A concentrated sunlight treatment system and method for activating chlorine dioxide to degrade contaminants in water

Abstract

The present application belongs to the technical field of sewage, and particularly relates to a concentrated sunlight treatment system and a treatment method for activating chlorine dioxide to degrade pollutants in water. The present application adds chlorine dioxide into a concentrated sunlight system, activates the ability of chlorine dioxide, strengthens the chloro-oxidation inactivation function, and weakens the electrophilic substitution tendency of the precursor, realizes the synergistic degradation of light and heat, and controls the generation of disinfection by-products. After adjustment, the optimal reaction ratio is obtained. Under the condition of concentrated sunlight, the chlorine dioxide oxidant can efficiently remove typical new pollutants in water, and is an environment-friendly application with low carbon and no energy consumption. The present application proposes a method and application for activating chlorine dioxide by optical enrichment and spectral matching of a concentrated sunlight system (CSL) to efficiently degrade pollutants (such as SMX), aiming to significantly improve the degradation rate and mineralization degree, reduce energy consumption and by-product risk, and be suitable for remote or resource-limited scenes.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a concentrated solar treatment system and method for activating chlorine dioxide to degrade pollutants in water. Background Technology

[0002] With the acceleration of industrialization and urbanization, the detection frequency of new pollutants in water bodies is increasing year by year. In particular, antibiotics (such as sulfamethoxazole SMX) are commonly found in pharmaceutical, livestock, and domestic wastewater, posing risks of long-term residues, ecotoxicity, and resistance induction. Traditional advanced oxidation technologies for oxidative stresses (AOPs) and conventional oxidation disinfection processes have limited removal efficiency for these PPCPs, highlighting the urgent need for efficient and low-energy degradation technologies.

[0003] Chlorine dioxide (ClO2) is a broad-spectrum disinfectant with advantages such as strong oxidizing properties and low production of halogenated byproducts. However, under conventional dosing conditions, its degradation ability for some PPCPs, especially those with stable structures or whose absorption spectra are related to photosensitivity, is insufficient. In recent years, AOPs based on ultraviolet (UV) radiation have attracted widespread attention due to their generation of highly oxidizing free radicals (such as ·OH, Cl·, etc.). Among them, AOPs using UV combined with chlorine-based oxidants have shown good potential in removing trace organic pollutants. Studies have shown that the UV / ClO2 system can generate highly reactive free radicals through photoactivation of ClO2, significantly improving the degradation efficiency of organic pollutants.

[0004] However, existing UV / ClO2 technologies mainly rely on low-pressure mercury lamps as the light source, which has the following shortcomings: First, chlorine dioxide has a low molar absorptivity in the UVC band (approximately 60.7 MΩ). -1 ·cm -1 Firstly, UVC light sources have limited photolysis efficiency; secondly, they consume a lot of energy, and mercury lamps pose a risk of environmental pollution; thirdly, UVC radiation is easily absorbed by background matrix in water (such as dissolved organic matter, nitrates, etc.), which reduces the efficiency of light energy utilization; in addition, the traditional UV / ClO2 system is less efficient than the UV / H2O2 or UV / free chlorine system in degrading certain resistant pollutants (such as sulfamethoxazole).

[0005] Solar energy is a clean and renewable energy source, and solar photochemistry offers advantages in water treatment due to its low energy consumption. However, the natural solar photon flux is limited, thus restricting the photochemical rate. Concentrating optical systems can achieve significantly higher photon flux in localized areas and achieve spectral matching. Furthermore, ClO2 exhibits extremely high absorption coefficients (up to 1284.2 MΩ) in the UVA band (320-400 nm). -1 ·cm -1Its absorption peak is located near 360 nm, and its absorption coefficient in this band is 20 times that of UVC. Although the quantum yield of the UVA band is slightly lower than that of UVC, its higher light absorption capacity promises to achieve higher efficiency in generating active species. However, there is still room for improvement in existing focusing systems in terms of spectral optimization, equipment integration, and field applicability.

[0006] Based on this, this invention proposes a concentrated solar energy treatment system for activating chlorine dioxide to degrade new pollutants in water. Combining solar energy, a renewable energy source, with the highly efficient photochemical reaction characteristics of chlorine dioxide, this system reduces energy consumption while improving the degradation efficiency of target pollutants. This technology is not only applicable to conventional water treatment processes but is particularly suitable for distributed water treatment systems in remote areas or energy-constrained scenarios, demonstrating significant environmental benefits and promising application prospects. Summary of the Invention

[0007] To address the problems of high energy consumption, mercury pollution, numerous byproducts, and low light energy utilization in existing UVC / ClO2 technologies, this invention provides a simple, high-efficiency chlorine dioxide activation system and its application method that requires no external energy source and allows for precise control of light intensity. This invention achieves efficient water treatment by adjusting the wavelength matching of different light intensities with chlorine dioxide, utilizing a concentrated solar light system (CSL) for optical enrichment and spectral matching to activate chlorine dioxide, thereby efficiently degrading the antibiotic sulfamethoxazole (SMX).

[0008] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A concentrated solar treatment system (CSL) for activating chlorine dioxide to degrade pollutants in water includes a light-concentrating unit and a reaction unit.

[0009] Specifically, the light focusing unit includes a Fresnel lens, an adjustable support, and a magnetic base; The Fresnel lens is made of optical-grade high-transmittance material and has high transmittance. It can make full use of all direct and scattered light within the full spectrum of sunlight to converge natural sunlight into high-density concentrated sunlight.

[0010] Specifically, the adjustable bracket is connected to the Fresnel lens by a fixed connection, snap-fit, clamp, or detachable connection. The adjustable bracket is used to support and adjust the angle and height of the Fresnel lens.

[0011] Specifically, the adjustable bracket includes a connecting forearm, a height adjustment rod, an angle adjustment pivot, and a movable fulcrum and a fixed fulcrum; The lower end of the height adjustment rod is connected to the top end of the movable fulcrum and the fixed fulcrum. The height adjustment rod is used to adjust the vertical height of the Fresnel lens. The top end of the height adjustment rod is connected to one end of the forearm via an angle adjustment pivot. The other end of the connecting forearm is equipped with a crab claw clamp, which can hold the edge of the Fresnel lens to fix the Fresnel lens and prevent it from shifting position.

