Synthesis of a titania-silver adsorption catalyst on attapulgite by a fluidized bed with light

Abstract

This invention belongs to the field of photocatalytic preparation, specifically disclosing a method for synthesizing an attapulgite-based Ti / Ag adsorption catalyst via a photofluidized bed, comprising the steps of: 1) pretreatment of attapulgite; 2) preparation of the precursor; and 3) photofluidized synthesis. The catalyst prepared by this method exhibits significantly improved catalytic performance and efficiency while reducing costs, possessing a cost advantage for industrialization.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic preparation, and more specifically, relates to a method for synthesizing an attapulgite-based Ti and Ag adsorption catalyst in a photofluidized bed. Background Technology

[0002] In the field of environmental governance, the pollution problems caused by industrialization, such as persistent organic pollutants and heavy metals, are becoming increasingly serious. Traditional treatment methods such as physical adsorption and biodegradation have limitations such as incomplete removal of pollutants and easy to cause secondary pollution.

[0003] Photocatalysis, with its ability to utilize light energy to degrade pollutants into harmless small molecules such as CO2 and H2O, has become one of the core directions in the research and development of environmental protection materials. While photocatalytic materials, represented by TiO2, possess advantages such as high chemical stability and environmental friendliness, they still face key technological bottlenecks: First, their light response range is limited to the ultraviolet region, resulting in a solar energy utilization rate of less than 5%; second, the recombination rate of photogenerated electron-hole pairs is fast, leading to low quantum efficiency; and third, nanoscale photocatalytic particles are prone to agglomeration and deactivation, and the separation and recovery costs of suspended catalysts are high, hindering their practical application.

[0004] Attapulgite, a natural clay mineral, possesses a large specific surface area, excellent adsorption properties, and a stable rod-shaped crystal structure, making it an ideal catalyst support material. Meanwhile, Ag's surface plasmon resonance effect can effectively broaden the photoresponse range and promote the separation of photogenerated carriers, forming a synergistic catalytic effect with TiO2. However, existing preparation technologies for attapulgite-based Ti / Ag composite photocatalysts still have shortcomings: on the one hand, the loading of active components (Ti, Ag) often employs impregnation-calcination processes, which easily lead to problems such as poor dispersibility, weak binding force, and active component detachment, making it difficult to simultaneously achieve the synergistic effect of adsorption and photocatalysis; on the other hand, existing preparation methods are mostly batch processes, with complex procedures and high costs, lacking industrial-scale preparation technologies that can achieve continuous and large-scale production.

[0005] Therefore, it is necessary to develop a method for synthesizing attapulgite-based Ti and Ag adsorption catalysts based on photofluidized beds that can achieve efficient energy transfer, low energy consumption, and environmental friendliness, in order to meet the practical needs of efficient treatment of environmental pollutants and promote the industrial application of photocatalytic materials.

[0006] To address the problems existing in the prior art, the present invention aims to provide a photofluidized bed synthesis method for attapulgite-based Ti and Ag adsorption catalysts. Summary of the Invention

[0007] This invention addresses the limitations of traditional pollution treatment methods, the technical bottlenecks of existing photocatalytic materials, and the shortcomings of related composite catalyst preparation technologies. It provides a photofluidized bed synthesis method for attapulgite-based Ti and Ag adsorption catalysts, comprising the following steps: 1) Pretreatment of attapulgite soil Add natural attapulgite to water and stir for 1 to 2 hours, then add alkaline solution and stir for 0.5 to 3 hours, finally add H2O2 aqueous solution and continue stirring, centrifuge to separate the supernatant, and let it air dry at room temperature for later use. 2) Preparation of precursors (1) Mix Ti(OH)4 solution and AgNO3 solution in proportion for 0.5h to 3h to obtain mixed metal source solution; add the pretreated alkalized attapulgite in step 1) to H2O2 aqueous solution and stir at 800r / min to 1500r / min for 10min to 30min, then mix with mixed metal source solution and stir at 800r / min to 1500r / min for 10min to 30min to obtain preloaded catalyst precursor wet powder; 3) Photofluidization synthesis The pre-loaded wetted catalyst precursor powder was uniformly fed into a photothermal fluidized bed for photothermal fluidized synthesis. The reaction temperature was controlled at 100℃-300℃, and the carrier gas flow rate in the fluidized bed was 10-100 L / min. The light source was turned on to ensure that the catalyst precursor was fully exposed to light. The photothermal fluidized reaction was maintained for 3-10 min. During the reaction, the decomposition products were collected through the tail gas treatment device, and the temperature in the fluidized bed was monitored in real time. After the reaction was completed, the light source and carrier gas were turned off. After the temperature dropped to room temperature, the product was collected, which is the finished attapulgite-based Ti and Ag adsorption catalyst.

