阅读说明：本技术 利用高铁酸盐将碘离子氧化成碘酸盐并控制水中碘代消毒副产物生成的方法 (Method for oxidizing iodide ions into iodate by using ferrate and controlling generation of iodo-disinfection byproducts in water ) 是由 马军 张婧 王宪实 刘玉蕾 王鲁 于 2019-11-08 设计创作，主要内容包括：利用高铁酸盐将碘离子氧化成碘酸盐并控制水中碘代消毒副产物生成的方法,本发明涉及水处理方法领域。本发明要解决现有水体中存在碘离子和天然有机物,在传统消毒方式处理下,导致碘代消毒副产物生成的问题。方法：将高铁酸盐投加到含有碘离子的水源中,进行氧化反应,完成该方法。本发明将高铁酸钾作为强氧化剂,将水中的碘离子迅速氧化为次碘酸,次碘酸浓度在系统中积累到最大值时,次碘酸逐渐被高铁酸钾氧化变成碘酸盐使其浓度降低,减小了次碘酸与有机物反应生成碘代消毒副产物的可能。高铁酸钾浓度的增加会促进碘离子和次碘酸向碘酸盐的转化,碘代消毒副产物生成量少,适合大规模应用。本发明方法用于对含碘离子水源的处理。(The invention discloses a method for oxidizing iodide ions into iodate by using ferrate and controlling generation of iodo-disinfection byproducts in water, and relates to the field of water treatment methods. The invention aims to solve the problem that iodine disinfection byproducts are generated due to the fact that iodide ions and natural organic matters exist in the existing water body and are treated in a traditional disinfection mode. The method comprises the following steps: ferrate is added to a water source containing iodide ions for oxidation to complete the process. The invention takes potassium ferrate as a strong oxidant to rapidly oxidize iodide ions in water into hypoiodic acid, when the concentration of the hypoiodic acid is accumulated to the maximum value in a system, the hypoiodic acid is gradually oxidized by the potassium ferrate to become iodate so as to reduce the concentration of the hypoiodic acid, and the possibility that the hypoiodic acid reacts with organic matters to generate iodo disinfection byproducts is reduced. The increase of the concentration of the potassium ferrate can promote the conversion of iodide ions and hypoiodic acid into iodate, and the generation amount of iodo-disinfection byproducts is small, so that the potassium ferrate is suitable for large-scale application. The method is used for treating the water source containing the iodine ions.)

1. The method for oxidizing iodide ions into iodate and controlling the generation of iodo-disinfection byproducts in water by using ferrate is characterized by comprising the following steps of:

ferrate is added to a water source containing iodide ions for oxidation to complete the process.

2. The method of claim 1 wherein the ferrate is potassium ferrate, and oxidizing iodide to an iodate and controlling the formation of iodo-disinfectant byproducts in the water is performed using ferrate.

3. The method for oxidizing iodide ions into iodate and controlling generation of iodo-disinfection byproducts in water by using ferrate according to claim 1, wherein the concentration of ferrate in a water source is 30-100 μmol/L after ferrate is added.

4. The method of using ferrate to oxidize iodide ions to iodate and control the formation of iodo disinfection byproducts in water as claimed in claim 1, wherein the concentration of humic acid in the water source containing iodide ions is 5 mg/L.

5. The method of claim 1, wherein the pH of the aqueous source containing iodide ions is controlled to be between 5 and 10.5 prior to the addition of ferrate.

6. The method of claim 1, wherein the ferrate is used to pre-oxidize a water source containing iodide ions, and the molar concentration of ferrate in the water source is controlled to be greater than 3 times the molar concentration of iodide ions after the ferrate is added.

7. The method of claim 6, wherein the oxidation of iodide to iodate using ferrate and the control of the formation of iodo disinfection byproducts in water is further characterized by adding liquid chlorine to the ferrate after the oxidation reaction, and chlorinating for 24 hours, wherein the concentration of liquid chlorine in the water source is 2mg/L after the addition of liquid chlorine.

8. The method of claim 6, wherein the ferrate oxidation reaction is followed by chloramine, chloramination is performed for 24 hours, and the concentration of chloramine in the water source is 2mg/L after the chloramine is added.

Technical Field

The invention relates to the field of water treatment methods.

