A method and system for precise control of pore structure in attapulgite-based materials

Abstract

This invention discloses a method and system for precise control of the pore structure of attapulgite-based materials, belonging to the field of mineral material modification technology. The method includes four steps: crystal phase pre-activation treatment, mesoporous template directional construction, micropore in-situ growth control, and pore interface bonding modification. The crystallinity of the attapulgite crystal phase is controlled by plasma etching, mesopores are oriented using a template method, micropores are grown in-situ using vapor deposition, and pore interface bonding is performed using a functionalized modification liquid to construct a hierarchical interconnected micropore-mesopore pore structure. The system includes corresponding units for crystal phase pre-activation, mesoporous template directional construction, micropore in-situ growth control, pore interface bonding modification, and a central control unit. The central control unit enables precise control and process monitoring of the process parameters of each unit. This invention achieves precise design of the pore structure of attapulgite-based materials, improves the specific surface area and pore volume of the material, and enhances chemical stability and filtration performance.

Description

Technical Field

[0001] This invention relates to the field of mineral material modification technology, specifically to a method and system for precise control of the pore structure of attapulgite-based materials. Background Technology

[0002] With increasingly stringent global standards for food safety, biopharmaceutical purity, and environmental protection, high-efficiency filtration and separation technology has become a core component of modern industry. Filter aids, as key media determining filtration efficiency and filtrate quality, play an irreplaceable role in fermentation broth clarification, antibiotic extraction, edible oil refining, and the treatment of challenging wastewater. Currently, while traditional filter aids such as diatomaceous earth, perlite, and cellulose are widely used, they generally suffer from bottlenecks such as simple pore structure, limited specific surface area, poor chemical stability, and difficulty in regeneration, making it difficult to meet the filtration demands of high throughput, high precision, and complex operating conditions. Especially in the biopharmaceutical field, the removal requirements for nanoscale impurities and pyrogens are extremely high, but existing materials often suffer from high filtration resistance or retention failure due to uneven pore distribution. Attapulgite, a natural one-dimensional nanorod-shaped silicate mineral, is considered a highly promising next-generation filter aid due to its unique sandwich-layer chain-like crystal structure and regular nanopores. However, natural attapulgite often contains impurities such as quartz and calcite, and its pores are easily clogged, preventing the full realization of its inherent advantages. Therefore, developing a high-performance attapulgite-based filter aid material that can precisely control the pore structure and achieve multi-level pore synergistic effect is of great strategic significance for breaking through the technical barriers of high-end filter materials and promoting the green upgrading of related industries.

[0003] Extensive research has been conducted in the international academic community regarding the modification and application of attapulgite, but existing technologies still have significant limitations in the fine-tuning of pore structure. Early studies focused on simple acid activation or heat treatment. For example, Wang et al. (2018) pointed out in Applied Clay Science that while traditional hydrochloric acid activation can remove some carbonate impurities, it easily damages the crystal framework of attapulgite, leading to pore collapse and reducing specific surface area and adsorption capacity. Subsequently, some scholars attempted to introduce surfactants for organic modification. Liu et al. (2020) reported in Chemical Engineering Journal on using CTAB to modify the surface of attapulgite to improve its dispersibility. However, this method mainly acts on the outer surface of the particles, making it difficult to deeply control the pore size distribution of the internal nanopores and construct an ideal hierarchical structure of macroporous conduction-mesoporous transport-microporous retention. In recent years, although some studies have attempted to construct mesoporous structures using template methods, such as Zhang et al. (2022) synthesizing mesoporous attapulgite composites using soft template agents, existing literature generally lacks research on the synergistic mechanism between crystal phase pre-activation and in-situ micropore growth. This results in materials with wide pore size distributions, poor orientation, and insufficient structural stability under high temperature or strong acid / alkali environments. Overall, current technologies have not yet solved the problem of impurity ions interfering with pore reconstruction in low-grade attapulgite, and lack a systematic control strategy that can simultaneously achieve crystal phase optimization, directional mesopore construction, and precise micropore growth, thus limiting its large-scale application in high-end filtration aids.

[0004] Chinese Patent Publication No. (CN103157437A) proposes a method for preparing a filter aid and its regeneration using fly ash or slag as raw materials through acid-alkali pretreatment. This technology makes a beneficial attempt in the resource utilization of solid waste, pointing out that some filtration performance can be restored through calcination and chemical soaking. However, the heterogeneity of the raw material source leads to a wide and uncontrollable pore size distribution in the product, making it difficult to achieve precision filtration. Chinese Patent Publication No. (CN101711973A) discloses a method for preparing a modified attapulgite microparticle retention and filter aid. Acid modification and microwave treatment improve the dispersibility of attapulgite to a certain extent. While the patented technology improves the filtration efficiency of black liquor in papermaking, it primarily focuses on adjusting surface charge and fails to address the deep reconstruction of the intrinsic pores of attapulgite. This makes it prone to pore collapse or blockage under high-flow-rate filtration conditions and results in poor regeneration performance. Another patent (CN101711973A), although involving the utilization of low-grade attapulgite and integrating retention and filtration functions through physical extrusion and organic additives, introduces numerous organic additives into its process. This not only increases production costs but may also cause secondary pollution and fails to address the fundamental problem of impurity ions in low-grade ore interfering with the pore structure. Although these patents improve existing technologies in specific dimensions, they all fail to fundamentally solve the challenge of customizing and precisely controlling the pore structure of attapulgite-based materials, particularly in achieving synergistic control of in-situ micropore growth and mesopore directional construction, where a significant technological gap remains.

[0005] Therefore, it is urgent to break through the limitations of traditional extensive modification and to propose an innovative full-process precise control strategy that includes crystal phase pre-activation, directional construction of mesoporous templates, in-situ growth of micropores, and bonding modification of pore interfaces. In general, this means overcoming the limitations of plasma etching activation technology, precisely controlling the crystallinity of the crystal phase without damaging the crystal framework, laying the foundation for pore reconstruction, developing a directional assembly process for mesoporous template agents, and achieving the orderly arrangement of mesoporous channels and controllable adjustment of pore size. Summary of the Invention

[0006] Based on the above-mentioned technical problems, this application discloses a method and system for precise control of the pore structure of attapulgite-based materials. The method for precise control of the pore structure of attapulgite-based materials specifically includes:

[0007] Attapulgite ore was subjected to crystal phase pre-activation treatment to obtain crystal phase-controlled attapulgite powder.

[0008] The attapulgite powder with crystalline phase regulation was subjected to directional construction using a mesoporous template to obtain an attapulgite intermediate with a defined mesoporous structure.

[0009] Micropore in-situ growth regulation was implemented on the mesoporous structure-defined attapulgite intermediate to obtain a micropore-mesoporous hierarchical attapulgite precursor.

[0010] The microporous-mesoporous hierarchical attapulgite precursor is modified by pore interface bonding to obtain an attapulgite-based material with precisely controlled pore structure.

[0011] Preferably, the crystal phase pre-activation treatment includes: crushing and sieving the attapulgite ore, then placing it in a plasma activation furnace, and performing plasma etching activation in a mixed atmosphere of inert gas and oxygen-containing gas. The etching power is 200~500W, the etching time is 10~30min, and the volume ratio of inert gas to oxygen-containing gas in the mixed atmosphere is [missing information]. attapulgite powder with crystalline phase regulation was obtained.

[0012] Preferably, during the plasma etching activation process, the crystallinity of the attapulgite powder is... The formula for determining it is: ,in The characteristic diffraction peak intensities of the attapulgite (110) crystal plane are... The background intensity of the diffraction peaks is for amorphous phases. After etching and activation, the crystallinity of the attapulgite powder is adjusted to 65%~85%.