[0008] Preferably, in step 1), the alkaline solution is selected from NaOH solution, KOH solution, and ammonia water.

[0009] Preferably, in step 1), the concentration of the alkaline solution is 0.5 mol / L to 15 mol / L, more preferably 1.0 mol / L to 12 mol / L.

[0010] Preferably, in step 1), the concentration of the attapulgite is controlled to be from 0.1 g / mL to 5.5 g / mL, more preferably from 0.1 g / mL to 2.0 g / mL, and even more preferably from 0.1 g / mL to 1.2 g / mL.

[0011] Preferably, in step 1), the concentration of the H2O2 aqueous solution is 5 mol / L to 25 mol / L, more preferably 5 mol / L to 10 mol / L.

[0012] Preferably, in step 1), the mass ratio of the H2O2 aqueous solution to attapulgite is in the range of 1:5 to 5:1, more preferably 1:2 to 2:1.

[0013] Preferably, in step 1), the mass ratio of the alkali to attapulgite is 1:20 to 1:60. Alkali treatment of natural attapulgite can open and enlarge its internal pores, increasing adsorption space; it also makes the material surface alkaline, increasing hydroxyl active sites, improving the adsorption effect on various pollutants, and enhancing ion exchange capacity, resulting in better overall material performance.

[0014] Preferably, in step 2), the concentration of the Ti(OH)4 solution is 0.1 mol / L to 10 mol / L, more preferably 0.1 mol / L to 1.5 mol / L.

[0015] Preferably, in step 2), the concentration of the AgNO3 solution is from 0.01 mol / L to 0.6 mol / L, more preferably from 0.05 mol / L to 0.15 mol / L.

[0016] Preferably, in step 2), the mass ratio of Ti(OH)4 to AgNO3, calculated based on Ti ions and Ag ions, is 50:1 to 1:1, more preferably 30:1 to 5:1, and even more preferably 15:1 to 10:1. The selected mass ratio is the optimal ratio for performance testing; a mass ratio that is too large or too small will lead to poor performance test results.

[0017] Preferably, in step 2), the ratio of the total Ti ions and Ag ions to attapulgite is 1.0 mol / g to 5.0 mol / g, more preferably 1.0 mol / g to 2.0 mol / g. The selected ratio is the optimal ratio for performance testing; a ratio that is too high will affect the overall uneven mixing of the catalyst and lead to poor performance test results.

[0018] Preferably, in step 3), the carrier is selected from air or nitrogen.

[0019] Preferably, in step 3), the residence time of the reactants in the optical fluidized bed is 3 to 10 minutes.

[0020] Preferably, in step 3), the light source system in the optical fluidized bed is a metal halide lamp with a power of 30-50mW.

[0021] Preferably, the photofluidization synthesis in step 3) can be carried out continuously.

[0022] According to another aspect of the present invention, another object of the present invention is to provide an attapulgite-based Ti, Ag adsorption catalyst prepared by the above method.

[0023] Beneficial effects 1. Enhanced catalytic performance and efficiency: The high specific surface area of ​​attapulgite can enhance the adsorption and enrichment of pollutants. Combined with the photocatalytic activity of Ti and Ag, it forms a synergistic effect of "adsorption-degradation", which can significantly improve the degradation efficiency of low-concentration pollutants (such as VOCs) and rapidly degrade pollutants into harmless small molecules.

