Integrated device and method for photocatalytic treatment of laboratory wastewater

Abstract

The present application discloses an integrated device and method for photocatalytic treatment of laboratory wastewater, which relates to the field of sewage treatment technology. It solves the problem of complex treatment process and high treatment cost of existing integrated laboratory wastewater treatment equipment. The device includes a feeding chamber, a sedimentation chamber and a photocatalytic reaction chamber that are connected in sequence; the feeding chamber is arranged above the sedimentation chamber, and the photocatalytic reaction chamber is arranged on the outside of the sedimentation chamber; the feeding chamber includes a wastewater addition chamber, a waste acid addition chamber, a waste alkali addition chamber and a flocculant addition chamber; a stirring assembly is provided in the sedimentation chamber; the photocatalytic reaction chamber is made of a light-transmitting material; a photocatalyst plate is provided in the photocatalytic reaction chamber; a driving device is provided outside the photocatalyst reaction chamber; the driving device can drive the photocatalyst plate and the stirring assembly to rotate; a photocatalyst is attached to the photocatalyst plate. The present application also provides a photocatalytic treatment method based on the above-mentioned integrated device for photocatalytic treatment of laboratory wastewater.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and in particular to an integrated device and method for photocatalytic treatment of laboratory wastewater. Background Art

[0002] With the development of society, more and more researchers are entering the laboratory. During the experimental process, the samples collected, reagents used, and washing solutions are not large in volume. As a result, some people do not pay enough attention to the collection and treatment of wastewater, which has a great impact on the surrounding environment, human water use, and human health. At the same time, because the harm caused is chronic and not immediately apparent, there is an urgent need to collect and treat laboratory wastewater in a timely manner.

[0003] The Chinese patent "Integrated Laboratory Wastewater Treatment Equipment" (publication number: CN202440397U) discloses an integrated laboratory wastewater treatment device, including a wastewater inlet, an integrated device box, a centralized controller, a nano-coated wastewater collection box, a physical sediment collection device, a physical sediment drain valve, a stainless steel filter, an ozone generator, a sensor device, a quartz glass sleeve UV lamp, a nano-titanium dioxide delivery box, a water outlet, a circulation pipe, and an activated carbon filter device. This integrated laboratory wastewater treatment equipment has the ability to treat inorganic, organic, biochemical and microbial wastewater, has a wide range of applications, and has strong treatment capabilities. However, this equipment has the disadvantages of complex treatment processes and high treatment costs. Summary of the Invention

[0004] The embodiments of the present application provide an integrated device and method for photocatalytic treatment of laboratory wastewater, which solves the problems of complex treatment process and high treatment cost of existing integrated laboratory wastewater treatment equipment.

[0005] To achieve the above-mentioned objectives, on the one hand, an embodiment of the present application provides an integrated device for photocatalytic treatment of laboratory wastewater, comprising a feeding chamber, a sedimentation chamber and a photocatalytic reaction chamber connected in sequence; the feeding chamber is arranged above the sedimentation chamber, and the photocatalytic reaction chamber is arranged outside the sedimentation chamber, and the photocatalytic reaction chamber and the sedimentation chamber are controlled by a first valve; the feeding chamber includes a wastewater feeding chamber, a waste acid feeding chamber, a waste alkali feeding chamber and a flocculant feeding chamber; a stirring assembly is provided in the sedimentation chamber; the photocatalytic reaction chamber is made of a light-transmitting material; a photocatalyst plate is provided in the photocatalytic reaction chamber; a driving device is provided outside the photocatalytic reaction chamber; the driving device can drive the photocatalyst plate and the stirring assembly to rotate; a photocatalyst is attached to the photocatalyst plate.

[0006] Furthermore, the feeding chamber is a cube, and its interior is divided into the wastewater feeding chamber, the waste acid feeding chamber, the waste alkali feeding chamber and the flocculant feeding chamber by a first partition; the first partition is placed along the diagonal of the feeding chamber; the wastewater feeding chamber, the waste acid feeding chamber, the waste alkali feeding chamber and the flocculant feeding chamber are all provided with a feeding port at the bottom; the lower part of the feeding port is connected to the sedimentation chamber through a feeding pipe.

[0007] Furthermore, the sedimentation chamber includes an upper cylindrical body and a hemispherical body sealed and connected to the lower part of the cylindrical body; the upper part of the sedimentation chamber is connected to the photocatalytic reaction chamber through a second partition; the bottom of the sedimentation chamber is connected to the outside of the device through a mud discharge pipe.

