A method for repairing sulfadiazine-contaminated soil using periodate

Abstract

The invention discloses a method for repairing sulfadiazine contaminated soil by using periodate, which involves adding periodate PI into the sulfadiazine SD contaminated soil to be treated, so as to achieve degradation of sulfadiazine SD; the Soil / PI system established by the invention can promote the generation of singlet oxygen and iodine free radicals, and the free Fe oxides and soil organic matter SOM in the soil can work together to quickly activate the periodate PI to degrade sulfadiazine SD; the invention does not require additional energy supply, does not require any exogenous addition of any activator, greatly reduces the cost, has the advantages of highly efficient degradation of sulfadiazine SD and environmental friendliness, and has broad application prospects in ensuring the ecological safety of water bodies and soil and the safe resource utilization of soil.

Description

Technical Field

[0001] The invention relates to the technical field of sulfadiazine degradation, and in particular to a method for repairing sulfadiazine-contaminated soil with periodate. Background Art

[0002] Sulfadiazine (SD) is a typical representative of the broad-spectrum sulfonamide antibiotics and has been widely used as a veterinary drug in recent decades. However, about 50% of SD is excreted intact and about 30% is excreted in the form of acetyl conjugates. It has been reported that N-acetyl derivatives of sulfonamide antibiotics undergo deacetylation reactions during fecal storage and return to the parent compound. Once SD and its metabolites in feces are released into agricultural fields, they may interact with various components in the soil or be washed into surface water and leached into groundwater. Therefore, they may enter the food chain and affect the environment and human health. In addition, it has been observed that the administration of antibiotics to farm animals has led to the development of drug-resistant bacteria and their presence in feces, milk, meat, and eggs. Antibiotics can migrate from the soil surface to aquifers through mineral layers, leading to surface water and groundwater contamination. Therefore, it is necessary to conduct a comprehensive study to explore efficient and cost-effective methods to remove SD from soil.

[0003] Over the past few decades, researchers have developed advanced oxidation processes (AOPs) based on periodate (PI). However, the efficacy of PI alone in oxidizing organic pollutants is limited and its effect on degrading pollutants in water is minimal. Therefore, many methods for activating PI have been proposed, including ultraviolet (UV), freezing, ultrasound, alkali, and transition metal ions. Depending on the activation method, PI can produce various reactive species (RS) (such as hydroxyl radicals (·OH), singlet oxygen ( 1 O 2 ), superoxide radicals (O 2 ·- ) and iodate radical (·IO 3 and IO 4 )). However, all of the above activation methods require additional addition of reagents or input of energy, which not only increases the operating cost of the system but also may increase potential environmental risks.

[0004] Recent studies have suggested that iron minerals and organic matter can also activate PI to form RS. Specifically, pyrite (FeS 2 ) is a naturally abundant mineral that can be used to activate PI and disinfect antibiotic-resistant bacteria within 20 minutes. Zong et al. reported that Fe(H 2 O) 6 2+ With IO 4 (H 2O) can effectively activate PI by forming hydrogen bond complexes, coupled with ligand exchange and oxygen atom transfer, to generate Fe(IV) species that promote pollutant degradation. Quinones such as catechol and o-benzoquinone can trigger PI through the advantage of quinone intermediates, thereby enhancing the degradation of organic pollutants. These materials are naturally present in soil and may affect the PI remediation process. In addition, natural soil is considered to be a persulfate activator that can effectively remediate bisphenol A in soil. However, the impact and mechanism of soil inherent components on PI-based oxidation have not been revealed. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for repairing sulfadiazine contaminated soil with periodate, which involves adding periodate PI to the sulfadiazine SD contaminated soil to be treated to achieve the degradation of sulfadiazine SD; the Soil / PI system established by the present invention can promote the generation of singlet oxygen and iodine free radicals, and the free Fe oxides and soil organic matter SOM present in the soil can work together to quickly activate the periodate PI to degrade sulfadiazine SD; the present invention does not require additional energy supply, does not require any exogenous addition of any activator, greatly reduces the cost, has the advantages of efficient degradation of sulfadiazine SD and environmental friendliness, and has broad application prospects in ensuring the ecological safety of water bodies and soil and the safe resource utilization of soil.