[0024] 2. Reduced costs: Attapulgite is a natural clay mineral with low raw material costs and abundant reserves; the photofluidized bed synthesis process is easy to scale up and has lower energy consumption compared to traditional thermocatalytic technology, giving it a cost advantage for industrialization.

[0025] 3. Environmental and practical value: The catalyst prepared by this method has no secondary pollution, and the degradation products are mostly harmless small molecules such as CO2 and H2O, which meet environmental protection requirements; the catalyst is easy to separate and recover from the reaction system and can be widely used in industrial waste gas, indoor air, wastewater treatment and other fields.

[0026] 4. Excellent catalyst performance: The prepared catalyst particles exhibit regular geometric morphology, uniform particle size, good dispersibility, no obvious agglomeration, and fully exposed active sites; it is superior to adsorption catalysts prepared by traditional methods in terms of degradation efficiency, reaction rate, and catalytic stability. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a transmission electron microscope image of the attapulgite-supported TiO2 / Ag catalyst prepared in Example 1; Figure 2 The left figure shows the antibacterial test results of the attapulgite adsorption catalyst prepared in Example 1 in Test Example 2, and the right figure shows the antibacterial test results without the addition of catalyst. Figure 3 A to Figure 3 D represents the antibacterial test results of the attapulgite adsorption catalysts prepared in Examples 2 to 4 and Comparative Example 1, respectively, in Test Example 2. Figure 4 This is a performance comparison chart of the attapulgite adsorption catalyst prepared in Example 1 and the blank control group without catalyst in Example 1. Figure 5This is a comparison chart showing the catalytic effects of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 used in Example 1. Figure 6 This is a schematic diagram illustrating the overall structure of the optical fluidized bed reactor according to the present invention; Figure label: 1-Gas source A; 2-Gas source B; 3-Photocatalytic fluidized bed reactor; 4-Cyclone separator dust collector; 5-Drying oven; 6-Feeder; 7-Microwave generator; 33-Discharge port; 11-Gas source A interface; 21-Gas source B interface; 41-Feed port; 42-Discharge port; 61-Feed port. Detailed Implementation

[0029] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general and dictionary meaning, but rather should be interpreted based on the principle of allowing the inventors to appropriately define the terminology for the best interpretation, and based on its meaning and concept corresponding to the technical level of the invention. Therefore, the description herein is merely a preferred example for illustrative purposes and is not intended to limit the scope of the invention; thus, it should be understood that other equivalent implementations and modifications can be made without departing from the spirit and scope of the invention.

[0030] In this document, the terms “comprising,” “including,” “having,” “containing,” or any other similar terms are open-ended conjunctions intended to cover non-exclusive inclusions. For example, a composition or article containing a plurality of elements is not limited to those listed herein, but may also include other elements not explicitly listed but typically inherent to the composition or article. Furthermore, unless explicitly stated to the contrary, the term “or” is inclusive, not exclusive. For example, the condition “A or B” is satisfied in any of the following cases: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); A and B are both true (or exist). Moreover, in this document, the terms “comprising,” “including,” “having,” and “containing” should be interpreted as specifically disclosed and simultaneously cover closed or semi-closed conjunctions such as “composed of” and “substantially composed of.”

[0031] In this document, all features or conditions defined in the form of numerical ranges or percentage ranges are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible secondary ranges and individual values ​​within those ranges, particularly integer values. For example, a range description of "1 to 8" should be considered as specifically disclosing all secondary ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., particularly secondary ranges defined by all integer values, and should be considered as specifically disclosing individual values ​​within those ranges such as 1, 2, 3, 4, 5, 6, 7, 8, etc. Unless otherwise specified, the foregoing interpretation applies to all content throughout this invention, regardless of its scope.

[0032] If a quantity or other numerical value or parameter is expressed as a range, a preferred range, or a series of upper and lower limits, it should be understood that this document has specifically disclosed all ranges consisting of any upper or preferred value of that range and the lower or preferred value of that range, regardless of whether such ranges are separately disclosed. Furthermore, when a range of numerical values ​​is mentioned herein, unless otherwise stated, the range shall include its endpoints and all integers and fractions within the range.

