A method utilizing UV 222 / Cl coupling UV 222 Sulfite oxidation-reduction technology is a new process for efficiently degrading pollutants and reducing the generation of disinfection byproducts.

Abstract

This invention discloses a method utilizing UV 222 / Cl coupling UV 222 / Sulfite redox technology is a novel process for efficiently degrading pollutants and reducing the generation of disinfection byproducts. The process includes the following steps: For the first time, a safer, biocompatible KrCl excimer lamp (far-UV, UV) is used as the light source. 222 ) to replace traditional low-pressure mercury lamps (LP-UV); with UV 222 As a light source, NaClO acts as an oxidant to produce ·OH and active chlorine substances (RCS) such as Cl· and Cl. 2‑ • and ClO· and other active free radicals degrade pollutants and inactivate pathogens; coupled with UV 222 / Sulfite advanced reduction process generates hydrated electrons (e aq — ), H·and SO 3 · — The free radicals further reduce and remove recalcitrant pollutants in water, and reduce the large amount of disinfection byproducts generated in traditional UV chlorination treatment processes. The process proposed in this invention can not only efficiently remove recalcitrant micropollutants in water while saving costs, but also reduce the generation of disinfection byproducts during UV chlorination treatment, achieving the key goals of high pollutant removal efficiency and low disinfection byproduct generation.

Description

A method utilizing UV 222 / Cl coupling UV 222 Sulfite oxidation-reduction technology is a new process for efficiently degrading pollutants and reducing the generation of disinfection byproducts. Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a method utilizing UV... 222 / Cl coupling UV 222 / Sulfite oxidation-reduction technology is a new process that efficiently degrades pollutants and reduces the generation of disinfection byproducts. Background Technology

[0002] In recent years, advanced oxidation processes (AOPs) have been increasingly used for drinking water disinfection and pollutant removal due to their potential to convert anthropogenic and biodegradable organic matter into minerals. Ultraviolet (UV) radiation has the ability to increase the quantum yield of free radicals and reduce their selectivity. Therefore, combining UV radiation with oxidants to generate reactive oxygen species (ROS) in AOPs has become a commonly used catalytic activation method. Traditional UV-AOPs are driven by mercury lamps, such as low-pressure (LP) and medium-pressure (MP) mercury lamps. LP-UV lamps are monochromatic ultraviolet radiation sources with an emission peak wavelength of approximately 254 nm (UV). 254 It is more energy-efficient than MP-UV lamps. However, oxidants (such as hydrogen peroxide, persulfate, and chlorine) have low molar absorption coefficients and quantum yields at 254 nm, leading to UV... 254 Driven AOPs radicals have low yields and limited effectiveness in removing micro-pollutants. One approach to improve UV-AOPs radical yield is to use alternative, high-efficiency UV radiation sources that induce higher molar absorptivity and quantum yields of the oxidant at its emission wavelength. The emission peak of a KrCl excimer lamp is approximately 222 nm (UV). 222 It has been used as a far-ultraviolet radiation source for air and object surface disinfection. (Compared to UV...) 254 Compared to UV 222 Mercury-free, requiring a short stabilization time (15s), highly effective in inactivating pathogens, and safer for organisms, chlorine-based advanced oxidation processes are particularly promising. Among the many developed advanced oxidation processes, chlorine-based processes are widely used in drinking water disinfection and circulating water purification due to their significant energy-saving advantages, high absorbance, quantum yield, and low chlorine residue.

[0003] Currently, a series of chlorides have been developed in theoretical research as oxidants in AOPs, such as monochloramine (NH2Cl), the emerging monochloroisocyanurate and dichloroisocyanurate, which have achieved significant improvements in free radical yield and pollutant removal efficiency. Compared with the emerging chlorides, traditional NaClO is the most widely used in practical water treatment due to its higher cost-effectiveness and effective control of microbial contaminants. However, when chlorine in the UV / NaClO system reacts with dissolved organic matter (DOM), anthropogenic pollutants, brominated and iodinated compounds, it can induce the generation of disinfection byproducts (DBPs) (such as THMs, HAAs, HANs, etc.). Long-term consumption of chlorinated drinking water with high DBP concentrations is significantly associated with adverse health risks.

