Composite photocatalytic material, preparation method and application thereof, purification device and purification apparatus

Abstract

The application provides a composite photocatalytic material and a preparation method and application thereof, a purification device and a purification apparatus, and belongs to the technical field of photocatalysis.The application provides a preparation method of a composite photocatalytic material, which comprises the following steps: mixing BiVO4, GO and water, and then performing heat treatment to obtain a slurry containing GO-wrapped BiVO4; mixing the slurry with a butyl titanate sol precursor, and then performing hydrothermal reaction and reduction reaction to generate nano-TiO2 gelatinization wrapped BiVO4 and rGO loaded on the outer surface of the nano-TiO2 gelatinization, so as to obtain the composite photocatalytic material.In the application, the butyl titanate sol precursor is used to prepare TiO2, and the prepared TiO2 has the property of gelatinization; the viscosity of the TiO2 is improved, the connection strength between the TiO2 and the rGO is improved, the loss of the TiO2 is reduced, and the purification time is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photocatalysis, in particular to a composite photocatalytic material, a preparation method and application thereof, a purification device and a purification apparatus. BACKGROUND

[0002] Water bodies are easily polluted by sewage discharge, such as the phenomenon of kitchen sewage leakage, poultry scattered point source pollution and so on. Discharge exceeding the self-purification carrying capacity of the water body leads to water quality deterioration, and also brings about the decline of ecological index IBI.

[0003] Environmental functional materials have a repairing effect on polluted water bodies. Photocatalytic materials are one of these materials, which have the characteristics of low operating energy consumption, green safety and the like. Photocatalysis utilizes light sources to generate corresponding types of free radicals to purify water quality, especially for the catalytic degradation of organic pollutants in water bodies, which is a green oxidation technology.

[0004] In the face of actual water purification applications, microorganisms are an unavoidable factor (unlike laboratory single-factor experiments), and are also an important link that can be utilized by us to purify water quality. Intensive coupling type photocatalysis and biological combined technology (ICPB) is often used to purify biologically refractory organic pollutants due to its functions of adsorption, catalytic degradation, biodegradation and biological transformation. For example, M.D. MARSOLE et al. used macroporous cellulose carriers and TiO2 catalysts to remove 2,4,5-trichlorophenol (TCP). In the purification process, for the ICPB system using composite catalyst materials, the components gradually separate due to loose connection, and the purification duration is short. SUMMARY

[0005] The purpose of the present application is to provide a composite photocatalytic material, a preparation method and application thereof, a purification device and a purification apparatus. The composite photocatalytic material of the present application has firm connection between components, and long purification time.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0007] The present application provides a preparation method of a composite photocatalytic material, comprising the following steps:

[0008] BiVO4, GO and water are mixed and then subjected to heat treatment to obtain a slurry containing GO wrapped BiVO4;

[0009] The slurry is mixed with a butyl titanate sol precursor to perform hydrothermal reaction and reduction reaction, to generate nano-TiO2 gelatinization wrapped BiVO4 and rGO loaded on the outer surface of the nano-TiO2 gelatinization, thereby obtaining the composite photocatalytic material.

[0010] Preferably, the mass ratio of the BiVO4 particles to the GO is 1:2-100;

[0011] The GO has a sheet diameter of 0.5-3 μm and an oxygen content of 2-20 wt%.

[0012] Preferably, the BiVO4 has a particle size of 150-280 nm; and the BiVO4 is monoclinic BiVO4.

[0013] Preferably, the volume ratio of the butyl titanate sol precursor to the GO is 8-40 mL:1 g.

[0014] The butyl titanate sol precursor has a butyl titanate concentration of 0.6-1 mol / L.

[0015] Preferably, the hydrothermal reaction and the reduction reaction are carried out in a programmed microwave-assisted hydrothermal device, and the temperature of the hydrothermal reaction and the reduction reaction is 140-170℃.

[0016] The application further provides a composite photocatalytic material prepared by the preparation method described in the above scheme, wherein the composite photocatalytic material comprises BiVO4, rGO wrapped on the BiVO4, and nano-TiO2 gel loaded on the outer surface of the rGO.

[0017] Preferably, the mass ratio of the nano-TiO2 gel to the rGO is 1:0.02-5; and the nano-TiO2 gel has an anatase-rutile mixed crystal type.

[0018] The application further provides an application of the composite photocatalytic material described in the above scheme in preparing a purification device.

[0019] The application further provides a purification device, which comprises a porous fiber fabric, a composite photocatalytic material loaded on the porous fiber fabric, and a conductive material.

[0020] The composite photocatalytic material is the composite photocatalytic material described in the above scheme.

[0021] The application further provides a purification device, which comprises a carbon felt and a photocatalytic unit; and the carbon felt and the photocatalytic unit are connected by a wire.

[0022] The photocatalytic unit comprises a sandwich porous cloth and a purification device sewn together with the sandwich porous cloth.

[0023] The pore diameter of the purification device is not less than the pore diameter of the sandwich porous cloth.

[0024] The purification device is the purification device described in the above scheme.

[0025] The application provides a preparation method of a composite photocatalytic material, comprising the following steps: mixing BiVO4, GO and water, and then performing heat treatment to obtain a slurry containing GO wrapped BiVO4; mixing the slurry with a butyl titanate sol precursor, and then performing hydrothermal reaction and reduction reaction to generate nano-TiO2 gelatinization wrapped BiVO4 and rGO loaded on the outer surface of the nano-TiO2 gelatinization, so as to obtain the composite photocatalytic material. In the application, TiO2 is prepared by using a butyl titanate sol precursor, and the prepared TiO2 has the property of gelatinization, the viscosity of which effectively improves the connection strength between the TiO2 and the rGO, reduces the loss of TiO2, and prolongs the purification time.