[0033] In this document, numerical values ​​are to be understood as having a precision with significant digits, provided that the purpose of the invention can be achieved. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0034] The preparation method according to the present invention achieves the following objectives: (1) Broaden the photoresponse range of photocatalytic materials to improve solar energy utilization and quantum efficiency; (2) Optimize the binding stability and dispersibility of active components (Ti, Ag) with the carrier to enhance the synergistic effect of "adsorption-degradation"; (3) Construct a continuous and large-scale preparation process to reduce production costs and energy consumption; (4) Obtain high-performance adsorption catalysts with regular morphology, good dispersibility, easy separation and recovery and no secondary pollution to meet the actual application needs of environmental governance.

[0035] By pretreating attapulgite with alkalization and H2O2 mixed modification, preparing a pre-loaded catalyst precursor—integrated dissociation and loading—and synthesizing it through photothermal fluidization, the resulting catalyst has advantages such as good dispersibility, sufficient active sites, and strong adsorption and catalytic synergy. It can efficiently degrade low-concentration pollutants without secondary pollution. At the same time, the raw material cost is low and the process is easy to scale up, so it can be widely used in pollution treatment in many fields and promote the industrial application of photocatalytic materials.

[0036] After alkalization pretreatment, attapulgite powder dissociates into a monodisperse structure. Compared to untreated attapulgite, the originally agglomerated rod crystals dissociate into independent monodisperse structures after alkalization pretreatment. This not only significantly increases the specific surface area of ​​the material, allowing subsequent reactions or functions to be fully realized, but also removes impurities from the raw ore and improves the purity of the material. In contrast, the rod crystals of untreated attapulgite remain agglomerated, resulting in a small specific surface area and low reaction efficiency. Furthermore, residual impurities also affect the stability of performance.

[0037] Attapulgite mixed with H2O2 achieves directional growth. When attapulgite is mixed with H2O2, the hydroxyl radicals and reactive oxygen species generated by the decomposition of H2O2 in the system can both oxidize the surface groups of the material to form active sites and construct a directional adsorption layer through hydrogen bonding by leveraging the polar molecular properties. This guides the monodisperse nanorods to achieve orderly arrangement along specific crystal axes, forming a regular rod-shaped array structure, which improves both the stability of performance and the specificity of function. If attapulgite is not mixed with H2O2, the monodisperse rods will randomly accumulate, resulting in a disordered structure. This not only easily leads to problems such as clogging and uneven dispersion, but also causes rapid degradation of various properties of the material and makes it difficult to customize the structure, thus limiting the expansion of functions.

[0038] The attapulgite-based Ti and Ag adsorption catalyst prepared according to the method of the present invention, relying on the high specific surface area and stable support structure of attapulgite clay, the photocatalytic degradation ability of TiO2, and the plasma resonance and antibacterial properties of Ag, can achieve a multi-effect synergistic effect of "adsorption enrichment-photocatalytic degradation-antibacterial protection". Its application fields cover multiple categories such as functional material modification, environmental remediation, and agricultural ecology, as detailed below: 1. Antibacterial and preservative modification of plastics It can be used as a functional filler to blend and modify various plastics (such as polyethylene, polypropylene, food-grade PET, etc.) to prepare antibacterial and preservative functional plastics. Ag is included in this blend. + It can destroy the cell membrane of microorganisms, inhibit their metabolism and DNA replication, and achieve highly efficient killing of Escherichia coli, Staphylococcus aureus and putrefactive molds, with an antibacterial rate of over 99%. The hydroxyl radicals generated by TiO2 under natural light can help enhance the antibacterial effect and degrade ethylene gas and putrefactive organic matter in the packaging. The porous structure of attapulgite can adsorb odor molecules and delay the ripening and spoilage of food. It is suitable for fresh fruit and vegetable preservation boxes, ready-to-eat food packaging bags, cold chain turnover boxes and other scenarios, and there is no risk of leaching of antibacterial ingredients, which combines safety and long-lasting effect.