[0004] In conclusion, there is an urgent need to explore a new technology that achieves high pollutant removal and low DBP generation. Summary of the Invention

[0005] To overcome the shortcomings of existing processes, this invention addresses the issues of low free radical yield, poor pollutant removal efficiency, high cost of emerging processes, and the generation of DBPs in current water treatment processes. It provides a method utilizing UV... 222 / Cl coupling UV 222 / Sulfite oxidation-reduction technology is a new process that efficiently degrades pollutants and reduces the generation of disinfection byproducts.

[0006] This invention utilizes UV 222 As a UV excitation source, it activates hypochlorite to produce ·OH, Cl·, and Cl. 2- • Active free radicals react with target pollutants through decarboxylation, dehydrogenation, substitution, and ring cleavage to degrade recalcitrant micropollutants; simultaneously, they utilize sulfite as a reducing agent to generate e aq — H· and SO3· — Highly reactive free radicals, of which e aq —It has a very high redox potential (E = -2.9V), and can attack the CX (Cl, Br and F) bonds of pollutants through electron-withdrawing reactions, and convert them into less toxic products.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows: a method utilizing UV... 222 / Cl coupling UV 222 Sulfite oxidation-reduction technology is a novel process for efficiently degrading pollutants and reducing the generation of disinfection byproducts. Its features include a photoreactor, a reactor, and a KrCl excimer lamp (UV). 222 ), magnetic stirrer, circulating water condenser, nitrogen purging device;

[0008] Photoreactor 1 is equipped with a dosing device 1 and a convenient sampling port 1. The dosing device 1 is used to add an oxidant to Photoreactor 1. Photoreactor 2 is equipped with a dosing device 2 and a convenient sampling port 2. The dosing device 2 is used to add a reducing agent to Photoreactor 2. UV 222 Installed above the reactor, it provides a collimated beam of UV light to the reactor via a collimator. 222 It is installed in a sealed wooden box to prevent diffuse scattering of ultraviolet light and is equipped with a lamp cooling device to ensure stable ultraviolet energy irradiation; a magnetic stirrer is set at the bottom of the reactor to ensure uniform mixing of the reaction solution; a circulating water condenser is connected to the reactor through a rubber tube to provide constant reaction conditions; a nitrogen purging device is connected to the reactor through a rubber tube to remove dissolved oxygen from the reduction system.

[0009] Photoreactor 1 is connected to Photoreactor 2 via a glass tube. The glass tube is equipped with a valve to transfer the oxidized wastewater to Photoreactor 2 for reduction reaction.

[0010] Furthermore, the UV 222 / Cl coupling UV 222 The / Sulfite process is characterized by using a phosphate buffer solution as the buffer, sodium hypochlorite reagent as the oxidant, and sodium sulfite stock solution as the reducing agent.

[0011] Furthermore, the UV 222 / Cl coupling UV 222 The Sulfite process is characterized by maintaining the circulating water condenser at 25°C; purging the solution in reactor two with nitrogen for 30 minutes, and then closing all valves in reactor two to prevent oxygen from entering the reaction system.

[0012] Furthermore, the UV 222 / Cl coupling UV 222 The Sulfite process is characterized in that the top of the reactor is covered with a quartz glass plate to prevent the chemical substances from evaporating from the reaction solution; the convenient sampling port is equipped with a sealing rubber stopper, and sampling can be completed by means of a syringe needle without affecting the system reaction; the reaction solution in the reactor should cover the convenient sampling port to achieve liquid seal conditions.