[0008] Furthermore, the driving device adopts a motor, which is arranged in a vertical direction; the output shaft of the motor is connected to a rotating shaft, and the stirring assembly and the photocatalyst plate are both connected to the rotating shaft; the rotating shaft is rotatably sealed to the bottom wall of the precipitation chamber and the photocatalytic reaction chamber.

[0009] Furthermore, the stirring assembly includes a plurality of scrapers and a plurality of sliders, the upper ends of the scrapers are connected to the corresponding sliders, and the lower ends are connected to the rotating shaft; the plurality of sliders are equidistantly distributed.

[0010] Furthermore, the inner wall of the sedimentation chamber is also provided with a plurality of through holes, and the through holes are located above the stirring assembly; the first valve is provided in the through hole; a mudguard is provided on the outside of the first valve; the mudguard includes a fan-shaped mudguard located below the through hole and a rectangular mudguard located on the left and right sides of the through hole.

[0011] Furthermore, the photocatalytic reaction chamber is a rectangular parallelepiped; the upper portion of the photocatalytic reaction chamber and the bottom of the feeding chamber are connected by a mortise and tenon structure.

[0012] Furthermore, a water inlet box is provided on the upper part of the outer wall of the photocatalytic reaction chamber, and a water outlet box is provided on the lower part; the outlet of the water inlet box and the inlet of the water outlet box are both connected to the photocatalytic reaction chamber; a third partition is provided in the water outlet box, and the height of the third partition is 1 / 3-1 / 2 of the height of the water outlet box.

[0013] Furthermore, the photocatalyst is a Cu2WS4 / Bi2WO6 composite photocatalyst; the preparation method of the photocatalyst comprises the following steps: Step 1, preparing bismuth tungstate: 1.1, dissolving 2mmol Bi(NO3)3·5H2O in 10mL EG, 0.5g CTAB in 10mL distilled water, and 1mmol Na2WO4·2H2O in 10mL distilled water; 1.2, dropping 10ml CTAB aqueous solution into 10ml 1.3. Mix the liquids obtained in steps 1.1 and 1.2 and stir for 20 minutes to obtain a precursor suspension; 1.4. Transfer the precursor suspension to a sealed autoclave and heat it at 180°C for 20 hours; After the autoclave is cooled to room temperature naturally, collect the original Bi2WO6 by centrifugation, wash it with distilled water and anhydrous ethanol three times, and then dry it in an oven at 80°C for 6 hours; Step 2. Prepare Cu2WS4 using CuCl, sodium tungstate and thioacetamide as copper source, tungsten source and sulfur source respectively: 2.1. Mix 15ml of ethanol and 15ml of Distilled water was mixed into solution A; 2.2, 2mmolCuCl, 1mmolNa2WO4·2H2O and 5mmol thioacetamide were dissolved in solution A and stirred for 1h; 2.3, after the mixed solution was stirred into a uniform brick-red suspension, it was transferred to a high-pressure reactor, and the reactor was heated in a blast oven at 120℃ for 24h, the reactor was taken out and cooled, and then washed and dried to collect Cu2WS4; Step 3: Preparation of Cu2WS4 / Bi2WO6 composite photocatalyst: 3.1, Cu2WS4 prepared in step 2 and 2mmol bismuth nitrate pentahydrate were dissolved in 10ml ethylene glycol, and stirred for half an hour to obtain a mixed solution B; 3.2, 1mmol Na2WO4·2H2O and 0.5g CTAB were dissolved in 10ml of distilled water and stirred for 10 minutes to obtain aqueous sodium tungstate solution and CTAB solution; 3.3. The aqueous CTAB solution was poured into mixed solution B, and after stirring for 10 minutes, the aqueous sodium tungstate solution was added to the mixed solution and stirred for another 20 minutes; 3.4. The mixed solution was transferred to an autoclave and sealed, and then moved to a 180-degree forced air oven and heated for 20 hours. After the reaction in the autoclave cooled, the composite photocatalyst was collected and washed with distilled water and anhydrous ethanol, and then dried in an 80°C oven for 6 hours to obtain a Cu2WS4 / Bi2WO6 composite photocatalyst.

