Method for removing smelly substances

Abstract

The invention provides a method for removing smelly substances. According to the method disclosed by the invention, two means of subacid electrolyzed water treatment and ultraviolet irradiation are combined, so that not only can geosmin and 2-methylisoborneol in water be effectively removed, but also geosmin and 2-methylisoborneol in aquatic organisms can be effectively removed. In addition, the removal effect of the method on geosmin and 2-methylisoborneol in water is obviously superior to the sum of the effect of singly using subacid electrolyzed water treatment and the effect of singly using ultraviolet irradiation; the two means of the subacid electrolyzed water treatment and the ultraviolet irradiation provided by the invention play a synergistic effect in the aspect of removing the geosmin and the 2-methylisoborneol.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment. More specifically, it relates to a method for removing odor substances. Background Art

[0002] Due to reasons such as agricultural runoff and sewage discharge, eutrophication may occur in flowing water ecosystems such as rivers, and algal organisms such as cyanobacteria will multiply in large numbers. Especially in summer when it is hot, in addition to flowing water ecosystems such as rivers, lentic ecosystems such as lakes and reservoirs will also experience outbreaks of algal organisms such as cyanobacteria. The metabolism of algal organisms will release a large amount of geosmin (GSM) and 2-methylisoborneol (2-MIB).

[0003] Excessive geosmin and 2-methylisoborneol in water will have various adverse effects: (1) Geosmin and 2-methylisoborneol may make the water produce a soil-like smell, affecting the sensory index and potability of the water; (2) Fish may directly absorb geosmin and 2-methylisoborneol in the water through organs such as gills or skin, or ingest geosmin and 2-methylisoborneol by directly preying on algal organisms. This will not only cause the enrichment of odor substances in the fish meat, seriously affecting the quality of the fish meat, but may also interfere with the endocrine system of the fish, affecting its growth and reproduction; (3) Most shellfish are filter-feeding animals and may enrich geosmin and 2-methylisoborneol through ways such as adsorbing and feeding on algal organisms. This will not only seriously affect their meat quality, but may also be transmitted to higher trophic level organisms through the food chain, further expanding the scope of influence; (4) Geosmin and 2-methylisoborneol may stimulate the overgrowth of aquatic vegetation, leading to sediment accumulation, a decrease in dissolved oxygen, and the destruction of the water self-purification ability, forming a vicious cycle.

[0004] Therefore, there is an urgent need to find a method that can effectively remove geosmin and 2-methylisoborneol in water. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention aims to provide a method for removing odor substances. By combining the treatment of slightly acidic electrolyzed water (SAEW) and ultraviolet (UV-C) irradiation, it can not only effectively remove geosmin and 2-methylisoborneol in water, but also effectively remove geosmin and 2-methylisoborneol in aquatic organisms.

[0006] The first object of the present invention is to provide a method for removing odor substances in water.

[0007] The second object of the present invention is to provide a method for removing odor substances in aquatic organisms.

[0008] The above objects of the present invention are achieved by the following technical solutions: The present invention provides a method for removing odor-causing substances in water, specifically: preparing water containing odor-causing substances into slightly acidic electrolyzed water containing odor-causing substances, and then irradiating it with ultraviolet light having a wavelength of 222-275 nm; wherein, the odor-causing substances include geosmin and / or 2-methylisoborneol.

[0009] Optionally, the concentration of geosmin in water is 5 μg / L or less, for example, it can be 1, 2.5, 3, 5 μg / L or the range between any of the above point values.

[0010] Optionally, the concentration of 2-methylisoborneol in water is 25 μg / L or less, for example, it can be 2.5, 5, 15, 25 μg / L or the range between any of the above point values.

[0011] According to the description of slightly acidic electrolyzed water in GB28234-2020 "Hygiene Requirements for Acidic Electrolyzed Water Generators", slightly acidic electrolyzed water is a colorless and transparent liquid with a slight chlorine smell, and the available chlorine content is 40-80 mg / L (for example, it can be 40, 60, 80 mg / L or the range between any of the above point values), and the pH is 5.0-6.5 (for example, it can be 5, 6.5, which can be adjusted by adding HCl and / or NaOH).