[0013] The beneficial effects of the process of this invention are as follows: the wastewater is first treated with UV... 222 Advanced oxidation of sodium hypochlorite is achieved through ultraviolet catalysis in conjunction with ultraviolet light. Under the catalytic action of ultraviolet light, sodium hypochlorite in water is converted into ·OH, Cl·, and Cl₂. 2- • Active free radicals can degrade and mineralize some target pollutants in the system into small molecules, but this is accompanied by the generation of disinfection byproducts (such as THMs, HAAs, HANs, etc.); followed by UV treatment. 222Ultraviolet catalysis synergistically reduces sodium sulfite to e-phosphorus compounds. Under the catalytic action of ultraviolet light, sodium sulfite in water is converted into e-phosphorus compounds. aq — H· and SO3· — Active free radicals can further degrade target pollutants on the basis of oxidation, and transform or degrade disinfection byproducts generated in the oxidation stage into substances that are harmless to the environment, or effectively reduce disinfection byproducts generated in the oxidation stage.

[0014] 1) The UV of this invention application 222 / Cl coupling UV 222 The Sulfite oxidation-reduction technology is a novel process for efficiently degrading pollutants and reducing disinfection byproducts. It is simple, combining UV / sulfite reduction with UV / chlorination, a process already used in water treatment. It requires minimal new equipment, simply replacing traditional low-pressure (LP) mercury lamps with KrCl excimer lamps (UV). 222 );

[0015] 2) The construction period is short and the operation is simple. During operation, only the oxidant and reducing agent need to be replaced as needed. All other operations can be carried out by mechanization.

[0016] 3) Low operating costs: This oxidation-reduction process only involves sodium hypochlorite as the oxidant and sulfite as the reducing agent, requiring no additional chemicals. While ensuring the process's efficiency in removing target pollutants from wastewater, it also guarantees the safety and harmlessness of the treated water. Preliminary estimates indicate that the water treated by this process will be colorless, odorless, clear, and transparent, with a pollutant removal rate of up to 95%.

[0017] 4) The UV of this invention application 222 / Cl coupling UV 222 The Sulfite oxidation-reduction technology is a novel process that efficiently degrades pollutants and reduces the generation of disinfection byproducts. It can be developed into an intensive water treatment plant and put into practical use in the water treatment field. Attached Figure Description

[0018] Figure 1 shows UV. 222 / Cl coupling UV 222 / Sulfite oxidation-reduction water treatment process flow diagram.

[0019] Figure 2 shows UV. 222 and UV 254 Emission spectrum.

[0020] Figure 3 shows the degradation kinetics of the pollutant ribavirin (RBV).

[0021] Figure 4 shows the generation and removal of DBPs after oxidation and reduction treatment. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to Figure 1.

[0023] Example 1: UV 222 / Cl coupling UV 222 The Sulfite oxidation-reduction water treatment process is characterized by including photoreactor 1 (3), photoreactor 2 (11), and a KrCl excimer lamp (UV). 222 )7 and 15 (the emission spectra of excimer lamps and conventional low-pressure mercury lamps are shown in Figure 2), magnetic stirrers 2 and 10, circulating water condenser 1 and 18, and nitrogen purging device 17;

[0024] Reactor 13 is equipped with dosing device 15 and convenient sampling port 14. Dosing device 15 is used to add oxidant to reactor 13. Reactor 21 is equipped with dosing device 23 and convenient sampling port 22. Dosing device 23 is used to add reducing agent to reactor 21. UV 222 7 and 15 are mounted above the reactor, providing collimated beams to reactors 3 and 11 via collimators 6 and 14, UV... 222 Units 7 and 15 are installed in a sealed wooden box to prevent diffuse scattering of ultraviolet light and are equipped with lamp cooling devices 8 and 16 to ensure stable ultraviolet energy irradiation; magnetic stirrers 2 and 10 are set at the bottom of reactors 3 and 11 to ensure uniform mixing of the reaction solution; circulating water condensation devices 1 and 18 are connected to the reactors via rubber tubes to provide constant reaction conditions; nitrogen purging device 17 is connected to reactor 11 via a rubber tube to remove dissolved oxygen from the reduction system;

[0025] Reactor 1 3 is connected to reactor 2 11 via a glass tube. The glass tube is equipped with a valve 9, which is used to transfer the oxidized wastewater to reactor 2 11 for reduction reaction.