[0039] 2. Environmental pollutant treatment It can be used for the targeted degradation of low-concentration VOCs (such as toluene and formaldehyde) and sulfur- and nitrogen-containing odorous pollutants in industrial waste gas, as well as the adsorption and purification of complex pollutants in indoor air. It can also be adapted to mobile purification equipment for the purification of air in cars and enclosed underground spaces. Through the integrated action of "adsorption-degradation", it achieves the harmless treatment of pollutants without the risk of secondary pollution.

[0040] 3. Agricultural ecological governance It can be used for the adsorption and degradation of pesticide residues and heavy metals in farmland irrigation tailwater, as well as the in-situ remediation of organic pollutants in facility agriculture soil. It enriches pollutants through the directional adsorption of attapulgite, and achieves pollutant mineralization through the photocatalytic activity of Ti and Ag. Moreover, the material is degradable and leaves no residue, avoiding secondary damage to the soil ecology.

[0041] Example 1: Preparation of attapulgite + Ti(OH)4 + AgNO3 (10%) catalyst 1) Attapulgite soil pretreatment Take 500g of natural attapulgite, add 5L of H2O and stir for 1h, then add 10.83mL of 10mol / L NaOH solution and stir for 1h, and finally add 500mL of 9.79mol / L H2O2 and stir for 1h. Centrifuge to separate the supernatant, and let it air dry at room temperature for later use.

[0042] 2) Precursor preparation (1) Take 10 ml of Ti(OH)4 solution with a concentration of 1.252 mol / L and 9.260 ml of AgNO3 solution with a concentration of 0.1 mol / L, mix and stir for 1 h to obtain a mixed metal source solution; (2) Weigh 100g of pretreated alkalized attapulgite soil, add 20.740ml of H2O2 with a concentration of 9.79mol / L, and stir at 1000r / min for 20min; (3) Mix the materials from steps (1) and (2) above, and stir at 1000 r / min for 20 min to obtain pre-loaded catalyst precursor wet powder (Ag). + A composite structure in which titanium peroxide complex is co-loaded onto the pores and rod-shaped surface of attapulgite soil.

[0043] 3) Photofluidization synthesis (1) The preloaded wet powder of the catalyst precursor is uniformly fed into the photo-fluidized bed through a screw propeller for photothermal fluidized synthesis reaction. The input of the screw propeller is 8 g / min. Gas cylinder 1 is turned on and air is introduced into the lower part of the photocatalytic fluidized bed reactor. The carrier gas drives the catalyst precursor to form a gas-solid fluidized state. Gas source B is turned on and air is introduced into the upper two sides of the inside of the photocatalytic fluidized bed reactor to purge the powder attached to the tube wall to avoid powder agglomeration and wall deposition. The reaction temperature is controlled at 100℃-300℃ and the gas flow rate in the fluidized bed is 10-100 L / min. Air is used as the fluidized carrier gas to ensure that the precursor is in a stable fluidized state.

[0044] (2) Turn on the light source system and select a metal halide lamp with a power of 30-50W to ensure that the catalyst precursor is fully exposed to light so that the catalyst precursor undergoes a photothermal synergistic catalytic reaction in the photocatalytic fluidized bed reactor. The pressure inside the reaction tube is 0.1~0.7MPa. (3) Maintain the photothermal fluidized reaction for 3-10 min. During the reaction, collect the decomposition products through the tail gas treatment device and monitor the temperature inside the fluidized bed in real time. (4) After the reaction is completed, the gas-solid mixture after the reaction enters the cyclone separator dust collector through the pipeline (control the inlet gas velocity to 15~20 m / s, the operating pressure to 0.1~0.7 MPa, and ensure that the critical separation particle size is ≤5µm and the residence time is ≥0.5~1s) to achieve the separation of gas and catalyst powder. The waste gas is discharged from the system through the exhaust port on the cyclone separator dust collector. The separated catalyst powder enters the drying furnace (control the drying temperature to 120~180℃ and the drying time to 1~10min) for drying treatment. The final catalyst product is obtained from the discharge port, which is the finished product of attapulgite-based Ti and Ag adsorption catalyst.

[0045] Figure 1 This is a transmission electron microscope image of the attapulgite-supported TiO2 / Ag catalyst prepared in Example 1.