[0026] In the composite photocatalytic material prepared by the application, BiVO4, nano-TiO2 gelatinization and rGO all have excellent visible light absorption performance, and BiVO4 and nano-TiO2 gelatinization can produce LSPR effect after being doped with noble metal (from the butyl titanate sol precursor), which can improve the visible light response performance of the composite photocatalytic material; in addition, the nano-heterostructure formed by BiVO4, rGO and nano-TiO2 gelatinization can further improve the visible light response performance of the composite photocatalytic material.

[0027] The conductive material in the purification device can quickly separate the photo-generated electrons from the photo-generated holes generated by photocatalysis, thereby avoiding the photo-generated electron-photo-generated hole recombination and improving the reaction efficiency. In addition, the addition of the conductive material can make the material form an electrode, which can form an electrode pair with the bottom mud, and promote the reaction to occur. The purification device and the sandwich porous cloth are sewn together, and the photocatalytic material (purification device) and the microbial carrier (sandwich porous cloth) are in two closely connected physical parts, so that the free radicals generated on the light receiving surface of the outside of the purification device are not easy to destroy the cell membrane of the aerobic microorganisms, thereby further improving the purification efficiency of the purification device. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Taucplot graph of the band gap of the composite photocatalytic material of Example 1;

[0029] Figure 2 SEM graph of the composite photocatalytic material of Example 1;

[0030] Figure 3 XRD graph of the composite photocatalytic material of Example 1;

[0031] Figures 4-5 EPR test result graph of the composite photocatalytic material of Example 1;

[0032] Figure 6 Raman spectrum graph of the composite photocatalytic material of Example 1;

[0033] Figure 7XPS chart of the composite photocatalytic material of Example 1;

[0034] Figure 8 Photocatalytic dye decolorization experiment results of the photocatalytic material of Comparative Example 1 before and after purification treatment;

[0035] Figure 9 Photocatalytic dye decolorization experiment results of the composite photocatalytic material of Example 1 before and after purification treatment;

[0036] Figure 10 ORP result chart of the purification device of Application Example 1 and Comparative Application Example 1;

[0037] Figure 11 SEM chart of the polyester mesh fabric used in the purification device of Application Example 1;

[0038] Figure 12 SEM chart of the purification device of Application Example 1;

[0039] Figure 13 Toxicity experiment results of the purification device of Application Example 2 in the ultrapure water immersion group;

[0040] Figure 14 Toxicity experiment results of the purification device of Application Example 2 in the PBS immersion group;

[0041] Figure 15 Photocatalytic degradation performance test results of the purification device of Application Example 2, Comparative Application Examples 2-3;

[0042] Figure 16 Structural chart of the water quality purification device;

[0043] Figure 17 Daily total nitrogen change of the water body after adding the water quality purification device;

[0044] Figure 18 Daily total phosphorus change of the water body after adding the water quality purification device. DETAILED DESCRIPTION

[0045] The application provides a preparation method of the composite photocatalytic material, and comprises the following steps:

[0046] BiVO4, GO and water are mixed and then subjected to heat treatment, so as to obtain a slurry containing GO wrapped BiVO4;

[0047] The slurry is mixed with a butyl titanate sol precursor to perform hydrothermal reaction and reduction reaction, so as to generate nano TiO2 gelatinization wrapped BiVO4 and rGO loaded on the outer surface of the nano TiO2 gelatinization, thereby obtaining the composite photocatalytic material.

[0048] The present application mixes BiVO4, GO and water, and then performs heat treatment to obtain a slurry containing GO-wrapped BiVO4.

[0049] In the present application, the mixing preferably comprises dispersing BiVO4 in water, and then adding GO to obtain a preliminary mixture; the preliminary mixture is treated under the alternating action of an ultrasonic device and a cell crushing device, and then ground.

[0050] In the present application, the mass ratio of BiVO4 to water is preferably 1:20-400, more preferably 1:100-300, and further preferably 1:150-200. In the present application, the particle size of BiVO4 is preferably 150-280 nm, and more preferably 200-250 nm; the BiVO4 is preferably monoclinic BiVO4.

[0051] In the present application, the mass ratio of BiVO4 to GO is preferably 1:2-100, more preferably 1:20-80, and further preferably 1:40-60. When the mass ratio of BiVO4 particles to GO is in the above range, full coating of BiVO4 by GO can be achieved. In the present application, the flake size of GO is preferably 0.5-3 μm, and more preferably 1-2 μm; the oxygen content is preferably 2-20 wt%, more preferably 5-15 wt%, and further preferably 8-12 wt%.

[0052] In the present application, the power of the ultrasonic device is preferably 180 W, and the single time is preferably 30 min; the power of the cell crushing device is preferably 300 W, and the single time is preferably 10 min. In the present application, the number of alternations is preferably 5; the power of the grinding and crushing is preferably 300 W, the frequency is preferably 25 kHz, and the time is preferably 1-3 h.

[0053] In the present application, the temperature of the heat treatment is preferably 140-170℃, and the time is preferably 1-5 h; the heating rate to the heat treatment temperature is preferably 0.13-0.15℃ / min. During the heat treatment, GO wraps BiVO4, and thus the color of the slurry becomes dark green.

