Deiodination method of iodine-containing aqueous solution

Abstract

The invention relates to the technical field of iodinated organic matter deiodination, in particular to a deiodination method of an iodine-containing aqueous solution. According to the method, efficient deiodination of iodinated organic matters such as iopamidol and iodinated phenol in the iodine-containing aqueous solution is promoted through radiation illumination treatment of a 222nm ultraviolet lamp. In addition, it is found that by prolonging the illumination time, enhancing the illumination intensity or increasing the pH value of the buffer solution, the deiodination reaction is obviously promoted. The deiodination method provided by the invention is convenient to operate, does not need to add chemical reagents, is harmless to the health of a user, and is an economical, efficient and green deiodination method.

Description

Technical Field

[0001] The invention relates to the technical field of deiodination of iodinated organic matter, in particular to a deiodination method of an iodine-containing aqueous solution. Background Art

[0002] Iodinated organic compounds (I-OCs) have attracted widespread attention in the environmental field due to their high chemical stability and significant bioaccumulation. Especially in the process of drinking water disinfection, I-OCs can easily act as organic precursors to induce the production of highly toxic iodinated disinfection byproducts (I-DBPs), further highlighting the importance of studying I-OC treatment technology. The fundamental reason why halogenated organic compounds are toxic is the presence of halogen atoms as highly toxic groups. Therefore, removing halogen atoms from compounds is an effective way to reduce the toxicity of halogenated organic compounds. For I-OCs, deiodination technology has become a key means to control their pollution.

[0003] At present, the mainstream deiodination technologies mainly include chemical reduction, ultraviolet photolysis (254nm) and electrochemical oxidation. Chemical reduction deiodination technology mainly uses reducing agents (such as iron powder, sulfide, zero-valent metal, etc.) in an oxygen-deficient environment to remove iodine atoms in I-OCs into iodide ions or further convert them into volatile iodine to achieve iodine removal. However, this technology has obvious defects. On the one hand, secondary pollution is easily generated during the reaction process. For example, when iron powder is used as a reducing agent, Fe 2+ / Fe 3+ complexes; on the other hand, the reaction conditions are harsh and the environmental parameters (dissolved oxygen, pH, etc.) are high, which limits its promotion in practical applications. Based on the 254nm ultraviolet irradiation technology emitted by a low-pressure mercury lamp, its deiodination principle is mainly through direct photolysis of CI bonds or excitation of free radicals (such as ·OH) to achieve deiodination. However, this technology has many problems. First, the light absorption efficiency is low, resulting in limited degradation effect on I-OCs; second, low-pressure mercury lamps have the risk of mercury leakage, posing a potential threat to the environment and human health. In addition, in high-concentration or complex matrix environments, the deiodination rate of this technology is difficult to meet actual needs. Electrochemical oxidation technology degrades I-OCs through anodic oxidation, but is limited by the life of the electrode material (such as the easy wear of boron-doped diamond electrodes), high energy consumption (high current density requirements) and poor selectivity. More importantly, during the electrochemical oxidation process, chloride ions in the solution may react at the anode to generate toxic Cl2 or HClO, further exacerbating the environmental risk.

[0004] In summary, chemical reduction technology requires an anaerobic environment and is prone to secondary pollution and high energy consumption. 254nm ultraviolet photolysis technology is limited by low light absorption efficiency, and the photon energy is insufficient to directly break the CI bond. Electrochemical oxidation technology causes electrode loss and carries the risk of chloride ion interference. Existing deiodination technologies generally have core defects such as high risk of secondary pollution, high energy consumption, or limited applicability. Therefore, the development of a new deiodination process that does not require chemical reagents, has low energy consumption, and is environmentally friendly has important practical significance and application value. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a deiodine method based on 222nm far ultraviolet irradiation, which can effectively deiodine.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for deiodination of an iodine-containing aqueous solution, comprising the following steps:

[0008] (1) adding an iodine-containing aqueous solution into a buffer solution to obtain a mixed aqueous solution;

[0009] (2) The mixed aqueous solution is placed under a 222 nm ultraviolet lamp for reaction for 30-90 minutes to obtain a deiodinated mixed aqueous solution.