[0012] Optionally, the preparation method is: using water containing odor-causing substances as raw materials, and preparing according to the method in GB28234-2020 "Hygiene Requirements for Acidic Electrolyzed Water Generators", that is: adding water containing odor-causing substances to hydrochloric acid and / or sodium chloride, and electrolyzing in a diaphragm or non-diaphragm electrolytic cell to obtain.

[0013] Optionally, the wavelength of the ultraviolet light is 222, 255, 275 nm or the range between any of the above point values.

[0014] Optionally, the irradiation time is 0.5 min or more, for example, it can be 0.5, 1, 1.5, 2, 3, 5, 7 min or the range between any of the above point values.

[0015] Optionally, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 or more.

[0016] Optionally, the irradiation temperature is 20-30 °C, for example, it can be 20, 25, 30 °C or the range between any of the above point values.

[0017] Optionally, stirring is carried out during the irradiation, such as stirring at 800-1200 r / min, and most preferably at 1000 r / min.

[0018] Meanwhile, the present invention also provides a method for removing odor substances in aquatic organisms, specifically: soaking the aquatic organisms containing odor substances in slightly acidic electrolyzed water, and then irradiating with ultraviolet light having a wavelength of 222 - 275 nm; wherein, the odor substances include geosmin and / or 2-methylisoborneol.

[0019] Optionally, the aquatic organisms are fish and / or shellfish.

[0020] Further optionally, the fish are freshwater fish, such as one or more of tilapia, grass carp, silver carp, snakehead, and carp.

[0021] Further optionally, the shellfish are freshwater shellfish, such as one or more of Bellamya chinensis, Corbicula fluminea, and Anodonta woodiana.

[0022] Optionally, the aquatic organisms are fish meat and / or shellfish meat.

[0023] Optionally, the content of geosmin in the aquatic organisms is below 0.40 μg / kg.

[0024] Optionally, the content of 2-methylisoborneol in the aquatic organisms is below 4.19 μg / kg.

[0025] Optionally, the dosage ratio of the aquatic organisms to the slightly acidic electrolyzed water is 23 - 27 g: 1.5 L, for example, it can be 23 g: 1.5 L, 25 g: 1.5 L, 27 g: 1.5 L or the range between any of the above point values.

[0026] Optionally, the wavelength of the ultraviolet light is 222, 255, 275 nm or the range between any of the above point values.

[0027] Optionally, the irradiation time is above 0.5 min, for example, it can be 0.5, 1, 1.5, 2, 3, 5, 7 min or the range between any of the above point values.

[0028] Optionally, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 above.

[0029] Optionally, the irradiation temperature is 20 - 30 °C, for example, it can be 20, 25, 30 °C or the range between any of the above point values.

[0030] Optionally, stirring is carried out during the irradiation, such as stirring at 800 - 1200 r / min, and most preferably at 1000 r / min.

[0031] The present invention has the following beneficial effects: 1. The present invention combines microacidic electrolyzed water treatment and ultraviolet irradiation, which can not only effectively remove geosmin and 2-methylisoborneol in water, but also effectively remove geosmin and 2-methylisoborneol in aquatic organisms.

[0032] 2. The present invention combines microacidic electrolyzed water treatment and ultraviolet irradiation, and its removal effect on geosmin and 2-methylisoborneol in water is significantly better than the sum of the effects of using microacidic electrolyzed water treatment alone and using ultraviolet irradiation alone, indicating that these two means play a synergistic role in removing geosmin and 2-methylisoborneol.

[0033] 3. The present invention combines microacidic electrolyzed water treatment and ultraviolet irradiation, and its removal effect on geosmin and 2-methylisoborneol is significantly better than that of the method of combining other methods (such as plasma-activated water treatment, chloramine solution treatment, etc.) with ultraviolet irradiation. Detailed implementation mode

[0034] The following specific examples are used to further illustrate the present invention, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0035] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available, and the reagents used are all of analytical grade.

[0036] I. Reagents Geosmin (GSM) standard solution: with a concentration of 100 μg / mL, purchased from Supelco, USA.