[0014] On the other hand, the embodiment of the present application also provides a photocatalytic treatment method based on the above-mentioned laboratory wastewater photocatalytic treatment integrated device, comprising the following steps: step 1, adding the wastewater in the laboratory into the wastewater addition chamber, the waste acid addition chamber and the waste alkali addition chamber according to classification; step 2, after the wastewater enters the sedimentation chamber and reaches the preset capacity, turning on the motor; step 3, testing the pH value of the stirred wastewater, if it meets the requirements, proceeding to step 4; if it does not meet the requirements, continuing to add wastewater from the waste acid addition chamber or the waste alkali addition chamber and stirring until the pH value of the wastewater meets the requirements. After the requirement, proceed to step four; step four, add the flocculant into the sedimentation chamber through the flocculant addition chamber and continue stirring; step five, stop the motor, and let the wastewater obtained in step four stand to obtain flocculated wastewater, and open the first valve to allow the flocculated wastewater to enter the photocatalytic reaction chamber; step six, close the first valve, and restart the motor. The photocatalyst plate rotates in the flocculated wastewater driven by the motor to play a stirring role. At the same time, the flocculated wastewater contacts the photocatalyst on the photocatalyst plate under the action of light to produce a photocatalytic reaction, thereby eliminating organic matter in the wastewater.

[0015] Compared with the prior art, this application has the following beneficial effects:

[0016] 1. The integrated device for photocatalytic treatment of laboratory wastewater in the embodiment of the present application combines the upper feeding chamber and the lower treatment chamber (precipitation chamber and photocatalytic reaction chamber) together. The embedded combination of the precipitation chamber and the photocatalytic reaction chamber greatly reduces the footprint of the device and is more convenient for storage and use in the laboratory.

[0017] 2. The integrated device for photocatalytic treatment of laboratory wastewater in the embodiment of the present application can effectively classify and treat different wastewaters by setting four dosing chambers on the upper level of the device, which not only reduces the treatment process but also makes full use of waste acid and waste alkali to enable them to participate in the subsequent process of wastewater treatment; at the same time, the stirring assembly in the sedimentation chamber in the lower level of the device and the photocatalyst plate in the photocatalytic reaction chamber share a motor, thereby reducing energy consumption; in addition, the wastewater in the device mostly flows in each chamber by its own weight, further reducing energy consumption.

[0018] 3. The upper and lower parts of the integrated device for photocatalytic treatment of laboratory wastewater in the embodiment of the present application are combined by a mortise and tenon structure, which is convenient for dismantling for cleaning and adding materials.

[0019] 4. The integrated device for photocatalytic treatment of laboratory wastewater in the embodiment of the present application achieves the purpose of isolating flocculants and other suspended matter flowing out of the sedimentation chamber by setting a third partition in the water outlet tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 This is a schematic diagram of the three-dimensional structure of the integrated device for photocatalytic treatment of laboratory wastewater according to an embodiment of the present application;

[0022] Figure 2 This is a schematic diagram of the three-dimensional structure of the feeding chamber in the integrated device for photocatalytic treatment of laboratory wastewater in an embodiment of the present application;

[0023] Figure 3 This is a schematic diagram of the connection structure between the sedimentation chamber and the photocatalytic reaction chamber in the integrated device for photocatalytic treatment of laboratory wastewater in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0026] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0028] Reference Figures 1 to 3 , an embodiment of the present application provides an integrated device for photocatalytic treatment of laboratory wastewater, comprising a feeding chamber 1, a sedimentation chamber 2 and a photocatalytic reaction chamber 3 connected in sequence, the feeding chamber 1 is arranged above the sedimentation chamber 2, the photocatalytic reaction chamber 3 is arranged on the outside of the sedimentation chamber 2, and the photocatalytic reaction chamber 3 and the sedimentation chamber 2 are controlled by a first valve 25 to control the on-off between the photocatalytic reaction chamber 3 and the sedimentation chamber 2, and the sedimentation chamber 2 and the photocatalytic reaction chamber 3 together form a treatment chamber. A motor accommodating chamber 5 is also provided below the treatment chamber. A driving device, such as a motor 6, is installed in the motor accommodating chamber 5. A stirring assembly 4 is provided in the sedimentation chamber 2. The photocatalytic reaction chamber 3 is made of a light-transmitting material, such as glass. A photocatalyst plate 31 is provided in the photocatalytic reaction chamber 3.

[0029] The motor 6 is arranged in a vertical direction. The output shaft of the motor 6 is connected to the rotating shaft 7. The upper end of the rotating shaft 7 extends through the bottom wall of the photocatalytic reaction chamber 3 and the precipitation chamber 2 and enters the precipitation chamber 2. The stirring assembly 4 and the photocatalyst plate 31 are both connected to the rotating shaft 7. The rotating shaft 7 is rotatably and sealedly connected to the bottom wall of the precipitation chamber 2 and the photocatalytic reaction chamber 3.

[0030] The photocatalyst plate 31 is preferably a square plate so as to facilitate the water flow to stir. A photocatalyst (not shown) is attached to the photocatalyst plate 31 .