[0010] The invention provides a deiodine method based on 222nm far ultraviolet radiation.

[0011] After extensive research, the present invention found that compared with traditional ultraviolet photolysis technology, deiodination by relying on 222nm far ultraviolet radiation light treatment has a better deiodination effect.

[0012] The main technical problem solved by the present invention is to provide a method that mainly relies on high energy, the photon energy at a wavelength of 222nm (539kJ Einstein -1 ) is higher than the average bond dissociation energy (BDE) of almost all single bonds (except HF bonds) and many double bonds (e.g., O=O bonds and N=N bonds), and is minimally harmful to the human body. Irradiating an iodine-containing aqueous solution with 222nm far-ultraviolet light can destroy the CI bonds of iodinated organic compounds, achieving efficient deiodination. The present invention is simple to operate and does not require the addition of chemical reagents, making it an economical, efficient, and environmentally friendly deiodination method.

[0013] Preferably, the buffer comprises an acidic buffer, a neutral buffer or an alkaline buffer.

[0014] The present invention adds buffer solutions of different pH values, which can adjust the pH of the reaction on the one hand, and stabilize the reaction system on the other hand, so that the reaction proceeds smoothly.

[0015] Preferably, the buffer comprises at least one of an acetate buffer, a sodium dihydrogen phosphate buffer, and a sodium tetraborate buffer.

[0016] Preferably, the pH value of the buffer solution is 4-10.

[0017] More preferably, the pH value of the buffer solution is 7-10.

[0018] The present invention has found in research that as the pH value of the buffer solution increases, the deiodination effect can be further promoted.

[0019] Preferably, the iodine-containing aqueous solution is an aqueous solution containing iodinated organic matter; the concentration of the iodinated organic matter contained in the mixed aqueous solution in step (1) is 0.5-2 μmol / L.

[0020] Preferably, the iodinated organic compound includes at least one of iopamidol, 2-iodophenol, and 4-iodophenol.

[0021] Preferably, the light intensity of the ultraviolet lamp is 185.36-363.46uW / cm 2 .

[0022] More preferably, the light intensity of the ultraviolet lamp is 225.35-363.46 uW / cm 2 .

[0023] Preferably, in step (2), the reaction time is 60-90 min.

[0024] The present invention has found in research that extending the illumination time or increasing the illumination intensity both have a significant promoting effect on the deiodination reaction.

[0025] The present invention is beneficial in that:

[0026] The present invention is treated with 222nm ultraviolet light radiation, which promotes the efficient deiodination of iodinated organic compounds such as iopamidol and iodophenol in iodine-containing aqueous solution. In addition, the present invention finds that by extending the light exposure time, enhancing the light intensity or increasing the pH value of the buffer solution, the deiodination reaction is significantly promoted. The deiodination method provided by the present invention is easy to operate, does not need to add chemical reagents, and has no health hazards to users. It is an economical, efficient and green deiodination method. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The schematic diagram of the present invention is a method for deiodination by irradiation with a 222nm ultraviolet lamp. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0029] In the examples of the present invention, the iodinated organic compounds used are iopamidol (IPM), 2-iodophenol (2-Iodophenol, 2-IP), and 4-iodophenol (4-Iodophenol, 4-IP), all of which were purchased from Aladdin.

[0030] Before use, prepare the powder of each iodinated organic compound into an iodine-containing aqueous solution before proceeding with the following operations:

[0031] Dissolve IPM powder in deionized water to prepare an IPM aqueous solution with a concentration of 0.501 mmol / L. Dissolve 2-IP powder in deionized water to prepare an 2-IP aqueous solution with a concentration of 1.49 mmol / L. Dissolve 4-IP powder in deionized water to prepare an 4-IP aqueous solution with a concentration of 0.352 mmol / L.