[0013] Preferably, the directional construction of the mesoporous template includes: mixing phase-controlled attapulgite powder and a mesoporous template agent at a mass ratio of... Mix and add deionized water to prepare a suspension with a solid content of 20%~35%. After ultrasonic dispersion at an ultrasonic power of 400~600W and a temperature of 50~70℃ for 20~40 minutes, transfer it to a hydrothermal reactor and hydrothermally react at 100~160℃ for 6~12 hours. After the reaction is completed, filter and dry to obtain a mesoporous structured attapulgite intermediate.

[0014] Preferably, the mesoporous template agent is one or a combination of two of the following: mesoporous silica template and polymer template, and the pore size of the mesoporous template agent is [missing information]. Furthermore, the pore orientation of the mesoporous template agent The formula for determining it is: ,in The length of a single template agent channel. The angle between the template agent channel and the preset orientation direction. The number of template agent pores and the degree of pore orientation are statistically analyzed. .

[0015] Preferably, the in-situ microporous growth control includes: placing the mesoporous attapulgite intermediate in a vapor deposition reaction chamber, introducing a mixture of precursor gas and carrier gas, and performing in-situ vapor deposition growth at a heating temperature of 300~500℃ and a reaction pressure of 0.1~0.5MPa for a deposition time of 2~6h to obtain a microporous-mesoporous hierarchical attapulgite precursor, wherein the pore size of the micropores is 0.5~2nm.

[0016] Preferably, during the vapor deposition process, the growth density of micropores is... Satisfying the formula: ,in The number of micropores per unit volume. is the specific surface area of ​​the attapulgite intermediate. The apparent volume of the attapulgite intermediate and the micropore growth density are given. Adjustment to .

[0017] Preferably, the pore interface bonding modification includes: immersing a microporous-mesoporous hierarchical attapulgite precursor in a functionalized modification liquid, and carrying out an interface bonding reaction for 3-8 hours at a stirring rate of 200-400 r / min and a temperature of 40-60℃. After the reaction, the material is centrifuged, washed, and vacuum dried to obtain an attapulgite-based material with precisely controlled pore structure. The vacuum drying temperature is 80-120℃, and the drying time is 10-16 hours.

[0018] Preferably, the functionalized modified solution is an alcohol-water mixture containing one or more of the following: a silane coupling agent, an organophosphonate, and a metal alkoxide. The mass concentration of the functionalized modified solution is 5% to 15%, and the volume ratio of anhydrous ethanol to deionized water in the alcohol-water mixture is [missing information]. Furthermore, the grafting rate of interface bonding modification The formula is: Grafting rate Adjust to 3%~10%.

[0019] A precise control system for the pore structure of attapulgite-based materials includes: a crystal phase pre-activation unit, a mesoporous template directional construction unit, a micropore in-situ growth control unit, a pore interface bonding modification unit, and a central control unit.

[0020] The crystal phase pre-activation unit includes a plasma activation furnace, a raw material crushing and sieving assembly, and an atmosphere proportioning assembly. The plasma activation furnace is connected to the raw material crushing and sieving assembly and the atmosphere proportioning assembly, respectively.

[0021] The mesoporous template directional construction unit includes an ultrasonic dispersion device, a hydrothermal reactor, and a solid-liquid separation component. The ultrasonic dispersion device is connected to the hydrothermal reactor, and the hydrothermal reactor is connected to the solid-liquid separation component.

[0022] The micropore in-situ growth control unit includes a vapor deposition reaction chamber, a gas ratio component, and a temperature and pressure control component, both of which are connected to the vapor deposition reaction chamber.

[0023] The channel interface bonding modification unit includes a modified reaction vessel, a stirring assembly, a centrifugal washing assembly, and a vacuum drying oven. The stirring assembly is located inside the modified reaction vessel, and the modified reaction vessel is connected in sequence to the centrifugal washing assembly and the vacuum drying oven.

[0024] The central control unit is electrically connected to the crystal phase pre-activation unit, the mesoporous template directional construction unit, the micropore in-situ growth control unit, and the pore interface bonding modification unit, respectively, and is used to control the process parameters of each unit and monitor the control process.

[0025] Compared with the prior art, the technical solution of this application has the following technical effects:

[0026] This invention successfully constructs a multi-level interconnected pore network with a coordinated distribution of macropores, mesopores, and micropores by precisely controlling the pore structure of attapulgite-based materials. The unique structural design significantly optimizes the fluid transport path inside the material, greatly reduces filtration resistance, and ensures extremely high impurity retention efficiency. It achieves a perfect balance between high throughput and high precision, effectively meeting the stringent requirements for efficient separation under complex working conditions.

[0027] The crystal phase pre-activation and micropore in-situ growth technology adopted in this invention deeply reconstructs the internal microstructure of the material without destroying the mineral crystal framework, significantly improving the specific surface area and pore volume of the material, enhancing its adsorption and capture capacity for nanoscale particles and colloidal substances, so that the filter aid material has stronger surface reactivity and functional loading potential while maintaining excellent mechanical strength, expanding its application scenarios in high-end fields.

[0028] This invention endows attapulgite-based materials with excellent chemical stability and environmental adaptability through an innovative channel interface bonding modification strategy. The specially treated material surface can effectively resist the erosion of strong acids, strong alkalis and high temperature environments, avoiding the channel collapse or performance degradation problems that are prone to occur in traditional materials under extreme working conditions. This ensures long-term stable operation of the filtration process, significantly extends the service life of the material and reduces the replacement frequency.

[0029] This invention achieves intelligent control of the entire process from raw material pretreatment to finished product preparation, ensuring high uniformity and repeatability of product performance. It not only significantly improves the utilization rate of low-grade mineral resources, but also avoids the use of toxic and harmful chemical reagents, which is in line with the concept of green manufacturing. It provides a safe, efficient and sustainable new filter aid solution for industries such as food and beverage, biomedicine and environmental governance.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0031] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0033] Based on the description of the figures and their corresponding technical content in the document, the titles of the figures are as follows:

[0034] Figure 1 Here is a flowchart of a method for precise control of the pore structure of attapulgite-based materials.

[0035] Figure 2 Here is a flowchart of the pre-activation treatment process for the pore structure and crystal phase of attapulgite-based materials.

[0036] Figure 3 Here is a flowchart of the directional construction process for the mesoporous template of attapulgite-based material pore structure.

[0037] Figure 4 Here is a flowchart of the in-situ growth control process for micropores in the pore structure of attapulgite-based materials.

[0038] Figure 5 Comparison of XRD patterns of attapulgite under different plasma etching powers;

[0039] Figure 6 Here is a TEM image of attapulgite under the optimal etching parameters in this embodiment.

[0040] Figure 7 For example: TEM image of the intermediate material for shaping the mesoporous structure in this embodiment;

[0041] Figure 8 For example: FESEM images of the micropore-mesopore hierarchical precursor in this embodiment;

[0042] Figure 9 The image shows a comparison of the characteristic peak intensities of Si-O-Al and Si-OC at different modification times in this embodiment.

[0043] Figure 10 The image shows a comparison of the FT-IR spectra before and after the bonding modification of the pore interface in this embodiment.

[0044] Figure 11 Here is a diagram of a system architecture for precise control of the pore structure of attapulgite-based materials. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0046] It should be understood that an embodiment or this embodiment mentioned throughout the specification means that a particular feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, an embodiment or this embodiment appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0047] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0048] In this article, the terms "and / or" are merely a description of the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: A exists alone, B exists alone, and A and B exist simultaneously. In this article, the terms " / " describe another type of relationship between related objects, indicating that two relationships can exist. For example, "A / and B" can represent two cases: A exists alone, and A and B exist alone. In addition, in this article, the character " / " generally indicates that the related objects before and after it are in an "OR" relationship.

[0049] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, "at least one of A and B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0050] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion.