[0031] Reference Figure 1 and Figure 2 In some embodiments, the cross-section of the feeding chamber 1 is a cube, and its interior is divided into a wastewater feeding chamber 12, a waste acid feeding chamber 13, a waste alkali feeding chamber 14, and a flocculant feeding chamber 15 by multiple first partitions 11 placed along two diagonal corners. The wastewater feeding chamber 12, the waste acid feeding chamber 13, the waste alkali feeding chamber 14, and the flocculant feeding chamber 15 are each provided with a feeding port at the top and a feeding port at the bottom. For ease of description, the feeding port of the wastewater feeding chamber is denoted as 121, and the feeding port of the wastewater feeding chamber is denoted as 122. The feeding port of the waste acid feeding chamber is denoted as 131, and the feeding port of the waste acid feeding chamber is denoted as 132. The feeding port of the waste alkali feeding chamber is denoted as 141, and the feeding port of the waste acid feeding chamber is denoted as 142. The feeding port of the flocculant feeding chamber is denoted as 151, and the feeding port of the flocculant feeding chamber is denoted as 152.

[0032] The wastewater dosing chamber's feed port 121, waste acid dosing chamber's feed port 131, waste alkali dosing chamber's feed port 141, and flocculant dosing chamber's feed port 151 are all circular holes. The wastewater dosing chamber's feed port 122, waste acid dosing chamber's feed port 132, waste acid dosing chamber's feed port 142, and flocculant dosing chamber's feed port 152 are all located at the intersection of the partitions and are all quarter-circular holes, forming a single circular hole.

[0033] A dosing pipe 16 is provided at the dosing port. Its upper portion is connected to the dosing port, and its lower portion extends into the sedimentation chamber 2 and into its center. The wastewater dosing chamber's dosing port 122 is directly connected to the dosing pipe 16. The dosing ports 132, 142, and 152 of the waste acid dosing chamber are each equipped with a second valve (not shown). A pH detector 17 is provided at the outlet of the dosing pipe 16.

[0034] A vertical filter screen 18 is provided at the edge of the wastewater addition chamber's addition port 122 , and its height is the same as the wastewater addition chamber 12 . Thus, the filter screen 18 can isolate the wastewater addition chamber's addition port 122 from the wastewater addition chamber 12 , thereby preventing large particles of suspended matter from entering the sedimentation chamber 2 .

[0035] Reference Figure 3 In some embodiments, the sedimentation chamber 2 is formed by splicing an upper cylindrical body and a lower hemispherical body. The upper edge of the sedimentation chamber 2 is connected to the inner wall of the photocatalytic reaction chamber 3 via a second partition 21. A mud discharge port 22 is provided at the bottom of the sedimentation chamber 2, and a mud discharge pipe 23 is provided at the mud discharge port 22. The upper portion of the mud discharge pipe 23 is connected to the outer edge of the mud discharge port 22, and the lower portion is connected to the outside of the device. Thus, the sedimentation chamber 2 is fixedly connected to the photocatalytic reaction chamber 3 and isolated from the photocatalytic reaction chamber 3.

[0036] In some embodiments, the stirring assembly 4 includes four scrapers 41 and four sliders 42. The scrapers 41 are fan-shaped, with their bottoms shaped to match the inner wall of the hemisphere. The upper ends of the scrapers 41 are connected to the corresponding sliders 42, and the lower ends are connected to the rotating shaft 7. Specifically, the sliders 42 have a semi-arched longitudinal cross-section and an arc-shaped cross-section. Their length is 1 / 8 the circumference of the hemisphere's mouth, and the four sliders 42 are equidistantly spaced along the circumference.

[0037] In some embodiments, the inner wall of the sedimentation chamber 2 is further provided with four through-holes 24, which are located above the slider 42. A first valve 25 is disposed within the through-hole 24, and a fender 26 is disposed on the outer side of the first valve 25. The fenders 26 include a fan-shaped fender 261 located below the through-hole 24 and semi-arched fenders 262 located on either side of the through-hole 24. The fan-shaped fender 261 has a semi-arched longitudinal section and an arc-shaped cross-section. Therefore, when flocculation and sedimentation begin, the curved structure of the fender surface does not hinder the sedimentation of the flocs. Furthermore, when the flocculation and sedimentation are complete, the fender surface blocks the outflow of the wastewater supernatant through the through-hole 24, effectively separating the supernatant.

