A modified porous material, its preparation method and application thereof in killing bacteria / fungi, inactivating viruses in water body

Abstract

The application provides a modified porous material, a preparation method thereof and application of the modified porous material in killing bacteria / fungi and inactivating viruses in a water body. The modified porous material comprises a porous material and a long carbon chain quaternary ammonium salt; the long carbon chain quaternary ammonium salt is fixed inside the porous material; the long carbon chain quaternary ammonium salt comprises a quaternary ammonium salt containing one and / or two long carbon chains; the long carbon chain comprises C6-C 20 Alkanes, alkenes, alkynes or arenes. When the modified porous material is used to treat a water body, the sterilization and disinfection process is transferred to the pores of the porous material, sterilization and disinfection are achieved, and quaternary ammonium salt molecules are prevented from remaining in the water, causing secondary pollution. In addition, the porous material has strong adsorption capacity, can adsorb microorganisms in the water into the pores, concentrate relatively dispersed microorganisms in the water, improve the sterilization and disinfection efficiency, and reduce the use of quaternary ammonium salt.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of porous material modification, in particular to a modified porous material, a preparation method thereof and application thereof in killing bacteria / fungi and inactivating viruses in water bodies. BACKGROUND

[0002] The quality of the circulating water of a swimming pool during use can be contaminated by bacteria and viruses carried by swimmers, dust particles in the air and other factors, and the pool water can have excessive bacteria. According to investigations, about 43.3% of people can have symptoms such as dry and itchy skin, dry and painful eyes or respiratory bacterial infection after swimming. Therefore, with the popularization of swimming, the health and safety of pool water quality have attracted widespread attention from the government and the public. GB37488-2019 public place health indicators and limits requires that the number and limit of water quality health indicators of swimming places are greatly improved. The microbial indicators are more stringent than before, the total number of bacteria is not more than 1000 / mL, which is adjusted to the number of bacteria not more than 200 CFU / mL, and the total number of coliform bacteria is not more than 18 / L, which is adjusted to not detected (CFU / 100mL). Therefore, in order to ensure that the pool water quality meets the standard requirements and protect the health of swimmers, disinfection treatment is very important.

[0003] Swimming pool water purification and disinfection treatment is a systematic process, which usually includes six parts, namely pre-purification, coagulant addition, filtration, disinfection, water quality balance, and water quality monitoring and detection. The disinfection part is the key of the system. The commonly used disinfection technologies for swimming pools mainly include chlorine disinfection, ultraviolet disinfection, ozone disinfection, etc. Ultraviolet disinfection has the advantages of short contact time, small occupied area, no by-products, etc. The pool water after disinfection is colorless and odorless, but the system investment and maintenance cost is high, and the water treatment capacity is small, which is difficult to meet the requirement of large water treatment capacity of swimming pools. Ozone has strong bactericidal effect, and the raw materials and by-products of ozone preparation contain oxygen. Ozone does not cause secondary pollution. However, the whole process of preparing ozone includes ozone production, control and detection, etc., which requires many equipment and a large amount of capital investment. In addition, because ozone is a strong oxidizing agent, after swimmers inhale ozone, it will react with the cells and tissues of the respiratory tract, causing loss of lung function and tissue damage. In addition, ozone can also oxidize the skin of swimmers, leading to aging.