[0046] Example 2: Preparation of Attapulgite + Ti(OH)4 Catalyst 1) Attapulgite soil pretreatment The same pretreatment steps for attapulgite soil as in Example 1.

[0047] 2) Precursor preparation (1) Take 10 ml of Ti(OH)4 solution with a concentration of 1.252 mol / L and set it aside as a metal source solution; (2) Weigh 100g of pretreated alkalized attapulgite soil, add 20.740ml of H2O2 with a concentration of 9.79mol / L, and stir at 1000r / min for 20min; (3) Mix the materials from steps (1) and (2) above and stir at 1000 r / min for 20 min to obtain preloaded catalyst precursor wet powder (a composite structure of peroxytitanium complex loaded on the pores and rod-shaped surface of attapulgite).

[0048] 3) Photofluidization synthesis Same as the photofluidization synthesis steps in Example 1.

[0049] Example 3: Preparation of Attapulgite + AgNO3 Catalyst 1) Attapulgite soil pretreatment The same pretreatment steps for attapulgite soil as in Example 1.

[0050] 2) Precursor preparation (1) Take 9.260 ml of 0.1 mol / L AgNO3 solution and stir for 1 h. Set aside as a metal source solution. (2) Weigh 100g of pretreated alkalized attapulgite soil, add 20.740ml of H2O2 with a concentration of 9.79mol / L, and stir at 1000r / min for 20min; (3) Mix the materials from steps (1) and (2) above, and stir at 1000 r / min for 20 min to obtain pre-loaded catalyst precursor wet powder (Ag). + A composite structure loaded on the pores and rod-shaped surface of attapulgite soil.

[0051] 3) Photofluidization synthesis Same as the photofluidization synthesis steps in Example 1.

[0052] Example 4: Preparation of attapulgite + Ti(OH)4 + AgNO3 (5%) catalyst 1) Attapulgite soil pretreatment The same pretreatment steps for attapulgite soil as in Example 1.

[0053] 2) Precursor preparation (1) Take 5 ml of Ti(OH)4 solution with a concentration of 1.252 mol / L and 4.630 ml of AgNO3 solution with a concentration of 0.1 mol / L and stir for 1 h to obtain a mixed metal source solution; (2) Weigh 100g of pretreated alkalized attapulgite soil, add 20.740ml of H2O2 with a concentration of 9.79mol / L, and stir at 1000r / min for 20min; (3) Mix the materials from steps (1) and (2) above, and stir at 1000 r / min for 20 min to obtain pre-loaded catalyst precursor wet powder (Ag). + A composite structure in which titanium peroxide complex is co-loaded onto the pores and rod-shaped surface of attapulgite soil.

[0054] 3) Photofluidization synthesis Same as the photofluidization synthesis steps in Example 1.

[0055] Comparative Example 1: Preparation of Attapulgite + Ti(OH)4 + AgNO3 (10%) Catalyst by Photothermal Synthesis 1) Attapulgite soil pretreatment The same pretreatment steps for attapulgite soil as in Example 1.

[0056] 2) Precursor preparation The precursor preparation steps are the same as in Example 1.

[0057] 3) Photothermal synthesis (1) The preloaded catalyst precursor wet powder is evenly spread in the photochemical fixed bed reactor for photothermal synthesis reaction.

[0058] (2) Turn on the light source system and select an ultraviolet lamp with a power of 30-50W to ensure that the catalytic precursor is fully exposed to light; (3) Control the reaction temperature to 300~500℃, the heating rate to 5~10℃ / min, and the reaction time to 2h to carry out photothermal catalytic reaction; (4) After the reaction is completed, the catalyst product is in the form of agglomerated blocks. After grinding or dispersing, it becomes the finished product of attapulgite-based Ti and Ag adsorption catalyst.

[0059] Test Example 1: Photocatalyst Decomposition Performance Test (1) Using an electronic analytical balance with an accuracy of 0.1 mg, 50 mg of the catalyst samples prepared in Examples 1 to 4 and Comparative Example 1 were accurately weighed and carefully transferred to the metal reactor. At the same time, a toluene blank control group was set up. Except for the absence of catalyst sample, the reaction conditions of this group were the same as those of the catalyst test group. This was to eliminate the interference of factors such as toluene volatilization and reactor adsorption on the experimental results and to ensure the accuracy and reliability of the test data.