[0032] Example 1:

[0033] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0034] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0035] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 30-90 min to obtain a deiodinated mixed aqueous solution.

[0036] Example 2:

[0037] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0038] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 1.5 μmol / L;

[0039] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0040] Example 3:

[0041] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0042] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 1.0 μmol / L;

[0043] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0044] Example 4:

[0045] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0046] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 0.5 μmol / L;

[0047] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0048] Example 5:

[0049] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0050] (1) A certain amount of IPM aqueous solution was added to a glass container containing acetic acid buffer (2 mmol / L acetic acid) at pH = 4.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0051] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0052] Example 6:

[0053] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0054] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH 5.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0055] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0056] Example 7:

[0057] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0058] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH 6.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0059] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0060] Example 8:

[0061] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0062] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium tetraborate buffer (2 mmol / L sodium tetraborate) at pH = 8.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0063] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0064] Example 9:

[0065] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0066] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium tetraborate buffer (2 mmol / L sodium tetraborate) at pH = 9.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0067] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0068] Example 10:

[0069] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0070] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium tetraborate buffer (2 mmol / L sodium tetraborate) at pH = 10.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0071] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0072] Example 11:

[0073] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0074] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0075] (2) The obtained mixed aqueous solution was placed under a light intensity of 225.35 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0076] Example 12:

[0077] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0078] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0079] (2) The obtained mixed aqueous solution was placed under a light intensity of 185.36 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0080] Example 13:

[0081] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0082] (1) A certain amount of 2-IP aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of 2-IP in the mixed aqueous solution was 2 μmol / L;

[0083] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0084] Example 14:

[0085] An embodiment of the method for deiodination of an iodine-containing aqueous solution of the present invention comprises the following steps:

[0086] (1) A certain amount of 4-IP aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH 7.0 to obtain a mixed aqueous solution such that the concentration of 4-IP in the mixed aqueous solution was 2 μmol / L;

[0087] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 222 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0088] Comparative Example 1:

[0089] A comparative example of the deiodination method of the iodine-containing aqueous solution of the present invention comprises the following steps:

[0090] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0091] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction was carried out under a 222 nm ultraviolet lamp for 15 min to obtain a deiodinated mixed aqueous solution.

[0092] Comparative Example 2:

[0093] A comparative example of the deiodination method of the iodine-containing aqueous solution of the present invention comprises the following steps:

[0094] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0095] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 254 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0096] Comparative Example 3:

[0097] A comparative example of the deiodination method of the iodine-containing aqueous solution of the present invention comprises the following steps:

[0098] (1) A certain amount of IPM aqueous solution was added to a glass container containing sodium dihydrogen phosphate buffer (2 mmol / L sodium dihydrogen phosphate) at pH = 7.0 to obtain a mixed aqueous solution such that the concentration of IPM in the mixed aqueous solution was 2 μmol / L;

[0099] (2) The obtained mixed aqueous solution was placed under a light intensity of 363.46 uW / cm 2 The reaction is carried out under a 365 nm ultraviolet lamp for 60-90 min to obtain a deiodinated mixed aqueous solution.

[0100] Test Example 1:

[0101] 1. Take the mixed aqueous solution of Example 1 step (2) at 30, 45, 60, 75, and 90 min of reaction, and the mixed aqueous solution of Comparative Example 1 step (2) at 15 min of reaction as test samples, respectively, and measure the concentration of residual iodinated organic matter in the aqueous solution by high performance liquid chromatography, and measure the concentration of iodide ions released in the aqueous solution by ion chromatography. The iodinated organic matter removal rate is calculated according to formula (1), and the deiodination rate is calculated according to formula (2).