[0054] After the heat treatment is completed, the present application preferably cools the product obtained by the heat treatment to room temperature, and then adds water with the same mass as the water used for mixing to obtain a slurry.

[0055] After the slurry is obtained, the present application mixes the slurry with a butyl titanate sol precursor to perform hydrothermal reaction and reduction reaction, to generate nano-TiO2 gel wrapping BiVO4 and rGO loaded on the outer surface of the nano-TiO2 gel, and thus obtain the composite photocatalytic material.

[0056] In the present application, the volume-to-mass ratio of the butyl titanate sol precursor to the GO is preferably 8-40 mL:1 g, more preferably 10-30 mL:1 g, and further preferably 15-20 mL:1 g.

[0057] The concentration of butyl titanate in the butyl titanate sol precursor is preferably 0.6-1 mol / L, and more preferably 0.8-0.9 mol / L.

[0058] In the present application, the butyl titanate sol precursor is preferably the butyl titanate sol precursor in the patent with the application number 202111575890.5, and more preferably the butyl titanate sol precursor prepared from metal ions in the patent with the application number 202111575890.5. The doping of metal ions can control the effective TiO2 component to enter the composite photocatalytic material. In the present application, the metal ion is preferably Zn 2+ . Zn 2+ can improve the visible light photosensitivity of TiO2 and make it have antibacterial effect. In addition, Zn can also make the composite photocatalytic material have certain biological affinity at low concentration, is a biological essential element, and has certain growth-promoting effect. In the embodiments of the present application, the preparation method of the butyl titanate sol precursor is preferably as follows: 130 mL of butyl titanate is mixed with 25 mL of anhydrous ethanol at 4℃, and then slowly added into 340 mL of a 0.95 wt% nitric acid aqueous solution after uniform stirring, wherein the nitric acid aqueous solution contains zinc nitrate, and the amount of substance of Zn 2+ is preferably 3.5% of the amount of substance of butyl titanate. The final mixed solution has a molar ratio of butyl titanate:nitric acid:ethanol:water of 0.38:0.11:0.43:18.61, the system pH is 3, and a semi-transparent butyl titanate sol precursor is prepared.

[0059] In the present application, the mixing preferably includes adding the butyl titanate sol precursor into the slurry dropwise. In the present application, the dropwise adding is preferably performed under stirring, and the stirring speed is preferably not lower than 700 rpm, and the stirring speed cannot cause the liquid to splash. The present application does not have special limitation on the stirring time, and the stirring can be performed until a grayish green suspension is obtained. During the stirring process, the butyl titanate sol precursor is uniformly wrapped on the surface of BiVO4 / rGO, and the suspension becomes grayish green.

[0060] In the application, the hydrothermal reaction and the reduction reaction are preferably carried out in a programmed microwave-assisted hydrothermal device; the temperature of the hydrothermal reaction is preferably 120-170 DEG C, more preferably 150-160 DEG C; the time is preferably 0.1-5h, more preferably 1-4h, and further preferably 2-3h. The time of the hydrothermal reaction and the reduction reaction is counted from the end of dropwise addition. The hydrothermal reaction and the reduction reaction are preferably carried out in a programmed microwave-assisted hydrothermal device. The filling ratio of the programmed microwave-assisted hydrothermal device is preferably 60-70%.

[0061] During the hydrothermal reaction and the reduction reaction, GO is reduced to rGO by supercritical water generated in the hydrothermal environment, and the butyl titanate sol precursor generates nano-TiO2 gelation in the hydrothermal reaction and is loaded on rGO.

[0062] Ideal G graphene has almost no functional groups and very good conductivity, but has poor dispersibility in solvents and is not easy to be compounded with other nanoparticles to synthesize new materials. GO graphene oxide has good dispersibility in solvents (mainly water) due to the presence of many oxygen-containing functional groups, but also leads to a decrease in the conductivity of the material. Compared with GO and G graphene, rGO can maintain a certain conductivity and also has some functional groups (containing -OH, -COOH, C-O-C on the surface) to ensure dispersibility; and the functional groups of rGO are also easy to be compounded with other materials to prepare photocatalytic materials.

[0063] In addition, after preparation, under light irradiation during application, TiO2 and BiVO4 will also release electrons to continue reducing rGO, and the reduction degree is related to the treatment time and method. The reduction degree of GO is related to the conductivity, and the higher the reduction degree, the stronger the conductivity.

[0064] The temperature of the hydrothermal reaction and the reduction reaction in the application is low, which can reduce the energy consumption in actual production. The traditional preparation process is high-temperature annealing sintering, which generally requires 300-500 DEG C. The treatment temperature of the programmed microwave hydrothermal treatment device is lower than 170 DEG C. The reason is that the microwave hydrothermal method is to alternately control the rotation direction of polar molecules by a magnetron, so as to generate heat inside the molecules. Generally, such action is generated on solvents, i.e. water, of course, the solute or dispersed material is also a polar molecule, which will also generate heat inside, resulting in a higher heating method than the traditional muffle air heat, i.e. thermal radiation method.

[0065] The application does not need high-temperature calcination in the subsequent process, which ensures the easy dispersibility of TiO2, and TiO2 has gel properties, the viscosity of which helps to adhere to rGO, reduces the loss of TiO2, and improves the purification efficiency.

[0066] The application further provides the composite photocatalytic material prepared by the preparation method.

[0067] In the application, the band gap of the composite photocatalytic material is preferably 2.14 eV, and the absorption wavelength is preferably 578.76 nm.

