In-situ iodine-producing water purification material, water purification method, and water purification material regeneration method

Abstract

This invention discloses an in-situ iodine-generating water purification material, a water purification method, and a method for regenerating the water purification material, solving the technical problems of poor storage stability of elemental iodine, uncontrollable addition, and potential secondary pollution in existing technologies. The in-situ iodine-generating water purification material includes a catalyst and an oxidant, which undergo a catalytic oxidation reaction in organic wastewater to generate elemental iodine; wherein the catalyst includes a metal oxyiodide generated by a solvothermal reaction of a soluble bismuth salt and a soluble alkali metal iodide. The water purification method includes the steps of adding the catalyst and oxidant from the aforementioned in-situ iodine-generating water purification material to the organic wastewater. The method for regenerating the aforementioned in-situ iodine-generating water purification material includes the steps of adding the deactivated water purification material to an iodide solution, reacting for a period of time, and then collecting the solid to obtain the regenerated catalyst.

Description

Technical Field

[0001] This invention relates to the technical field of water purification materials and water treatment, and more specifically, to an in-situ iodine-producing water purification material, a water purification method, and a method for regenerating the water purification material. Background Technology

[0002] With the continuous advancement of industrialization, the discharge of industrial wastewater containing recalcitrant organic pollutants continues to increase. These pollutants are typically complex in composition, highly toxic, and persistent in the environment, making them difficult to remove effectively using traditional biological methods. Once discharged into water bodies, they can adversely affect aquatic ecosystems and human health. Iodine-based water purification technologies have attracted widespread attention due to their rapid reaction rate and wide applicability. Elemental iodine, as a mild oxidant, can selectively oxidize organic pollutants and effectively kill pathogenic microorganisms in water, making it widely used in advanced drinking water treatment, medical and emergency water supply disinfection, and decentralized or small-scale water supply systems.

[0003] Currently, the main method of applying iodine in water treatment relies on the direct addition of exogenous elemental iodine. However, this application model has significant limitations in actual operation: Firstly, elemental iodine has low solubility in water and is easily volatile and decomposes easily in light, resulting in poor stability of its aqueous solution and difficulty in maintaining the effective components over a long period, thus affecting its continuous water purification effect. Although some studies have introduced organic substances such as carboxylic acids and alcohols to react with iodine and form a dynamic equilibrium between elemental iodine and iodides to maintain the concentration of elemental iodine in the system, its application is still limited by storage conditions and transportation methods. Secondly, the one-time addition of excessive elemental iodine can easily lead to the risk of iodine residue in the water. Although some studies have attempted to load iodine into slow-release materials to delay its release process, it is still difficult to achieve controlled release of iodine, posing a risk of secondary pollution. Summary of the Invention

[0004] The main objective of this invention is to provide in-situ iodine-producing water purification materials, water purification methods, and water purification material regeneration methods to solve the technical problems of poor storage stability of elemental iodine, uncontrollable addition, and potential secondary pollution in the prior art.

[0005] To achieve the above objectives, the technical solutions provided by this invention, including in-situ iodine-producing water purification materials, water purification methods, and water purification material regeneration methods, are as follows:

[0006] An in-situ iodine-producing water purification material includes a catalyst and an oxidant, wherein the catalyst and oxidant undergo a catalytic oxidation reaction in organic wastewater to generate elemental iodine; wherein the catalyst includes a metal oxyiodide generated by a solvothermal reaction of a soluble bismuth salt and a soluble alkali metal iodide.

[0007] As a further improvement to the above-mentioned in-situ iodine-producing water purification material, the preparation method of the metal oxyiodide includes the following steps:

[0008] Prepare a mixed solution of soluble bismuth salt and soluble alkali metal iodide;

[0009] The mixed solution was placed in a high-pressure reactor for solvothermal treatment to obtain a solid-liquid mixture.

[0010] The solid in the solid-liquid mixture is collected, washed, and dried to obtain the metal oxyiodide.