[0026] The specific operating process includes: carrying out an advanced oxidation reaction in reactor 3, utilizing far-ultraviolet / sodium hypochlorite advanced oxidation technology (UV). 222 / NaClO), where sodium hypochlorite reagent is used as the oxidant, and the amount of sodium hypochlorite added is m(NaClO). Simultaneously, phosphate buffer is added to adjust to acidic conditions. Magnetic stirrer 2 and circulating water condenser 1 are turned on, and KrCl excimer lamp (UV) is used. 222The reaction occurs under irradiation until the free chlorine concentration in the system is zero. The wastewater after oxidation treatment is transferred to reactor 2 11 by opening valve 9. Buffer solution is added to adjust the system to alkaline conditions, and reducing agent sodium sulfite is added at a concentration of m(sulfite). Then, nitrogen purging device 17 is opened to remove dissolved oxygen from reactor 2 11 through a rubber tube. After purging, all valves in reactor 2 11 are closed. With magnetic stirrer 10 and circulating water condenser 18 open, KrCl excimer lamp 15 is turned on to carry out the reduction reaction. The wastewater after oxidation-reduction treatment is discharged through pipe 20.

[0027] Example 2: Using the UV described in Example 1 under laboratory conditions 222 / Cl coupling UV 222 The Sulfite oxidation-reduction water treatment process was used to treat wastewater containing ribavirin (RBV). The degradation efficiency of RBV and the generation of disinfection byproducts in the treated wastewater were analyzed by liquid chromatography and gas chromatography.

[0028] Wastewater containing RBV is transported to photoreactor 3 through wastewater input pipe 19. Phosphate buffer solution and NaClO solution are added to photoreactor 3 through dosing device 5. Magnetic stirrer 2 is turned on for mixing. Circulating water condenser 1 is connected to ensure that the reaction system is stable at 25°C. Advanced oxidation reaction is carried out under far-ultraviolet (far-UV) irradiation. The photoreaction is carried out for 30 minutes until the free chlorine concentration in the system is zero.

[0029] During the photocatalytic reaction, 1 ml of reaction solution was taken through convenient sampling port 4 at predetermined time intervals, filtered through a 0.22 μm PTFE membrane, and transferred to an amber vial pre-filled with ascorbic acid. The residual concentration of the target pollutant was analyzed using a high-performance liquid chromatography (HPLC) system. At predetermined time intervals, 5 ml of reaction solution was taken through convenient sampling port 4 into a 10 ml centrifuge tube, quenched with ascorbic acid, and then MTBE solution and anhydrous Na2SO4 were added. The mixture was vortexed for 2 min until fully dissolved, and the aqueous and organic phases were mixed evenly. After standing for 30 min to separate into layers, 1 ml of the upper organic phase was pipetted into a gas chromatography vial, and the formation of disinfection byproducts was detected by chromatography.

[0030] The oxidized wastewater is transferred to reactor 2 11 by opening valve 9. Buffer solution and Sulfite stock solution are added to photoreactor 2 11 through dosing device 2 13. The system is adjusted to alkaline conditions, and nitrogen purging device 17 is turned on to purge dissolved oxygen for 30 minutes. After purging, all valves in reactor 2 11 are closed, magnetic stirrer 10 and circulating water condenser 18 are turned on to stabilize the temperature at 25°C, and KrCl excimer lamp 15 is turned on to carry out the reduction reaction. The wastewater after oxidation-reduction treatment is discharged through pipe 20 for analysis of RBV degradation and disinfection byproduct formation.