[0012] Specifically, the bottom ends of the movable fulcrum and the fixed fulcrum are fixedly connected to the top of the magnetic base, and the adjustable bracket is connected to a highly stable magnetic base through the movable fulcrum and the fixed fulcrum.

[0013] Specifically, the movable fulcrum and the fixed fulcrum are used to assist in adjusting the spatial position of the Fresnel lens to ensure that the light spot accurately covers the reaction area; Specifically, the magnetic base is used to support the entire adjustable bracket, ensuring system stability.

[0014] Specifically, the reaction unit includes a transparent reaction container located in the focal region or focal line region of the Fresnel lens, the transparent reaction container being used to contain water to be treated containing chlorine dioxide and the target pollutant; The transparent reaction vessel is a cylindrical quartz glass bottle made of high-transmittance quartz glass, with a transmittance of ≥90% for light wavelengths of 200–800 nm, and can withstand localized temperature rises caused by focusing (up to 60–80°C). A magnetic stirrer is installed at the bottom of the transparent reaction vessel, and a magnetic stir bar is also installed inside. The magnetic stirrer drives the rotation of the magnetic stir bar to stir the reaction solution inside the transparent reaction vessel, maintaining uniform mixing of the solution during the reaction process.

[0015] The angle adjustment shaft allows the top of the height adjustment rod to be rotatably connected to one end of the connecting forearm, thereby adjusting the tilt angle of the Fresnel lens to track the solar altitude angle and azimuth angle, and to ensure that the focused light spot accurately illuminates the center position of the transparent reaction vessel according to the solar altitude angle and azimuth angle.

[0016] Furthermore, the present invention also provides the application of the concentrated solar treatment system (CSL) in the treatment of water bodies containing pollutants.

[0017] Furthermore, the present invention also provides the application of the concentrated solar processing system (CSL) in the degradation of pollutants in water bodies.

[0018] Specifically, the contaminants are one or more of fluoroquinolone (FQ) antibiotics, nonsteroidal anti-inflammatory drugs, and tetracycline antibiotics.

[0019] Specifically, the contaminants are one or more of the following: sulfamethoxazole (SMX), diflufloxacin (DIF), ofloxacin (OFX), sulfadiazine (SD), sulfisoxazole (SIZ), sulfathiazole (STZ), norfloxacin (NFX), ciprofloxacin (CIP), tetracycline, oxytetracycline, etc.

[0020] Furthermore, the present invention also provides a method for treating polluted water bodies or degrading pollutants in water bodies using the aforementioned concentrated solar power (CSL) system, comprising the following steps: a. Mix the water containing pollutants with chlorine dioxide in a mixing container and stir at 45-55°C for 1-5 minutes to obtain a pre-reaction solution; b. Inject the pre-reaction liquid into the transparent reaction vessel of the Concentrated Solar Processing System (CSL); c. By adjusting the adjustable support, the Fresnel lens focuses natural sunlight into focused sunlight, which then irradiates the pre-reaction liquid in the transparent reaction container to carry out the degradation reaction. At this time, the ultraviolet / visible light band in the focused sunlight triggers the photochemical activation of chlorine dioxide, while the infrared band generates an in-situ photothermal effect. Through the photothermal synergy, the new pollutants are efficiently degraded. d. After the reaction is complete, quenching can be achieved by adding a quenching agent to the reaction solution.

[0021] Specifically, the final concentration of chlorine dioxide in step a is 50–300 µM, preferably 150–200 µM; the pH value of the water to be treated is adjusted to 4.0–8.0, preferably 5.0–6.0. ​​The water to be treated is ultrapure water, tap water, or natural water or wastewater containing inorganic interfering ions and natural organic matter.

[0022] Specifically, the irradiation time for focusing sunlight in step c is 1-5 minutes, and the total cumulative solar radiation irradiance at the target focal spot is 300-2800 J / cm². 2 During irradiation, the diameter of the focused spot is controlled by changing the diameter of the light-shielding ring on the Fresnel lens or adjusting the distance between the lens and the reaction container, thereby precisely controlling the irradiation input power.

[0023] Specifically, the reaction time in step c is 1–30 min, preferably 5 min, during which the total cumulative solar radiation irradiance at the target focal spot is preferably 1200–1800 J / cm². 2 .

[0024] Specifically, the quenching agent in step d is ascorbic acid to eliminate residual chlorine dioxide and byproducts (chlorite, chlorate), and the molar ratio of the quenching agent to residual chlorine is 1.2:1 to 2:1, preferably 1.5:1.

[0025] Specifically, the contaminants include antibiotic contaminants; preferably, the antibiotic contaminants are selected from at least one of sulfonamide drugs or quinolone drugs.

[0026] Specifically, the contaminant is selected from one or more of fluoroquinolone (FQ) antibiotics, nonsteroidal anti-inflammatory drugs, tetracycline antibiotics, and organic dyes.

[0027] Specifically, the contaminants are one or more of the following: sulfamethoxazole (SMX), diflufloxacin (DIF), ofloxacin (OFX), sulfadiazine (SD), sulfisoxazole (SIZ), sulfathiazole (STZ), norfloxacin (NFX), ciprofloxacin (CIP), tetracycline, oxytetracycline, etc.

[0028] Furthermore, the present invention also provides applications of the concentrated solar power (CSL) system in advanced drinking water treatment, wastewater resource utilization, natural water body restoration, or handling of sudden water pollution incidents.

