Method for degrading ribavirin in water

Abstract

The present application relates to the technical field of water treatment, and particularly relates to a method for degrading a triazole nucleoside antiviral drug in water. The method comprises the following steps: adding a chloramine disinfectant to a water sample to be treated, and then placing the water sample in an ultraviolet light irradiation environment to perform a photo-induced oxidation reaction, wherein the wavelength of the ultraviolet light is 200-300 nm, the irradiation intensity is 0.079-0.25 mW / cm 2 , the temperature is 10-30 DEG C, and the time is 90-150 min, so as to destroy the chemical structure of the drug and degrade the triazole nucleoside antiviral drug. The method utilizes the synergy of ultraviolet and chloramine combined disinfection to economically and efficiently remove the triazole nucleoside antiviral drug in water, without the need to add additional equipment and reagents, and the operation is simple.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and particularly relates to a method for degrading a triazole nucleoside antiviral drug in water. BACKGROUND

[0002] Micro-antiviral drugs in water environment can cause a series of negative effects on human health and aquatic ecosystems, including acute or chronic toxicity, enhanced microbial drug resistance, etc. Even at a low concentration, they can seriously endanger the health of organisms or humans due to their relatively high biological stability and accumulation in organisms and humans through the food chain. Therefore, it is of great significance to remove antiviral drugs in water environment to improve water safety.

[0003] At present, compared with other micro-pollutants in water environment, the removal of antiviral drugs in water environment is less studied at home and abroad. Due to the large differences in structure and physicochemical properties of antiviral drugs, the removal effect of most antiviral drugs is poor after being treated by traditional water treatment processes (coagulation, sedimentation, filtration), and the removal of antiviral drugs by activated sludge method and biofilm method commonly used in sewage treatment also has great differences due to the differences in drug structure, environmental factors (temperature, pH, etc.) and operating conditions (hydraulic retention time, sludge retention time, etc.) of sewage treatment plant. In actual production, the treatment conditions still need to be further optimized. At present, many studies use advanced oxidation processes to remove antiviral drugs in water, such as ultraviolet / hydrogen peroxide, photocatalytic oxidation, electrochemical oxidation and photoelectrocatalytic coupling methods. These methods are limited by the types of antiviral drugs, the cost of reagents, the activity and stability of catalytic materials, and the treatment efficiency, etc. At present, most of them are in the laboratory research stage, and it is difficult to realize production application.

[0004] Triazole nucleoside antiviral drugs have good chemical stability due to their stable triazole structure, and are difficult to degrade in nature, such as ribavirin. Investigations have found that a high concentration of ribavirin (50-100 ng / L) has been detected in the water environment of some areas. At the same time, triazole nucleosides have high solubility in water, which further increases the difficulty of removal, and therefore increases the possibility of accumulation in the environment. Moreover, they have biological accumulation, and even a small amount of residue can accumulate in organisms, which has a great toxic effect on aquatic and terrestrial organisms and water environment, and its ecological impact has attracted widespread attention. SUMMARY

[0005] To address the limitations of existing advanced oxidation technologies due to factors such as reagent costs, catalysis, or electrode materials, and the difficulty in removing triazole nucleoside antiviral drugs due to their good chemical stability and water solubility, this invention provides a method for degrading triazole nucleoside antiviral drugs in water. This method utilizes the synergistic effect of combined ultraviolet and chloramine disinfection to economically and efficiently remove triazole nucleoside antiviral drugs from sewage or drinking water, without the need for additional equipment or reagents, and is simple to operate.

[0006] The technical solution of this invention is as follows:

[0007] A method for degrading triazole nucleoside antiviral drugs in water, comprising at least the following steps:

[0008] Chloramine disinfectant was added to the water sample to be treated, and then the sample was placed in an ultraviolet irradiation environment for photo-induced oxidation. The ultraviolet light wavelength was 200~300 nm, and the irradiation intensity was 0.079~0.25 mW / cm². 2 The temperature is 10~30℃ and the time is 90~150 min, in order to destroy the chemical structure of the drug and degrade the triazole nucleoside antiviral drug.

[0009] Furthermore, the concentration of triazole nucleoside antiviral drugs in the water samples to be treated was 0.1~10 μmol / L.

[0010] Furthermore, the triazole nucleoside antiviral drug is ribavirin.