[0060] (2) Construct a complete toluene adsorption-photocatalytic degradation test system, the core of which includes a toluene gas generator, a metal reactor, and a xenon lamp light source system (equipped with a 50mW power module and 70mW / cm²). 2 The apparatus consists of an intensity modulation assembly and a gas chromatograph (model GC-2014). Before the experiment, the airtightness of each connection should be checked, and then the pipeline should be purged with nitrogen for 30 minutes to eliminate interference from air in the pipeline on the detection of toluene concentration.

[0061] (3) Toluene gas was introduced into the reactor at a flow rate of 0.6 mL / min through a toluene gas generator for 17 hours to ensure that the initial concentration of toluene in the reactor remained stable at 35 ppm. After the adsorption process reached equilibrium, the xenon lamp light source system was started for 20 minutes of preheating.

[0062] (4) After preheating, point the xenon lamp light source at the center of the reactor and start the photocatalytic degradation timer. According to the experimental design, gas samples were automatically and continuously collected from the reactor through the gas sampling port every 25 minutes. The chromatographic peak area of ​​toluene was recorded by the gas chromatograph workstation, and the toluene concentration at the corresponding time point was calculated by combining the standard curve. The sampling process lasted for a total of 305 minutes, and 13 sets of toluene concentration data were finally obtained (including the initial adsorption equilibrium concentration, the 0-minute light concentration, and the concentration data every 25 minutes thereafter).

[0063] The toluene concentration data of the catalyst test group and the blank control group were organized in chronological order, and a "toluene concentration-time" curve was plotted. The curve of the catalyst test group reflects the concentration change of toluene under the synergistic effect of catalyst adsorption and photocatalysis, while the curve of the blank control group reflects the concentration change of toluene without catalyst. By comparing the degradation differences between the two sets of curves, the photocatalytic degradation effect of the catalyst on toluene was clarified.

[0064] Figure 4 This is a performance comparison chart of the attapulgite adsorption catalyst used in Example 1 and the blank control group without catalyst. Figure 5 The graph shows a comparison of the catalytic effects of the catalysts prepared in Examples 1 to 4 and Comparative Example 1.

[0065] Test Example 2: Antibacterial Test (1) Preparation of bacterial suspension: Escherichia coli ATCC 25922 was inoculated into LB medium and cultured at 37℃ with shaking for 18-24 h to reach the logarithmic phase. Take 1 mL of the original bacterial suspension and add 9 mL of H2O; take 1 mL of the diluted bacterial suspension and add 9 mL of H2O; repeat the dilution twice, for a total of 3 dilutions, and dilute to 10. 3 CFU / mL available for use.

[0066] (2) Sample preparation: Take 0.35g of the sample prepared in Example 1 and 35mL of PBS water, and place them into 150mL conical beakers, and then sterilize them by autoclaving at 121℃. Mix the sterilized sample with 5mL of bacterial suspension and let it stand at 37℃ for a specified time (usually 24h). At the same time, a blank control group without powder is set up.

[0067] (3) Serial dilution: The treated bacterial culture and the blank group bacterial culture were serially diluted with sterile physiological saline (10-fold serial dilution to 10-fold serial dilution). 3(CFU / mL).

[0068] (4) Plate culture: Take 0.1 mL of bacterial solution of each dilution and spread it on LB agar plate. After incubation at 37℃ for 24 h, count the number of colonies on the plate (select plates with a colony count of 30-300 for counting).

[0069] Figure 2 The left figure shows the antibacterial test results of the attapulgite adsorption catalyst prepared in Example 1 in Test Example 2, while the right figure shows the antibacterial test results without the addition of catalyst. Figure 3 A to Figure 3 D represents the antibacterial test results of the attapulgite adsorption catalysts prepared in Examples 2 to 4 and Comparative Example 1, respectively, in Test Example 2.