[0038] In some embodiments, the device further includes a control unit (not shown), and both the second valve and the first valve 25 are electrically powered valves. Specifically, the control unit is electrically connected to the three second valves, the four first valves 25, and the pH detection device 17. The control unit is capable of receiving the pH value of the wastewater detected by the pH detection device 17, controlling the opening or closing of the corresponding valve among the three second valves, and controlling the opening of the first valve 25 after the wastewater has been allowed to stand in the sedimentation chamber 2, allowing the wastewater to enter the photocatalytic reaction chamber 3, and then controlling the closing of the first valve 25.

[0039] In some embodiments, the photocatalytic reaction chamber 3 is a rectangular parallelepiped with a square cross-section that matches the shape of the loading chamber 1. The upper portion of the photocatalytic reaction chamber 3 is connected to the bottom of the loading chamber 1 via a mortise and tenon structure. Specifically, the bottom of the loading chamber 1 is provided with two rectangular parallelepiped tenons 19, and the upper portion of the photocatalytic reaction chamber 3 is provided with two mortises 31 of equal length to the sides of the device. The mortises 31 mate with the tenons 19, thereby facilitating assembly and disassembly.

[0040] In some embodiments, the outer wall of the photocatalytic reaction chamber 3 is provided with a water inlet box 32 at the upper portion and a water outlet box 33 at the lower portion. The water inlet box 32 is provided with a water inlet outlet 321, and the water outlet box 33 is provided with a water outlet inlet 331. Both the water inlet outlet 321 and the water outlet inlet 331 are in communication with the photocatalytic reaction chamber 3. A third partition 34 is provided in the middle of the water outlet box 33, which is the same length as the water outlet box 33 and has a height of 1 / 3 to 1 / 2 the height of the water outlet box 33.

[0041] In some embodiments, lamps 35 are placed at the four corners of the photocatalytic reaction chamber 3 and are separated from the middle of the photocatalytic reaction chamber 3 by transparent baffles 36 . The transparent baffles 36 can be glass partitions.

[0042] In some embodiments, the photocatalyst is a Cu2WS4 / Bi2WO6 composite photocatalyst. The preparation method of the photocatalyst comprises the following steps:

[0043] Step 1: Preparation of bismuth tungstate:

[0044] 1.1. Dissolve 2 mmol Bi(NO3)3·5H2O in 10 mL EG, 0.5 g CTAB in 10 mL distilled water, and 1 mmol Na2WO4·2H2O in 10 mL distilled water;

[0045] 1.2. Add 10 ml of CTAB aqueous solution to 10 ml of Bi(NO3)3·5H2O solution, stir magnetically for 10 min, and add Na2WO4·2H2O aqueous solution;

[0046] 1.3. Mix the liquids obtained in steps 1.1 and 1.2, and stir for 20 minutes to obtain a precursor suspension;

[0047] 1.4. Transfer the precursor suspension to a sealed autoclave and heat at 180°C for 20 h. After the autoclave is cooled to room temperature, collect the original Bi2WO6 by centrifugation, wash it three times with distilled water and anhydrous ethanol, and then dry it in an oven at 80°C for 6 h.

[0048] Step 2: Prepare Cu2WS4 using CuCl, sodium tungstate and thioacetamide as copper source, tungsten source and sulfur source respectively:

[0049] 2.1. Mix 15 ml of ethanol and 15 ml of distilled water to form solution A.

[0050] 2.2. Dissolve 2 mmol of CuCl, 1 mmol of Na2WO4·2H2O, and 5 mmol of thioacetamide in solution A and stir for 1 h.

[0051] 2.3. After the mixed solution is stirred into a uniform brick-red suspension, it is transferred to a high-pressure reactor and heated in a forced-air oven at 120°C for 24 hours. After the reactor is removed and cooled, the Cu2WS4 is washed and dried to collect the Cu2WS4.

[0052] Step 3: Preparation of Cu2WS4 / Bi2WO6 composite photocatalyst:

[0053] 3.1. Dissolve the Cu2WS4 prepared in step 2 and 2 mmol of bismuth nitrate pentahydrate in 10 ml of ethylene glycol and stir for half an hour to obtain a mixed solution B;

[0054] 3.2. Dissolve 1 mmol of Na2WO4·2H2O and 0.5 g of CTAB in 10 ml of distilled water, respectively, and stir for 10 minutes to obtain a sodium tungstate aqueous solution and a CTAB aqueous solution;

[0055] 3.3. Pour the CTAB aqueous solution into the mixed solution B, stir for 10 minutes, then add the sodium tungstate aqueous solution into the mixed solution and stir for another 20 minutes;

[0056] 3.4. Transfer the mixed solution to a high-pressure reactor and seal it. Move it to a 180-degree forced air oven and heat it for 20 hours. After the high-pressure reactor cools down, collect the composite photocatalyst, wash it with distilled water and anhydrous ethanol, and then dry it in an 80-degree oven for 6 hours to obtain a Cu2WS4 / Bi2WO6 composite photocatalyst.