[0031] The results of treating RBV-containing wastewater using this process are as follows:

[0032] In the examples, RBV in UV 222 The process begins to slowly degrade under the action of NaClO oxidation, while under the coupling of UV... 222 The degradation rate increases rapidly after treatment with the Sulfite reduction process, thus achieving highly efficient degradation of the target pollutants on top of the oxidation stage; after UV treatment... 222 After treatment with the Sulfite reduction process, the number and types of disinfection byproducts generated during the oxidation stage, such as chloroform, dibromochloromethane, and unidentified disinfection byproducts with a peak time of 6.488, were significantly reduced. Some results are shown in Figures 3 and 4.

[0033] The reaction conditions in the above embodiments can be adjusted according to actual conditions, such as the dosage of oxidant and reducing agent, the temperature of the reaction system, the pH conditions of the oxidation treatment stage and the reduction treatment stage, etc. In order to make the description as concise as possible, the reaction conditions in the above embodiments are not described in combination. However, as long as the combination of these reaction conditions does not affect the pollutant degradation and disinfection by-product removal performance of the process of the present invention, they should be considered to be within the scope of this specification.

[0034] The above examples merely illustrate embodiments suitable for the description in this patent, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this invention. It should be noted that researchers or those skilled in the art can make various modifications and optimizations based on the actual conditions and properties of the treated water and pollutants without departing from the concept of this invention; these modifications and optimizations all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A method utilizing UV 222 / Cl coupling UV 222 A method for efficiently degrading pollutants and reducing disinfection byproducts using Sulfite redox technology, characterized by... Includes the following steps: 1) In photoreactor one, wastewater containing the target pollutant, a buffer solution for adjusting the pH of the reaction system, and an oxidant are mixed evenly on a magnetic stirrer. A circulating water condenser is connected to ensure the reaction system is stable at a temperature suitable for efficient reaction. An advanced oxidation reaction is carried out under far-ultraviolet irradiation until the free chlorine concentration in the system is zero. The buffer solution is a phosphate buffer solution; the oxidant is sodium hypochlorite reagent. 2) The effluent from step 1) is transferred to photoreactor two through a valve, and a reducing agent and buffer solution are added through a dosing device two. The pH is adjusted to a suitable level for the reduction reaction. A nitrogen purging device is opened to remove dissolved oxygen. After purging, all valves are closed, and the magnetic stirrer and circulating water condenser are opened. An advanced reduction reaction is carried out under far-ultraviolet irradiation. The reducing agent is a sodium sulfite stock solution. Photoreactor one is equipped with a dosing device one and a convenient sampling port one. Dosing device one is used to add the oxidant to reactor one. Photoreactor two is equipped with a dosing device two and a convenient sampling port two. Dosing device two is used to add the reducing agent to reactor two. 222 Installed above the reactor, it provides a collimated beam of UV light to the reactor via a collimator. 222 The reactor is installed in a sealed wooden box to prevent diffuse scattering of ultraviolet light and is equipped with a lamp cooling device to ensure stable ultraviolet energy irradiation. A magnetic stirrer is placed at the bottom of the reactor to ensure uniform mixing of the reaction solution. A circulating water condenser is connected to the reactor via a rubber tube to provide constant reaction conditions. A nitrogen purging device is connected to reactor two via a rubber tube to remove dissolved oxygen from the reduction system. Photoreactor one is connected to photoreactor two via a glass tube equipped with a valve to transfer the oxidized wastewater to photoreactor two for reduction reaction.

2. The method according to claim 1, characterized in that, The circulating water condenser is kept at 25°C; nitrogen is used to purge the solution in reactor 2 for 30 minutes, and after purging, all valves in reactor 2 are closed to prevent oxygen from entering the reaction system.

3. An intensive water treatment device, characterized in that, Water treatment is performed using the method described in claim 1 or 2.

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