Claims

1. A method for photofluidized bed synthesis of attapulgite-based Ti, Ag adsorption catalysts, the method comprising the following steps: 1) Pretreatment of attapulgite soil Add natural attapulgite to water and stir for 1 to 2 hours, then add alkaline solution and stir for 0.5 to 3 hours, finally add H2O2 aqueous solution and continue stirring, centrifuge to separate the supernatant, and let it air dry at room temperature for later use. 2) Preparation of precursors (1) Mix Ti(OH)4 solution and AgNO3 solution in proportion for 0.5h to 3h to obtain mixed metal source solution; add the pretreated alkalized attapulgite in step 1) to H2O2 aqueous solution and stir at 800r / min to 1500r / min for 10min to 30min, then mix with mixed metal source solution and stir at 800r / min to 1500r / min for 10min to 30min to obtain preloaded catalyst precursor wet powder; 3) Photofluidization synthesis The pre-loaded wetted catalyst precursor powder was uniformly fed into a photothermal fluidized bed for photothermal fluidized synthesis. The reaction temperature was controlled at 100℃-300℃, and the carrier gas flow rate in the fluidized bed was 10-100 L / min. The light source was turned on to ensure that the catalyst precursor was fully exposed to light. The photothermal fluidized reaction was maintained for 3-10 min. During the reaction, the decomposition products were collected through the tail gas treatment device, and the temperature in the fluidized bed was monitored in real time. After the reaction was completed, the light source and carrier gas were turned off. After the temperature dropped to room temperature, the product was collected, which is the finished attapulgite-based Ti and Ag adsorption catalyst.

2. The synthesis method according to claim 1, characterized in that, In step 1), the alkaline solution is selected from NaOH solution, KOH solution, and ammonia water; Preferably, in step 1), the concentration of the alkaline solution is 0.5 mol / L to 15 mol / L, more preferably 1.0 mol / L to 12 mol / L; Preferably, in step 1), the concentration of the attapulgite is controlled to be from 0.1 g / mL to 5.5 g / mL, more preferably from 0.1 g / mL to 2.0 g / mL, and even more preferably from 0.1 g / mL to 1.2 g / mL; Preferably, in step 1), the concentration of the H2O2 aqueous solution is 5 mol / L to 25 mol / L, more preferably 5 mol / L to 10 mol / L; Preferably, in step 1), the mass ratio of the H2O2 aqueous solution to attapulgite is in the range of 1:5 to 5:1, more preferably 1:2 to 2:1; Preferably, in step 1), the mass ratio of the alkali to the attapulgite is 1:20 to 1:

60. Natural attapulgite, after alkalization treatment, can open up and expand its internal channels, increasing the adsorption space; make the material surface alkaline, increase the number of hydroxyl active sites, improve the adsorption effect on various pollutants, and enhance the ion exchange capacity, making the overall performance of the material better.

3. The synthesis method according to claim 1, characterized in that, In step 2), the concentration of the Ti(OH)4 solution is from 0.1 mol / L to 10 mol / L, more preferably from 0.1 mol / L to 1.5 mol / L; Preferably, in step 2), the concentration of the AgNO3 solution is from 0.01 mol / L to 0.6 mol / L, more preferably from 0.05 mol / L to 0.15 mol / L; Preferably, in step 2), the mass ratio of Ti(OH)4 to AgNO3, calculated according to Ti ions and Ag ions, is 50:1 to 1:1, more preferably 30:1 to 5:1, and even more preferably 15:1 to 10:

1. Preferably, in step 2), the ratio of the total amount of Ti ions and Ag ions to attapulgite is 1.0 mol / g to 5.0 mol / g, more preferably 1.0 mol / g to 2.0 mol / g, calculated based on Ti ions and Ag ions.

4. The synthesis method according to claim 1, characterized in that, In step 3), the carrier is selected from air and nitrogen. Preferably, in step 3), the residence time of the reactants in the photofluidized bed is 3 to 10 minutes; Preferably, in step 3), the light source system in the optical fluidized bed is a metal halide lamp with a power of 30-50mW; Preferably, the photofluidization synthesis in step 3) can be carried out continuously.

5. An attapulgite-based Ti and Ag adsorption catalyst prepared by the synthesis method according to any one of claims 1 to 4.

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