[0029] Furthermore, the present invention also provides a method for treating polluted water bodies or degrading pollutants in water bodies using the aforementioned concentrated sunlight treatment system and chlorine dioxide to form a pollutant degradation system (CSL / ClO2), comprising the following steps: 1) Adjust the pH of the pollutant-containing water to 4.0-8.0 (preferably 5.0-6.0). If the turbidity of the water is too high, filtration pretreatment can be performed to reduce light attenuation. 2) Add chlorine dioxide to the pretreated water until the concentration of chlorine dioxide is 50-300 µM (preferably 150-200 µM, most preferably 200 µM, corresponding to a mass concentration of approximately 10 mg / L), and add it in a single dose. 3) The water body is irradiated by the aforementioned concentrated sunlight treatment system to carry out the degradation reaction. During this process, the Fresnel lens is adjusted by adjusting the adjustable support to concentrate natural sunlight onto the transparent reaction container. The irradiation time is 1-30 min (preferably 5 min). The irradiation intensity and cumulative irradiance can be precisely controlled by changing the aperture diameter (10-50 mm) on the Fresnel lens or adjusting the distance between the lens and the reactor. 4) After the reaction is complete, to prevent residual chlorine dioxide or byproducts in the water from continuing to react, quench them by adding a quenching agent (such as ascorbic acid).

[0030] Specifically, the contaminants include antibiotic contaminants; preferably, the antibiotic contaminants are selected from at least one of sulfonamide drugs or quinolone drugs.

[0031] Specifically, the contaminant is selected from one or more of fluoroquinolone (FQ) antibiotics, nonsteroidal anti-inflammatory drugs, tetracycline antibiotics, and organic dyes.

[0032] Specifically, the contaminants are one or more of the following: sulfamethoxazole (SMX), diflufloxacin (DIF), ofloxacin (OFX), sulfadiazine (SD), sulfisoxazole (SIZ), sulfathiazole (STZ), norfloxacin (NFX), ciprofloxacin (CIP), tetracycline, oxytetracycline, etc.

[0033] Specifically, the molar ratio of quencher to residual chlorine is 1.2:1 to 2:1, preferably 1.5:1.

[0034] Furthermore, the Concentrated Sunlight Processing System (CSL) described in this invention can be used to optically concentrate and modulate natural sunlight, significantly enhancing the photon flux in the UVA / UVB bands at the target location. Chlorine dioxide exhibits a molar absorptivity as high as 1284.2 M in the UVA band. -1 ·cm -1 It is more than 20 times that of the UVC band, therefore the system described in this invention can achieve highly efficient photoactivation.

[0035] Furthermore, the method of using the aforementioned concentrated sunlight treatment system and chlorine dioxide to form a pollutant degradation system (CSL / ClO2) to treat polluted water bodies or degrade pollutants in water bodies utilizes the photothermal synergistic effect and high photon flux generated by concentrated light to jointly enhance the excitation and decomposition rate of ClO2, accelerating the generation of active free radicals (·OH, Cl·, etc.). The absorption peak of ClO2 is located at 360 nm, with the strongest absorption in the UVA band.

[0036] This invention achieves target removal and minimizes byproduct formation by adjusting key operating parameters (pH, ClO2 dosage, and light intensity).

[0037] Furthermore, the method described in this invention is not only applicable to the degradation of sulfamethoxazole (SMX), but also to the removal of other contaminants. Specifically, the contaminants include, but are not limited to, the following categories: antibiotics and anti-inflammatory analgesics.

[0038] Further preferred, the method of the present invention has the best degradation effect on antibiotic pollutants (especially sulfamethoxazole and quinolones), and the removal rate can reach more than 85% within 5 minutes under optimized conditions.

[0039] Compared with the prior art, the advantages of the present invention are: 1. Based on the absorption characteristics of sulfamethoxazole (SMX) and chlorine dioxide (ClO2), this invention optimizes the spectral range, makes full use of the high-efficiency excitation region of the UVA / UVB band, reduces the dissipation of ineffective light energy, and promotes the formation of ClO2 excited state and triplet state by high photon flux, significantly improving the photochemical reaction rate and shortening the processing time.

[0040] 2. This invention uses a concentrated solar light system (CSL) in combination with ClO2 to accelerate the generation and reaction rate of free radicals by utilizing the photothermal synergistic effect, thereby achieving efficient degradation of a variety of typical new pollutants in water (sulfonamides, quinolones, etc.), proving that it has a broad-spectrum and efficient removal capability.

[0041] 3. This invention employs a Concentrated Solar System (CSL) that is entirely driven by solar energy, requiring no external power, thus significantly reducing operating costs and carbon emissions. The optical focusing of the Fresnel lens increases the local photon flux by 5-10 times, and the photothermal synergy further accelerates the reaction kinetics, shortening the processing time to 5 minutes, making it suitable for distributed water treatment in remote areas and resource-constrained scenarios.

[0042] 4. The chlorine dioxide application method of the present invention can improve the problems of many by-products in the existing UV / chlorine disinfection technology. The present invention optimizes the light conditions and oxidant addition method, which helps to reduce the generation of by-products, suppress the risk of halogenated by-products, and further control them by combining post-treatment. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the solar concentrating system described in Embodiment 1 of this application; Figure 2 The degradation kinetics of sulfamethoxazole (SMX) after 5 min of reaction in CSL / ClO2 of Example 2, CSL-only treatment of Comparative Example 1, ClO2-only treatment of Comparative Example 2, and SL / ClO2 of Comparative Example 3 are shown. Figure 3 The degradation kinetics of sulfamethoxazole (SMX) by CSL / ClO2 in Example 2 of this application at a concentration range of chlorine dioxide (ClO2) (2.5-15 mg / L) for 5 min is shown in the figure. Figure 4 The degradation kinetics of sulfamethoxazole (SMX) by CSL / ClO2 in Example 2 of this application after 5 min of reaction within the pH range (4-8); Figure 5 The degradation kinetics of sulfamethoxazole (SMX) by CSL / ClO2 in Example 4 of this application for 5 min within the aperture diameter range (10-50 mm); Figure 6This is a kinetic diagram of the degradation of sulfamethoxazole (SMX) by CSL / ClO2 under different wavelength light source conditions for 5 min in Example 5 of this application; Figure 7 This is a kinetic diagram of the degradation of sulfamethoxazole (SMX) by CSL / ClO2 in different ions and natural organic compounds for 5 min, as described in Example 6 of this application. Figure 8 This is a degradation kinetic diagram of different pollutants in CSL / ClO2 after 5 min of reaction in Example 2 of this application; Figure 9 This is a kinetic diagram of the degradation of sulfamethoxazole (SMX) by CSL / ClO2 in a natural water sample for 5 min, as described in Example 2 of this application. Detailed Implementation

[0044] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0045] In the following embodiments, the devices used include Fresnel lenses, magnetic bases, and magnetic stirrers, which are all common devices in the prior art. Their specific structures are not the inventive point of this invention, so they will not be described in detail.