[0057] Continue to refer to Figures 1 to 3 The working principle of the integrated device for photocatalytic treatment of laboratory wastewater in the embodiment of the present application is as follows:

[0058] Before use, laboratory wastewater should be separated into waste acid, waste alkali and other wastewater.

[0059] Then, the wastewater is added to the wastewater addition chamber 12, the waste acid addition chamber 13, and the waste alkali addition chamber 14 according to the classification. At this time, the wastewater in the wastewater addition chamber 12 is first filtered by the filter 18, and the large particles of suspended matter are trapped in the wastewater addition chamber 12. The remaining wastewater enters the addition pipe 16 through the wastewater addition chamber addition port 122 under the action of gravity, and then enters the sedimentation chamber 2 through the addition pipe 16.

[0060] The wastewater entering the sedimentation chamber 2 is accumulated several times. When the wastewater reaches a specified volume, the motor 6 is started, and the slider 42 and the scraper 41 at the bottom of the sedimentation chamber 2 are driven by the rotating shaft 7 to perform a circular motion in the sedimentation chamber 2. In this way, the slider 42 and the scraper 41 can drive the wastewater in the sedimentation chamber 2 to flow, thereby achieving a stirring effect.

[0061] After the rotating shaft 7 rotates for 5-10 minutes, the pH detection device 17 detects the pH value of the wastewater in real time. When the pH value does not meet the requirements, the control unit controls the corresponding second valve to open, and the corresponding waste acid or waste alkali is added through the waste acid adding chamber 13 or the waste alkali adding chamber 14. The waste acid or waste alkali flows into the adding pipe 16 through the adding port and then into the sedimentation chamber 2. Driven by the rotating shaft 7, the overall pH value in the sedimentation chamber 2 is made uniform.

[0062] When the pH value of the wastewater in the sedimentation chamber 2 reaches the standard and remains stable, the control unit controls the second valve at the flocculant dosing port 152 to open, and flocculant is added from the flocculant dosing chamber. The flocculant also enters the dosing pipe 16 through the flocculant dosing port 152 and finally flows into the sedimentation chamber 2. Under the stirring action of the slider 42, the flocculant and the experimental wastewater are fully mixed.

[0063] After the flocculant and the experimental wastewater are thoroughly mixed, stirring is stopped and the stirred wastewater is allowed to stand overnight. After the flocs have settled and accumulated at the bottom of the sedimentation chamber 2, the first valve 25 in the sedimentation chamber 2 is opened. The flocculated wastewater in the sedimentation chamber 2 flows through the first valve 25 into the photocatalytic reaction chamber 3. The flocs at the bottom are blocked by the slider 42 in the sedimentation chamber 2 and the fenders 26 on three sides of the first valve 25, thereby separating the flocs from the wastewater. Simultaneously, the flocs at the bottom of the sedimentation chamber 2 and a small amount of wastewater flow through the mud discharge port 22 at the bottom of the sedimentation tank 2 into the mud discharge pipe 23 and are discharged.

[0064] After the wastewater enters the photocatalytic reaction chamber 3 from the sedimentation chamber 2, the first valve 25 in the sedimentation chamber 2 is closed, and the photocatalytic reaction begins. It should be noted that at this point, if new organic wastewater is added, it can be added separately through the water inlet tank 32 and enter the photocatalytic reaction chamber 3. Then, the motor 6 is turned on again, and the photocatalyst plate 31, driven by the rotating shaft 7, rotates in the wastewater, stirring it. At the same time, under the action of light, the wastewater contacts the photocatalyst on the photocatalyst plate 31, generating a photocatalytic reaction, thereby eliminating the organic matter in the wastewater.

[0065] It should be noted that at night or in areas with insufficient lighting, the lamps 35 located at the four corners can be turned on to provide sufficient light energy for the reaction. The treated water can then enter the outlet tank 33 through the outlet tank inlet 331. The third baffle 34 in the outlet tank 33 can isolate some flocculants and other debris, achieving further purification.