[0011] As a further improvement to the above-mentioned in-situ iodine-producing water purification material: the soluble alkali metal iodide is sodium iodide and / or potassium iodide; the concentration of soluble bismuth salt in the mixed solution is 0.5-1.5 mol / L, the molar ratio of soluble bismuth salt to soluble alkali metal iodide is (0.5-1.5):1, and the solvent used in the mixed solution is at least one of ethanol, ethylene glycol or deionized water.

[0012] As a further improvement to the above-mentioned in-situ iodine-producing water purification material: the temperature of the solvent heat treatment is 150-170℃, and the duration is 1-3 hours.

[0013] As a further improvement to the above-mentioned in-situ iodine-producing water purification material: the oxidant is at least one of hydrogen peroxide, persulfate, or peracetic acid.

[0014] The water purification method includes the steps of adding the catalyst and oxidant from the above-mentioned in-situ iodine-producing water purification material to the organic wastewater.

[0015] As a further improvement to the above water purification method: the dosage of catalyst is 0.1-0.6 g / L; the dosage of oxidant is 1-3 mmol / L.

[0016] As a further improvement to the above-mentioned water purification method: the organic wastewater contains p-chlorophenol.

[0017] The above-mentioned in-situ iodine-producing water purification material regeneration method includes the following steps: adding the deactivated water purification material into an iodide solution, reacting for a period of time, and then collecting the solid to obtain the regenerated catalyst.

[0018] As a further improvement to the above regeneration method: the solid-liquid ratio of the deactivated water purification material to the iodide solution is 1 g:(200-400 mL), and the concentration of the iodide solution is 1-3 g / L; the iodide solution has the same metal element as the soluble alkali metal iodide used to prepare the metal oxy iodide.

[0019] The advantages of the in-situ iodine-producing water purification material, water purification method, and water purification material regeneration method of the present invention include:

[0020] (1) This invention breaks through the bottleneck of traditional iodine storage, transportation and addition, and has high safety: The in-situ iodine-producing water purification material of this invention uses metal oxyiodide as catalyst and peroxide as oxidant to generate iodine in-situ in organic wastewater through catalytic oxidation reaction, and uses the generated iodine to treat recalcitrant organic wastewater; Compared with the method of directly adding iodine, this invention can effectively avoid the safety hazards and environmental risks brought about by iodine in the storage and transportation process.

[0021] (2) The present invention constructs a unique “lattice iodine release-targeted repair” cycle system, realizing the controllable release of iodine and the ultra-long-term use of materials: In the in-situ iodine-producing water purification material of the present invention, metal oxyiodides can be used as catalyst carriers to construct an iodine cycle system, realizing the continuous generation and on-demand release of elemental iodine in the reaction system, effectively avoiding the environmental risk of excessive addition of elemental iodine, and reducing the possibility of secondary pollution caused by iodine residue.

[0022] (3) The present invention has high degradation efficiency and excellent removal performance for recalcitrant organic matter: the in-situ iodine-producing water purification material of the present invention generates iodine in organic wastewater in situ, which can quickly react with the target pollutants, realize efficient, stable and sustainable treatment of recalcitrant organic wastewater, and has broad industrial application prospects.

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their related descriptions can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 The image shows the XRD pattern of the metal oxyiodide in the in-situ iodine-producing water purification material of this embodiment.

[0026] Figure 2 The images show the UV-Vis absorption spectra of the in-situ iodine-producing water purification material in this embodiment reacting in pure water for different durations.

[0027] Figure 3 This is a curve showing the change in the concentration of elemental iodine generated in pure water by the in-situ iodine-producing water purification material in this embodiment over time.

[0028] Figure 4 The curve showing the change of p-chlorophenol concentration over time in the reaction system of the in-situ iodine-producing water purification material and organic wastewater in this embodiment is shown.

[0029] Figure 5This is a schematic diagram of the device for evaluating the recycling effect of the in-situ iodine-producing water purification material in this embodiment.

[0030] Figure 6 This diagram illustrates the recycling effect of the in-situ iodine-producing water purification material in this embodiment.