[0006] In order to achieve the above technical effects, the following technical solutions are adopted:

[0007] A method for repairing sulfadiazine-contaminated soil with periodate, comprising: using periodate PI as an oxidant to directly degrade the drug sulfadiazine SD in the soil at room temperature; specifically comprising the following steps:

[0008] Step S1: collecting sulfadiazine SD contaminated soil, wherein the contaminated soil contains the drug sulfadiazine SD;

[0009] Step S2: adding periodate PI to the contaminated soil containing the drug sulfadiazine SD in step S1, stirring and mixing evenly, and obtaining soil in which the drug sulfadiazine SD is degraded after the reaction is completed.

[0010] Furthermore, in step S1, the sulfadiazine SD contaminated soil is prepared into soil slurry and reacted with periodate PI, or in step S2, the periodate PI is prepared into a solution and then directly added to the soil to form soil slurry for reaction.

[0011] Furthermore, in the contaminated soil, the content of free iron oxides is greater than or equal to 9459.15 mg / kg and the content of soil organic matter (SOM) is less than or equal to 21.01 g / kg.

[0012] Furthermore, the periodate PI includes sodium periodate.

[0013] Furthermore, the concentration of periodate PI in the contaminated soil slurry is 0.8-1.6 mmol / L.

[0014] Furthermore, the initial concentration of sulfadiazine SD in the contaminated soil is 2-20 mg / kg.

[0015] Furthermore, the pH of the contaminated soil is 3-13.

[0016] Furthermore, the reaction temperature in step S2 is 15-45°C.

[0017] Furthermore, the reaction in step S2 is carried out under a water bath shaker.

[0018] Furthermore, the rotation speed of the water bath shaker is 100-300 rpm.

[0019] The beneficial effects of the present invention are:

[0020] 1. The purpose of the present invention is to introduce periodate PI into sulfadiazine SD contaminated soil to form a Soil / PI system to achieve the degradation of organic pollutants in the contaminated soil; the operation is simple, the reaction conditions are mild, no additional energy supply is required, no exogenous addition of any activator is required, the energy consumption is low, and toxic metal ions can be prevented from entering the ecosystem to cause secondary pollution. The method has the characteristics of economy and environmental protection, strong adaptability, and broad application prospects.

[0021] 2. The degradation efficiency of the drug sulfadiazine SD in the contaminated soil of the present invention is high. After the sulfadiazine SD contaminated soil is treated for 30 minutes, the degradation rate can reach 100.00%.

[0022] 3. The periodate PI used in the present invention is low-priced, safe and stable, and easy to store and transport. Its use can also avoid the problem of secondary pollution of the water body after treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings in the following description are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 The degradation curves of SD in soil by different systems of the present invention are shown;

[0025] Figure 2This is a degradation curve diagram of SD in soil under different PI dosage conditions of the present invention;

[0026] Figure 3 This is a graph showing the degradation of SD in soil under different SD concentration conditions of the present invention;

[0027] Figure 4 It is a degradation curve diagram of SD in soil under different soil slurry temperature conditions of the present invention;

[0028] Figure 5 This is a degradation curve diagram of SD in soil under different pH conditions of the present invention;

[0029] Figure 6 This is the contribution diagram of RS (ascorbic acid for all RS) in the degradation soil SD in the present invention;

[0030] Figure 7 RS (phenol for IO 3 and IO 4 ) Contribution diagram of SD in degraded soil;

[0031] Figure 8 RS (furfuryl alcohol) in the present invention 1 O 2 ) Contribution diagram of SD in degraded soil;

[0032] Fig. 9 This is the contribution diagram of RS (tert-butyl alcohol to ·OH) in the degradation of SD in soil in the present invention;

[0033] Fig.10 RS (nitro blue tetrazolium for O 2 ·- ) Contribution diagram of SD in degraded soil;

[0034] Fig.11 is the electron paramagnetic resonance spectrum of the Soil / PI system of the present invention;

[0035] Fig.12 is a degradation curve diagram of SD in soil under different chloride ion concentrations of the present invention;

[0036] Fig.13 It is the degradation curve diagram of SD in soil under different nitrate ion concentrations of the present invention;

[0037] Fig.14 is a degradation curve diagram of SD in soil under different bicarbonate ion concentrations of the present invention;

[0038] Fig.15 The degradation curve of SD in soil under different iron ion concentrations of the present invention;

[0039] Fig.16is a degradation curve diagram of SD in soil under different manganese ion concentrations of the present invention;

[0040] Fig.17 This is a graph showing the degradation of SD in soil under different HA dosage conditions of the present invention;