[0011] Furthermore, the concentration of chloramine disinfectant is expressed as the concentration of monochloramine in the water sample to be treated. The initial concentration of chloramine disinfectant in the water sample to be treated is 1~4 mg / mL, that is, the amount of chloramine disinfectant added to the water sample to be treated is 1~4 mg / mL; and the chloramine disinfectant satisfies the Cl / N molar ratio of 3.

[0012] Furthermore, the ultraviolet light wavelength is preferably 254 nm, and the irradiation intensity is preferably 0.141~0.243 mW / cm². 2 The preferred temperature is 25℃±2℃, and the preferred processing time is 120 min.

[0013] Furthermore, before adding chloramine disinfectant, adjust the pH of the water sample to be treated to 6-9.

[0014] Furthermore, the pH value of the water sample to be treated is adjusted using a phosphate buffer solution; wherein the phosphate buffer solution is a mixed solution of sodium dihydrogen phosphate and disodium hydrogen phosphate.

[0015] Furthermore, before adjusting the pH value, the water sample to be treated is pressure filtered to remove suspended solids in the water; preferably, a 0.45 μm cellulose acetate membrane can be used as the filter membrane, 99.99% high-purity nitrogen can be used as the carrier gas, and the filtration pressure can be controlled at 0.1 MPa.

[0016] The technical principle of this invention is as follows:

[0017] NH₂Cl, under 200–300 nm ultraviolet light irradiation, can generate free radicals such as HO·, Cl·, and NH₂·. Triazole nucleoside antiviral drugs can only be partially degraded under ultraviolet light or NH₂Cl alone, but can be effectively removed under the combined action of free radicals, ultraviolet light, and NH₂Cl. The specific reaction formula is as follows:

[0018] NH2Cl NH2·+Cl·(1)

[0019] Cl·+H2O ClOH· - +H + (2)

[0020] Cl - +H2O / OH - ClOH· - (3)

[0021] ClOH· - Cl - +HO·(4)

[0022] Cl·+Cl - Cl2· - (5)

[0023] NH2·+O2 NH2OO·(6)

[0024] NH2OO·+H2O HNOOH-H2ONH2· NO·+H2O(7)

[0025] The carboxamide structure in the chemical formula of triazole nucleoside antiviral drugs is hydrolyzed, which leads to an increase in the electron cloud density of the triazole structure attached to it. Triazole is then attacked by free radicals and decomposes. Therefore, the combination of ultraviolet light and chloramine can effectively remove triazole nucleoside antiviral drugs.

[0026] The beneficial effects of this invention are as follows:

[0027] (1) The advanced oxidation method of combined ultraviolet / chloramine for removing triazole nucleoside antiviral drugs provided by the present invention has a better removal effect and a higher reaction rate for antiviral drugs containing triazole nucleoside structures compared with traditional ultraviolet irradiation and chloramine disinfection, and can significantly reduce time costs. Experimental results show that the method of the present invention has a significant promoting effect on the degradation of ribavirin, with a degradation rate of up to 98%.

[0028] (2) The advanced oxidation method of composite ultraviolet / chloramine provided by the present invention uses chloramine as an oxidant. Compared with hydrogen peroxide, it has the advantages of strong ultraviolet absorption capacity, high photon yield and high ultraviolet utilization rate. Compared with free chlorine, it has the advantages of long disinfection time and less disinfection byproducts (DBPs).

[0029] (3) The present invention utilizes a variety of active substances such as hydroxyl radicals, active chlorine and nitrogen-containing radicals with strong oxidizing power generated in the ultraviolet / chloramine advanced oxidation technology to synergistically oxidize, while the existing Fenton oxidation method, photocatalytic oxidation method and electrochemical oxidation method mainly degrade organic matter through a single hydroxyl radical. Compared with the existing technology, the method of the present invention has a higher efficiency in removing antiviral drugs.

[0030] (4) The method of the present invention can be carried out at room temperature, the reaction parameters are easy to control, the experimental process is simple, and the operability and feasibility are high. The chemical reagents used are all conventional agents in the water treatment industry, and no other toxic or harmful substances are introduced, so the safety and practicality are high. It meets the actual conditions of engineering application and can realize large-scale engineering application.

[0031] (5) The pH operating parameters of the present invention are in line with the pH range of natural water bodies (mostly between 6.0 and 9.0). Therefore, in practical applications, the pH value of the water body does not need to be adjusted, thus achieving the purpose of saving costs and reducing operation.