[0031] The relevant markings in the above figures are:

[0032] 100 - First container, 200 - Second container, 300 - First valve, 400 - Second valve, 500 - Pump, 600 - Reaction column, 700 - Adsorption column, 800 - Concentration detector. Detailed Implementation

[0033] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0034] The technical solutions and features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0035] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0036] Regarding the terminology and units used in this invention: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0037] A preferred embodiment of the in-situ iodine-producing water purification material of the present invention comprises a catalyst and an oxidant, wherein the catalyst and oxidant react in organic wastewater to generate elemental iodine. The catalyst is a metal oxyiodide generated by a solvothermal reaction of a soluble bismuth salt and a soluble alkali metal iodide. The oxidant is hydrogen peroxide.

[0038] The preparation method of the metal oxy iodide includes the following steps:

[0039] (1) Bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and potassium iodide (KI) were dispersed in ethylene glycol and stirred at 25 °C for 60 minutes to obtain a homogeneous mixed solution; the concentration of bismuth nitrate in the mixed solution was 1 mol / L and the molar ratio of bismuth nitrate to potassium iodide was 1:1.

[0040] (2) The mixed solution is transferred to a high-pressure reactor lined with polytetrafluoroethylene, and the solvothermal reaction temperature is set to 160 °C and the reaction time is 2 hours. After the solvothermal reaction is completed, a solid-liquid mixture is obtained.

[0041] (3) Collect the solid in the solid-liquid mixture, wash it and dry it at 60 °C for 8 hours to obtain the bismuth iodide catalyst.

[0042] Figure 1 This is the XRD pattern of the metal oxyiodide in the in-situ iodine-producing water purification material of this embodiment. Figure 1 As shown, the characteristic diffraction peaks of the metal oxy iodide all match those of the standard card (BiOI, PDF#73-2062), confirming that the bismuth iodide catalyst was successfully prepared in this embodiment.

[0043] Figure 2 The images show the UV-Vis absorption spectra of the in-situ iodine-producing water purification material in this embodiment reacting in pure water for different durations. Figure 2 As shown, after the addition of catalyst and oxidant, a distinct characteristic absorption peak of elemental iodine appeared at 460 nm, indicating that elemental iodine was generated in situ in the reaction system.

[0044] Figure 3 This is a curve showing the change in the concentration of elemental iodine generated in pure water by the in-situ iodine-producing water purification material in this embodiment over time. Figure 3 As shown, after the addition of catalyst and oxidant, the iodine concentration reached a plateau of approximately 0.08 mmol / L within 2 minutes, proving that the in-situ iodine-producing water purification material of this embodiment can achieve rapid generation of iodine.

[0045] A preferred embodiment of the water purification method of the present invention includes the following steps: adding the in-situ iodine-producing water purification material to organic wastewater containing p-chlorophenol, wherein the dosage of the catalyst is 0.3 g / L and the dosage of the oxidant is 2 mmol / L, thereby initiating a catalytic oxidation reaction to generate elemental iodine in situ in the reaction system for the degradation of p-chlorophenol in the wastewater.

[0046] Figure 4 This is a curve showing the change in p-chlorophenol concentration over time in the reaction system of the in-situ iodine-producing water purification material and organic wastewater in this embodiment. Figure 4 As shown, when a catalyst and oxidant were added to a beaker containing a p-chlorophenol solution (initial concentration C0 = 0.05 mmol / L), the p-chlorophenol concentration C was not detected after 20 minutes of reaction, indicating that the in-situ iodine-producing water purification material of this embodiment can completely degrade p-chlorophenol and has a significant purification effect on recalcitrant organic wastewater.

[0047] A preferred embodiment of the in-situ iodine-producing water purification material regeneration method of the present invention includes the following steps: recovering the deactivated water purification material after the reaction, placing it in a potassium iodide solution (i.e., the iodide solution and the soluble alkali metal iodide used to prepare the metal oxy iodide) for regeneration treatment, wherein the solid-liquid ratio of the deactivated water purification material to the potassium iodide solution is 1g:300mL, the concentration of the potassium iodide solution is 2g / L, and the regeneration is carried out by soaking or rinsing at 20-30 °C, so that the iodine sites on the catalyst surface are regenerated, thereby realizing the continuous generation of elemental iodine and obtaining a regenerated catalyst.