[0041] Fig.18 The degradation diagram of SD in different regions and different types of soils according to the present invention;

[0042] Fig.19 This is the degradation diagram of SD in different regions and different types of soil when the dosage of PI in the present invention is 0;

[0043] Fig. 20 This is the contribution diagram of free iron oxides in the degraded soil of the present invention;

[0044] Fig.21 This is a graph showing the contribution of dissolved iron and amorphous iron to SD in degraded soil according to the present invention;

[0045] Fig. 22 This is the contribution diagram of SOM in the degraded soil of the present invention;

[0046] Fig.23 The change of Fourier transform infrared spectrum before and after the soil reaction of the present invention;

[0047] Fig.24 The X-ray diffraction changes of the soil before and after the reaction of the present invention;

[0048] Fig.25 This is a comparison chart of the plant toxicity test of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0051] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0052] Embodiment 1:

[0053] The method of using periodate PI to degrade the drug sulfadiazine SD in soil in this embodiment is achieved by the following steps:

[0054] (Soil / PI): 0.5 g of sulfadiazine SD contaminated soil (free iron oxide content equal to 98567.33 mg / kg and soil organic matter SOM content equal to 18.64 g / kg) was loaded into the reactor. The initial concentration of sulfadiazine SD in the soil C 0 The concentration of sodium periodate was 10 mg / kg, and the total volume of the soil slurry was 2 mL, and the amount of sodium periodate was 1.2 mmol / L. After the reactor was placed on a 25°C water bath shaker for full reaction, a mixture of 2 mL of methanol and 200 mmol / L of sodium thiosulfate (V1:V2=9:1) was added to terminate the reaction and continued to extract for 60 minutes. The extracted slurry was centrifuged to obtain a clear liquid sample for testing. The concentration C of sulfadiazine SD in the system was detected at different reaction times, and the degradation of sulfadiazine SD within 30 minutes was obtained.

[0055] Comparative Example 1:

[0056] (Soil / SPC): 0.5 g of sulfadiazine SD contaminated soil (same as in Example 1) was placed in the reactor. The initial concentration of sulfadiazine SD in the soil was C 0 The concentration of sodium percarbonate SPC is 10 mg / kg, and the total volume of the soil slurry is 2 mL. After the reactor is placed on a 25°C water bath shaker for full reaction, a mixture of 2 mL of methanol and 200 mmol / L of sodium thiosulfate (V1:V2 = 9:1) is added to terminate the reaction and continue extraction for 60 minutes. The extracted slurry is centrifuged to obtain a clear liquid sample for testing. The concentration C of sulfadiazine SD in the system under different reaction times is detected, and the degradation of sulfadiazine SD within 30 minutes is obtained.

[0057] Comparative Example 2:

[0058] (Soil / H 2 O 2 ) : 0.5 g of sulfadiazine SD contaminated soil (same as in Example 1) was placed in the reactor. The initial concentration of sulfadiazine SD in the soil was C 0 The total volume of soil slurry is 2 mL. 2 O 2The dosage is 1.2mmol / L. After the reactor is placed on a 25°C water bath shaker for full reaction, a mixture of 2mL methanol and 200mmol / L sodium thiosulfate (V1:V2=9:1) is added to terminate the reaction and continue extraction for 60 minutes. The extracted mud is placed in a centrifuge for centrifugation to obtain a clear liquid sample for testing. The concentration C of sulfadiazine SD in the system at different reaction times is detected to obtain the degradation of sulfadiazine SD within 30 minutes.

[0059] Comparative Example 3:

[0060] (Soil / PDS): 0.5 g of sulfadiazine SD contaminated soil (same as in Example 1) was placed in the reactor. The initial concentration of sulfadiazine SD in the soil was C 0 The concentration of sodium persulfate PDS is 10 mg / kg, and the total volume of the soil slurry is 2 mL. After the reactor is placed on a 25°C water bath shaker for full reaction, a mixture of 2 mL of methanol and 200 mmol / L of sodium thiosulfate (V1:V2=9:1) is added to terminate the reaction and continue extraction for 60 minutes. The extracted slurry is centrifuged to obtain a clear liquid sample for testing. The concentration C of sulfadiazine SD in the system under different reaction times is detected, and the degradation of sulfadiazine SD within 30 minutes is obtained.