[0032] In summary, the method of the present invention can achieve economical and efficient treatment of drinking water, domestic sewage and medical wastewater. It is simple, practical and easy to implement in engineering applications. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a comparison graph of the ribavirin degradation rate curves of the three treatment groups in Example 1.

[0035] Figure 2This is a comparison graph of the ribavirin degradation rate curves at different chloramine concentrations in Example 2.

[0036] Figure 3 This is a comparison graph of the ribavirin degradation rate curves under different UV intensities in Example 3.

[0037] Figure 4 This is a comparison graph of the ribavirin degradation rate curves at different pH values ​​in Example 4.

[0038] Figure 5 This is a comparison graph of the ribavirin degradation rate curves under different matrix organic matter concentrations in Example 5. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0040] In all specific embodiments of this invention, a 1 μmol / L ribavirin aqueous solution is used as the water sample to be treated, and the water sample contains no suspended solids. Unless otherwise specified, the pH value of the water sample to be treated is 7.0 ± 0.2. In other embodiments, domestic sewage, medical wastewater, river water, etc., can also be used as the water sample to be treated. Suspended solids in the water sample are removed by pressure filtration, and the pH value of the water sample is tested to see if it is within the range of 6 to 9. If it exceeds this range, a mixed solution of sodium dihydrogen phosphate and disodium hydrogen phosphate can be used to adjust the pH value of the water sample to be treated to obtain a better degradation effect.

[0041] In the specific embodiments of the present invention, the chloramine disinfectant used in each example is prepared from sodium hypochlorite and ammonium chloride. The specific preparation method is as follows: dissolve ammonium chloride in water, and slowly add sodium hypochlorite solution to ammonium chloride solution according to the ratio of Cl / N=3, mix well and set aside for use.

[0042] In the specific embodiments of the present invention, the ultraviolet light source used in each embodiment is a low-pressure mercury lamp. In other embodiments, sunlight, mercury lamps, xenon lamps and / or halogen lamps may also be used as ultraviolet light sources.

[0043] Example 1

[0044] Chloramine disinfectant was added to the water sample to achieve an initial concentration of 3 mg / mL. The ultraviolet light wavelength was set to 254 nm, and the irradiation intensity was 0.161 mW / cm². 2The group was irradiated with ultraviolet light at 25℃±2℃ for 120 min and named the UV / chloramine group.

[0045] The chloramine-only group (containing only chloramine disinfectant without UV irradiation) and the UV-only group (containing only UV irradiation without chloramine disinfectant) served as controls. Treatment time and temperature were kept consistent across all three treatment groups. Samples were taken periodically to test and record the ribavirin concentration in each treatment group, and the ribavirin degradation rate was calculated.

[0046] The degradation rate of ribavirin in the three treatment groups as a function of treatment time is shown in the curves. Figure 1 As shown. By Figure 1 It can be seen that the degradation rate of ribavirin under UV / chloramine conditions was 74% after 120 min, while the degradation rates under chloramine alone and UV alone were 20% and 8%, respectively. This shows that the UV / chloramine system can significantly improve the degradation rate of ribavirin.

[0047] Example 2

[0048] Four equal volumes of water samples were taken, and chloramine disinfectant was added to each sample to achieve initial concentrations of 1 mg / mL, 2 mg / mL, 3 mg / mL, and 4 mg / mL, respectively. The ultraviolet light wavelength was set to 254 nm, and the irradiation intensity was 0.161 mW / cm². 2 Expose the sample to ultraviolet light for 120 min at 25℃±2℃.

[0049] Four water samples were taken at regular intervals, and the concentration of ribavirin in each treatment group was tested and recorded. The degradation rate of ribavirin was calculated.

[0050] The degradation rate of ribavirin with treatment time at different chloramine concentrations is shown in the curves. Figure 2 As shown. By Figure 2 It can be seen that after 120 min of reaction, the degradation rate of ribavirin was 82% when the chloramine concentration was 4 mg / L, and only 26% when the chloramine concentration was 1 mg / L.

[0051] Example 3

[0052] Four identical water samples were taken, and chloramine disinfectant was added to each sample to ensure an initial concentration of 3 mg / mL. The four samples were then subjected to different irradiation intensities (0.079 mW / cm²). 2 0.141 mW / cm 2 0.161 mW / cm 2 0.243 mW / cm 2The samples were subjected to ultraviolet light treatment, with the ultraviolet light wavelength, temperature and treatment time kept constant at 254 nm, 25℃±2℃ and 120 min respectively.