[0066] On the other hand, an embodiment of the present application further provides a photocatalytic treatment method based on the above-mentioned integrated device for photocatalytic treatment of laboratory wastewater, comprising the following steps:

[0067] Step 1: Add the wastewater in the laboratory into the wastewater addition chamber 12, the waste acid addition chamber 13 and the waste alkali addition chamber 14 according to the classification;

[0068] Step 2: After the wastewater enters the sedimentation chamber 2 and reaches the preset capacity, start the motor 6 and stir for 5-10 minutes;

[0069] Step 3: The control unit controls the pH detection device 17 to perform real-time detection on the pH value of the stirred wastewater. If the pH value meets the requirements, the process proceeds to step 4. If the pH value does not meet the requirements, the control unit controls the second valve in the waste acid addition chamber 13 or the waste alkali addition chamber 14 to open, and continues to add wastewater from the waste acid addition chamber 13 or the waste alkali addition chamber 14 and stir until the pH value of the wastewater meets the requirements, and then proceeds to step 4.

[0070] Step 4: When the pH value of the wastewater reaches the standard and remains stable, the control unit controls the second valve in the flocculant addition chamber 15 to open, and adds the flocculant into the sedimentation chamber 2 through the flocculant addition chamber 15, and then starts the motor 6 again;

[0071] Step 5: After the flocculant and the experimental wastewater are fully mixed, the motor 6 is turned off, and the wastewater obtained in step 4 is allowed to stand to obtain flocculated wastewater, and the first valve is opened to allow the flocculated wastewater to enter the photocatalytic reaction chamber 3;

[0072] Step 6: Close the first valve and restart the motor 6. The photocatalyst plate 31 rotates in the flocculated wastewater driven by the rotating shaft 7 to stir the wastewater. At the same time, the flocculated wastewater contacts the photocatalyst on the photocatalyst plate 31 under the action of light to produce a photocatalytic reaction, thereby eliminating organic matter in the wastewater.

[0073] This is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or replacements within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An integrated device for photocatalytic treatment of laboratory wastewater, characterized in that: It comprises a feeding chamber, a precipitation chamber and a photocatalytic reaction chamber which are connected in sequence; the feeding chamber is arranged above the precipitation chamber, the photocatalytic reaction chamber is arranged outside the precipitation chamber, and the photocatalytic reaction chamber and the precipitation chamber are controlled by a first valve; the feeding chamber comprises a wastewater feeding chamber, a waste acid feeding chamber, a waste alkali feeding chamber and a flocculant feeding chamber; a stirring assembly is provided in the precipitation chamber; the photocatalytic reaction chamber is made of a light-transmitting material; a photocatalyst plate is provided in the photocatalytic reaction chamber; a driving device is provided outside the photocatalytic reaction chamber; the driving device can drive the photocatalyst plate and the stirring assembly to rotate; a photocatalyst is attached to the photocatalyst plate; The photocatalyst is a Cu2WS4 / Bi2WO6 composite photocatalyst; the preparation method of the photocatalyst comprises the following steps: Step 1: Preparation of bismuth tungstate: 1.

1. Dissolve 2 mmol Bi(NO3)3·5H2O in 10 mL EG, 0.5 g CTAB in 10 mL distilled water, and 1 mmol Na2WO4·2H2O in 10 mL distilled water; 1.

2. Add 10 ml of CTAB aqueous solution to 10 ml of Bi(NO3)3·5H2O solution, stir magnetically for 10 min, and add Na2WO4·2H2O aqueous solution; 1.

3. Mix the liquids obtained in steps 1.1 and 1.2, and stir for 20 minutes to obtain a precursor suspension; 1.

4. Transfer the precursor suspension to a sealed autoclave and heat at 180°C for 20 h. After the autoclave is cooled to room temperature, collect the original Bi2WO6 by centrifugation, wash it three times with distilled water and anhydrous ethanol, and then dry it in an oven at 80°C for 6 h. Step 2: Prepare Cu2WS4 using CuCl, sodium tungstate and thioacetamide as copper source, tungsten source and sulfur source respectively: 2.

1. Mix 15 ml of ethanol and 15 ml of distilled water to form solution A. 2.

2. Dissolve 2 mmol of CuCl, 1 mmol of Na2WO4·2H2O, and 5 mmol of thioacetamide in solution A and stir for 1 h. 2.

3. After the mixed solution is stirred into a uniform brick-red suspension, it is transferred to a high-pressure reactor and heated in a forced-air oven at 120°C for 24 hours. After the reactor is removed and cooled, the Cu2WS4 is washed and dried to collect the Cu2WS4. Step 3: Preparation of Cu2WS4 / Bi2WO6 composite photocatalyst: 3.

1. Dissolve the Cu2WS4 prepared in step 2 and 2 mmol of bismuth nitrate pentahydrate in 10 ml of ethylene glycol and stir for half an hour to obtain a mixed solution B; 3.