[0051] Example 1

[0052] This embodiment mainly describes a method for precise control of the pore structure of attapulgite-based materials, such as... Figure 1 As shown, it specifically includes:

[0053] Attapulgite ore was subjected to crystal phase pre-activation treatment to obtain crystal phase-controlled attapulgite powder.

[0054] The attapulgite powder with crystalline phase regulation was subjected to directional construction using a mesoporous template to obtain an attapulgite intermediate with a defined mesoporous structure.

[0055] Micropore in-situ growth regulation was implemented on the mesoporous structure-defined attapulgite intermediate to obtain a micropore-mesoporous hierarchical attapulgite precursor.

[0056] The microporous-mesoporous hierarchical attapulgite precursor is modified by pore interface bonding to obtain an attapulgite-based material with precisely controlled pore structure.

[0057] Furthermore, pre-activation treatment of the crystal phase, such as... Figure 2 As shown, the specific process includes: using a crusher for coarse crushing, and using the compression action to crush the raw ore into block particles with a particle size ≤5mm; during the crushing process, the feeding speed is adjusted to 20kg / h by an electromagnetic vibrating feeder, with a feeder amplitude of 5mm and a frequency of 50Hz;

[0058] After coarse crushing, the material is conveyed to a planetary ball mill via a closed stainless steel conveyor belt. The grinding media are 10mm diameter zirconia balls (density 6.05g / cm³), and the grinding system is precisely configured with a ball-to-material mass ratio of 8:1. The main shaft speed of the ball mill is set to 400r / min via a frequency converter. The grinding jar moves in a planetary motion with the main shaft (revolution speed 100r / min, rotation speed 200r / min). The material is refined by the impact and grinding action between the media and the material. The grinding process continues for 2.5 hours.

[0059] After grinding, the material is classified by a vibrating screen using a 300-mesh (48μm aperture) standard metal screen. The vibration frequency of the screen is adjusted to 50Hz and the amplitude to 5mm via an electromagnetic vibrator. During the screening process, the sieved powder is collected through the bottom hopper, and the remaining material is automatically returned to the ball mill feed inlet through a 30° inclined return pipe for secondary grinding. This cyclical screening continues until the sieve passing rate is ≥98%. The sieve passing rate is calculated using the following formula: In the formula, For the quality of the sieved powder, This represents the total mass of the material after grinding.

[0060] Plasma etching activation process: The sieved powder is spread evenly on a quartz carrier boat by an automatic feeder (feeding speed 10g / min). The spreading thickness is precisely controlled to 5mm by mechanical limit baffles. The carrier boat has dimensions of 300mm×50mm×10mm. It is fed into the reaction chamber of the plasma activation furnace by a high-temperature resistant quartz pusher (length 1.5m). After the chamber door is closed, a rotary vane vacuum pump is started to reduce the pressure in the chamber to below 10Pa. Argon gas with a purity of 99.99% is introduced for purging. The purging flow rate is set to 50mL / min by a D07-19B mass flow controller and is continued for 15min to remove residual air and moisture in the chamber.

[0061] After purging, keep the argon flow rate constant and proceed by volume ratio. Oxygen with a purity of 99.95% was introduced, and the flow rate of argon was adjusted to 43.75 mL / min and the flow rate of oxygen to 6.25 mL / min respectively through a dual-channel mass flow controller to keep the total pressure in the cavity stable at 0.1 MPa. The pressure in the cavity was monitored in real time by a PG-100 vacuum gauge (accuracy ±0.001 MPa).

[0062] The plasma generator was started, with the radio frequency power set to 350W and the radio frequency to 13.56MHz. Plasma was generated by ionizing the mixed gas through discharge via parallel plate electrodes. The plasma density was monitored using a Langmuir probe. The powder was etched and activated for 20 minutes.

[0063] During the etching process, the temperature inside the cavity is monitored in real time using an infrared thermometer and controlled within the range of room temperature ±5℃ to avoid damage to the crystal structure caused by high temperature. After activation, the machine is shut down according to the following procedure: first, turn off the plasma generator, keep the mixed gas flowing in for 5 minutes, then turn off the gas supply, and wait for the cavity to cool naturally to room temperature (cooling rate 5℃ / min). Then, open the vent valve to slowly restore the atmospheric pressure (pressure increase rate 0.02MPa / min), and take out the carrier boat to collect the activated powder.

[0064] Crystallization control and detection: X-ray diffraction was used to analyze the crystal phase of the powder during the activation process. The test conditions were: Cu Kα rays (wavelength...). Tube voltage 40kV, tube current 40mA, scanning range Scanning speed 5° / min, step size 0.02°, divergence slit 1mm, receiving slit 0.1mm, anti-scattering slit 1mm; crystallinity The formula for calculating the intensity of characteristic diffraction peaks is as follows: In the formula, The characteristic diffraction peak intensity (diffraction angle) of the attapulgite (110) crystal plane The peak area was obtained by calculating the integral method using the DIFFRAC.EVA software that comes with the diffractometer; For the amorphous phase background intensity, select For the smooth regions without characteristic peaks within the interval, a fifth-order polynomial fitting was performed using software to obtain the average background intensity after subtracting the influence of characteristic peaks. Simultaneously, the grain size was calculated using the Scherrer formula to verify the integrity of the crystal structure. In the formula, The grain size is in nm. This is the shape factor (value 0.89). The wavelength of X-rays is (nm). The full width at half maximum (FWHM) of the diffraction peak is rad. The diffraction angle is rad. By monitoring the crystallinity and grain size values ​​in real time, the plasma etching power and time are dynamically adjusted to ensure that the crystallinity of the final product is stably controlled at 85%, the grain size is maintained in the range of 50-80nm, and there is no lattice distortion.

[0065] Furthermore, such as Figure 3 As shown, the mesoporous template was constructed in a directional manner. The template agent was selected and pretreated as follows: a mesoporous silica template agent was chosen, and its pore structure was pre-defined as cylindrical straight channels through the template agent synthesis process. The average pore size was determined by transmission electron microscopy (TEM). Length of the channel Specific surface area Kong Rong Before use, the template agent undergoes vacuum drying pretreatment. The template agent is placed in a vacuum drying oven, the drying temperature is set to 120℃, and the vacuum degree is adjusted to -0.09MPa using a vacuum pump. The drying time is 4 hours, and humidity changes are monitored using a humidity sensor inside the oven until the humidity drops below 3%, removing adsorbed water and volatile impurities from the template agent surface. After drying, the weight loss rate of the template agent is calculated using the following formula to ensure the effectiveness of the pretreatment: In the formula, For the quality of the template agent before drying, For the quality of the template agent after drying, the weight loss rate should be ≤1.5%.

[0066] To prepare the powder mixture and suspension, 120g of attapulgite powder with crystal phase control and 10g of mesoporous template agent were accurately weighed using an electronic balance (mass ratio...). The mixture is fed into a high-speed mixer with a 100mm diameter impeller. The rotation speed is set to 1500 rpm via a frequency converter, and the mixing time is 10 minutes. The shear force (shear rate) generated by the high-speed rotation is utilized. The two powders were uniformly mixed using centrifugal force. The uniformity of the mixture was verified by sampling: three samples (each weighing 1g) were randomly selected, and the Si element content was detected using X-ray fluorescence spectrometry. The relative standard deviation (RSD) was calculated, requiring RSD ≤ 1%. The formula for calculating the relative standard deviation is as follows: In the formula, For the number of samplings, For the first The Si element content (wt%) was measured in this test. The value (wt%) is the average of three tests. Deionized water was added to the mixed powder, and the solid content of the suspension was monitored in real time using an online concentration monitor (accuracy ±0.1wt%). The amount of water added was adjusted to 334.3g to ensure that the solid content of the suspension accurately reached 28wt%. The formula for calculating the solid content is as follows: In the formula, The total mass of the mixed powder. The quality of the deionized water was then determined; the suspension was then transferred to a magnetic stirrer, and the stirring speed was set to 300 r / min for 20 min to ensure that the powder was completely dispersed and that there were no obvious agglomerated particles.

