Photocatalytic optical fiber in-situ remediation well device for treating organic pollution of underground water

Abstract

The invention discloses a photocatalytic optical fiber in-situ remediation well device for treating organic pollution of underground water, and relates to the technical field of environmental remediation, the photocatalytic optical fiber in-situ remediation well device comprises a light source, a shaft and an optical fiber, the in-situ remediation well device is fixed by the shaft, the optical fiber is arranged in the shaft, and the light source is arranged at the top of the optical fiber. The photocatalytic oxidation method is combined and used in the in-situ chemical oxidation remediation process of the underground water, the in-situ chemical oxidation remediation efficiency of organic pollution of the underground water is enhanced, the using amount of an oxidizing agent is reduced, and then the risk of secondary pollution is reduced. The coating technology is adopted, the light-emitting diode is used as a light source, the coating technology is combined with optical fiber conduction to achieve direct irradiation of light to the catalyst, the photocatalytic efficiency is improved, the catalyst can be recycled, and the problems that illumination is insufficient, and the photocatalyst is difficult to recycle are solved.

Description

Technical Field

[0001] This invention relates to the field of environmental remediation technology, and in particular to a photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater. Background Technology

[0002] Currently, in-situ remediation wells are the main method for treating organic pollution in groundwater. This technology involves introducing oxidants into the target water body through remediation wells. However, this method has three main drawbacks: 1. Excessive use of oxidants: Due to factors such as non-targeted consumption of oxidants in the polluted groundwater environment, limited diffusion capacity of oxidants, and low mass transfer efficiency of pollutants, the actual amount of oxidants added is often more than three times the theoretical requirement; 2. Risk of secondary pollution: Because the reaction between the oxidant and the target pollutants is incomplete, some more toxic intermediate products may be generated. In addition, the non-targeted consumption of oxidants may also cause secondary environmental problems such as the activation and migration of heavy metals and fluctuations in the pH value of the water body; 3. Low efficiency of non-advanced oxidation: Traditional oxidants have limited ability to degrade persistent organic compounds (POPs), their reactivity is significantly reduced at low temperatures, and the groundwater matrix interferes with the oxidation process.

[0003] Therefore, those skilled in the art are dedicated to developing a novel photocatalytic fiber optic in-situ remediation well device, aiming to enhance the in-situ chemical oxidation remediation efficiency of organic pollution in groundwater.

[0004] This invention proposes a highly efficient and sustainable technology—photocatalytic oxidation—for in-situ chemical oxidation remediation of groundwater. The photocatalyst receives light energy and generates oxidizing substances such as ·OH to degrade organic pollutants in the water. The photogenerated electrons (e) produced during the photocatalytic process... - It can directly drive the activation of oxidants such as persulfate (PMS). - +HSO5 - →SO4 ·— +OH - Improving oxidant utilization rate reduces oxidant usage and consequently the risk of secondary pollution. Photocatalytic activation of PMS produces SO4. ·— The ·OH dual free radicals, through electron transport inhibition and recombination, synergistically degrade pollutants, and the synergistic remediation effect of photocatalysis and PMS is significantly better than that of single technologies. However, applying heterogeneous photocatalysis technology to in-situ groundwater remediation faces problems such as the difficulty in recovering powdered photocatalysts and the lack of light in the groundwater environment, making it difficult to introduce light. This device proposes to use LED lights as the light source and optical fibers as the light transmission channel and the fixed carrier of the photocatalyst, thereby solving the problems of insufficient light and difficulty in recovering the photocatalyst. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to use photocatalytic oxidation in the in-situ chemical oxidation remediation process of groundwater.

[0006] To achieve the above objectives, the present invention provides a photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater, characterized in that it includes a light source, a well casing, and an optical fiber, wherein the in-situ remediation well device is fixed by the well casing, the optical fiber is disposed inside the well casing, and the light source is disposed at the top of the optical fiber.

[0007] Furthermore, the surface of the optical fiber has a photocatalyst.

[0008] Furthermore, the photocatalyst is attached to the surface of the optical fiber using a coating technique.

[0009] Furthermore, the light emitted by the light source is transferred inside the optical fiber and leaks out at the end or side of the optical fiber.