[0037] 2-Methylisoborneol (2-MIB) standard solution: with a concentration of 100 μg / mL, purchased from Supelco, USA.

[0038] Sodium thiosulfate standard solution: with a concentration of 0.1 mol / L, purchased from Anpel Laboratory Technologies Inc.

[0039] Sodium chloride: purchased from Shanghai Macklin Biochemical Co., Ltd.

[0040] II. Instruments Rtx-5MS fused silica capillary column: with a specification of 30 m×0.25 mm ×0.25 µm, purchased from Shimadzu Corporation, Japan.

[0041] 50 / 30 μm DVB / CAR / PDMS solid phase extraction needle: purchased from Supelco, USA.

[0042] GCMS-TQ8050NX Gas Chromatograph-Mass Spectrometer: Purchased from Shimadzu Corporation, Japan.

[0043] Anywhere-320W Slightly Acidic Electrolyzed Water Generator: Purchased from Beijing Liande Environmental Protection Equipment Company.

[0044] DK-98-Ⅱ Water Bath: Purchased from Tianjin Test Instrument Co., Ltd.

[0045] JYL-c50T Food Processor: Purchased from Joyoung Co., Ltd.

[0046] JIDI-UP Basic Ultra-pure Water Machine: Purchased from Guangzhou Jidi Instrument Co., Ltd.

[0047] III. Determination of Geosmin and 2-Methylisoborneol Contents in Water Take 5 mL of water, 5 mL of saturated sodium chloride solution and 2 mL of sodium thiosulfate standard solution in a 40 mL headspace vial, place it in a 70 °C water bath for headspace equilibration for 5 min, and then use a 50 / 30 μm DVB / CAR / PDMS solid phase extraction needle to perform headspace adsorption on the volatile substances of the sample for 35 min, and then determine the contents of geosmin and 2-methylisoborneol by GC-MS.

[0048] Among them, the conditions of GC-MS are as follows: Use a GC / MS-TQ8050NX gas chromatograph-mass spectrometry system, equipped with an Rtx-5MS fused silica capillary analytical column (30 m × 0.25 mm × 0.25 µm); the carrier gas is helium (purity 99.999%); the flow rate is 1.0 mL / min; the column temperature program: the initial temperature is 60 °C, hold for 2 min, increase the temperature at a rate of 10 °C / min to 120 °C and hold for 3 min, increase the temperature at a rate of 3 °C / min to 150 °C and hold for 1 min, and finally increase the temperature at a rate of 20 °C / min to 230 °C and hold for 1 min; the ionization energy is 70 eV, the interface temperature is 250 °C, and the ion source temperature is 250 °C; the scanning mode: selected ion monitoring (MRM), the qualitative ion pairs, quantitative ion pairs and retention times are shown in Table 1.

[0049] Table 1 Qualitative Ion Pairs, Quantitative Ion Pairs and Retention Times

[0050] IV. Determination of Geosmin and 2-Methylisoborneol Contents in Fish Meat The fish meat was broken up. 5.0 g of fish meat, 5 mL of saturated sodium chloride solution and 2 mL of sodium thiosulfate standard solution were placed in a 40 mL headspace vial, and headspace equilibration was carried out in a water bath at 70 °C for 5 min. Then, after 35 min of headspace adsorption of the volatile substances of the sample using a 50 / 30 μm DVB / CAR / PDMS solid-phase extraction needle, the contents of geosmin and 2-methylisoborneol were determined by GC-MS.

[0051] Among them, the conditions of GC-MS were as follows: A GC / MS-TQ8050NX gas chromatography-mass spectrometry system equipped with an Rtx-5MS fused silica capillary analytical column (30 m × 0.25 mm × 0.25 µm) was used; the carrier gas was helium (purity 99.999%); the flow rate was 1.0 mL / min; the column temperature program: the initial temperature was 60 °C, held for 2 min, heated at a rate of 10 °C / min to 120 °C and held for 3 min, heated at a rate of 3 °C / min to 150 °C and held for 1 min, and finally heated at a rate of 20 °C / min to 230 °C and held for 1 min; the ionization energy was 70 eV, the interface temperature was 250 °C, and the ion source temperature was 250 °C; the scanning mode: selected ion monitoring (MRM), and the qualitative ion pairs, quantitative ion pairs and retention times were shown in Table 1.