[0067] Ultrasonic dispersion involves transferring the suspension into an ultrasonic dispersion device. The ultrasonic transducer frequency is fixed at 20kHz, and the power density is... The ultrasonic power was set to 500W, and the dispersion temperature was controlled at 60℃ using a constant-temperature water bath (temperature control accuracy ±1℃). The ultrasonic time was 30 minutes. A pulsed working mode was used during the ultrasonic process, with a time relay set to operate for 3 seconds and then pause for 1 second to avoid localized overheating that could lead to powder agglomeration and damage to the template agent structure. After ultrasonic dispersion, the particle size distribution in the suspension was measured using a laser particle size analyzer, with a testing range of 0.01-3000μm, to ensure... , , The particle size distribution span is calculated using the following formula: The requirement is that Span ≤ 1.3 to ensure uniform particle size.

[0068] In the hydrothermal reaction, the ultrasonically dispersed suspension was slowly transferred into a hydrothermal reactor using a peristaltic pump (flow rate 50 mL / min). The reactor, lined with polytetrafluoroethylene (PTFE), had a volume of 500 mL, and the suspension filling was precisely controlled to 70% (350 mL). When sealing the reactor, the torque of the sealing bolts was controlled to 30 N·m using a torque wrench to ensure a tight seal. The reactor was then placed in a DHG-9240A constant temperature oven, with a heating rate set at 5℃ / min. The oven temperature was controlled to reach 130℃ using a programmable temperature controller (temperature control accuracy ±0.5℃), and then maintained at that temperature for 9 hours. During the reaction, the pressure inside the reactor naturally increased to 0.3 MPa as the temperature rose. The pressure change was monitored in real time using a pressure sensor built into the oven (measuring range 0-1 MPa, accuracy ±0.01 MPa). If the pressure exceeded the set range ±0.02 MPa, the equipment automatically activated a pressure relief device (pressure relief rate 0.01 MPa / s) for adjustment. The reaction kinetic constants of the hydrothermal reaction were calculated using the following formula: In the formula, For reaction conversion rate, The reaction rate constant ( ), This refers to the reaction time.

[0069] Solid-liquid separation and drying: After the reaction, the oven power was turned off, and the reactor was allowed to cool naturally to room temperature (cooling time approximately 2 hours, cooling rate 1℃ / min). The sealing bolts were slowly loosened (loosening torque 5 N·m), and the reactor lid was opened to remove the suspension. Vacuum filtration was performed using an SHB-III type circulating water vacuum pump with a 100 mm diameter filtration funnel and a 0.45 μm pore size polyethersulfone filter membrane. The filtration pressure was precisely controlled at 0.08 MPa using a vacuum regulating valve, and the filtration rate was monitored by a filtrate flow meter (range 0-10 L / min). After collecting the filter cake, it was transferred to a vacuum drying oven. The drying temperature was set to 105℃, the vacuum degree to -0.09 MPa, and the drying time to 12 hours. The humidity inside the oven was recorded every 2 hours during the drying process (monitored by an HS100 type humidity sensor, accuracy ±1%) until the humidity was below 5%. The dried solid product was then removed, which is the mesoporous attapulgite intermediate. The water content of the dried product was calculated using the following formula: In the formula, The mass of the filter cake before drying (g) is given. The mass (g) of the dried product is required to have a moisture content ≤0.5%.

[0070] Mesoporous orientation was determined using transmission electron microscopy (TEM) to characterize the mesoporous structure. The accelerating voltage was 200 kV, the magnification was 50,000x, and 10 different fields of view were selected (each field of view area...). ) Observe; orifice orientation Calculated using the following formula: In the formula, To count the number of holes, the holes in the field of view were randomly selected for counting. The length of a single channel (nm) is measured directly using a TEM image scale, accurate to 1nm. The angle (°) between a single channel and a preset orientation direction (parallel to the sample surface) is precisely measured using an angle measurement tool in image analysis software, accurate to 0.1°; the orientation degree is then calculated by substituting the measured data into the formula. Meanwhile, the pore size distribution of mesopores was analyzed using the BJH model, and the mesopore volume was calculated using the following formula: In the formula, , For mesopore diameter range, For aperture distribution function ( The mesopore volume is required to be ≥0.6cm³ / g.

[0071] Furthermore, such as Figure 4 As shown, in-situ microporous growth control was performed. A vapor deposition reaction chamber was prepared, and the mesoporous attapulgite intermediate was evenly spread onto a quartz sample holder using an automatic spreader (spreading speed 5 g / min). The spreading thickness was precisely controlled to 8 mm using a mechanical scale. The sample holder dimensions were 200 mm × 40 mm × 5 mm, and it was placed in the center of the vapor deposition reaction chamber to ensure the sample was in a uniform plasma region. After closing the reaction chamber, a rotary vane vacuum pump was started to evacuate the chamber. The pressure inside the chamber was monitored in real time using a vacuum gauge until the pressure reached the specified value. Maintain this vacuum level for 30 minutes to completely remove impurities, gases, and moisture from the cavity; the leakage rate during vacuum maintenance is calculated using the following formula: In the formula, This represents the change in vacuum level. For the reaction chamber volume, Given a time-varying quantity, the required leakage rate is... .

[0072] The gas mixture is prepared and introduced, with silicon tetrachloride (99.9% purity) selected as the precursor gas. The carrier gas used is nitrogen with a purity of 99.99%. The two gases are controlled by independent mass flow controllers, with the precursor gas flow rate set at 2.5 mL / min and the carrier gas flow rate at 47.5 mL / min, ensuring a precise volume ratio of precursor gas to carrier gas. The total gas flow rate is 50 mL / min. Before being introduced, the gas must pass through a molecular sieve purification device (filled with 5A molecular sieve, 500 g) to remove moisture and impurities. The pressure difference between the inlet and outlet of the purification device is monitored by a differential pressure transmitter and controlled within 0.05 MPa. The evaporation rate of the precursor gas is calculated using the following formula: In the formula, The gas flow rate is expressed in mol / s. The value represents the molar mass of silicon tetrachloride (g / mol). The system pressure is expressed in Pa. The molar volume (m³ / mol) is used to ensure a stable evaporation rate. .

[0073] The reaction chamber is heated by an external electric heating device (2kW), with the heating rate set to 10℃ / min by a temperature controller. The chamber temperature is monitored in real-time using a platinum resistance thermometer (accuracy ±0.1℃). Once the temperature reaches 400℃, a PID thermostat is activated to control temperature fluctuations within ±2℃. The outlet pressure of the reaction chamber is adjusted by a pressure regulating valve to maintain a stable internal pressure of 0.3MPa. The deposition time is set to 4 hours by a timer. During deposition, the concentration of silicon tetrachloride gas in the chamber is monitored in real-time using a GC-7900 gas chromatograph with a thermal conductivity detector (TCD) for high accuracy. To ensure the concentration remains stable at If the concentration deviates from the set range, the precursor gas flow rate is adjusted via the PID controller. The flow rate adjustment is calculated using the following formula: In the formula, This refers to the flow rate adjustment (mL / min). This represents the concentration deviation (vol%). , , These are the PID control parameters.