[0010] Furthermore, it also includes seepage holes, and the well shaft is provided with multiple seepage holes, through which groundwater can flow into or out of the well shaft.

[0011] Furthermore, it also includes an oxidant injection pipe disposed inside the wellbore.

[0012] Furthermore, it also includes an oxidant addition port through which the oxidant is injected into the oxidant injection tube.

[0013] Furthermore, it also includes a pressure pump, which is disposed between the oxidant addition port and the oxidant injection pipe, and the oxidant enters the oxidant injection pipe after being acted upon by the pressure pump.

[0014] Furthermore, the light source is a light-emitting diode (LED) light source.

[0015] Furthermore, the diameter of the optical fiber is 10 mm.

[0016] The beneficial technical effects of the present invention are as follows: 1. Existing in-situ chemical oxidation technologies suffer from problems such as excessive use of oxidants, low treatment efficiency, and secondary pollution. Photocatalysis technology also needs to address the issue of how to directionally transmit light into the underground environment. This invention enhances the ISCO (In-situ Chemical Oxidation) of persulfate (PMS) through photocatalysis, resulting in synergistic effects, improved removal efficiency, and reduced PMS dosage. Optical fiber is used to achieve directional light transmission. The photocatalyst receives light energy and generates oxidizing active substances such as ·OH, which can directly degrade organic pollutants in water without relying on oxidants, thus reducing oxidant usage. The photogenerated electrons from photocatalysis react with oxidants such as PMS to generate free radicals (·OH and SO4·). -This synergistic enhancement of oxidation capacity reduces PMS usage and thus mitigates secondary pollution. Light travels through optical fibers, leaking at the fiber surface or end. PMS, CNT-PMMA / LED, CNT-PMMA / LED / PMS (CNT- g The degradation rates of benzo(a)pyrene (BaP) in the three systems (C3N4 / TiO2, LED, and PMMA) were 4.33%, 47.13%, and 91.58%, respectively. Light transmitted via optical fiber can directly reach the core pollution area, with a transmission efficiency far exceeding other methods (natural light has difficulty penetrating underground polluted bodies, and incident light directly hitting the water surface is subject to scattering, refraction, and other losses).

[0017] 2. Photocatalysts themselves may cause secondary pollution, and powdered catalysts present recycling challenges. In practical applications, it is also necessary to improve the efficient excitation of photocatalysts by light in groundwater environments. This invention employs coating technology, which, combined with optical fiber transmission, enables direct light irradiation of the catalyst, improving photocatalytic efficiency and eliminating the need for catalyst recycling. This invention attaches the photocatalyst to the outer surface of the optical fiber, preventing the free diffusion of powdered photocatalysts in water and thus avoiding pollution. The photocatalyst is recovered along with the optical fiber. Light is transmitted radially through the optical fiber, directly irradiating the catalyst coating from the inside out, avoiding light loss due to refraction and scattering in water, thereby improving photocatalytic efficiency. The coated optical fiber prevents secondary pollution of the catalyst in water. After repair, the device can be removed without requiring catalyst recycling in the water. Through comparative experiments, using the presence or absence of optical fiber as the experimental variable, the degradation rates of BaP in the CNT-PMMA / LED / PMS system and the CNT / LED / PMS system were 91.58% and 82.71%, respectively.

[0018] 3. Traditional light sources have high energy consumption, short lifespan, and wide radiated wavelengths. This invention uses light-emitting diodes (LEDs), which have low power consumption, long lifespan, and narrow spectral density. The emission wavelength of LEDs can be precisely matched to the absorption peak of photocatalysts (e.g., TiO2 requires the ultraviolet region of 365nm), and the narrow-band spectrum (half-width at half maximum < 15nm) avoids energy loss in ineffective wavelengths. LED power consumption is reduced by 80% (only 5-10W / m is required), and the lifespan is >100,000 hours, avoiding the energy consumption and solid waste problems associated with frequent replacement of traditional ultraviolet lamps. Through comparative experiments, using the presence or absence of LED illumination as the experimental variable, the degradation rates of BaP in the CNT-PMMA / LED / PMS system and the CNT-PMMA / PMS system were 91.58% and 24.18%, respectively.