[0052] Example 1 Scavenging effects of different action modes on geosmin and 2-methylisoborneol in water I. Test method ① Treatment with slightly acidic electrolyzed water alone S1. At room temperature (25 ± 5 °C), water was electrolyzed according to the method of GB28234-2020 Hygienic requirements for acidic electrolyzed water generators, and water, HCl or NaOH was added to adjust its available chlorine content to 60 mg / L and pH to 5 to obtain slightly acidic electrolyzed water; S2. Geosmin and 2-methylisoborneol were added to the slightly acidic electrolyzed water obtained in S1 to make the final concentration of geosmin 2.5 μg / L and the final concentration of 2-methylisoborneol 2.5 μg / L, obtaining slightly acidic electrolyzed water containing odor substances; S3. Magnetic stirring was carried out at 1000 r / min for 5 min.

[0053] ② Ultraviolet irradiation alone S1. At room temperature (25 ± 5 °C), geosmin and 2-methylisoborneol were added to water to make the final concentration of geosmin 2.5 μg / L and the final concentration of 2-methylisoborneol 2.5 μg / L, obtaining water containing odor substances; S2. Stir magnetically at 1000 r / min and irradiate with ultraviolet light at wavelengths of 222, 255, and 275 nm for 5 min respectively; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0054] ③Combined use of slightly acidic electrolyzed water treatment and ultraviolet irradiation S1. At room temperature (25 ± 5 °C), electrolyze water according to the method of GB28234-2020 "Hygiene Requirements for Acidic Electrolyzed Water Generators", and add water, HCl or NaOH to adjust its available chlorine content to 60 mg / L and pH to 5 to obtain slightly acidic electrolyzed water; S2. Add geosmin and 2-methylisoborneol to the slightly acidic electrolyzed water obtained in S1 so that the final concentration of geosmin is 2.5 μg / L and the final concentration of 2-methylisoborneol is 2.5 μg / L to obtain slightly acidic electrolyzed water containing odor substances; S3. Stir magnetically at 1000 r / min and irradiate with ultraviolet light at wavelengths of 222, 255, and 275 nm for 5 min respectively; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0055] ④Combined use of plasma-activated water treatment and ultraviolet irradiation; S1. At room temperature (25 ± 5 °C), add geosmin and 2-methylisoborneol to the plasma-activated water so that the final concentration of geosmin is 2.5 μg / L and the final concentration of 2-methylisoborneol is 2.5 μg / L to obtain plasma-activated water containing odor substances; wherein, the plasma-activated water is prepared by discharging 500 mL of pure water at a power of 200 W for 15 min, and the pH and oxidation-reduction potential are 4.72 and 374 mV respectively; S2. Stir magnetically at 1000 r / min and irradiate with ultraviolet light at a wavelength of 222 nm for 5 min; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0056] ⑤Combined use of chloramine solution treatment and ultraviolet irradiation S1. At room temperature (25 ± 5 °C), add water, HCl or NaOH to adjust the available chlorine content of chloramine to 60 mg / L and pH to 5 to obtain a chloramine solution; S2. Add geosmin and 2-methylisoborneol to the chloramine solution so that the final concentration of geosmin is 2.5 μg / L and the final concentration of 2-methylisoborneol is 2.5 μg / L to obtain a chloramine solution containing odor substances; S3. Stir magnetically at 1000 r / min and irradiate with ultraviolet light at a wavelength of 222 nm for 5 min; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0057] II. Test Results Measure the contents of geosmin and 2-methylisoborneol in water at the 0.5, 1, 1.5, 2, and 5 min of magnetic stirring in S2 or S3 respectively, and calculate the clearance rates of different action modes on geosmin and 2-methylisoborneol according to "Clearance rate (%) = (Content before treatment - Content after treatment) / Content before treatment × 100%". The results are shown in Tables 2 - 4 below.