[0074] After deposition, shut down the system according to the following procedure: First, turn off the electric heating device and precursor gas supply, keep the carrier gas flowing until the temperature inside the chamber drops below 100℃ (cooling rate 8℃ / min), then turn off the carrier gas and vacuum pump, open the vent valve to slowly restore atmospheric pressure (pressure ramp rate 0.02MPa / min), and remove the sample; observe the micropore growth using a frontal emission scanning electron microscope (FESEM) with an accelerating voltage of 5kV and a magnification of 50,000x; determine the specific surface area and pore volume of the material using a surface area and porosity analyzer (BET) using the liquid nitrogen adsorption-desorption method, with a degassing temperature of 120℃, a degassing time of 3h, and a vacuum degree ≤ after degassing. Micropore growth density Calculated using the following formula: In the formula, To determine the number of micropores per unit volume, 10 micropores with an area of ​​[missing information] were selected based on statistical analysis using TEM images. ( The field of view was calculated, and the number of micropores in each field of view was counted and averaged (272 / 272). ), converted to the quantity per unit volume ; The specific surface area of ​​the attapulgite intermediate was calculated using the Brunauer-Emmett-Teller model based on the BET adsorption-desorption curve, and the measured value was 185 m² / g. The apparent volume of the attapulgite intermediate was determined by measuring its bulk density using a bulk density meter. ,according to Calculated Substitute the data into the formula to calculate the micropore growth density. The average pore size of the micropores was determined by analyzing the hysteresis loop in the adsorption-desorption curve using the BJH model. The micropore volume is calculated using the following formula: In the formula, , For the range of micropore diameters, For aperture distribution function ( The micropore volume is required to be ≥0.15cm³ / g.

[0075] Preparation of functionalized modified liquid: Silane coupling agent KH560 (γ-glycidyl etheroxypropyltrimethoxysilane, molecular formula 98%) with a purity of 98% was selected. (Molar mass 236.34 g / mol) was used as the modifier, and the solvent was anhydrous ethanol with a purity of 99.7%. A mixture of ) and deionized water, by volume ratio Prepare a precise mixture of solvents (225g anhydrous ethanol and 75g deionized water); calculate the amount of modifier needed based on a 10wt% mass concentration of the modified solution, using the following formula: In the formula, The mass concentration of the modified solution. This refers to the mass of anhydrous ethanol. For the mass of deionized water, the following was calculated: KH560 was slowly added dropwise to the mixed solvent using a constant pressure dropping funnel at a dropping rate of 5 mL / min, while simultaneously stirring with a magnetic stirrer at a speed of 200 r / min for 30 min, until the modifier was completely dissolved. The pH value of the modified solution was monitored using a pH meter (accuracy ±0.01). If the pH value deviated from 6.8, 0.1 mol / L hydrochloric acid was used. ) or sodium hydroxide ( The pH was adjusted using a standard solution, with the rate of pH change controlled within 0.1 pH / min during the adjustment process to ensure the pH of the modified solution remained stable. .

[0076] 100g of microporous-mesoporous attapulgite precursor was immersed in the above-mentioned functionalized modification liquid, with the liquid-to-solid mass ratio precisely controlled at 15:1. The liquid volume was measured using a graduated cylinder (accuracy ±1mL). The mixture was transferred to a reaction vessel lined with polytetrafluoroethylene (PTFE), and the stirring device (80mm diameter impeller) was turned on at a stirring speed of 300r / min. The reaction temperature was controlled at 50℃ using a constant temperature water bath (temperature control accuracy ±1℃), and the reaction time was 6h. During the reaction, a small sample was taken every 1h using a sampler (5mL sample volume), and the infrared spectrum of the sample was detected using a Nicolet iS50 Fourier transform infrared spectrometer (FT-IR), with a testing range of 4000-400cm. - ¹, resolution 4cm - ¹, through analysis of 1030cm - The intensity change of the Si-O-Al characteristic peak at point ¹ was used to monitor the interfacial bonding reaction process. The intensity of the characteristic peak was calculated using the following formula: In the formula, The transmittance of the blank sample is... The transmittance of the sample after the reaction is defined as the characteristic peak intensity change rate ≤ 1% / h, indicating that the reaction has reached equilibrium.

[0077] After the reaction was complete, the mixture was transferred to a high-speed centrifuge and the centrifugation speed was set to 8000 r / min (centrifugal acceleration). Centrifuge for 15 minutes and collect the lower precipitate; wash the precipitate with deionized water, adding 1000g of deionized water each time, stirring for 5 minutes, then transfer to a centrifuge and set the centrifugation speed to 5000r / min (centrifugal acceleration). Centrifuge for 10 min, repeat washing 3 times; after each wash, measure the conductivity of the washing solution using a conductivity meter (accuracy ±0.1 μS / cm) until the conductivity is ≤5 μS / cm, indicating that unreacted modifiers and byproducts have been completely washed away; the consumption rate of the washing agent during the washing process is calculated by the following formula: In the formula, The total mass (g) of the washing water. The mass (g) of the sample before modification. Requirements for the number of washes .

[0078] The washed precipitate was transferred to a vacuum drying oven and dried using a programmed temperature rise drying mode. The drying curve was set as follows: first, dry at 60℃ and a vacuum of -0.09MPa for 6 hours, then raise the temperature to 90℃ and maintain the vacuum for another 8 hours. The heating rate was controlled at 5℃ / min to avoid rapid drying that could cause the pore structure to collapse. During the drying process, the operating parameters were monitored in real time by a temperature sensor and a vacuum gauge inside the oven to ensure that the set requirements were met. After drying, the sample was removed and cooled to room temperature (cooling rate 10℃ / min). The mass of the modified attapulgite precursor was then weighed using an electronic balance (accuracy 0.001g). ) and the quality of the modified material ( ), grafting rate Calculated using the following formula: The grafting rate is calculated by substituting the weighing data into the formula. Simultaneously, the elemental composition of the material surface was analyzed by X-ray photoelectron spectroscopy (XPS), and the relative content change of Si was calculated to verify the bonding effect. The relative elemental content was calculated using the following formula: In the formula, The characteristic peak intensity of the target element, The sensitivity factor for the target element. For the first Characteristic peak intensities of the elements For the first Sensitivity factor of a certain element.

[0079] This implementation details how a micropore-mesopore hierarchical interconnected structure is precisely constructed through synergistic regulation of crystal phase preactivation, mesopore orientation construction, in-situ micropore growth, and interface bonding modification. This significantly increases the specific surface area and pore volume of the material, optimizes pore orientation and interface characteristics, and achieves simultaneous improvement in filtration speed, retention accuracy, and operational stability, thus meeting the needs of high-precision filtration scenarios.

[0080] Based on Example 1, this example details how, to verify the necessity and optimization of parameter control in the crystal phase pre-activation treatment, X-ray diffraction (XRD) was performed on attapulgite powder under different parameter combinations by changing the plasma etching power (200W, 350W, 500W) and etching time (10min, 20min, 30min), and the intensity of the characteristic diffraction peaks (I) of the (110) crystal plane was recorded. 110 ) and amorphous phase background intensity (I am The crystallinity (Cr) was calculated, and the results are shown in Table 1. The crystallinity was calculated using the formula Cr = (I... 110 -I am ) / I 110 The crystallinity is calculated by multiplying by 100%, and the grain size is calculated using the Scherrer formula D=Kλ / (βcosθ).

[0081] Table 1. Crystal phase characteristics of attapulgite powder under different etching parameters

[0082]

[0083] In Table 1, Etching Power is the plasma etching power; Etching Time is the etching duration; I 110 The integral intensity of the characteristic diffraction peak of the attapulgite (110) crystal plane; I am The background diffraction intensity represents the amorphous phase in the 2θ = 15°–20° range; Cr represents the crystallinity of the crystalline phase, expressed as a percentage (%); Grain Size represents the average grain size; Lattice Strain represents the lattice strain, reflecting the integrity of the crystal structure. It can be seen that when the etching power is 350W and the etching time is 20min, all indicators reach their optimal levels: I 110 Reaching a maximum of 2876 counts, I am The crystallinity was reduced to a minimum of 431 counts, with a Cr content of 85.0% and a lattice strain of only 1.92 × 10⁻⁶. - ³, the grain size stabilizes at 65nm. When the etching power is below 350W, the plasma energy is insufficient to effectively remove amorphous impurities and defects on the crystal surface, leading to I 110 Too low an etching power results in insufficient crystallinity; while etching power above 350W can damage the crystal lattice structure, leading to abnormally large grain size, increased lattice strain, and a decrease in crystallinity. Etching time less than 20 minutes results in insufficient etching and limited improvement in crystallinity; etching time exceeding 20 minutes causes surface damage, also leading to performance degradation. Therefore, 350W and 20 minutes are the optimal parameter combination for crystal phase pre-activation.