[0046] In the following examples, the raw materials or reagents used are commercially available or self-made. In the following examples, chlorine dioxide is referred to as ClO2, and the method of activating chlorine dioxide by concentrated sunlight treatment system (CSL) is referred to as CSL / ClO2.

[0047] Example 1 like Figure 1 As shown, Example 1 provides a concentrated solar treatment system (CSL) for activating chlorine dioxide to degrade pollutants in water, which includes a light-concentrating unit and a reaction unit.

[0048] The light focusing unit includes a Fresnel lens (1), an adjustable support (2), and a magnetic base (3). The Fresnel lens (1) is made of optical-grade high-transmittance material and has high transmittance. It can make full use of all direct and scattered light within the full spectrum of sunlight to converge natural sunlight into high-density concentrated sunlight.

[0049] The adjustable bracket (2) is connected to the Fresnel lens (1) by clamping. The adjustable bracket (2) is used to support and adjust the angle and height of the Fresnel lens (1).

[0050] The adjustable bracket (2) includes a connecting forearm (not shown in the figure), a height adjustment rod (2-1), an angle adjustment pivot (2-2), and a movable fulcrum and a fixed fulcrum (2-3). The lower end of the height adjustment rod (2-1) is connected to the top end of the movable fulcrum and the fixed fulcrum (2-3). The height adjustment rod (2-1) is used to adjust the vertical height of the Fresnel lens (1). The top end of the height adjustment rod (2-1) is connected to one end of the forearm via the angle adjustment pivot (2-2). The other end of the connecting forearm is provided with a crab claw clamp (2-4), which can clamp the edge of the Fresnel lens (1) to fix the Fresnel lens (1) and prevent it from shifting position.

[0051] The bottom ends of the movable fulcrum and the fixed fulcrum (2-3) are fixedly connected to the top end of the magnetic base (3), and the adjustable bracket (2) is connected to a highly stable magnetic base (3) through the movable fulcrum and the fixed fulcrum (2-3).

[0052] The movable and fixed fulcrums (2-3) are used to assist in adjusting the spatial position of the Fresnel lens (1) to ensure that the light spot accurately covers the reaction area; The magnetic base (3) is used to support the entire adjustable bracket (2) to ensure system stability.

[0053] Reaction unit: includes a transparent reaction container (4) disposed in the focal region or focal line region of the Fresnel lens (1), the transparent reaction container (4) being used to contain water to be treated containing chlorine dioxide and the target pollutant; The transparent reaction container (4) is a cylindrical quartz glass bottle made of high-transmittance quartz glass with a transmittance of ≥90% for light with wavelengths of 200–800 nm. It can withstand the local temperature rise caused by focusing (up to 60–80°C). The bottom of the transparent reaction container (4) is equipped with a magnetic stirrer (not shown in the figure), and the transparent reaction container (4) is equipped with a magnetic stir bar. The magnetic stirrer can drive the rotation of the magnetic stir bar to stir the reaction solution in the transparent reaction container (4) to maintain the uniform mixing of the solution in the transparent reaction container (4) during the reaction process.

[0054] The angle adjustment shaft (2-2) allows the top of the height adjustment rod (2-1) to be rotatably connected to one end of the connecting forearm, thereby adjusting the tilt angle of the Fresnel lens (1) to track the solar altitude angle and azimuth angle, and to make the focused light spot accurately illuminate the center position of the transparent reaction container (4) according to the solar altitude angle and azimuth angle.

[0055] The specific operation mode of the concentrated solar processing system (CSL) is as follows: (1) Light calibration: Place the water sample to be treated containing the target pollutant (e.g., SMX) in a transparent reaction vessel (4); According to the real-time solar altitude angle and azimuth angle, adjust the angle adjustment shaft (2-2) so that the plane of the Fresnel lens (1) is perpendicular to the natural sunlight; at the same time, adjust the height adjustment rod (2-1) to accurately irradiate and cover the central liquid surface of the transparent reaction container (4) with the concentrated solar spot transmitted through the Fresnel lens (1). After the adjustment is completed, lock the angle adjustment shaft (2-2) and the height adjustment rod (2-1) to fix the angle and height of the Fresnel lens (1).

[0056] (2) Mixing and addition: Turn on the magnetic stirrer at the bottom of the transparent reaction container (4) and start stirring. Then add the set concentration of chlorine dioxide (ClO2) to the water sample.

[0057] (3) Photothermal synergistic degradation: Concentrated sunlight not only provides high photon flux in the ultraviolet / visible band, but also generates a significant photothermal effect in the infrared band in situ, which can rapidly raise the local liquid phase temperature to 50°C. Through the synergistic effect of photochemistry and thermodynamics, the pollutants are efficiently degraded in the transparent reaction vessel (4).

[0058] Example 2 A wastewater treatment method utilizing the solar energy collection system described in Example 1 includes the following specific steps: Take a simulated water sample containing 10 mg / L sulfamethoxazole (SMX) and place it in a mixing container, adjusting the pH to 5-6. Add ClO2 to the mixing container to a concentration of 200 µM (corresponding to a mass concentration of approximately 10 mg / L), and stir at 50°C for 1 min to obtain a pre-reaction solution.

[0059] The pre-reaction liquid was injected into the transparent reaction container (4), and magnetic stirring was turned on. By adjusting the height adjustment rod (2-1) and angle adjustment shaft (2-2) of the adjustable support (2), the Fresnel lens (1) was made to precisely focus natural sunlight onto the transparent reaction container (4). The incident natural sunlight intensity in front of the lens was measured to be approximately 1005 W / m² using an optical power meter. 2 After being focused by the lens, the light intensity in the focal area increases several times. The irradiation time is 5 minutes, and 1 ml of sample is taken every 1 minute and added to ascorbic acid (quencher) for quenching. The molar ratio of ascorbic acid to chlorine is 1.5:1.