[0102] Iodine organic matter removal rate (%) = (C t -C0) / C0×100%——Formula (1)

[0103] In the above formula, C t =I represents the concentration of IPM after treatment, and C0 represents the initial concentration of IPM before treatment. Deiodination rate (%) = (iodine ion concentration after treatment) / (iodine organic matter concentration before reaction - iodine organic matter concentration after reaction) × 100% - Formula (2)

[0104] In the above formula, when the iodinated organic matter is IPM, the iodide ion concentration after treatment needs to be divided by 3.

[0105] The test results are shown in Table 1.

[0106] Table 1

[0107]

[0108]

[0109] The above table shows that extending the light reaction time has a significant promoting effect on the deiodination reaction, especially when the reaction time reaches more than 60 minutes, the IPM removal rate in the aqueous solution reaches more than 98% and the deiodination rate exceeds 80%.

[0110] 2. The mixed aqueous solutions of Example 1-14 and Comparative Example 2-3, respectively, after 60 and 90 min of reaction, were used as test samples. The concentration of the remaining iodinated organic matter in the aqueous solution was determined by high performance liquid chromatography, and the concentration of the released iodide ions in the aqueous solution was determined by ion chromatography. The iodinated organic matter removal rate was calculated according to formula (1), and the deiodination rate was calculated according to formula (2). The test results are shown in Tables 2 and 3.

[0111] Table 2

[0112]

[0113]

[0114] Table 3

[0115]

[0116]

[0117] The test results of Examples 1-14 show that the deiodination method provided by the present invention can effectively remove iodine-containing organic matter from iodine-containing aqueous solution. Figure 1 shown.

[0118] Compared with the test results of Examples 5-10, the present invention found that alkaline buffer (alkaline environment) is more conducive to efficient deiodination.

[0119] Comparing the test results of Examples 1, 11, and 12, the present invention found that increasing the light intensity has a significant promoting effect on the deiodination reaction.

[0120] Comparing the test results of Example 1 and Comparative Examples 2-3, the present invention found that compared with other wavelengths, the deiodination treatment based on 222nm far ultraviolet irradiation light treatment has a significantly better deiodination effect.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for deiodination of an iodine-containing aqueous solution, characterized in that: The steps include: (1) adding an iodine-containing aqueous solution into a buffer solution to obtain a mixed aqueous solution; (2) The mixed aqueous solution is placed under a 222 nm ultraviolet lamp for reaction for 30-90 minutes to obtain a deiodinated mixed aqueous solution.

2. The deiodination method of an iodine-containing aqueous solution as claimed in claim 1, wherein The buffer includes an acidic buffer, a neutral buffer or an alkaline buffer.

3. The deiodination method of iodine-containing aqueous solution as claimed in claim 1, wherein The buffer comprises at least one of an acetate buffer, a sodium dihydrogen phosphate buffer, and a sodium tetraborate buffer.

4. The deiodination method of iodine-containing aqueous solution as claimed in claim 2, wherein The pH value of the buffer solution is 4-10.

5. The deiodination method of iodine-containing aqueous solution as claimed in claim 4, wherein The pH value of the buffer solution is 7-10.

6. The deiodination method of an iodine-containing aqueous solution as claimed in claim 1, wherein The iodine-containing aqueous solution is an aqueous solution containing iodinated organic matter; the concentration of the iodinated organic matter contained in the mixed aqueous solution in step (1) is 0.5-2 μmol / L.

7. The deiodination method of an iodine-containing aqueous solution as claimed in claim 6, wherein: The iodinated organic compound includes at least one of iopamidol, 2-iodophenol, and 4-iodophenol.

8. The deiodination method of an iodine-containing aqueous solution as claimed in claim 1, wherein The light intensity of the ultraviolet lamp is 185.36-363.46uW / cm 2 .

9. The deiodination method of an iodine-containing aqueous solution as claimed in claim 8, wherein The light intensity of the ultraviolet lamp is 225.35-363.46uW / cm 2 .

10. The deiodination method of an iodine-containing aqueous solution according to claim 8, wherein In the step (2), the reaction time is 60-90 min.

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