[0058] Table 2 Geosmin Clearance Rates of ① - ③

[0059] Table 3 2-Methylisoborneol Clearance Rates of ① - ③

[0060] Table 4 Odor Substance Clearance Rates of ④ - ⑤

[0061] Analysis of the action results of ① - ③ shows that the clearance rates of the combined use of slightly acidic electrolyzed water treatment and ultraviolet irradiation in ③ for the two odor substances of geosmin and 2-methylisoborneol in water are both higher than the sum of the clearance rates of ① using slightly acidic electrolyzed water alone and ② using ultraviolet irradiation alone for the corresponding odor substances. This indicates that the combined use of slightly acidic electrolyzed water treatment and ultraviolet irradiation in the present invention has a significantly better clearance effect on geosmin and 2-methylisoborneol in water than the sum of the effects of using slightly acidic electrolyzed water treatment alone and using ultraviolet irradiation alone, that is: these two means play a synergistic effect in removing geosmin and 2-methylisoborneol.

[0062] Analysis of the action results of ③ - ⑤ shows that the clearance rates of the combined use of slightly acidic electrolyzed water treatment and ultraviolet irradiation in ③ for the two odor substances of geosmin and 2-methylisoborneol in water are both higher than those of ④ - ⑤ using other methods (such as plasma-activated water treatment, chloramine solution treatment, etc.) combined with ultraviolet irradiation. This indicates that it is precisely the specific selection of slightly acidic electrolyzed water treatment in the present invention combined with ultraviolet irradiation that enables such excellent clearance effects of geosmin and 2-methylisoborneol.

[0063] Example 2 Clearance Effect of Slightly Acidic Electrolyzed Water with Different Available Chlorine Contents on Geosmin and 2-Methylisoborneol in Water I. Test Method S1. At room temperature (25 ± 5 °C), electrolyze water according to the method in GB28234-2020 Hygienic Requirements for Acidic Electrolyzed Water Generators, and add water, HCl or NaOH to adjust its available chlorine content to 40, 60, 80 mg / L and its pH to 5 to obtain slightly acidic electrolyzed water; S2. Add geosmin and 2-methylisoborneol to the slightly acidic electrolyzed water obtained in S1 so that the final concentration of geosmin is 2.5 μg / L and the final concentration of 2-methylisoborneol is 2.5 μg / L to obtain slightly acidic electrolyzed water containing odor substances; S3. Irradiate under ultraviolet light at a wavelength of 255 nm for 5 min while magnetically stirring at 1000 r / min; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0064] II. Test Results Measure the contents of geosmin and 2-methylisoborneol in the water at the 0.5, 1, 1.5, 2, and 5 min of magnetic stirring in S3 respectively, and calculate the clearance rates of slightly acidic electrolyzed water with different available chlorine contents for geosmin and 2-methylisoborneol according to "Clearance rate (%) = (Content before treatment - Content after treatment) / Content before treatment × 100%". The results are shown in Table 5.

[0065] Table 5 Odor Substance Clearance Rates

[0066] It can be seen that in the method of the present invention, the combination of treatment with slightly acidic electrolyzed water with different available chlorine contents and ultraviolet irradiation can effectively eliminate geosmin and 2-methylisoborneol in the water, and as the available chlorine content increases, the overall clearance rates of geosmin and 2-methylisoborneol in the water also show an increasing trend.

[0067] Example 3 Scavenging Effect of Slightly Acidic Electrolyzed Water with Different pH on Geosmin and 2-Methylisoborneol in Water I. Test Method S1. At room temperature (25 ± 5 °C), electrolyze water according to the method in GB28234-2020 Hygienic Requirements for Acidic Electrolyzed Water Generators, and add water, HCl or NaOH to adjust its available chlorine content to 80 mg / L and its pH to 5 and 6.5 to obtain slightly acidic electrolyzed water; S2. Add geosmin and 2-methylisoborneol to the slightly acidic electrolyzed water obtained in S1 so that the final concentration of geosmin is 2.5 μg / L and the final concentration of 2-methylisoborneol is 2.5 μg / L to obtain slightly acidic electrolyzed water containing odor substances; S3. Stir magnetically at 1000 r / min and irradiate with ultraviolet light at a wavelength of 255 nm for 5 min; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0068] II. Test Results Measure the contents of geosmin and 2-methylisoborneol in water at the 1.5th, 2nd, and 5th minutes of magnetic stirring in S3 respectively, and calculate the clearance rates of geosmin and 2-methylisoborneol by different pH slightly acidic electrolyzed water according to "Clearance rate (%) = (Content before treatment - Content after treatment) / Content before treatment × 100%". The results are shown in Table 6.