[0060] Example 3 A wastewater treatment method utilizing the solar energy collection system described in Example 1 is presented. This example investigates the effect of different pH values ​​on the degradation effect. The specific steps are as follows: A simulated water sample containing 20 μM sulfamethoxazole (SMX) was placed in a mixing container, and the pH was adjusted to 4.0, 5.0, 6.0, 7.0, and 8.0, respectively. Chlorine dioxide was added to the mixing container to a concentration of 200 μM. The sample was irradiated using the CSL system described in Example 1, and the reaction was allowed to proceed for 5 min. The SMX removal rate was then measured. The remaining steps, unless otherwise specified, were the same as in Example 2.

[0061] Example 4 A wastewater treatment method utilizing the solar concentrating system described in Example 1 is presented. This example investigates the effect of different aperture sizes on the degradation effect. The specific steps are as follows: A simulated water sample containing 20 µM sulfamethoxazole (SMX) was placed in a mixing container, and the pH was adjusted to 5.0-6.0. Chlorine dioxide was added to the mixing container to a concentration of 200 µM. Using the CSL system described in Example 1, the incident light intensity was controlled by changing the focusing spot diameter of the Fresnel lens (1) using an adjustable support (2), and different aperture diameters (10 mm, 20 mm, 30 mm, 40 mm, 50 mm). The cumulative irradiance decreased as the aperture size decreased. The SMX removal rate was measured after 5 min of irradiation using the CSL system described in Example 1. The remaining steps were the same as in Example 2.

[0062] The results are as follows Figure 5 As shown, Figure 5 Data shows that with an aperture diameter of 10mm, the SMX removal rate reached over 85% after 5 minutes of irradiation; further reducing the aperture did not significantly improve the removal rate. This indicates that the system of the present invention can adjust the irradiation power by flexibly changing the lens aperture size, thereby adapting to the needs of different water treatment loads. Therefore, an aperture diameter of 10mm is preferred.

[0063] Example 5 A method for treating wastewater using LED lights of different colors is described in this embodiment. This embodiment investigates the effect of different wavelengths / light sources on the degradation effect. The specific steps are as follows: Take a simulated water sample containing 20µM sulfamethoxazole (SMX) and place it in a mixing container. Adjust the pH to 5.0~6.0 and add chlorine dioxide to the mixing container to a concentration of 200µM.

[0064] UV irradiation with the same power 365 Ultraviolet lamps, violet LED lamps, blue LED lamps, green LED lamps, orange LED lamps, red LED lamps, and infrared lamps were used as light sources to replace natural sunlight for photocatalytic reaction. The SMX removal rate was measured after 5 minutes of reaction.

[0065] The results are as follows Figure 6As shown, Figure 6 Experimental results show that, since the strongest absorption peak of chlorine dioxide is located near 360 nm, in a single wavelength light source, UV... 365 The degradation rate of ultraviolet lamps is relatively high (k=0.2088 min). -1 Blue and purple LEDs have a certain activation effect (k = 0.062 min). -1 Red light and infrared light alone have no significant degradation effect.

[0066] In contrast, the CSL / ClO2 system of this invention exhibits a significant performance advantage (using the treatment method of Example 2), with a degradation rate constant as high as 0.57 min. -1 They are pure UV 365 The efficiency is 2.7 times and more than 9 times that of blue / violet LED irradiation systems, respectively. Therefore, the CSL system of this invention not only utilizes the ultraviolet to blue light band for direct photochemical activation, but also converts the infrared band into in-situ local thermal energy through full-spectrum focusing, stimulating a strong photothermal synergistic effect. This coupling effect breaks through the rate bottleneck of a single photochemical reaction, making its overall degradation efficiency significantly better than that of traditional single-wavelength light source systems.

[0067] Example 6 A wastewater treatment method utilizing the concentrated sunlight treatment system described in Example 1 is disclosed. This example investigates the influence of common coexisting ions and natural organic matter in the water on the degradation effect. The specific steps are as follows: (1) Take a simulated water sample and add sulfamethoxazole (SMX) to it to a concentration of 10 mg / L. Add specific concentrations of chloride ions (Cl) to different water samples respectively. - ), copper ions (Cu) 2+ ), magnesium ions (Mg 2+ ), bicarbonate (HCO3) - ) and humic acid (HA) were added to simulate coexisting interfering substances in complex aquatic environments. Chlorine dioxide was added to a concentration of 200 μM, the pH was adjusted to 5.0-6.0, and the mixture was stirred thoroughly.

[0068] (2) The irradiation reaction was carried out using the concentrated solar treatment system (CSL) described in Example 1. Samples were taken at specific time intervals, filtered, and excess ascorbic acid was added to terminate the reaction. The reaction solution was used for HPLC detection of pollutant content, and the degradation rate constant k and removal rate were calculated. The remaining steps were the same as in Example 2.

[0069] The results are as follows Figure 7 As shown, Figure 7 Experimental results show that the CSL / ClO2 system of this invention exhibits excellent anti-interference ability against multiple coexisting substances. After 5 min of reaction, the system in Cl...- Cu 2+ and Mg 2+ The removal rates under the given conditions all exceeded 90%, indicating that these common inorganic ions have virtually no inhibitory effect on the photothermal synergistic catalytic process. When HCO3- is present in the system... - When HA was used, the degradation rate constant decreased by 0.4177 min. -1 and 0.3992 min -1 This is mainly due to HCO3 - As a typical free radical quencher, HA competitively consumes active free radicals generated within the system. HA, as a natural organic compound, not only competitively consumes free radicals but also possesses a certain light-shielding effect. However, even in HCO3... - Despite the significant inhibitory effect of HA, the removal rate of SMX remained above 85% after 5 minutes of reaction. This result fully demonstrates the strong robustness and broad practical application prospects of the system described in this invention in complex water matrices.

[0070] Comparative Example 1 SMX removal was performed according to the method in Example 2, except that ClO2 was not added; all other conditions were the same as in Example 2.