[0068] In the application, the mass ratio of the nano-TiO2 gel to the rGO is preferably 1:0.02-5, more preferably 1:1-4, and further preferably 1:2-3; the crystal form of the nano-TiO2 gel is preferably anatase-rutile mixed crystal type; and the particle size of the nano-TiO2 gel is preferably 5-30 nm.

[0069] The application further provides application of the composite photocatalytic material in preparation of a purification device.

[0070] The application further provides a purification device comprising a porous fiber fabric, a composite photocatalytic material and a conductive material loaded on the porous fiber fabric.

[0071] The composite photocatalytic device is the composite photocatalytic material.

[0072] In the application, the loading amount of the conductive material in the purification device is preferably 0.10-0.3 mg / cm 2 , the conductive material preferably comprises SWCNT and / or MWCNT; the loading amount of the composite photocatalytic material is 1.2-1.6 mg / cm 2 , and the resistance is ≤60 kΩ.

[0073] In the application, the preparation method of the purification device preferably comprises the following steps:

[0074] After the porous fiber fabric is soaked with water, the porous fiber fabric is sequentially sprayed with the conductive material and first dried to obtain a purification device base blank.

[0075] The purification device base blank is sequentially washed with water and second dried to obtain a purification device base.

[0076] The dispersion liquid of the composite photocatalytic material is sprayed on the purification device base and third dried to obtain the purification device.

[0077] The porous fiber fabric is soaked with water, then sprayed with conductive material, and first dried to obtain a purification device base blank. In the present application, the porous fiber fabric is preferably cleaned and dried before being soaked with water. The wet porous fiber fabric obtained after the porous fiber fabric is soaked with water does not drip water. In the present application, the porous fiber fabric preferably includes polyester mesh fabric, the thickness of the porous fiber fabric is preferably 0.5 mm, the pore size is preferably 0.5 cm, and the diameter of the fiber in the porous fiber fabric is preferably 130 μm.

[0078] The present application does not have special restrictions on the spraying, and the known methods in the art can be used to fully spray each part. Specifically, in the embodiments of the present application, a plastic spray bottle or a self-made spraying device is used to spray the porous fiber fabric on one side.

[0079] After obtaining the purification device base blank, the present application sequentially washes and secondly dries the purification device base blank to obtain a purification device base.

[0080] The present application does not have special restrictions on the washing, and the known methods in the art can be used to wash and elute unstable attached materials.

[0081] After obtaining the purification device base, the present application sprays a dispersion liquid of a composite photocatalytic material on the purification device base and thirdly dries to obtain the purification device. In the present application, the concentration of the dispersion liquid of the composite photocatalytic material is preferably 0.01-10 mg / L, more preferably 2-8 mg / L, and further preferably 4-6 mg / L.

[0082] In the present application, the purification device is preferably applied to a water body that already has submerged plants or to a low-DO black and odorous water body; the number of submerged plants per square meter of the water body is 400-700; and the water body is visible to the bottom when measured by the black and white disc method.

[0083] The present application also provides a purification device, which comprises a carbon felt and a photocatalytic unit; the carbon felt and the photocatalytic unit are connected by wires;

[0084] The photocatalytic unit comprises a sandwich porous cloth and a purification device sewn together with the sandwich porous cloth;

[0085] The purification device is the purification device described in the above scheme;

[0086] The pore size of the purification device is not less than the pore size of the sandwich porous cloth.

[0087] In the present application, the carbon felt is preferably connected to the light-facing surface of the photocatalytic unit by wires.

[0088] In the present application, the position relationship between the carbon felt and the photocatalytic unit is preferably parallel relationship. The preparation method of the purification device comprises the following steps:

[0089] stitching the purification device and the sandwich porous cloth to obtain the photocatalytic unit;

[0090] connecting the photocatalytic unit with the carbon felt by wires to obtain the purification device.

[0091] The present application stitches the purification device and the sandwich porous cloth to obtain the photocatalytic unit. In the present application, the areas of the purification device and the sandwich porous cloth are preferably the same. In the present application, the stitching is performed along the purification device and the sandwich porous cloth, 1 line per 10 cm in the vertical cloth unwinding direction, and 1 line per 5 cm parallel to the cloth unwinding direction; the resistance of the stitching is not greater than 10 3 Ω conductive wire. In the present application, the pore diameter of the sandwich porous cloth is preferably higher than 0.5 cm, the diameter of the fiber in the sandwich porous cloth is preferably less than 3 mm, and in the case that the pore diameter of the purification device is not less than the pore diameter of the sandwich porous cloth, the pore diameter and the fiber in the above range are selected to make the photocatalytic unit not be lifted by the bubbles generated by the algae in the local area close to the net bottom during the day, especially when the sunlight is strong, resulting in the buoyancy of the entire net surface being too strong, protruding out of the water surface, and some places being shaded from the sun and sinking underwater.

[0092] In the present application, the material of the sandwich porous cloth is preferably PET. Compared with PP, PET has more excellent ultraviolet weather resistance and mechanical strength and is not easy to be damaged.

[0093] The composite photocatalytic material generates active free radicals in water in a very small range, and can only build a micro-oxidized water layer near the photocatalytic unit, that is, the ORP is high in a very small range, so the microorganisms (mostly aerobic microorganisms at the water-air interface) in the sandwich porous cloth must be close to the composite photocatalytic material to be affected by the high ORP, promote life metabolism, and degrade pollutants in the water body. The sandwich porous cloth has a thickness and pores, which can prevent the shading of the composite photocatalytic material due to the biomass expansion of microorganisms.