[0061] Comparative Example 4:

[0062] (PI alone): Add sulfadiazine SD to pollute the water body in the reactor. The initial concentration of sulfadiazine SD in the water body is C 0 The reaction mixture was 10 mg / kg, and the amount of sodium periodate was 1.2 mmol / L, while the total reaction volume was 2 mL. The reactor was placed on a 25°C water bath shaker for full reaction, and a mixture of 2 mL of methanol and 200 mmol / L of sodium thiosulfate (V1:V2=9:1) was added to terminate the reaction, and the sample was obtained for testing. The concentration C of sulfadiazine SD in the system was detected at different reaction times, and the degradation of sulfadiazine SD within 30 minutes was obtained.

[0063] Comparative Example 5:

[0064] (Soil alone): 0.5 g of sulfadiazine SD contaminated soil (same as in Example 1) was placed in the reactor. The initial concentration of sulfadiazine SD in the soil was C 0The concentration of sulfadiazine SD in the system was 10 mg / kg, and pure water was added to ensure that the total volume of the soil slurry was 2 mL. After the reactor was placed on a 25°C water bath shaker for full reaction, a mixture of 2 mL of methanol and 200 mmol / L of sodium thiosulfate (V1:V2=9:1) was added to terminate the reaction and continued to extract for 60 minutes. The extracted slurry was centrifuged to obtain a clear liquid sample for testing. The concentration C of sulfadiazine SD in the system was detected at different reaction times, and the degradation of sulfadiazine SD within 30 minutes was obtained.

[0065] from Figure 1 It can be seen that when using Soil / SPC, Soil / H 2 O 2 When sulfadiazine SD was treated by , Soil / PDS, sodium periodate alone and soil alone, the degradation rates of sulfadiazine SD were 17.93%, 9.22%, 10.15%, 2.2% and 1.1% respectively. It is worth noting that Soil / PI has an excellent degradation effect on sulfadiazine SD in soil, with a degradation rate of 100.00%.

[0066] Embodiment 2:

[0067] In this example, the effect of the dosage of sodium periodate PI on the degradation rate of sulfadiazine SD was investigated.

[0068] Example 1 is used as a reference, except that the concentration of sodium periodate PI in the contaminated soil slurry is changed to 0.8, 1, 1.2, 1.4 and 1.6 mmol / L respectively; Figure 2 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 88.75%, 92.97%, 100.00%, 100.00% and 100.00%, respectively.

[0069] Embodiment 3:

[0070] Example 1 is used as a reference, except that the concentration of sulfadiazine SD in the soil slurry is changed to 2, 5, 10, 15 and 20 mg / kg, respectively. Figure 3 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 100.00%, 100.00%, 76.76% and 76.62%, respectively.

[0071] Embodiment 4:

[0072] Example 1 is used as a reference, except that the reaction temperature of the soil slurry is changed to 15, 25, 35 and 45°C. Figure 4 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 80.84%, 100.00%, 100.00% and 100.00%, respectively.

[0073] Embodiment 5:

[0074] Example 1 is used as a reference, the only difference is that the pH value of the soil slurry is changed to 3, 5, 7, 9, 11 and 13, respectively. Figure 5 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 100.00%, 100.00%, 27.04%, 20.71% and 12.11%, respectively.

[0075] Embodiment 6:

[0076] In a water bath shaker at 25°C, sulfadiazine SD and sodium periodate PI were added to the soil to ensure that the initial concentration was C 0 Under the premise of ensuring that the total volume of soil slurry was 2 mL, different RS quenchers were added, ascorbic acid 2, 20 and 50 mmol / L (quencher for all RS), phenol 10, 25 and 50 mmol / L (corresponding to RS ·OH, ·IO 3 and IO 4 ), furfuryl alcohol 10, 25 and 50 Mm (corresponding to RS 1 O 2 ), tert-butyl alcohol 100, 250 and 500 mmol / L (corresponding to RS is ·OH), nitro blue tetrazolium 0.1, 0.25 and 0.5 mmol / L (corresponding to RS is O 2 ·- ).like Figure 6-Figure 10 As shown, the RS of Soil / PI system is 1 O 2 , IO 3 , IO 4 and OH, the most important role is played by 1 O 2 .