[0071] A simulated water sample containing 20 μM of SMX was taken, and the pH was adjusted to 5.0–6.0. ​​Without adding ClO2, the sample was irradiated for 5 minutes using the concentrated sunlight treatment system described in Example 1. The SMX removal rate was measured to be only 22%, demonstrating that using the concentrated sunlight treatment system alone has limited effectiveness in degrading SMX.

[0072] Comparative Example 2 SMX removal was performed according to the method in Example 2, with the only difference being that only ClO2 was added and there was no light exposure; all other conditions were exactly the same as in Example 2.

[0073] A simulated water sample containing 20 μM of SMX was taken, the pH was adjusted to 5.0–6.0, and chlorine dioxide was added to a concentration of 200 μM. The mixture was reacted for 30 min under light-protected conditions. The SMX removal rate was measured to be 20%, demonstrating that the oxidation capacity of chlorine dioxide alone is limited.

[0074] Comparative Example 3 SMX removal was performed according to the method of Example 2, except that sunlight (SL) was used instead of the CSL system; all other conditions were exactly the same as in Example 2.

[0075] A simulated water sample containing 20 μM SMX was taken, the pH was adjusted to 5.0-6.0, and chlorine dioxide was added to a concentration of 200 μM. The sample was then directly irradiated with sunlight for 5 minutes. The SMX removal rate was determined to be 37%, which differs significantly from the method of this invention. Furthermore, the detection of byproducts revealed ClO3... - The amount produced was 1.24 mg / L, exceeding the WHO standard, and chlorinated organic byproducts such as chloroform were detected.

[0076] The above comparative examples demonstrate that the method of the present invention has the significant advantage of low by-product generation while maintaining high degradation efficiency.

[0077] The SMX degradation performance of CSL / ClO2 in Example 2 compared with that of CSL-only treatment in Comparative Example 1, ClO2-only treatment in Comparative Example 2, and SL / ClO2 treatment in Comparative Example 3. The degradation performance of the CSL / ClO2 system provided in Example 2, the CSL-only treatment in Comparative Example 1, the ClO2-only treatment in Comparative Example 2, and the SL / ClO2 treatment in Comparative Example 3 were tested and compared as follows: In the aforementioned experiments, the spectral amplification capability of the CSL system has been quantitatively demonstrated, but its actual effectiveness depends on the light absorption characteristics of the target pollutant itself. Figure 2 As shown, the removal rates of SMX by CSL irradiation, ClO2 oxidation, CSL / ClO2, and SL / ClO2 were 22%, 19%, 93%, and 37%, respectively. SMX is almost impossible to be photodegraded because its quantum yield is very low. Figure 2 The SMX system, which showcases SL and CSL, was demonstrated. Comparative analysis of degradation rates. At a constant degradation temperature of 50°C, the CSL system exhibited a degradation rate 5.7 times higher than the SL system. This temperature increase highlights the role of CSL as a free heat energy source, generating in-situ infrared radiation (>750 nm, approximately 50% of sunlight). CSL's superior solar energy utilization capability suggests that this technology holds promise as a highly efficient, zero-energy water treatment method for SMX degradation.

[0078] Application Experiment 1 This experiment is an example of optimizing key operating parameters for the method in Example 2 for treating sulfamethoxazole (SMX) in natural water bodies. The specific steps are as follows: I. Optimization Experiment of Chlorine Dioxide Dosage (1) Take purified water and add sulfamethoxazole (SMX) to a concentration of 5 mg / L, and dispense into 50 mL aliquots. Add different volumes of chlorine dioxide stock solution to make the final ClO2 concentrations in the reaction system 50, 100, 150, 200, 250, and 300 µM (corresponding to mass concentrations of approximately 2.5, 5, 10, 12.5, and 15 mg / L). Stir at 50°C for 1 minute to mix thoroughly.

[0079] (2) The water body was irradiated using the concentrated solar power system described in Example 1, and the spectral / photon flux and local temperature changes were recorded. The total reaction time was 5 min. At specific time intervals (0, 1, 2, 3, 4, 5 min), 1 mL of the reaction solution was taken and filtered through a 0.45 µm microporous filter. After each sampling, excess ascorbic acid was added immediately to terminate the reaction. The residual concentration of SMX was determined by liquid chromatography and denoted as C. The removal rate N of SMX was calculated according to the formula N = (C0 - C) × 100%, where C0 is the initial concentration of SMX.

[0080] Figure 3 The degradation kinetics of SMX by the CSL / ClO2 system in Example 2 at different ClO2 concentrations (50–300 µM) are shown. Figure 3 It was found that when the ClO2 dosage was 50-150 µM, the SMX removal rate significantly increased with increasing dosage after 5 min of reaction, and the reaction rate accelerated significantly. Further increasing the ClO2 dosage to 200 µM (approximately 10 mg / L) further increased the SMX removal rate to 94%, achieving the optimal degradation effect. When the ClO2 dosage exceeded 250 µM (approximately 12.5 mg / L), the SMX removal rate no longer increased significantly. Considering both degradation effect and reagent cost, the preferred ClO2 dosage is 150–200 µM, and more preferably 200 µM (approximately 10 mg / L).

[0081] II. pH Optimization Experiment (1) Take purified water and add sulfamethoxazole (SMX) to a concentration of 5 mg / L, and dispense into 50 mL aliquots. Adjust the pH of the reaction system to 4.0, 5.0, 6.0, 7.0, and 8.0 using hydrochloric acid or sodium hydroxide solution. Add ClO2 to a final concentration of 200 µM and stir at 50°C for 1 minute to ensure uniform mixing.

[0082] (2) The water body was irradiated using the concentrated sunlight treatment system described in Example 1. The total reaction time was 5 min. Samples were taken, filtered, the reaction was terminated, and the remaining concentration of SMX was measured within a specific time interval. The steps were the same as before.

[0083] Figure 4The degradation kinetics of SMX by the CSL / ClO2 system of Example 2 under different pH conditions (4–8) are shown. Figure 4 It was found that the CSL / ClO2 system exhibited the best degradation effect on SMX under slightly acidic conditions (pH 5–6), with a removal rate of 90–98% after 5 min of reaction. When the pH was further increased to 8.0, the SMX removal rate significantly decreased to 85%, which may be because the formation pathway of active species is inhibited under alkaline conditions. The results indicate that the CSL / ClO2 system has the best degradation performance under slightly acidic conditions (pH 5–6).