[0094] After obtaining the photocatalytic unit, the photocatalytic unit is connected with the carbon felt to obtain the purification device. In the present application, the purification device in the photocatalytic unit is the sun-facing surface. In the present application, the area of the photocatalytic unit is preferably 0.5-1 times the area of the carbon felt. In the present application, the connection preferably includes connecting the vertices and the midpoints of the side lengths of the photocatalytic unit and the carbon felt with wires, and the wires preferably include one or more of copper wire, iron wire, stainless steel wire and organic conductive fiber. The purification device of the present application can guide the photo-generated electrons generated by the photocatalytic unit (cathode) to the microorganisms on the lower carbon felt for use, and then the microorganisms output electrons through the carbon felt.

[0095] In the present application, for high-pollution-load water bodies such as black and odorous water bodies, the sandwich porous cloth preferably carries slow-release expanded original river water quality purification microorganisms. The slow-release expanded original river water quality purification microorganisms can improve the purification speed, and the purification device can provide a good habitat for these microorganisms, and the purification device can generate effects such as increasing ORP and decomposing pollutants to promote the metabolism of microorganisms, i.e., to promote the continuous purification effect of the microorganisms, without frequent implementation of microorganism sparging.

[0096] In the present application, the preparation method of the sandwich porous cloth carrying slow-release expanded original river water quality purification microorganisms preferably includes the following steps:

[0097] Select river water and sludge, and use a high-temperature steam sterilized triangular flask to culture under the condition of constant temperature 30℃ and 150r / min. The supernatant after standing for 1h is replaced every day, and the culture period is 15d; then, according to 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 and 10 -6 times, perform step-by-step gradient dilution; then, inoculate the bacterial liquid of the last three concentrations in LB liquid medium and culture at 30℃. Perform continuous inoculation for three times; isolate the dominant strain, purify by plate streaking, enrich culture in LB medium, and then prepare a suspension liquid with sterile water to obtain in-situ indigenous microorganisms;

[0098] After 10 parts of sodium alginate and 1000 parts of deionized water are thoroughly mixed, 20 parts of in-situ indigenous microorganisms are thoroughly mixed with them to prepare A liquid;

[0099] 50 parts of calcium chloride are prepared into B liquid with 1000 parts of deionized water;

[0100] After the sandwich porous cloth is soaked in the A liquid for 12 hours, then impregnated with the B liquid, immediately, a self-made ballast machine double roller is rolled to squeeze off the excess liquid, with a speed of 70%; or a cement mortar special spray gun is connected to an air compressor, the A liquid is uniformly sprayed onto the surface of the sandwich porous cloth, then the excess liquid is removed through a roller, and then the B liquid is uniformly sprayed through the spray gun;

[0101] The total load amount needs to be controlled to be not less than 400g (wet weight) / m 2 The treated sandwich porous cloth is dried to obtain the load expanded river channel water quality purification microorganism sandwich porous cloth.

[0102] In the application, the photocatalytic unit is suitable for purifying water bodies with a depth of less than 0.2 m or a depth of more than 4 m.

[0103] In the application, the photocatalytic unit in the purification device is preferably parallel to the carbon felt.

[0104] In the application, the use method of the purification device preferably comprises:

[0105] The photocatalytic unit is placed on the water surface, and the carbon felt is placed on the sediment surface.

[0106] In the application, the carbon felt is preferably placed on the sediment surface by a counterweight.

[0107] The photocatalytic unit placed on the water surface can purify the water-gas interface, provide a carrier (achieved by the sandwich porous carrier) and a good habitat index (achieved by the porous fiber fabric loaded with composite photocatalytic materials, i.e. the above-mentioned purification device) for aerobic organisms, such as a high ORP environment; and the carbon felt part is connected to the above-mentioned part placed on the water surface by a conductive wire, and is placed on the sediment surface, which can act as an anaerobic biological carrier and purify the sediment.

[0108] "ICPB Technology and Its Research Progress in Removing Polycyclic Aromatic Hydrocarbons in Sewage, Industrial Water Treatment" combines photocatalysis and microorganisms on the same carrier, which causes a certain conflict between catalysis and biochemical reaction. The application separates the catalytic function and the microbial carrier function, and combines the two parts in the application form to form the water surface purification part.

[0109] "Degradation Characteristics of Cu-EDTA by Coupling of Photocatalysis and Microbial Fuel Cell, Chemical Engineering Journal" couples PEC photocatalysis and MFC microbial fuel cell, but cannot implement large-scale water purification. In the application, the carbon felt is placed on the sediment, and the in-situ anaerobic microorganisms in the river sediment can be loaded on the carbon felt to promote life metabolism by photocatalytic electricity generation.

[0110] Oilfield Chemistry, which sets the upper water phase as the cathode zone, and the cathode material is suspended on the water surface; the lower mud phase is the anode zone, and the anode material is at the bottom of the anode zone. The cathode and anode are connected in series with a 1000Ω resistor through a wire, and connected to a data collector. The plant is planted in the anode bottom mud, and the root system directly contacts the anode material, and the plant stems and leaves extend above the water phase through the cathode zone. The difference from the present application is that the comparative document uses carbon felt as the electrode material, and the cathode material is not subjected to photocatalysis. The electron generation pathways are different. Photocatalysis drives the photocatalytic material to generate photo-generated electrons by sunlight, and then the electrons are conducted to the underwater carbon felt through the conductive layer and the wire.