[0084] To visually demonstrate the influence of etching power on crystal structure, XRD patterns at different etching powers were compared, such as... Figure 5 As shown, they correspond to 200W respectively. Figure 5 a) 350W ( Figure 5 b) 500W Figure 5 c) Under three power conditions, the test parameters for all subplots remained consistent (Cu Kα rays, tube voltage 40kV, tube current 40mA, scan speed 5° / min). Figure 5 It can be clearly observed that Figure 5 The (110) crystal plane diffraction peak at 2θ=8.4° in b (350W) not only has the highest intensity, but also the sharpest and most symmetrical peak shape, with a half width at half maximum (FWHM) of only 0.21° and the lowest background noise of the amorphous phase, which fully proves that the crystal structure is the most regular at this power. Figure 5The diffraction peaks in a(200W) are weak and broadened, with a full width at half maximum (FWHM) of 0.28°, indicating a high content of amorphous phase. Figure 5 The diffraction peak intensity decreased at c(500W), and the peak shape showed slight distortion, indicating that excessively high power caused minor lattice damage. Meanwhile, to verify the microstructure and lattice integrity of the crystal under optimal parameters, the powder treated at 350W for 20 minutes was characterized using transmission electron microscopy (TEM). Figure 6 As shown, including Figure 6 (a) Figure 6 (b) The accelerating voltage of the image is 200kV, and the magnification is 100,000 times. The image shows that the attapulgite crystals are regular one-dimensional nanorod structures with a length of about 500-800nm ​​and a diameter of about 60-70nm. The crystals are arranged in an orderly manner without obvious aggregation. High-resolution TEM image ( Figure 6 The inset shows that the lattice fringes are clearly visible with a spacing of 0.45 nm, which perfectly matches the interplanar spacing of the attapulgite (110) crystal plane. Furthermore, the lattice is free of distortion and defects, further confirming that the crystal phase regulation under the optimal parameters not only improves the crystallinity but also preserves the original structure of the crystal.

[0085] Based on the above, mesoporous orientation was detected, and high-resolution characterization of the attapulgite intermediate with a defined mesoporous structure was performed using transmission electron microscopy (TEM). Figure 7 As shown, the accelerating voltage is 200kV, the magnification is 50,000x, and the image field of view is 2μm×2μm. Figure 7 It can be clearly observed that a large number of cylindrical mesoporous structures are arranged in a regular array along a preset orientation direction (parallel to the horizontal direction of the image). The channels are parallel to each other and the spacing is uniform, with an average spacing of about 30 nm. The pore diameter of a single mesopore, measured by image analysis software, is 14.8 nm, with an error of only 1.3% compared to the pore diameter (15 nm) of the selected SBA-15 template agent, proving that the pore structure of the template agent is accurately replicated in the attapulgite matrix. To quantify the orientation consistency of the mesopores, 500 channels were randomly selected using image analysis software, and the length (Lᵢ) of each channel and the angle (θ) between the channel axis and the preset orientation direction were measured one by one. i Substituting into the orientation degree calculation formula D=∑ ni=1 (L i ×cosθ i ) / ∑ ni=1 L i ×100%, the orientation degree D is calculated to be 96.6%, where θ i The proportion of channels with an angle ≤10° reached 89%, θ iWith 97% of the channels having an angle of ≤15°, it is evident that the vast majority of mesopores are aligned with the predetermined direction, exhibiting excellent uniformity in channel orientation. This highly oriented mesoporous structure provides a regular substrate and channels for subsequent in-situ micropore growth, while simultaneously reducing mass transfer resistance within the channels, thus laying a structural foundation for improving the material's filtration performance.

[0086] After the in-situ growth regulation of micropores was completed, the microstructure of the micropore-mesopore hierarchical precursor was characterized using field emission scanning electron microscopy (FESEM), such as... Figure 8 As shown, the test conditions were an accelerating voltage of 5kV, a magnification of 50,000x, a working distance of 8mm, and the image was captured using secondary electron imaging mode. From... Figure 8 It can be clearly observed that the surface of the mesoporous structure is uniformly covered with a dense layer of nanoscale protrusions. These protrusions are the in-situ grown micropores. The micropores are spherical, with a diameter of 1.2±0.1 nm as measured by software. They are uniform in size and distribution, without obvious agglomeration or blockage of the mesoporous channels. The cylindrical structure of the mesopores remains intact, with the pore size maintained at 14.8±0.2 nm, which is basically consistent with the size before growth. This proves that the vapor deposition process only grows micropores on the surface of the mesopore walls and does not damage the mesoporous structure. A hierarchical porous network with two interconnected mesopores and micropores was successfully constructed. To further quantify the pore properties of the material, nitrogen adsorption-desorption tests were performed on the samples using a surface area and porosity analyzer (BET). The degassing conditions were 120℃ for 3 h, and the vacuum degree after degassing was ≤1×10⁻³ Pa. Test results show that the adsorption-desorption isotherm of the sample exhibits a typical Type IV isotherm with an H1 hysteresis loop, which is a characteristic isotherm type of mesoporous materials. The specific surface area calculated using the Brunauer-Emmett-Teller (BET) model is 356 m² / g, which is 92.4% higher than that of the mesoporous intermediate without micropore growth (specific surface area 185 m² / g). The mesopore size distribution analyzed using the Barrett-Joyner-Halenda (BJH) model shows a mesopore volume of 0.64 cm³ / g and an average mesopore diameter of 14.8 nm. The micropore volume calculated using the t-plot method is 0.18 cm³ / g, and the total pore volume reaches 0.82 cm³ / g, which is 95.2% higher than that of the mesoporous intermediate (total pore volume 0.42 cm³ / g). This fully demonstrates that the in-situ micropore growth process effectively increases the specific surface area and pore volume of the material and optimizes the hierarchical structure of the pores.

[0087] The bonding modification effect at the pore interface was verified using Fourier transform infrared spectroscopy (FT-IR), with a test range of 4000-400 cm⁻¹. - ¹, resolution 4cm -¹, 32 scans were performed, with KBr as the background correction. To track the reaction progress, FT-IR tests were performed on samples before modification (0h), after 2h, 4h, and after 6h, focusing on monitoring changes in characteristic peaks related to interfacial bonding, including the peak at 1030 cm⁻¹. - The stretching vibration peak of the Si-O-Al bond at ¹, 3450 cm⁻¹ - The stretching vibration peak of the hydroxyl group (-OH) at ¹ and 1100 cm⁻¹ - The stretching vibration peak of the Si-OC bond at position ¹ (a characteristic peak of the reaction between silane coupling agent KH560 and hydroxyl groups on the surface of attapulgite) is summarized in Table 2.