[0084] Based on the above experimental results, the optimal operating parameters for the CSL / ClO2 system to treat sulfamethoxazole were determined to be: ClO2 dosage of 150–200 µM (preferably 200 µM) and pH of the reaction system controlled within the range of 5–6. Under these optimized conditions, the SMX removal rate can reach over 90% within 5 minutes of reaction, which is significantly better than other parameter combinations.

[0085] Application Experiment 2 This experiment is an application example of the method in Example 2 for treating different types of pollutants in natural wastewater. The specific steps are as follows: (1) Simulated water samples containing different sulfonamides and quinolones were prepared, including sulfadiazine (SD), sulfamethoxazole (SMX), sulfathiazole (STZ), norfloxacin (NFX), ofloxacin (OPX), ciprofloxacin (CIP), sulfisoxazole (SIZ), and sulfapyridine (SPD), with an initial concentration of 5 mg / L. 50 mL of each sample was placed in a reaction vessel. 250 µL of chlorine dioxide (effective chlorine concentration of 10 mg / L) was added, and the mixture was stirred at 50 °C for 1 minute to ensure homogeneity. An ultrapure water system was set up as a control group, and experiments were conducted on CSL irradiation alone, ClO2 oxidation alone, and CSL / ClO2 synergistic effects.

[0086] (2) Then, the water body was irradiated with the concentrated sunlight treatment system described in Example 1 to carry out an oxidation reaction, and the spectrum / photon flux and local temperature changes were recorded. At specific time intervals (0, 1, 2, 3, 4, 5 min), 1 mL of the reaction solution was taken and filtered through a 0.45 µm microporous filter. After each sampling, excess ascorbic acid was added to terminate the reaction. The reaction solution was then used for liquid chromatography to detect the residual concentration of each pollutant, which was recorded as C. The removal rate N of each pollutant was calculated according to the formula N = (C0 - C) × 100%, where C0 is the initial concentration of the pollutant.

[0087] Figure 8The degradation kinetics of different sulfonamides and quinolones in the CSL / ClO2 system of Example 1 within 5 min of reaction are shown. Figure 8 The CSL / ClO2 system exhibited excellent degradation effects on various sulfonamide and quinolone pollutants. Specifically, the removal rate of the non-photosensitive pollutant SMX reached 94% within 5 minutes, while the removal rates under CSL irradiation alone and ClO2 oxidation alone were only 4% and 15%, respectively, confirming the highly efficient activation effect of CSL on chlorine dioxide. The degradation effects on sulfadiazine (SD), norfloxacin (NFX), and ciprofloxacin (CIP) were also significant, with removal rates exceeding 90% after 5 minutes of reaction. The degradation effects on sulfathiazole (STZ) and sulfisoxazole (SIZ) were slightly lower, but the removal rates still exceeded 60%. These results indicate that the CSL / ClO2 system can effectively activate chlorine dioxide, generating highly active oxide species, and possesses broad-spectrum and highly efficient degradation capabilities for sulfonamide and quinolone pollutants with different structural characteristics and photosensitivity.

[0088] Application Experiment 3 This experiment is an application example of the method in Example 2 for treating sulfamethoxazole (SMX) in different complex natural water bodies. The specific steps are as follows: (1) Take actual water bodies such as tap water, river water, lake water, seawater and groundwater respectively, and add sulfamethoxazole (SMX) to them to make the SMX concentration in these actual waters 10 mg / L. Add ClO2 to the final concentration of 200 µM, and stir at 50℃ for 1 minute to mix evenly. During this process, ultrapure water (simulated water sample) is taken as a control group.

[0089] (2) Then, the water body was irradiated with the concentrated sunlight treatment system described in Example 1 to carry out an oxidation reaction, and the spectrum / photon flux and local temperature changes were recorded. At specific time intervals (0, 1, 2, 3, 4, 5 min), 1 mL of the reaction solution was taken and filtered through a 0.45 µm microporous filter. After each sampling, excess ascorbic acid was added to terminate the reaction. The reaction solution was then used for liquid chromatography to detect the residual concentration of each pollutant, which was recorded as C. The removal rate N of each pollutant was calculated according to the formula N = (C0 - C) × 100%, where C0 is the initial concentration of the pollutant.

[0090] Figure 9 Experimental results demonstrate the degradation kinetics of SMX by the CSL / ClO2 system in different real natural water samples after 5 min of reaction. The treatment system of this invention exhibits good degradation effects on SMX in both ultrapure water and other natural water bodies. The degradation effect is best in tap water and seawater systems, with a degradation rate constant (k) reaching 0.4465 min after 5 min of reaction.-1 and 0.4198 min -1 The removal rates all reached over 87%. In river water, lake water, and groundwater with more complex compositions, although the naturally occurring organic matter (NOM) and coexisting ions in the actual water bodies may compete with the active oxide species, the system's removal rates for SMX remained at approximately 58%, 48%, and 46%, respectively. This indicates that the CSL / ClO2 system of this invention has extremely strong anti-interference capabilities and is fully capable of practical engineering applications in various complex natural water qualities such as river water, lake water, and wastewater.

[0091] In summary, this invention provides a method for degrading aquatic pollutants (represented by sulfonamides) based on concentrated solar radiation (CSL) system-activated chlorine dioxide. It significantly enhances the production of reactive free radicals (·OH / Cl·, etc.) by utilizing high photon flux and photothermal synergy, achieving highly efficient degradation of various novel pollutants, particularly the non-photosensitive pollutant sulfamethoxazole (SMX), fully verifying the highly efficient activation effect of concentrated solar radiation system on chlorine dioxide. Furthermore, this invention provides a new approach to solar-driven advanced oxidation technologies and offers a reference for developing green, energy-saving, and efficient water treatment technologies. Therefore, it has broad application prospects in advanced drinking water treatment, wastewater resource utilization, and emergency response to sudden water pollution incidents.

