed Embodiments

[0055] Example 1

[0056] A method for detecting sulfur element in domestic waste includes the following steps:

[0057] S1 Dry and grind sulfanilamide, and sieve it;

[0058] S2 Accurately weigh the sieved sulfanilamide, put it into an oxygen bomb bucket, add an absorbent solution, burn it, transfer the absorbent solution into a volumetric flask after cooling, make up the volume, and shake well to obtain the analyte;

[0059] S3 Detect the analyte prepared in step S2 with an ion chromatograph.

[0060] The drying temperature in step S1 is 105 °C.

[0061] The sieving in step S1 is through a 60-mesh sieve.

[0062] The accurately weighed weight of sulfanilamide in step S2 is 1 g.

[0063] In step S2, combustion is ignited using an oxygen bomb ignition device.

[0064] The absorbent solution in step S2 is ultrapure water.

[0065] In step S2, the volume is fixed to 50 mL using ultrapure water.

[0066] The analyte obtained in step S2 is filtered through a disposable aqueous microfiltration membrane syringe filter before being detected by an ion chromatograph. The pore size of the disposable aqueous microfiltration membrane syringe filter is 0.45 μm.

[0067] The chromatographic column in the ion chromatograph is an SH-AC-4 anion chromatographic column, and the column temperature of the anion chromatographic column is 35 °C.

[0068] The eluent in the ion chromatograph is a combination of sodium carbonate aqueous solution and sodium bicarbonate aqueous solution. The molar concentration of the sodium carbonate aqueous solution in the eluent is 2 mol / L; the molar concentration of the sodium bicarbonate aqueous solution in the eluent is 10 mmol / L.

[0069] The flow rate of the eluent is 1.5 mL / min.

[0070] The detector in the ion chromatograph is a suppressed conductivity detector, and the current of the suppressed conductivity detector is 65 mA.

[0071] The injection volume of the ion chromatograph is 25 μL.

[0072] Standard solutions with concentrations of 0 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, and 40 mg / L are prepared using a sulfanilamide standard to obtain the regression equation for sulfur element: Y = 2.771e+006 + 6.455e+006X, r = 0.999450.

[0073] According to the chromatogram, the abscissa is the mass concentration of the ion, and the ordinate is the peak area (or peak height). The calculation formula for the result is as follows:

[0074]

[0075] In the formula: c: the mass concentration of the anion in the sample (i.e., the mass concentration of the sulfur element), mg / kg;

[0076] h: the peak area (or peak height) of the anion in the sample;

[0077] h 0: Peak area (or peak height) of anions in the blank sample (ultrapure water);

[0078] a: Intercept of the regression equation;

[0079] b: Slope of the regression equation;

[0080] V: Fixed volume, mL;

[0081] m: Sampling mass of the sample, g;

[0082] f: Dilution factor of the sample.

[0083] The dilution factor of the sample is 5 times.

[0084] Example 2

[0085] A method for detecting sulfur elements in domestic waste, comprising the following steps:

[0086] S1 Dry and grind the domestic waste, and sieve it;

[0087] S2 Accurately weigh the sieved domestic waste, put it into an oxygen bomb bucket, add the absorption liquid, burn it, transfer the absorption liquid into a volumetric flask after cooling, fix the volume, and shake well to obtain the analyte;

[0088] S3 Detect the analyte prepared in step S2 with an ion chromatograph.

[0089] The drying temperature in step S1 is 105 °C.

[0090] The sieving in step S1 is through a 60-mesh sieve.

[0091] The weight of sulfanilamide accurately weighed in step S2 is 1 g.

[0092] In step S2, the combustion is ignited by an oxygen bomb ignition device.

[0093] The absorption liquid in step S2 is ultrapure water.

[0094] In step S2, the fixed volume is to fix the volume to 50 mL with ultrapure water.

[0095] The analyte obtained in step S2 is filtered with a disposable aqueous microporous membrane syringe filter before being detected by an ion chromatograph, and the pore size of the disposable aqueous microporous membrane syringe filter is 0.45 μm.