[0077] Embodiment 7:

[0078] In a water bath shaker at 25°C, sulfadiazine SD and sodium periodate PI were added to the soil to ensure that the initial concentration was C 0 The concentrations of 2,2,6,6-tetramethyl-4-piperidone (TEMP) were added to the soil slurry to ensure that the total volume was 2 mL, and the generation of free radicals was analyzed using an electron paramagnetic resonance spectrometer. Fig.11 As shown, the electron paramagnetic resonance spectrum shows 1 O 2 The signal further proves that the main RS of Soil / PI system is 1 O2 .

[0079] Embodiment 8:

[0080] In a water bath shaker at 25°C, sulfadiazine SD and sodium periodate PI were added to the soil to ensure that the initial concentration was C 0 The concentrations of 1, 10, 20 and 40 mmol / L Cl were added respectively. – ,like Fig.12 As shown in Figure 2, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 100.00%, 100.00% and 100.00% respectively. 3 – ,like Fig.13 As shown in Figure 2, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 100.00%, 100.00% and 100.00%, respectively. 3 – ,like Fig.14 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 66.05%, 60.59% and 44.90%, respectively.

[0081] Embodiment 9:

[0082] In a water bath shaker at 25°C, sulfadiazine SD and sodium periodate PI were added to the soil to ensure that the initial concentration was C 0 The concentrations of 10 mg / kg and 1.2 mmol / L were respectively 10 mg / kg and 1.2 mmol / L. Under the premise of ensuring that the total volume of soil slurry was 2 mL, different types of cations were added to verify their effects on the degradation of sulfadiazine SD. 0.1, 0.2, 0.4, 0.6 and 1 mmol / L of Fe 3+ ,like Fig.15 As shown in Figure 2, the degradation rates of SD after 30 minutes were 100.00%, 100.00%, 100.00%, 100.00% and 100.00%, respectively. 2+ ,like Fig.16 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 100.00%, 100.00%, 100.00% and 100.00%, respectively.

[0083] Embodiment 10:

[0084] In a water bath shaker at 25°C, sulfadiazine SD and sodium periodate PI were added to the soil to ensure that the initial concentration was C 0 10mg / kg and 1.2mmol / L respectively. Under the premise of ensuring that the total volume of soil slurry is 2mL, humic acid HA is added to verify its effect on the degradation of sulfadiazine SD. 10, 20, 30 and 40mg / kg HA are added respectively. Fig.17 As shown, the degradation rates of sulfadiazine SD after 30 minutes were 100.00%, 100.00%, 100.00% and 100.00%, respectively.

[0085] Embodiment 11:

[0086] Example 1 is used as a reference, and the only difference is that the types of soils tested are changed, namely, soil S1 in Nanchang, Jiangxi, soil S2 in Dehong, Yunnan, soil S3 in Chongqing, soil S4 in Hanzhong, Shaanxi, soil S5 in Huai'an, Jiangsu, soil S6 in Guyuan, Ningxia, soil S7 in Pingliang, Gansu, soil S8 in Huai'an, Anhui, soil S9 in Fuzhou, Fujian, and paddy soil S10 in Nanchang, Jiangxi. Fig.18 As shown, the degradation rates of sulfadiazine SD in the 10 soils after 30 min were 100.00%, 90.15%, 52.35%, 100.00%, 58.79%, 37.82%, 29.48%, 34.98%, 50.17% and 41.95%, respectively.

[0087] Embodiment 12:

[0088] Example 11 is used as a reference, the only difference is that the dosage of sodium periodate PI is changed to 0 mmol / L. Fig.19 As shown, the degradation rates of sulfadiazine SD in the 10 soils after 30 minutes were 0.33%, 2.42%, 1.98%, 5.18%, 1.99%, 0.89%, 0.96%, 0.40%, 3.22% and 0.67%, respectively.

[0089] Embodiment 13:

[0090] Ten soil samples (1 g) were mixed with 20 mL 0.3 mmol / L trisodium citrate and 2.5 mL 1 mmol / L bicarbonate in a water bath at 80 °C, and then 1 g sodium dithionite powder was added to the suspension. After stirring for 15 minutes, the suspension was centrifuged and the remaining soil was washed three times with 1 mmol / L NaCl. The extraction of free iron oxides in the soil was completed. Fig. 20As shown, the degradation rates of sulfadiazine SD in the 10 soils after the free iron oxides were removed were 14.00%, 1.28%, 18.08%, 15.84%, 12.16%, 12.40%, 12.32%, 10.08%, 14.08% and 14.48%, respectively. The 10 soil samples (1 g) and 50 mL of 0.2 mmol / L ammonium oxalate buffer solution (pH = 3.0-3.2) were placed in a centrifuge tube wrapped in aluminum foil, shaken and centrifuged, and the amorphous iron oxides in the soil were extracted. Fig.21 As shown, after removing amorphous iron oxides, the degradation rates of sulfadiazine SD in soil were 100.00%, 100.00%, 42.24%, 100.00%, 48.40%, 35.68%, 30.56%, 87.04%, 100.00% and 100.00%, respectively. Ten soil samples (1 g) were mixed with 10 mL of pure water, shaken and centrifuged, and the dissolved iron in the soil was extracted. Fig.21 As shown, after removing dissolved iron, the degradation rates of sulfadiazine SD in soil were 75.04%, 67.36%, 38.32%, 78.16%, 0.80%, 26.56%, 28.96%, 31.20%, 55.76% and 63.68%, respectively.

[0091] The free iron oxide contents and degradation rates of sulfadiazine SD in the above 10 soil samples are shown in Table 1.

[0092] Table 1 Effect of free iron oxide content in soil samples on SD degradation in soil

[0093]

[0094]

[0095] According to the analysis results of soil samples, there is a certain correlation between the free iron oxide content and the degradation rate. When the free iron oxide content exceeds 9459.15 mg / kg, the soil samples show a good degradation effect (>90%), such as samples S1 and S4, whose free iron oxide contents are 9459.15 mg / kg and 10561.75 mg / kg, respectively, and the degradation rate reaches 100%. However, although the free iron oxide content of sample S10 reaches 10242.57 mg / kg, it shows a lower degradation rate (41.95%), which may be attributed to its high SOM content (58.7 g / kg). High concentrations of SOM may inhibit the degradation process of SD in soil, which indicates that the interaction between free iron oxides and SOM must be considered when degrading SD in soil. Therefore, by optimizing the ratio of free iron oxides to SOM in soil, the degradation efficiency of soil can be improved, providing a theoretical basis for soil remediation.

[0096] The amorphous iron oxide contents and degradation rates of sulfadiazine SD in the above 10 soil samples are shown in Table 2.

[0097] Table 2 Effect of amorphous iron oxide content in soil samples on SD degradation in soil

[0098]

[0099]

[0100] According to the analysis results of soil samples, there is no obvious correlation between the content of amorphous iron oxides and the degradation rate. Although the degradation rate of SD showed some changes, these changes were small and not obvious. Overall, the removal of amorphous iron oxides had a limited effect on the degradation rate and was not a decisive factor.

[0101] The dissolved iron content and degradation rate of sulfadiazine SD in the above 10 soil samples are shown in Table 3.

[0102] Table 3 Effect of dissolved iron content in soil samples on SD degradation in soil

[0103]

[0104] The analysis results of soil samples are similar to those of amorphous iron oxides, and there is no obvious correlation between the dissolved iron content and the degradation rate. The effect of removing dissolved iron on the degradation rate is relatively limited and is not a decisive factor.

[0105] Embodiment 14:

[0106] The 10 soils were placed in a water bath at 80°C and mixed with 30% H 2 O 2 The reaction is continued until no bubbles are generated, and the extraction of organic matter SOM in the soil is complete. Fig. 22 As shown, after removing SOM, the degradation rates of sulfadiazine SD in soil were 100.00%, 100.00%, 36.24%, 37.02%, 36.58%, 37.47%, 63.87%, 34.25%, 44.42% and 73.17%, respectively.

[0107] The organic matter SOM content and degradation rate of sulfadiazine SD of the above 10 soil samples are shown in Table 4.

[0108] Table 4 Effect of organic matter (SOM) content of soil samples on SD degradation in soil

[0109]

[0110] According to the analysis results of soil samples, when the SOM content is less than or equal to 21.01g / kg and the free iron oxide content is greater than 9459.15mg / kg, the degradation effect is very good, such as soil samples S1, S2 and S4. Therefore, when the SOM content is less than 21.01g / kg and the free iron oxide content is greater than 9459.15mg / kg, the degradation effect of sulfadiazine SD is more than 90%. When it exceeds the threshold of 21.01g / kg, the degradation process may be interfered by competition or other mechanisms.