[0088] Table 2. FT-IR characteristic peak parameters of samples at different modification times

[0089]

[0090] The parameters in Table 2 are explained as follows: Si-O-Al Peak, -OH Peak, and Si-OC Peak represent the characteristic peak intensity and area at their respective wavenumbers, respectively. Intensities are expressed as relative intensities, and peak areas are calculated using the integration method. Peak Area Ratio is the ratio of the peak areas of Si-OC bonds to Si-O-Al bonds, reflecting the progress of the grafting reaction. Grafting Rate G is the grafting rate, calculated from the mass change of the sample before and after modification. Analysis of the data in Table 2 shows that with the extension of modification time, the characteristic peak intensity and area of ​​the Si-O-Al bond continuously increase, from 1.25 (intensity) and 42.3 (area) at 0h to 1.98 (intensity) and 59.2 (area) at 6h, indicating that the interfacial bonding reaction enhances the vibrational activity of this group. The characteristic peak intensity and area of ​​the hydroxyl (-OH) group continuously decrease, from 2.31 (intensity) and 58.7 (area) at 0h to 1.76 (intensity) and 43.5 (area) at 6h. (Area), because the hydroxyl groups on the surface of attapulgite undergo a dehydration condensation reaction with the silane coupling agent and are consumed; the characteristic peak of the Si-OC bond appears from 2h, and the intensity and peak area gradually increase with time, reaching 0.86 (intensity) and 0.94 (area) at 6h, proving that KH560 was successfully grafted to the pore interface; the grafting rate G increased from 2.8% at 2h to 6.2% at 6h, and after 6h, if the reaction time is extended further, the increase in grafting rate is less than 0.3%, indicating that the reaction has reached equilibrium.

[0091] To visually represent the dynamic changes in characteristic peaks, a comparison of the characteristic peak intensities of Si-O-Al and Si-OC bonds at different modification times is shown, such as... Figure 9 As shown, this figure contains 4 subplots, corresponding to 0h ( Figure 9 a) 2h Figure 9 b), 4h Figure 9 c), 6h Figure 9 d) Each sub-image is labeled with the corresponding characteristic peak position and intensity value. From Figure 10 It can be clearly observed that at 0h, only the characteristic peaks of Si-O-Al and -OH bonds are present, and Si-OC bonds are not detected; at 2h, weak peaks of Si-OC bonds begin to appear; at 4h, the intensity of Si-OC bonds significantly increases; at 6h, the intensity of Si-OC bonds stabilizes, and the intensity of Si-O-Al bonds also tends to its maximum value, which is completely consistent with the data in Table 2. Simultaneously, complete FT-IR spectra comparisons before and after modification (0h and 6h) are obtained, as shown below. Figure 10 As shown, the horizontal axis of the spectrum represents the wavenumber (cm). - ¹), with the vertical axis representing absorbance, shows that the modified (6h) spectrum is at 1100 cm⁻¹. - A distinct Si-OC bond characteristic peak was newly added at ¹, at 3450 cm⁻¹. - The intensity of the characteristic peak of the -OH bond at ¹ is significantly reduced, at 1030 cm⁻¹ - The intensity of the Si-O-Al bond characteristic peak at ¹ was significantly enhanced. In addition, a weak CH bond stretching vibration peak (from the organic group of KH560) appeared at 2960 cm⁻¹. The changes in these characteristic peaks together confirm the successful implementation of the bonding modification of the pore interface, which effectively improves the chemical properties and compatibility of the material pore interface and lays the foundation for improving the stability of the material in complex systems.

[0092] To further verify the practical application potential of the hierarchical pore structure, core performance tests were conducted on the final attapulgite-based material with precisely controlled pore structure. The test results showed that the material achieved a 98.5% rejection rate for particles ≥0.1μm and a filtration rate of 52mL / 20min. Compared with traditional attapulgite filter aids (rejection rate 85%, filtration rate 30mL / 20min), the rejection rate increased by 15.9% and the filtration rate increased by 73.3%. In acid-base systems with pH = 3-11, the specific surface area and pore volume change rate of the material were both less than 3%, and the lattice strain remained within 2.0×10⁻³, exhibiting excellent chemical stability. After 5 cycles of use, the rejection rate remained above 95%, and the filtration rate decreased by less than 5%, demonstrating good reusability. These performance data are highly correlated with the previous structural characterization results, fully demonstrating that the precise design of the pore structure of attapulgite-based materials was successfully achieved through the synergistic regulation of crystal phase pre-activation, mesoporous directional construction, micropore in-situ growth, and interfacial bonding modification. All performance indicators have reached the expected targets, providing a solid experimental basis for its industrial application in the field of high-precision filtration.

[0093] Example 2 describes in detail a precise control system for the pore structure of attapulgite-based materials, used to implement the aforementioned method for precise control of the pore structure of attapulgite-based materials. Figure 11 As shown, it specifically includes: a crystal phase pre-activation unit, a mesoporous template directional construction unit, a micropore in-situ growth control unit, a pore interface bonding modification unit, and a central control unit;

[0094] The crystal phase pre-activation unit includes a plasma activation furnace, a raw material crushing and sieving assembly, and an atmosphere proportioning assembly. The plasma activation furnace is connected to the raw material crushing and sieving assembly and the atmosphere proportioning assembly, respectively.

[0095] The mesoporous template directional construction unit includes an ultrasonic dispersion device, a hydrothermal reactor, and a solid-liquid separation component. The ultrasonic dispersion device is connected to the hydrothermal reactor, and the hydrothermal reactor is connected to the solid-liquid separation component.

[0096] The micropore in-situ growth control unit includes a vapor deposition reaction chamber, a gas ratio component, and a temperature and pressure control component, both of which are connected to the vapor deposition reaction chamber.

[0097] The channel interface bonding modification unit includes a modified reaction vessel, a stirring assembly, a centrifugal washing assembly, and a vacuum drying oven. The stirring assembly is located inside the modified reaction vessel, and the modified reaction vessel is connected in sequence to the centrifugal washing assembly and the vacuum drying oven.

[0098] The central control unit is electrically connected to the crystal phase pre-activation unit, the mesoporous template directional construction unit, the micropore in-situ growth control unit, and the pore interface bonding modification unit, respectively, and is used to control the process parameters of each unit and monitor the control process.

[0099] Furthermore, the crystal phase pre-activation unit completes the crushing, grinding, screening and plasma etching activation of the attapulgite ore, realizing precise control of the crystal phase structure of the ore. It consists of raw material crushing and screening components, atmosphere proportioning components, plasma activation furnace and supporting material conveying device and temperature control sensor.

[0100] The plasma activation furnace uses a radio frequency plasma generator and is equipped with a quartz reaction chamber, a quartz support boat, a temperature monitoring module, and a vacuum pumping system. The reaction chamber can be sealed and evacuated. The furnace body is equipped with a radio frequency power adjustment module (adjustment range 0-600W) and an etching time timing module. An infrared thermometer and a pressure sensor are arranged inside the chamber to monitor the temperature and pressure during the etching process in real time. The quartz support boat is equipped with an automatic material spreading and unloading mechanism, which can accurately control the powder spreading thickness. The activated powder is transported to the material buffer tank of the next process through the unloading device to complete the crystal phase pre-activation.

[0101] Furthermore, the mesoporous template directional construction unit completes the mixing, dispersion, hydrothermal reaction, and solid-liquid separation of crystal phase-controlled attapulgite powder and mesoporous template agent, realizing the directional construction and shaping of the mesoporous structure. It consists of an ultrasonic dispersion device, a hydrothermal reactor, a solid-liquid separation component, and supporting powder mixer, deionized water injection device, and temperature control system. Each piece of equipment achieves closed material transportation through peristaltic pumps and sealed pipelines to avoid contamination by external impurities.

[0102] Furthermore, the micropore in-situ growth control unit receives the material from the mesopore template directional construction unit. Its core function is to realize the in-situ growth of micropores by vapor deposition on the pore wall of the mesopore structure shaping intermediate, and to construct a micropore-mesopore hierarchical porous structure. It consists of a vapor deposition reaction chamber, a gas ratio component, a temperature and pressure control component, and a supporting vacuum pumping system and material spreading device.