[0048] Figure 5 This is a schematic diagram of the device for evaluating the recycling effect of the in-situ iodine-producing water purification material in this embodiment. Figure 5 As shown, the evaluation device includes a first container 100, a second container 200, a first valve 300, a second valve 400, a pump 500, a reaction column 600, an adsorption column 700, and a concentration detector 800. The first container 100 stores a p-chlorophenol solution (concentration denoted as C0) and an oxidant. The second container 200 stores a potassium iodide solution. The reaction column 600 is filled with a catalyst, and the adsorption column 700 is filled with an adsorbent (ion exchange resin). During testing, the first valve 300 is opened and the second valve 400 is closed, allowing the liquid in the first container 100 to flow into the reaction column 600. After each test, the second valve 400 is opened and the first valve 300 is closed, allowing the liquid in the second container 200 to flow into the reaction column 600 to achieve catalyst rinsing and regeneration. A sampling port is set on the pipeline between the reaction column 600 and the adsorption column 700. The concentration detector 800 detects the concentration of the sampled p-chlorophenol and records the concentration as C. Then the removal rate is calculated as (C0-C) / C0.

[0049] Figure 6 This diagram illustrates the recycling effect of the in-situ iodine-producing water purification material in this embodiment. Figure 6 As shown, using Figure 5 The evaluation device shown consistently maintained a removal rate of over 93% for p-chlorophenol during 15 consecutive cycles (with regeneration treatment performed before each cycle), indicating that the in-situ iodine-producing water purification material of this embodiment has good operational stability and application potential for continuous treatment of recalcitrant organic wastewater.

[0050] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. An in-situ iodine-producing water purification material, characterized in that: It includes a catalyst and an oxidant, which undergo a catalytic oxidation reaction in organic wastewater to generate elemental iodine; wherein the catalyst includes a metal oxyiodide generated by a solvothermal reaction of a soluble bismuth salt and a soluble alkali metal iodide.

2. The in-situ iodine-producing water purification material as described in claim 1, characterized in that: The preparation method of the metal oxy iodide includes the following steps: Prepare a mixed solution of soluble bismuth salt and soluble alkali metal iodide; The mixed solution was placed in a high-pressure reactor for solvothermal treatment to obtain a solid-liquid mixture. The solid in the solid-liquid mixture is collected, washed, and dried to obtain the metal oxyiodide.

3. The in-situ iodine-producing water purification material as described in claim 2, characterized in that: The soluble alkali metal iodide is sodium iodide and / or potassium iodide; the concentration of soluble bismuth salt in the mixed solution is 0.5 to 1.5 mol / L, the molar ratio of soluble bismuth salt to soluble alkali metal iodide is (0.5 to 1.5):1, and the solvent used in the mixed solution is at least one of ethanol, ethylene glycol or deionized water.

4. The in-situ iodine-producing water purification material as described in claim 2, characterized in that: The solvent heat treatment temperature is 150–170℃, and the duration is 1–3 hours.

5. The in-situ iodine-producing water purification material as described in claim 1, characterized in that: The oxidant is at least one of hydrogen peroxide, persulfate, or peracetic acid.

6. A water purification method, characterized in that: The steps include: adding the catalyst and oxidant from the in-situ iodine-producing water purification material according to any one of claims 1-5 to the organic wastewater.

7. The water purification method as described in claim 6, characterized in that: The catalyst dosage is 0.1–0.6 g / L; the oxidant dosage is 1–3 mmol / L.

8. The water purification method as described in claim 6, characterized in that: The organic wastewater contains p-chlorophenol.

9. The regeneration method of the in-situ iodine-producing water purification material according to any one of claims 1-5, characterized in that: The process includes the following steps: adding the deactivated water purification material into an iodide solution, reacting for a period of time, and then collecting the solid to obtain the regenerated catalyst.

10. The regeneration method as described in claim 9, characterized in that: The solid-liquid ratio of the deactivated water purification material to the iodide solution is 1 g:(200-400 mL), and the concentration of the iodide solution is 1-3 g / L; the iodide solution has the same metal element as the soluble alkali metal iodide used to prepare the metal oxy iodide.

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