[0111] The composite photocatalytic material provided by the present application, the preparation method and application thereof, the purification device and the purification apparatus will be described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0112] In the examples:

[0113] Bismuth vanadate BiVO4, tetrabutyl titanate, rhodamine B, anhydrous ethanol, sodium sulfide and nitric acid are all purchased from the National Pharmaceutical Group Co., Ltd., and are AR grade and do not need to be further purified;

[0114] GO (sheet diameter: 0.5-2 μm) and single-walled carbon nanotubes (diameter: 1-2 nm, purity: >95%) are purchased from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.;

[0115] P25 is purchased from Wacker;

[0116] Polyester mesh cloth (white, fiber diameter 130 μm, thickness 0.5 mm, pore size 0.5 cm) is purchased from Yongsheng Mesh Cloth Co., Ltd.;

[0117] Sandwich porous cloth (280 g / Y, thickness 0.4 cm, pore size 0.3 cm x 0.5 cm) is purchased from Jixing Garment Co., Ltd.;

[0118] Carbon felt (density 0.1 g / cm3, thickness 15 mm, resistance value 30Ω) is purchased from Maipengcheng Electronic Technology Co., Ltd.;

[0119] Conductive fiber textile thread (long fiber, fineness 420D / 3, resistance value 10 3 Ω) is purchased from Shijieyouxin Co., Ltd.;

[0120] Deionized water is used throughout the test process;

[0121] The resistance value is the measurement result of the two-point method of a multimeter based on the arbitrary diameter of any single hole of the polyester mesh cloth.

[0122] Example 1

[0123] 0.4 g of monoclinic BiVO4 with a particle size of 150-200 nm was uniformly dispersed in 12 mL of water to prepare a slurry, 2 g of GO with a solid content of 2.5 wt% was directly added and treated by alternately using ultrasonic waves (power of 180 W, time of 30 min) and a cell crushing device (power of 300 W, time of 10 min) for 5 times, so that the materials were fully mixed, and then ground in a grinder (power of 300 W, frequency of 25 kHz) for 1 h. The collected material was heated to 150℃ at a temperature rising speed of 0.14℃ / min, and then treated for 2 h, and after cooling to room temperature, 12 mL of water was added for dispersion, to prepare A.

[0124] 130 mL of butyl titanate was mixed with 25 mL of anhydrous ethanol at 4℃, and then slowly added dropwise into 340 mL of a 0.95 wt% nitric acid aqueous solution containing zinc nitrate, wherein the amount of substance of Zn 2+ is preferably 3.5% of the amount of substance of butyl titanate. The final mixed solution has a molar ratio of butyl titanate:nitric acid:ethanol:water of 0.38:0.11:0.43:18.61, and the pH of the system is 3, to prepare a semi-transparent butyl titanate sol precursor B.

[0125] 28 mL of the precursor solution B of butyl titanate with a concentration of 0.78 mol / L was slowly added dropwise into A, and stirring was performed at a stirring speed of 900 rpm until a yellow-green suspension was formed, and then a programmed microwave-assisted hydrothermal device (filling ratio is set to 70%) was used to treat at a temperature of 140℃ for 2 h, to obtain a composite photocatalytic material.

[0126] The mass ratio of the nano TiO2 gel to rGO in the composite photocatalytic material is 28:1; and the particle size of the nano TiO2 gel is preferably 5-10 nm.

[0127] The band gap of the composite photocatalytic material of Example 1 was plotted by using the Taucplot method, and the result is shown in Figure 1 It can be known from Figure 1 that the band gap of the composite photocatalytic material is 2.14 eV. And the absorption wavelength is calculated to be 578.76 nm according to the absorption wavelength λ = 1240 / band gap.

[0128] SEM analysis was performed on the composite photocatalytic material of Example 1, and the result is shown in Figure 2 It can be known from Figure 2 that the composite photocatalytic material of Example 1 has TiO2 particles distributed on the surface layer of GO wrapping BiVO4.

[0129] XRD analysis was performed on the composite photocatalytic material of Example 1, and the result is shown in Figure 3As shown. By Figure 3 It is known that the composite photocatalytic material of the present invention has characteristic peak values ​​of anatase-rutile mixed crystal TiO2 and monoclinic BiVO4.

[0130] The EPR test was performed on the composite photocatalytic material of Example 1, and the results are as follows: Figures 4-5 As shown. By Figures 4-5 It can be seen that after 15 minutes, the composite photocatalytic material of the present invention has the function of generating superoxide anions and hydroxyl radicals.

[0131] Raman spectroscopy analysis was performed on the composite photocatalytic material of Example 1, and the results are as follows: Figure 6 As shown. By Figure 6 It is known that the composite photocatalytic material of the present invention has the characteristic peak of rGO.

[0132] XPS analysis was performed on the composite photocatalytic material of Example 1, and the results are as follows: Figure 7 As shown, where Figure 7 a represents the XPS analysis results of Ti element in the composite photocatalytic material. Figure 7 b represents the XPS analysis results of Bi element in the composite photocatalytic material. Figure 7 c represents the XPS analysis result of carbon element in the composite photocatalytic material. Figure 7 It is known that the composite photocatalytic material of the present invention has the characteristic peaks of the corresponding components.

[0133] Example 2

[0134] The only difference from Example 1 is that the filling ratio of the programmed microwave-assisted hydrothermal device is set to 60%, the hydrothermal reaction temperature is 150°C, and the time is 0.5h.

[0135] The mass ratio of nano-TiO2 gel to rGO in the composite photocatalytic material is 28:1; the particle size of the nano-TiO2 gel is 5-12 nm.