[0103] Furthermore, the pore interface bonding modification unit completes the functional bonding modification and post-processing of the pore interface of the micropore-mesopore hierarchical precursor, realizing the precise control of the pore interface characteristics, and obtaining the final attapulgite-based material with precise control of pore structure. It consists of a modified reaction vessel, a stirring assembly, a centrifugal washing assembly, a vacuum drying oven, and a matching functionalized modification liquid preparation tank and liquid filling device. Each piece of equipment is connected to the centrifugal conveying mechanism through a closed pipeline to realize the integration of modification reaction-centrifugal washing-drying.

[0104] Furthermore, the central control unit consists of an industrial control host, a touch screen operation terminal, a PLC programmable controller, a data acquisition module, an industrial bus, and various actuators and sensors. It is electrically connected to the crystal phase pre-activation unit, the mesoporous template directional construction unit, the micropore in-situ growth control unit, and the pore interface bonding modification unit, respectively. It undertakes the functions of precise control, real-time monitoring, data acquisition, fault alarm and linkage control of the entire process parameters, and is the core to ensure the stable operation of the system and the precise control of process parameters.

[0105] Seamless connection is achieved through dedicated material conveying devices and closed pipelines. The material conveying process is equipped with quantitative control and material buffering modules to ensure the material conveying accuracy and production continuity of each process. The entire system has a compact layout and smooth process. All parts that come into contact with materials are made of acid and alkali resistant and pollution-free materials to ensure the purity of the products. At the same time, it is equipped with environmental protection modules such as dust collection, exhaust gas treatment, and waste liquid collection to meet the process requirements of green production.

[0106] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments within the spirit and principles of the present invention, without departing from the principles and spirit of the present invention, through conventional substitutions or to achieve the same function, fall within the scope of protection of the present invention.

Claims

1. A method for precise control of the pore structure of attapulgite-based materials, characterized in that, include: Attapulgite ore was subjected to crystal phase pre-activation treatment to obtain crystal phase-controlled attapulgite powder. The attapulgite powder with crystalline phase regulation was subjected to directional construction using a mesoporous template to obtain an attapulgite intermediate with a defined mesoporous structure. Micropore in-situ growth regulation was implemented on the mesoporous structure-defined attapulgite intermediate to obtain a micropore-mesoporous hierarchical attapulgite precursor. The microporous-mesoporous hierarchical attapulgite precursor is modified by pore interface bonding to obtain an attapulgite-based material with precisely controlled pore structure.

2. The method for precise control of the pore structure of attapulgite-based materials according to claim 1, characterized in that, The crystal phase pre-activation treatment includes: crushing and sieving the raw attapulgite ore, then placing it in a plasma activation furnace for plasma etching activation in a mixed atmosphere of inert gas and oxygen-containing gas. The etching power is 200~500W, the etching time is 10~30min, and the volume ratio of inert gas to oxygen-containing gas in the mixed atmosphere is [missing information]. attapulgite powder with crystalline phase regulation was obtained.

3. The method for precise control of the pore structure of attapulgite-based materials according to claim 2, characterized in that, During the plasma etching activation process, the crystallinity of the attapulgite powder phase The formula for determining it is: ,in The intensity of the characteristic diffraction peaks of the attapulgite 110 crystal plane. The background intensity of the diffraction peaks is amorphous. After etching and activation, the crystallinity of the attapulgite powder is adjusted to 65%~85%.

4. The method for precise control of the pore structure of attapulgite-based materials according to claim 1, characterized in that, The directional construction of the mesoporous template includes: mixing phase-controlled attapulgite powder and a mesoporous template agent at a mass ratio. Mix and add deionized water to prepare a suspension with a solid content of 20%~35%. After ultrasonic dispersion at an ultrasonic power of 400~600W and a temperature of 50~70℃ for 20~40 minutes, transfer it to a hydrothermal reactor and hydrothermally react at 100~160℃ for 6~12 hours. After the reaction is completed, filter and dry to obtain a mesoporous structured attapulgite intermediate.

5. The method for precise control of the pore structure of attapulgite-based materials according to claim 4, characterized in that, The mesoporous template agent is one or a combination of two of the following: mesoporous silica template and polymer template. The pore size of the mesoporous template agent is [missing information]. Furthermore, the pore orientation of the mesoporous template agent The formula for determining it is: ,in The length of a single template agent channel, The angle between the template agent channel and the preset orientation direction. The number of template agent pores and the degree of pore orientation are statistically analyzed. .

6. The method for precise control of the pore structure of attapulgite-based materials according to claim 1, characterized in that, The micropore in-situ growth control includes: placing the mesoporous structured attapulgite intermediate in a vapor deposition reaction chamber, introducing a mixture of precursor gas and carrier gas, and performing in-situ vapor deposition growth at a heating temperature of 300~500℃ and a reaction pressure of 0.1~0.5MPa for a deposition time of 2~6h to obtain a micropore-mesopore graded attapulgite precursor, wherein the pore size of the micropores is 0.5~2nm.

7. The method for precise control of the pore structure of attapulgite-based materials according to claim 6, characterized in that, During the vapor deposition process, the growth density of micropores Satisfying the formula: ,in The number of micropores per unit volume. is the specific surface area of ​​the attapulgite intermediate. The apparent volume of the attapulgite intermediate and the micropore growth density are given. Adjustment to .

8. The method for precise control of the pore structure of attapulgite-based materials according to claim 1, characterized in that, The pore interface bonding modification includes: immersing a microporous-mesoporous hierarchical attapulgite precursor in a functionalized modification liquid, and carrying out an interface bonding reaction for 3-8 hours at a stirring rate of 200-400 r / min and a temperature of 40-60℃. After the reaction, the material is centrifuged, washed, and vacuum dried to obtain an attapulgite-based material with precisely controlled pore structure. The vacuum drying temperature is 80-120℃ and the drying time is 10-16 hours.

9. The method for precise control of the pore structure of attapulgite-based materials according to claim 8, characterized in that, The functionalized modified solution is an alcohol-water mixture containing one or more of the following: silane coupling agent, organophosphonate, and metal alkoxide. The mass concentration of the functionalized modified solution is 5%–15%, and the volume ratio of anhydrous ethanol to deionized water in the alcohol-water mixture is [missing information]. Furthermore, the grafting rate of interface bonding modification The formula is: Grafting rate Adjust to 3%~10%.

10. A system for precise control of the pore structure of attapulgite-based materials, characterized in that, include: Crystal phase pre-activation unit, mesoporous template directional construction unit, micropore in-situ growth control unit, pore interface bonding modification unit, and central control unit; The crystal phase pre-activation unit includes a plasma activation furnace, a raw material crushing and sieving assembly, and an atmosphere proportioning assembly. The plasma activation furnace is connected to the raw material crushing and sieving assembly and the atmosphere proportioning assembly, respectively. The mesoporous template directional construction unit includes an ultrasonic dispersion device, a hydrothermal reactor, and a solid-liquid separation component. The ultrasonic dispersion device is connected to the hydrothermal reactor, and the hydrothermal reactor is connected to the solid-liquid separation component. The micropore in-situ growth control unit includes a vapor deposition reaction chamber, a gas ratio component, and a temperature and pressure control component, both of which are connected to the vapor deposition reaction chamber. The channel interface bonding modification unit includes a modified reaction vessel, a stirring assembly, a centrifugal washing assembly, and a vacuum drying oven. The stirring assembly is located inside the modified reaction vessel, and the modified reaction vessel is connected in sequence to the centrifugal washing assembly and the vacuum drying oven. The central control unit is electrically connected to the crystal phase pre-activation unit, the mesoporous template directional construction unit, the micropore in-situ growth control unit, and the pore interface bonding modification unit, respectively, and is used to control the process parameters of each unit and monitor the control process.

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