[0019] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a fiber optic photocatalytic in-situ repair well structure according to a preferred embodiment of the present invention; Among them, 1-LED light, 2-well barrel, 3-coated optical fiber, 4-water seepage hole, 5-oxidant injection pipe, 6-oxidant addition port, 7-pressure pump. Detailed Implementation

[0021] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0022] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0023] like Figure 1 As shown, the present invention discloses an optical fiber device for in-situ photocatalytic remediation of groundwater, including an LED light 1, a well shaft 2, a coated optical fiber 3, a seepage hole 4, an oxidant injection pipe 5, an oxidant addition port 6, and a pressure pump 7.

[0024] The main body of this device consists of a coated optical fiber 3 with a photocatalyst attached to its surface using coating technology, and an LED light 1 at the top of the optical fiber. The main body of the device is fixed externally by a well casing 2, and groundwater can flow into and out of the main body of the device through seepage holes 4. Inside the well casing 2, there is also an oxidant injection pipe 5. The oxidant enters the treated water body through the oxidant addition port 6 and is then pumped into the water body by a pressure pump 7.

[0025] During operation, contaminated groundwater enters the device through seepage hole 4. The optimal wavelength of light from LED lamp 1 is determined based on the properties of the coated catalyst. The light is transferred within the coated optical fiber 3, eventually leaking out at the fiber end or side. Simultaneously, the oxidant enters the device through addition port 6 and pressurization pump 7. The photocatalyst, activated by light, synergistically interacts with the oxidant, significantly enhancing oxidation capacity. In the experiment, the optimal diameter of 10 mm was determined by fitting the photocatalytic enhancement of BaP degradation by PMS using optical fibers of different diameters based on experimental data and a first-order reaction kinetic model. At 25℃, pH=7, with the contaminated wastewater containing 1 mg / L benzo(a)pyrene (BaP) and the oxidant being 0.15 g / L persulfate (PMS), a 30-minute dark adsorption followed by a 150-minute photoreaction resulted in a BaP degradation rate of 91.58%.

[0026] Stability tests on the coated optical fiber 3 showed that after four cycles of use, the photocatalytic coating still maintained a BaP degradation rate of 69.12%. XRD analysis indicated that the crystal phase structure of the catalyst remained stable before and after use, and the performance degradation was mainly due to physical loss and the blockage of active sites by intermediate products.

[0027] The present invention discloses a photocatalytic fiber optic in-situ remediation device for wells. Through experiments at pH=7, with the wastewater containing 1 mg / L benzo(a)pyrene (BaP) and the oxidant being 0.15 g / L persulfate (PMS), and after four consecutive cycles, the removal rate of BaP was 91.58%–90.12%.

[0028] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater, characterized in that, The device includes a light source, a well casing, and an optical fiber. The in-situ repair well device is fixed by the well casing, the optical fiber is disposed inside the well casing, and the light source is disposed on top of the optical fiber.

2. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 1, characterized in that, The surface of the optical fiber has a photocatalyst.

3. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 2, characterized in that, The photocatalyst is attached to the surface of the optical fiber using a coating technique.

4. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 3, characterized in that, The light emitted by the light source is transferred inside the optical fiber and leaks out at the end or side of the optical fiber.

5. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 1, characterized in that, It also includes seepage holes, and the well barrel is provided with multiple seepage holes, through which groundwater can flow into or out of the well barrel.

6. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 1, characterized in that, It also includes an oxidant injection pipe, which is disposed inside the wellbore.

7. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 6, characterized in that, It also includes an oxidant inlet, through which the oxidant is injected into the oxidant injection tube.

8. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 7, characterized in that, It also includes a pressure pump, which is located between the oxidant addition port and the oxidant injection pipe, and the oxidant enters the oxidant injection pipe after being acted upon by the pressure pump.

9. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 1, characterized in that, The light source is a light-emitting diode (LED) light source.

10. The photocatalytic fiber optic in-situ remediation well device for treating organic pollution in groundwater as described in claim 1, characterized in that, The diameter of the optical fiber is 10 mm.

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