2. Dissolve 1 mmol of Na2WO4·2H2O and 0.5 g of CTAB in 10 ml of distilled water, respectively, and stir for 10 minutes to obtain a sodium tungstate aqueous solution and a CTAB aqueous solution; 3.

3. Pour the CTAB aqueous solution into the mixed solution B, stir for 10 minutes, then add the sodium tungstate aqueous solution into the mixed solution and stir for another 20 minutes; 3.

4. Transfer the mixed solution to a high-pressure reactor and seal it. Move it to a 180-degree forced air oven and heat it for 20 hours. After the high-pressure reactor cools down, collect the composite photocatalyst, wash it with distilled water and anhydrous ethanol, and then dry it in an 80-degree oven for 6 hours to obtain a Cu2WS4 / Bi2WO6 composite photocatalyst.

2. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 1, characterized in that: The feeding chamber is a cube, and its interior is divided into the wastewater feeding chamber, the waste acid feeding chamber, the waste alkali feeding chamber and the flocculant feeding chamber by a first partition; the first partition is placed along the diagonal of the feeding chamber; the bottom of the wastewater feeding chamber, the waste acid feeding chamber, the waste alkali feeding chamber and the flocculant feeding chamber are all provided with a feeding port; the lower part of the feeding port is connected to the sedimentation chamber through a feeding pipe.

3. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 1, characterized in that: The sedimentation chamber includes an upper cylindrical body and a hemispherical body sealed and connected to the lower part of the cylindrical body; the upper part of the sedimentation chamber is connected to the photocatalytic reaction chamber through a second partition; the bottom of the sedimentation chamber is connected to the outside of the device through a mud discharge pipe.

4. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 1, characterized in that: The driving device adopts a motor, which is arranged in a vertical direction; the output shaft of the motor is connected to a rotating shaft, and the stirring assembly and the photocatalyst plate are both connected to the rotating shaft; the rotating shaft is rotatably sealed and connected to the bottom wall of the precipitation chamber and the photocatalytic reaction chamber.

5. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 4, characterized in that: The stirring assembly includes a plurality of scrapers and a plurality of sliders. The upper ends of the scrapers are connected to the corresponding sliders, and the lower ends are connected to the rotating shaft. The plurality of sliders are equidistantly distributed.

6. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 1, characterized in that: The inner wall of the sedimentation chamber is provided with multiple through holes, and the through holes are located above the stirring assembly; the first valve is provided in the through hole; a mudguard is provided on the outside of the first valve; the mudguard includes a fan-shaped mudguard located below the through hole and rectangular mudguards located on the left and right sides of the through hole.

7. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 1, characterized in that: The photocatalytic reaction chamber is a rectangular parallelepiped; the upper portion of the photocatalytic reaction chamber and the bottom of the feeding chamber are connected via a mortise and tenon structure.

8. The integrated device for photocatalytic treatment of laboratory wastewater according to claim 1, characterized in that: A water inlet box is provided on the upper part of the outer wall of the photocatalytic reaction chamber, and a water outlet box is provided on the lower part; the outlet of the water inlet box and the inlet of the water outlet box are both connected to the photocatalytic reaction chamber; a third partition is provided in the water outlet box, and the height of the third partition is 1 / 3-1 / 2 of the height of the water outlet box.

9. A photocatalytic treatment method based on the integrated device for photocatalytic treatment of laboratory wastewater according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Add the wastewater in the laboratory into the wastewater addition room, waste acid addition room and waste alkali addition room according to classification; Step 2: After the wastewater enters the sedimentation chamber and reaches the preset capacity, start the motor; Step 3: Test the pH value of the stirred wastewater. If it meets the requirements, proceed to step 4. If it does not meet the requirements, continue to add wastewater from the waste acid addition chamber or the waste alkali addition chamber and stir until the pH value of the wastewater meets the requirements, then proceed to step 4. Step 4: Add flocculant into the sedimentation chamber through the flocculant addition chamber and continue stirring; Step 5: Stop the motor and let the wastewater obtained in step 4 stand to obtain flocculated wastewater, and open the first valve to allow the flocculated wastewater to enter the photocatalytic reaction chamber; Step 6. Close the first valve and restart the motor. Driven by the motor, the photocatalyst plate rotates in the flocculated wastewater to stir it. At the same time, the flocculated wastewater contacts the photocatalyst on the photocatalyst plate under the action of light to produce a photocatalytic reaction, thereby eliminating organic matter in the wastewater.

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