Claims

1. A concentrated solar power system for activating chlorine dioxide to degrade new pollutants in water, characterized in that, Includes light-gathering units and reaction units; The light focusing unit includes a Fresnel lens, an adjustable support, and a magnetic base; The adjustable bracket is connected to the Fresnel lens by means of fixed connection, snap-fit, clamping or detachable connection, and the adjustable bracket is used to support and adjust the angle and height of the Fresnel lens; The adjustable bracket includes a connecting forearm, a height adjustment rod, an angle adjustment pivot, and a movable fulcrum and a fixed fulcrum; The lower end of the height adjustment rod is connected to the top end of the movable fulcrum and the fixed fulcrum. The height adjustment rod is used to adjust the vertical height of the Fresnel lens. The top end of the height adjustment rod is connected to one end of the forearm via an angle adjustment pivot. The other end of the forearm is equipped with a crab claw clamp, which can hold the edge of the Fresnel lens to fix the Fresnel lens and prevent it from shifting position. The bottom ends of the movable fulcrum and the fixed fulcrum are fixedly connected to the top end of the magnetic base. The adjustable bracket is connected to a highly stable magnetic base through the movable fulcrum and the fixed fulcrum. The movable and fixed fulcrums are used to assist in adjusting the spatial position of the Fresnel lens to ensure that the light spot accurately covers the reaction area. The reaction unit includes a transparent reaction container located in the focal region or focal line region of the Fresnel lens, the transparent reaction container being used to contain water to be treated containing chlorine dioxide and the target pollutant.

2. The system according to claim 1, characterized in that, The Fresnel lens is made of optical-grade high-transmittance material and has high transmittance. It can make full use of all direct and scattered light within the full spectrum of sunlight to converge natural sunlight into high-density concentrated sunlight.

3. The system according to claim 1, characterized in that, The transparent reaction container is a cylindrical quartz glass bottle made of high-transmittance quartz glass with a transmittance of ≥90% for light with wavelengths of 200–800 nm, and can withstand the local temperature rise caused by focusing. The bottom of the transparent reaction container is equipped with a magnetic stirrer, and a magnetic stir bar is installed inside the transparent reaction container. The magnetic stirrer can drive the rotation of the magnetic stir bar to stir the reaction solution inside the transparent reaction container, so as to maintain the uniform mixing of the solution inside the transparent reaction container during the reaction process.

4. The application of the concentrated solar power system according to claim 1 in the degradation of water pollutants, characterized in that, The pollutants are one or more of the following: sulfamethoxazole, diflufloxacin, ofloxacin, sulfadiazine, sulfisoxazole, sulfathiazole, norfloxacin, ciprofloxacin, tetracycline, oxytetracycline, etc.

5. A method for treating polluted water bodies or degrading pollutants in water bodies using the concentrated solar power treatment system according to any one of claims 1-3, characterized in that, Includes the following steps: a. Mix the water containing pollutants with chlorine dioxide in a mixing container and stir at 45-55°C for 1-5 minutes to obtain a pre-reaction solution; b. Inject the pre-reaction liquid into the transparent reaction vessel of the focused sunlight treatment system; c. By adjusting the adjustable support, the Fresnel lens focuses natural sunlight into focused sunlight, which then irradiates the pre-reaction liquid in the transparent reaction container to carry out the degradation reaction. At this time, the ultraviolet / visible light band in the focused sunlight triggers the photochemical activation of chlorine dioxide, while the infrared band generates an in-situ photothermal effect. Through the photothermal synergy, the new pollutants are efficiently degraded. d. After the reaction is complete, quenching can be achieved by adding a quenching agent to the reaction solution; The pollutants are one or more of the following: sulfamethoxazole, diflufloxacin, ofloxacin, sulfadiazine, sulfisoxazole, sulfathiazole, norfloxacin, ciprofloxacin, tetracycline, oxytetracycline, etc.

6. The method according to claim 5, characterized in that, The final concentration of chlorine dioxide in step a is 50–300 µM; the pH of the water to be treated is adjusted to 4.0–8.0; the water to be treated is ultrapure water, tap water, or natural water or wastewater containing inorganic interfering ions and natural organic matter.

7. The method according to claim 5, characterized in that, The irradiation time for focusing sunlight in step c is 1-5 minutes, and the total cumulative solar radiation irradiance at the target focal spot is 300-2800 J / cm². 2 During irradiation, the diameter of the focused spot is controlled by changing the diameter of the light-shielding ring on the Fresnel lens or adjusting the distance between the lens and the reaction container, thereby precisely controlling the irradiation input power.

8. The method according to claim 5, characterized in that, The reaction time in step c is 1–30 min, during which the total cumulative solar radiation irradiance at the target focal spot is preferably 1200–1800 J / cm². 2 .

9. A method for treating polluted water bodies or degrading pollutants in water bodies using the concentrated sunlight treatment system of claim 1 and chlorine dioxide to form a pollutant degradation system, characterized in that, Includes the following steps: 1) Adjust the pH of the pollutant-containing water to 4.0-8.

0. If the turbidity of the water is too high, filtration pretreatment can be carried out to reduce light attenuation. 2) Add chlorine dioxide to the pretreated water until the concentration of chlorine dioxide is 50-300 µM. The addition method is a one-time addition. 3) The water body is irradiated by the aforementioned concentrated sunlight treatment system to carry out the degradation reaction. During this process, the Fresnel lens is adjusted by adjusting the adjustable support to concentrate natural sunlight onto the transparent reaction container. The irradiation time is 1-30 min. The irradiation intensity and cumulative irradiance can be precisely controlled by changing the aperture diameter (10-50 mm) on the Fresnel lens or adjusting the distance between the lens and the reactor. 4) After the reaction is complete, to prevent residual chlorine dioxide or byproducts in the water from continuing to react, quench them by adding a quenching agent.

10. The method according to claim 9, characterized in that, The pollutants are one or more of the following: sulfamethoxazole, diflufloxacin, ofloxacin, sulfadiazine, sulfisoxazole, sulfathiazole, norfloxacin, ciprofloxacin, tetracycline, oxytetracycline, etc.

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