[0136] Example 3

[0137] The only difference from Example 1 is that the filling ratio of the programmed microwave-assisted hydrothermal device is set to 60%, the hydrothermal reaction temperature is 170°C, and the time is 0.5h.

[0138] The mass ratio of nano-TiO2 gel to rGO in the composite photocatalytic material is 28:1; the particle size of the nano-TiO2 gel is preferably 5-30 nm.

[0139] 160 μL of the composite photocatalyst material from Examples 2 and 3 were added to 50 mL of a 2.5 mg / L Rhodamine B solution, respectively, and the solution was reacted with 60000 μW / cm². 2Irradiated with a xenon lamp source with a 420nm filter, the dark reaction and light reaction were each set for 30 minutes. After the dark reaction and light reaction were completed, the absorbance was measured after centrifugation at 12000 rpm for 10 minutes. The decolorization rates were 24.09% and 10.6%, respectively.

[0140] Comparative Example 1

[0141] The only difference from Example 1 is that A is omitted.

[0142] The composite photocatalytic material of Example 1 and the photocatalytic material of Comparative Example 1 were purified by immersion in ultrapure water for 24 hours using a dialysis bag with a molecular weight of 30,000. The photocatalytic dye decolorization results of the photocatalytic material of Comparative Example 1 before and after purification are as follows: Figure 8 As shown, the photocatalytic dye decolorization results of the composite photocatalytic material before and after purification treatment in Example 1 are as follows: Figure 9 As shown. By Figures 8-9 It is known that the composite photocatalytic material of the present invention has a high degree of bonding between its components, which will lead to the continuous performance of the material in actual water environment treatment applications. Compared with materials without Bi-based and graphene additions, the effectiveness of the novel composite photocatalytic material is enhanced.

[0143] Application Example 1

[0144] SWCNT single-walled carbon nanotubes were uniformly sprayed onto a polyester mesh fabric after being soaked in water, and then dried at 80°C. The fabric was then washed with water and dried again at 80°C. A dispersion of the 5.12 mg / L composite photocatalyst material prepared in Example 3 was sprayed onto the polyester mesh fabric and dried again at 80°C, resulting in a composite photocatalyst material loading of 1.5 mg / cm³. 2 The loading of SWCNT single-wall carbon nanotubes is 0.3 mg / cm³. 2 Purification devices with a resistance of 5-30kΩ (resistance values ​​are based on the two-point method measurement results of a multimeter with an arbitrary diameter of any single hole in the polyester mesh fabric).

[0145] Comparative Application Example 1

[0146] The only difference from Application Example 1 is that the composite photocatalytic material is replaced with P25 material.

[0147] Three parallel purification devices (5cm × 5cm) prepared according to Example 1 and Comparative Application Example 1 were placed in quartz colorimetric tubes, 50mL of water and 50mg / L Na2S·7H2O solution were added to reduce the ORP index of the water, and the colorimetric tubes were irradiated with a 500W xenon lamp with a 420nm filter for 5 hours. The results are as follows. Figure 10 As shown. By Figure 10It can be known that the water body oxidation-reduction potential ORP of the purification device prepared from the composite photocatalytic material has the optimal promotion effect. The reason is that the binding firmness of the components of the composite photocatalytic material is high, and other photocatalysts capable of generating active oxygen substances (ROS) such as hydroxyl radicals (·OH) and superoxide anion radicals (·O2 – ) to cause water body oxidation can also promote the ORP of the water body under certain conditions.

[0148] The polyester mesh fabric used in the purification device in application example 1 and the purification device in application example 1 were subjected to SEM analysis, and the results are shown in Figures 11-12 . It can be known from Figures 11-12 that the fiber surface and the fiber pores of the purification device are all loaded with the composite photocatalytic material after loading treatment.

[0149] Biological toxicity test was performed on the purification device prepared in application example 1: (1) 0.3 g of the purification device was weighed using an analytical balance, and 50 mL of ultrapure water and phosphate buffered saline solution (PBS) were added, respectively; (2) after soaking for 5 days (120 h), the soaking liquid was taken, and the soaking liquid was diluted by 10, 20, 40, 60, 80 and 100 times using serum-free RPMI1640 medium to prepare cell exposure liquid; (3) the toxicity of the above exposure liquid on mouse sperm cell GC-2spd(ts) was detected using the CCK8 method. The results are shown in Figures 13-14 , wherein Figure 13 is the toxicity test result of the ultrapure water soaking group, Figure 14 is the toxicity test result of the PBS soaking group. It can be known from Figures 13-14 that compared with the control group, the soaking liquid of the ultrapure water soaking group was not detected to have significant cell toxicity after being diluted by 10-100 times; and the soaking liquid of the PBS soaking group was not detected to have significant cell toxicity after being diluted by 10-100 times.

[0150] Comparative application example 2

[0151] The same amount of SWCNT single-walled carbon nanotubes as in application example 1, A liquid in example 1 and 28 mL of B liquid in example 1 were sprayed one by one using a plastic spray bottle in the manner of spraying-drying to prepare the purification device.

[0152] Comparative application example 3

[0153] The same amount of SWCNT single-walled carbon nanotubes as in application example 1, P25 material (with the same mass as the composite photocatalytic material in example 1) were sprayed one by one using a plastic spray bottle in the manner of spraying-drying to prepare the purification device.