[0111] Embodiment 15:

[0112] like Fig.23 As shown in Figure 2, in order to detect the changes in soil functional groups before and after the reaction, Fourier transform infrared spectroscopy (FTIR) analysis was performed on the soil. 2 O 2 After treatment, the changes in soil FTIR spectrum intensity were significant, but only slight changes occurred after the addition of PI and DBC. The number of peaks in the spectrum did not increase or decrease, and no peak shift was observed, indicating that the soil composition was stable after PI treatment. This may be due to the fact that H 2 O 2 SOM was removed during the treatment process, and the absorption signals of related functional groups were weakened. In addition, the FTIR spectra of soil samples treated with sodium disulfite-sodium citrate-bicarbonate (DCB) to remove free iron oxides did not show any significant changes compared with the original soil samples, indicating that the removal of Fe had little effect on the functional groups of the soil. In summary, the soil functional groups were almost not disturbed after the Soil / PI system treatment. This shows that the Soil / PI treatment technology has great potential in soil pollution remediation.

[0113] Embodiment 16:

[0114] like Fig.24 As shown in Figure 2, X-ray diffraction (XRD) analysis revealed the changes in the crystal structure before and after PI treatment. 2 O 2 The XRD spectra of the soil samples treated with DCB showed that only the compound SiO 2 , indicating that the reaction process has little effect on the crystal structure.

[0115] Embodiment 17:

[0116] Fifteen healthy radishes, Chinese cabbages, and Chinese cabbages were placed in three types of soil: (1) uncontaminated soil (US), (2) sulfadiazine SD-contaminated soil (CS), and (3) periodate PI-remediated soil (RS). Pure water (DW) was used as a control. The petri dishes were incubated in the dark at 25°C for 10 days, and finally 15 randomly selected germinated seeds were recorded to collect growth data, such as Fig.25 As shown in the results, it was found that sulfadiazine SD had toxic effects on the germination and growth of radish, Chinese cabbage and pakchoi seeds in the soil, and the Soil / PI system could effectively reduce the phytotoxicity of sulfadiazine SD contaminated soil.

[0117] In summary, the present invention discloses a method for repairing sulfadiazine contaminated soil with periodate, which involves adding periodate PI to the sulfadiazine SD contaminated soil to be treated to achieve the degradation of sulfadiazine SD; the Soil / PI system established by the present invention can promote the generation of singlet oxygen and iodine free radicals, and the free Fe oxides and soil organic matter SOM present in the soil can work together to quickly activate the periodate PI to degrade sulfadiazine SD; the present invention does not require additional energy supply, does not require any exogenous addition of any activator, greatly reduces the cost, has the advantages of efficient degradation of sulfadiazine SD and environmental friendliness, and has broad application prospects in ensuring the ecological safety of water bodies and soil and the safe resource utilization of soil.

[0118] At this point, those skilled in the art recognize that, although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the contents disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A method for remediating sulfadiazine-contaminated soil using periodate, characterized in that: The method is: using periodate PI as an oxidant to directly degrade the drug sulfadiazine SD in the soil under room temperature conditions; specifically comprising the following steps: Step S1: collecting sulfadiazine SD contaminated soil, wherein the contaminated soil contains the drug sulfadiazine SD; Step S2: adding periodate PI to the contaminated soil containing the drug sulfadiazine SD in step S1, stirring and mixing evenly, and obtaining soil in which the drug sulfadiazine SD is degraded after the reaction is completed; The free iron oxide content in the contaminated soil is 9459.15 mg / kg-19179.43 mg / kg, and the soil organic matter SOM content is 13.34 g / kg-21.01 g / kg; The method does not require additional energy supply and does not require any external activating agent to be added.

2. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: In step S1, the sulfadiazine SD contaminated soil is prepared into soil slurry to react with periodate PI, or in step S2, the periodate PI is prepared into a solution and then directly added to the soil to form soil slurry for reaction.

3. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: The periodate PI includes sodium periodate.

4. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: The concentration of the periodate PI in the contaminated soil slurry is 0.8-1.6 mmol / L.

5. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: The initial concentration of sulfadiazine SD in the contaminated soil is 2-20 mg / kg.

6. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: The pH of the contaminated soil is 3-13.

7. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: The reaction temperature in step S2 is 15-45°C.

8. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 1, characterized in that: In the step S2, the reaction is carried out under the condition of a water bath shaker.

9. A method for remediating sulfadiazine-contaminated soil with periodate as claimed in claim 8, characterized in that: The rotation speed of the water bath shaker is 100-300 rpm.

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