Background

A large number of animal experiments show that trihalomethanes are teratogenic, carcinogenic and mutagenic. If the trihalomethane reaches a certain concentration in the animal, intestinal, renal and liver tumors may result. Whereas, among the halogenated disinfection byproducts, iodo disinfection byproducts (I-DBPs) exhibit greater toxicity than the chloro-bromo disinfection byproducts. The iodo product is mainly produced during the disinfection process: in the process of disinfecting iodine-containing water, iodine ions are oxidized into hypoiodic acid with certain oxidizing capacity by disinfectants such as chlorine, chloramine and the like. Hypoiodic acid can be converted by three pathways: the first is to oxidize hypoiodic acid into non-toxic iodate by continuous oxidation of disinfectant; the second is that the hypoiodic acid is decomposed into non-toxic and harmless iodide ions and iodate through the self-disproportionation reaction of the hypoiodic acid; the third one is oxidized or substituted with humic acid, fulvic acid and other natural organic matters to produce iodine as side product. The selection of chloramine as a disinfectant may produce more iodine by-product than liquid chlorine disinfection. This is because oxidation of hypoiodic acid to iodate by chloramine is very slow, resulting in a large accumulation of hypoiodic acid in the water, and the natural organic substances present in the water interact with hypochlorous acid at a much faster rate than the reaction rate of hypoiodic acid with chloramine, so that hypoiodic acid tends to react with the naturally occurring organic substances in the water to form iodo disinfection by-products. Some city raw water in China has poor water quality and high organic matter content, but liquid chlorine is often used as a disinfectant of drinking water, so that the damage of iodine disinfection byproducts in the drinking water to human health cannot be ignored. Iodine ions are common substances in natural water, and with the continuous improvement of living standard and medical standard of people, more iodine-containing organic matters enter the natural water to become iodine sources and generate iodine disinfection byproducts.

Disclosure of Invention

The invention aims to solve the problem that iodine disinfection byproducts are generated due to iodine ions and natural organic matters in the existing water body under the treatment of the traditional disinfection mode, and provides a method for oxidizing the iodine ions into iodate by using ferrate and controlling the generation of the iodine disinfection byproducts in water

The method for oxidizing iodide ions into iodate by using ferrate and controlling generation of iodo-disinfection byproducts in water specifically comprises the following steps:

ferrate is added to a water source containing iodide ions for oxidation to complete the process.

Further, ferrate oxidizes iodide ions in the water source into non-toxic and harmless iodate, thereby controlling the production of iodine disinfection byproducts in the water.

Further, the ferrate is utilized to carry out pre-oxidation treatment on the water source containing the iodide ions, and after the ferrate is controlled to be added, the concentration of the ferrate in the water source is more than 3 times of that of the iodide ions.

Further, after ferrate oxidation reaction, adding liquid chlorine, and chlorinating for 24h, wherein the concentration of the liquid chlorine in the water source is 2mg/L after the liquid chlorine is added.

Further, after ferrate oxidation reaction, chloramine is added, chloramine is aminated for 24h, and after the chloramine is added, the concentration of the chloramine in the water source is 2 mg/L.

The invention has the beneficial effects that:

the ferrate is a green oxidant, has strong oxidizability in a wide pH range, has selectivity in oxidation, and is easy to oxidize compounds containing rich electron groups, such as phenols, amines, olefins and nitrogen and sulfur-containing compounds. The ferrate final reduction product is ferric iron, further hydrolysis has a certain coagulation effect, and is removed in the stages of coagulation, precipitation and filtration, and the ferrate final reduction product is environment-friendly, non-toxic and harmless after being discharged. Under the neutral condition, the rate constant of the reaction of the potassium ferrate and the hypoiodic acid is about 10 times of that of the reaction of the potassium ferrate and the iodine ions, which is far higher than that of other common oxidants in water treatment, and this shows that the iodine ions can be further quickly oxidized into non-toxic and harmless iodate by the potassium ferrate after being oxidized into the hypoiodic acid by the potassium ferrate, so that the hypoiodic acid cannot be accumulated in a system, and harmful iodo disinfection byproducts generated by the reaction of the hypoiodic acid and natural organic matters in a water body are avoided.

The invention takes potassium ferrate as a strong oxidant, can rapidly oxidize iodide ions in water into hypoiodic acid, when the concentration of the hypoiodic acid is accumulated to the maximum value in a system, the hypoiodic acid is gradually oxidized by the potassium ferrate to become iodate so that the concentration of the hypoiodic acid is reduced, and the possibility that the hypoiodic acid reacts with organic matters to generate iodo disinfection byproducts is greatly reduced. The increase of the concentration of the potassium ferrate can promote the conversion of iodide ions and hypoiodic acid into iodate, and the generation amount of iodo-disinfection byproducts is small, so that the potassium ferrate is suitable for large-scale application.

The method for controlling the generation of the iodo-disinfection byproducts in water by using potassium ferrate to oxidize the iodo ions ensures that when the molar concentration of potassium ferrate added into the water is more than 3 times of the molar concentration of the iodo ions in the water, the potassium ferrate can completely oxidize the iodo ions into iodate, so that no iodo-byproducts are generated. The iodoform is selected as a representative substance of the iodo-byproducts, no iodoform is generated when the molar concentration of potassium ferrate is 0.5, 2 and 4 times of that of the iodide ions in the water body, and the iodide ions are oxidized into iodate, so that iodine cannot be oxidized into hypoiodic acid in the subsequent chlorine/chloramine disinfection process, and the risk of generating the iodo-disinfection byproducts in the subsequent disinfection process can be greatly reduced when the potassium ferrate oxidation system is used for treating the iodine-containing water body.

The method is used for treating the water source containing the iodide ions, the iodide ions are oxidized into iodate, and the generation of iodide disinfection byproducts in water is controlled.

Detailed Description

The technical solution of the present invention is not limited to the specific embodiments listed below, and includes any combination of the specific embodiments.