[0069] Table 6 Clearance Rates of Odor Substances

[0070] It can be seen that in the method of the present invention, the combination of slightly acidic electrolyzed water treatment with different pH and ultraviolet irradiation can effectively eliminate geosmin and 2-methylisoborneol in water, and with the decrease of pH, the elimination rates of geosmin and 2-methylisoborneol in water also increase significantly.

[0071] Example 4 Scavenging Effects of Ultraviolet Light with Different Wavelengths on Geosmin and 2-Methylisoborneol in Water I. Test Method S1. At room temperature (25 ± 5 °C), electrolyze water according to the method of GB28234-2020 "Hygiene Requirements for Acidic Electrolyzed Water Generators", and add water, HCl or NaOH to adjust its available chlorine content to 80 mg / L and its pH to 5 to obtain slightly acidic electrolyzed water; S2. Add geosmin and 2-methylisoborneol to the slightly acidic electrolyzed water obtained in S1 so that the final concentration of geosmin is 2.5 μg / L and the final concentration of 2-methylisoborneol is 2.5 μg / L to obtain slightly acidic electrolyzed water containing odor substances; S3. Stir magnetically at 1000 r / min and irradiate with ultraviolet light at wavelengths of 222, 255, and 275 nm for 5 min respectively; wherein, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0072] II. Test Results Measure the contents of geosmin and 2-methylisoborneol in water at the 0.5th, 1st, 1.5th, 2nd, and 5th minutes of magnetic stirring in S3 respectively, and calculate the clearance rates of geosmin and 2-methylisoborneol by ultraviolet light with different wavelengths according to "Clearance rate (%) = (Content before treatment - Content after treatment) / Content before treatment × 100%". The results are shown in Table 7.

[0073] Table 7 Removal rate of odorants

[0074] It can be seen that in the method of the present invention, the combined use of ultraviolet irradiation with a wavelength of 222-275 nm and slightly acidic electrolyzed water treatment can effectively eliminate geosmin and 2-methylisoborneol in water, and as the wavelength of ultraviolet irradiation decreases, the overall removal rates of geosmin and 2-methylisoborneol in water also show an increasing trend.

[0075] Example 5 Removal effect of different substrate concentrations on geosmin and 2-methylisoborneol in water I. Test method S1. At room temperature (25±5 °C), electrolyze water according to the method of GB28234-2020 "Hygienic requirements for acidic electrolyzed water generators", add water, HCl or NaOH to adjust its available chlorine content to 80 mg / L and its pH to 5 to obtain slightly acidic electrolyzed water; S2. Add geosmin and 2-methylisoborneol to the slightly acidic electrolyzed water obtained in S1 to obtain slightly acidic electrolyzed water ①-③ containing odorants; among them, the final concentration of geosmin in ① is 1 μg / L, and the final concentration of 2-methylisoborneol is 5 μg / L; the final concentration of geosmin in ② is 3 μg / L, and the final concentration of 2-methylisoborneol is 15 μg / L; the final concentration of geosmin in ③ is 5 μg / L, and the final concentration of 2-methylisoborneol is 25 μg / L; S3. While magnetically stirring at 1000 r / min, irradiate under ultraviolet light with a wavelength of 222 nm for 5 min; among them, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 。

[0076] II. Test results Measure the contents of geosmin and 2-methylisoborneol in water at the 0.5th, 1st, 1.5th, 2nd, and 5th minutes of magnetic stirring in S3 respectively, and calculate the removal rates of different substrate concentrations on geosmin and 2-methylisoborneol according to "Removal rate (%) = (content before treatment - content after treatment) / content before treatment × 100%". The results are shown in Table 8.