[0154] The photocatalytic degradation performance test was performed on the purification devices in application example 1, comparative application examples 2-3, and the results are shown in Figure 15 . It can be known fromFigure 15 It can be seen that, compared with the method of coating each component of the composite photocatalytic material to the polymer substrate step by step, and compared with the method of coating P25 to the polymer substrate, the dye photocatalytic degradation performance of the sample obtained by the process of coating the composite photocatalytic material to the same polymer substrate at one time is more advantageous. The reason is that the material distributed and coated does not effectively form a heterojunction structure, thus not having good visible light response characteristics. P25 itself is a material responding to ultraviolet waves, and the visible light response effect is not good.

[0155] Application Example 2

[0156] The polyester mesh fabric is washed with water and dried at 80°C, cut into small pieces of 5cm x 5cm, and soaked in water without dripping. The SWCNT is sprayed on one side of the fabric using a common plastic spray bottle, and the fabric is fully sprayed in each part. The fabric is dried in a 80°C air drying oven. The fabric is washed again with water to remove unstable attached materials, and dried at 80°C.

[0157] The dispersion liquid material of the composite photocatalytic material of Example 1 with a concentration of 5.11 mg / L is sprayed on the fabric twice, and then washed and dried to obtain a SWCNT loading of 0.1 mg / cm 2 , a composite photocatalytic material loading of 1.5 mg / cm 2 , and a resistance value of 60 kΩ of the purification device.

[0158] The purification device and a sandwich porous fabric of the same size are sewn along the four edges with conductive fiber textile threads to obtain a photocatalytic unit. The sewing is performed every 10 cm along the perpendicular fabric unwinding direction and every 5 cm parallel to the fabric unwinding direction.

[0159] The top point and the midpoint of the side length of a square carbon felt with an area of 1.2 times the area of the fabric are sewn to the fabric at corresponding positions using conductive fibers. A certain length of conductive fiber textile thread is used to keep the space position of the carbon felt parallel and the distance is 9.4 cm. Finally, a water purification device is obtained, and the carbon felt is installed with a counterweight.

[0160] In 6 1L beakers, 200g of mixed black and odorous river sediment is added, and the river water is added to 1L. Three blanks and three experimental groups are set up, and the water purification device is added. The beakers are placed in a place where the sun can directly shine, and the changes in total nitrogen (TN) and total phosphorus (TP) indicators of the water body are measured every day. The initial values of the two indicators are 15 mg / L and 2 mg / L, respectively, and the results are shown in Figures 17-18 It can be seen from Figures 17-18 that the purification device prepared in Application Example 4 has a faster TN and TP index reduction effect than the blank control example.

[0161] Application Example 3

[0162] The motor speed was 50 Hz, the polyester mesh cloth was fed in the size of 3 m x 1.2 m per piece, the pressure of the air compressor connected with the nozzle was set to 0.7 MPa, 10 nozzles were used for liquid spraying, the distance between the nozzle and the fabric surface was 30 cm, the single nozzle polyester mesh cloth surface spraying width diameter was 25 cm, and the oven temperature was set to 120℃. 25 L of spraying liquid was added to the feeding barrel, the material was processed, the SWCNT was sprayed for 1 time, the dispersion liquid of the composite photocatalytic material of Example 1 was sprayed for 1 time, and the SWCNT loading amount was 0.27 mg / cm 2 , the composite photocatalytic material of Example 1 loading amount was 0.25 mg / cm 2 , and the resistance value of the purifier device was 10-50 kΩ (the resistance value was measured by the two-point method of the universal meter based on the arbitrary diameter of any single hole of the polyester mesh cloth).

[0163] The sample was cut into 5 cm x 5 cm purifier devices, and photocatalytic dye decolorization test was carried out under 60000 μW / cm 2 of light with a 420 nm filter. The dye was 20 mL of 2.5 mg / L rhodamine B, and the dark reaction and light reaction were each 30 min. The degradation effect of the sample was 37.6-45.8%.

[0164] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A purification device, characterized by The carbon felt and the photocatalytic unit are connected by a wire; The photocatalytic unit comprises a sandwich porous cloth and a purification device sewn together with the sandwich porous cloth, and the purification device in the photocatalytic unit is a sun-facing surface; The pore size of the purification device is not less than the pore size of the sandwich porous cloth; The pore size of the sandwich porous cloth is higher than 0.5 cm, the diameter of the fiber in the sandwich porous cloth is less than 3 mm, and the sandwich porous cloth is loaded with slow-release expanded original river water quality purification microorganisms; The purification device comprises a porous fiber fabric and a composite photocatalytic material and a conductive material loaded on the porous fiber fabric; The preparation method of the composite photocatalytic material comprises the following steps: BiVO4, GO and water are mixed and then heat-treated to obtain a slurry containing GO wrapped BiVO4; The slurry is mixed with a butyl titanate sol precursor to perform a hydrothermal reaction and a reduction reaction to generate rGO wrapped BiVO4 and nano-TiO2 gel loaded on the outer surface of the rGO, thereby obtaining the composite photocatalytic material; The butyl titanate sol precursor is a metal ion Zn 2+ The butyl titanate sol precursor is prepared by doping The particle size of the BiVO4 is 150-280 nm, and the BiVO4 is monoclinic BiVO4; The mass ratio of the BiVO4 particles to the GO is 1:2-100; The flake diameter of the GO is 0.5-3 μm, and the oxygen content is 2-20 wt%; The hydrothermal reaction and the reduction reaction are performed in a programmed microwave-assisted hydrothermal device, and the temperature of the hydrothermal reaction and the reduction reaction is 140-170 ℃; The volume ratio of the butyl titanate sol precursor to the mass of the GO is 8-40 mL:1 g; The concentration of butyl titanate in the butyl titanate sol precursor is 0.6-1 mol / L.

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