[0053] Four water samples were taken at regular intervals, and the concentration of ribavirin in each treatment group was tested and recorded. The degradation rate of ribavirin was calculated.

[0054] The degradation rate of ribavirin under different UV intensities as a function of treatment time is shown in the curves. Figure 3 As shown. By Figure 3 It can be seen that after 120 min of reaction, ribavirin has an ultraviolet intensity of 0.243 mW / cm. 2 The removal rate was highest at 98%.

[0055] Example 4

[0056] Four equal volumes of water samples were taken. The pH values ​​of the four samples were adjusted to 6, 7, 8, and 9 respectively using a mixed solution of sodium dihydrogen phosphate and disodium hydrogen phosphate. Chloramine disinfectant was added to the four samples to achieve an initial concentration of 3 mg / mL in each sample. The ultraviolet light wavelength was set to 254 nm, and the irradiation intensity was 0.161 mW / cm². 2 Expose the sample to ultraviolet light for 120 min at 25℃±2℃.

[0057] Four water samples were taken at regular intervals, and the concentration of ribavirin in each treatment group was tested and recorded. The degradation rate of ribavirin was calculated.

[0058] The degradation rate of ribavirin at different pH values ​​as a function of treatment time is shown in the following curves: Figure 4 As shown. By Figure 4 It can be seen that after 120 min of reaction, the removal rate of ribavirin was 94% at pH 6 and 50% at pH 9.

[0059] Example 5

[0060] Four identical water samples were taken, and different masses of humic acid were added to adjust the concentration of matrix organic matter in the water samples to 0 mg / L, 2 mg / L, 4 mg / L, and 8 mg / L, respectively. Chloramine disinfectant was then added to all four samples to achieve an initial concentration of 3 mg / mL. The ultraviolet light wavelength was set to 254 nm, and the irradiation intensity was 0.161 mW / cm². 2 Expose the sample to ultraviolet light for 120 min at 25℃±2℃.

[0061] Four water samples were taken at regular intervals, and the concentration of ribavirin in each treatment group was tested and recorded. The degradation rate of ribavirin was calculated.

[0062] The degradation rate of ribavirin with treatment time under different matrix organic matter concentrations is shown in the curves. Figure 5 As shown. By Figure 5 It can be seen that after 120 min of reaction, the degradation rate of ribavirin was only 14% when the humic acid concentration was 8 mg / L, while the degradation rate of ribavirin was 74% under humic acid-free conditions. This indicates that humic acid can act as a free radical scavenger, affecting the degradation of triazole nucleoside antiviral drugs by free radicals such as HO· and Cl·. This suggests that the method of this invention is more suitable for use at the end of the water treatment process, or for use after pretreatment methods such as pressure filtration and pH adjustment to reduce matrix interference in the water sample, thus ensuring that the degradation effect is not affected by the matrix.

[0063] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A method for degrading triazole nucleoside antiviral drugs in water, characterized in that, At least the following steps are included: Chloramine disinfectant was added to the water sample to be treated, and then the sample was placed in an ultraviolet irradiation environment for photo-induced oxidation. The ultraviolet light wavelength was 200~300 nm, and the irradiation intensity was 0.079~0.25 mW / cm². 2 The temperature is 10~30℃ and the time is 90~150min, in order to destroy the chemical structure of the drug and degrade the triazole nucleoside antiviral drug; The concentration of triazole nucleoside antiviral drugs in the water samples to be treated was 0.1–10 μmol / L; The concentration of chloramine disinfectant is expressed as the concentration of monochloramine in the water sample to be treated. The initial concentration of chloramine disinfectant in the water sample to be treated is 2~4 mg / mL, and the Cl / N molar ratio is 3.

2. The method as described in claim 1, characterized in that, The triazole nucleoside antiviral drug is ribavirin.

3. The method as described in claim 1, characterized in that, The ultraviolet light wavelength is 254 nm, and the irradiation intensity is 0.141~0.243 mW / cm². 2 The temperature was 25℃±2℃, and the processing time was 120 min.

4. The method as described in claim 1, characterized in that, Before adding chloramine disinfectant, adjust the pH of the water sample to be treated to 6-9.

5. The method as described in claim 4, characterized in that, The pH of the water sample to be treated was adjusted using a phosphate buffer solution, which was a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate.

6. The method as described in claim 1, characterized in that, Before adjusting the pH value, the water sample to be treated is pressure filtered to remove suspended solids from the water.

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