[0096] The chromatographic column in the ion chromatograph is an SH-AC-4 anion chromatographic column, and the column temperature of the anion chromatographic column is 35 °C.

[0097] The eluent in the ion chromatograph is a combination of an aqueous sodium carbonate solution and an aqueous sodium bicarbonate solution. The molar concentration of the aqueous sodium carbonate solution in the eluent is 2 mol / L; the molar concentration of the aqueous sodium bicarbonate solution in the eluent is 10 mmol / L.

[0098] The flow rate of the eluent is 1.5 mL / min.

[0099] The detector in the ion chromatograph is a suppressed conductivity detector, and the current of the suppressed conductivity detector is 65 mA.

[0100] The injection volume of the ion chromatograph is 25 μL.

[0101] Performance test

[0102] Test for sulfur content: Repeat the detection of Example 1 twice, denoted as Example 1-1 and Example 1-2. Calculate the test results of sulfur content according to the regression equation, and the results are shown in Table 1. The test spectra are shown in Figure 1 。

[0103] Relative deviation = [(measured value - theoretical value) / (measured value + theoretical value)] × 100%

[0104] Detect according to the method of Example 2. The test spectra are shown in Figure 2 , calculate the sulfur content according to the regression equation, and the test results of sulfur content are shown in Table 1.

[0105] Table 1

[0106] Sulfur content (wt%) Relative deviation / % Reference standard 18.61 / Example 1-1 18.67 -0.16 Example 1-2 17.55 2.9 Example 2 1.44 /

[0107] The theoretical value of the sulfur content of the standard product is 18.61%, and the relative deviations of the two test results are -0.16% and 2.9% respectively. The accuracy and repeatability meet the experimental requirements.

[0108] Figure 1 and Figure 2 The retention times of the peaks in are shown in Table 2.

[0109] Table 2

[0110] Retention time Name 1 3.250 <![CDATA[F - > 2 5.622 <![CDATA[Cl - > 3 7.255 <![CDATA[NO 2 - > 4 10.847 <![CDATA[NO 3 - <!-- 5 -->]]> 5 21.737 <![CDATA[SO 4 2- >

Claims

1. A method for detecting sulfur in domestic waste, characterized in that: The following steps are involved: S1 dries, grinds and sieves the domestic waste; S2 accurately weighs the sieved domestic waste, puts it into an oxygen bomb, adds absorption liquid, burns it, transfers the absorption liquid into a volumetric flask after cooling, fixes the volume, and shakes it to obtain the object to be tested; S3: using an ion chromatograph to detect the substance to be tested prepared in step S2.

2. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The drying temperature in step S1 is 100-110°C.

3. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The sieving in step S1 is through a 50-70 mesh sieve.

4. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The weight of the domestic waste accurately weighed in step S2 is 1-10g.

5. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The analyte obtained in step S2 is filtered by a disposable water-based microporous membrane syringe filter before being detected by an ion chromatograph, wherein the pore size of the disposable water-based microporous membrane syringe filter is 0.3-0.5 μm.

6. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The chromatographic column in the ion chromatograph is an anion chromatographic column, and the column temperature of the anion chromatographic column is 30-40°C.

7. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The eluent in the ion chromatograph is a carbonate eluent, and the carbonate eluent includes at least one of a sodium carbonate solution and a sodium bicarbonate solution.

8. The method for detecting sulfur in domestic waste according to claim 7, characterized in that: The molar concentration of the sodium carbonate solution in the eluent is 1-5 mol / L; the molar concentration of the sodium bicarbonate solution in the eluent is 5-15 mmol / L.

9. The method for detecting sulfur in domestic waste according to claim 1, characterized in that: The detector in the ion chromatograph is a suppressed conductivity detector, and the current of the suppressed conductivity detector is 60-80 mA.

10. An application of the method for detecting sulfur in domestic waste according to any one of claims 1 to 9, characterized in that: Used in the detection of domestic waste.

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