[0077] Table 8 Removal rate of odorants

[0078] It can be seen that the present invention combines slightly acidic electrolyzed water treatment with ultraviolet irradiation, which can effectively eliminate geosmin and 2-methylisoborneol at different concentrations in water, and as the substrate concentration decreases, the overall removal rate also shows an increasing trend.

[0079] Example 6 Scavenging Effects of the Combined Use of Slightly Acidic Electrolyzed Water Treatment and Ultraviolet Irradiation on Geosmin and 2-Methylisoborneol in Fish I. Test Method S1. Sudden death of live tilapia (1.50 ± 0.31 kg) purchased from Huguang Market with crushed ice, take the back fish meat of tilapia, cut it into fish slices with a thickness of 3.5 mm, and set aside; S2. Dissolve geosmin in distilled water to obtain immersion liquid 1 with a final concentration of 5 ng / mL; dissolve 2-methylisoborneol in distilled water to obtain immersion liquid 2 with a final concentration of 25 ng / mL; S3. Immerse 150 g of fish slices in 500 mL of immersion liquid 1 for 1 h, then take them out and drain to obtain fish slices containing 0.40 μg / kg of geosmin; immerse 150 g of fish slices in 500 mL of immersion liquid 2 for 1 h, then take them out and drain to obtain fish slices containing 4.19 μg / kg of 2-methylisoborneol; S4. At room temperature (25 ± 5 °C), electrolyze water according to the method of GB28234-2020 Hygienic Requirements for Acidic Electrolyzed Water Generators, and add water, HCl or NaOH to adjust its available chlorine content to 80 mg / L and its pH to 5 to obtain slightly acidic electrolyzed water; S5. Immerse 25 g of fish slices containing odor substances in 1.5 L of slightly acidic electrolyzed water, and irradiate them with ultraviolet light at a wavelength of 222 nm while magnetically stirring at 1000 r / min for 7 min; among them, the irradiation intensity of the ultraviolet light is 3 mW / cm 2 .

[0080] II. Test Results Measure the contents of geosmin and 2-methylisoborneol in the fish meat at the 0.5, 1, 1.5, 2, 3, 5, and 7 min of magnetic stirring in S5 respectively, and calculate their scavenging rates for geosmin and 2-methylisoborneol according to "Scavenging rate (%) = (Content before treatment - Content after treatment) / Content before treatment × 100%". The results are shown in Table 9.

[0081] Table 9 Scavenging Rates of Odor Substances

[0082] It can be seen that the combined use of slightly acidic electrolyzed water treatment and ultraviolet irradiation in the present invention can effectively eliminate geosmin and 2-methylisoborneol in fish meat.

[0083] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for removing odorous substances in water, characterized in that: The water containing odorous substances is prepared into slightly acidic electrolyzed water containing odorous substances, and then irradiated with ultraviolet rays with a wavelength of 222 to 275 nm; wherein the odorous substances include geosmin and / or 2-methylisoborneol.

2. The method according to claim 1, characterized in that The concentration of the geosmin in water is below 5 μg / L.

3. The method according to claim 1, characterized in that The concentration of 2-methylisoborneol in water is below 25 μg / L.

4. A method for removing odor substances from aquatic organisms, characterized in that: Aquatic organisms containing odorous substances are immersed in slightly acidic electrolyzed water and then irradiated with ultraviolet rays with a wavelength of 222 to 275 nm; wherein the odorous substances include geosmin and / or 2-methylisoborneol.

5. The method according to claim 4, characterized in that The content of the geosmin in aquatic organisms is less than 0.40 μg / kg.

6. The method according to claim 4, characterized in that: The content of 2-methylisoborneol in aquatic organisms is less than 4.19 μg / kg.

7. The method according to claim 4, characterized in that The usage ratio of the aquatic organism to the slightly acidic electrolyzed water is 23-27 g:1.5 L.

8. The method according to claim 4, characterized in that: The aquatic organisms are fish and / or shellfish.

9. The method according to claim 8, characterized in that: The fish is a freshwater fish.

10. The method according to claim 8, characterized in that: The shellfish are freshwater shellfish.

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