[0004] Compared with these technologies, chlorine disinfectants are widely used for disinfecting swimming pool water because of their low cost, easy availability, and good germicidal effect. Residual chlorine in water has the ability to continuously disinfect and sterilize, and is widely used. However, these chlorine-containing disinfectants have oxidizing properties, and they will react with organic matter and inorganic ions in the pool water to generate various disinfection by-products (DBPs) such as trihalomethane (THMs), haloacetic acid (HAAs), haloacetonitrile (HANs), haloacetaldehyde (HALs), organic DBPs, and inorganic DBPs such as chlorate (ClO 3- ), chlorite (ClO 2- ), and the like. These DBPs can cause great harm to people who swim for a long time, such as teratogenicity, carcinogenicity, mutagenicity, and the like. At the same time, these chlorine-containing disinfectants are also commonly used for disinfecting drinking water, and the disinfected drinking water also contains a certain amount of DBPs. When people drink water containing these DBPs, the DBPs are absorbed by the digestive system, causing greater harm to the human body and a wider range of damage. In addition, the DBPs generated during the disinfection process are difficult to separate and remove from water, and can only be controlled by adjusting the amount of chlorine disinfectant added to water. When less chlorine disinfectant is used, less DBPs are generated, but the disinfection of water does not meet the standard water quality requirements. In order to meet this requirement, the use of chlorine disinfectant needs to be increased, and the content of DBPs in water and the risk generated thereby also significantly increases. The results show that the side effects of chlorine disinfection are contradictory to meeting water quality requirements; at the same time, the development of human civilization has led to a large number of new types of organic pollutants in natural water bodies, which are often considered to be precursors of DBPs and will be converted into DBPs under the action of ultraviolet and ozone disinfection. Therefore, there is an urgent need to develop a high-efficiency, side-effect-free, and broad-spectrum disinfectant. SUMMARY

[0005] In view of the above problems, the long carbon chain quaternary ammonium salt is used to physically modify the porous material to prepare a modified porous material. The long carbon chain quaternary ammonium salt is adsorbed into the porous material due to the adsorption of the porous material, and the concentrated quaternary ammonium salt is aggregated by the hydrophobic group to form large-size aggregates, which are difficult to desorb from the pores of the porous material, so as to realize the fixation of the quaternary ammonium salt molecules in the pores of the porous material and reduce the release of the long carbon chain quaternary ammonium salt. When the modified porous material is used to treat water, the disinfection process is transferred to the pores of the porous material, which not only kills bacteria / fungi and inactivates viruses, but also prevents the quaternary ammonium salt molecules from remaining in the water to cause secondary pollution. In addition, the porous material has strong adsorption capacity, which can adsorb microorganisms in the water into the pores, concentrate the relatively dispersed microorganisms in the water, improve the disinfection efficiency, and reduce the use of quaternary ammonium salt.

[0006] According to an aspect of the present application, a modified porous material is provided, comprising a porous material and a long carbon chain quaternary ammonium salt; the long carbon chain quaternary ammonium salt is fixed in the porous material; the long carbon chain quaternary ammonium salt comprises a quaternary ammonium salt containing one and / or two long carbon chains; the long carbon chain comprises an alkane, an alkene, an alkyne or an aromatic hydrocarbon with a carbon chain length of C6-C 20 .

[0007] Optionally, the long carbon chain comprises an alkane and / or an aromatic hydrocarbon with a carbon chain length of C6-C 20 .

[0008] Optionally, the long carbon chain quaternary ammonium salt is fixed in the pores of the porous material.

[0009] Optionally, the porous material comprises an organic porous material and / or an inorganic porous material. That is, the porous material can be an organic porous material, an inorganic porous material, or an organic-inorganic composite porous material combined with both.

[0010] Optionally, the porous material is a porous carbon material.

[0011] Optionally, the porous carbon material comprises at least one of biochar, activated carbon and activated carbon fiber.

[0012] Optionally, the organic porous material comprises at least one of biochar, activated carbon and activated carbon fiber.

[0013] Optionally, the inorganic porous material comprises a zeolite molecular sieve and / or diatomite.

[0014] Optionally, the quaternary ammonium salt containing one and / or two long carbon chains is selected from at least one of the compounds having the structure of Formula I,

[0015]

[0016] wherein M n- is a negatively charged ion, n is the charge number of M; at least one of R1, R2 is selected from C6-C 20 alkane and / or arene with or without substituent; R3, R4 are independently selected from C1-C5 alkane with or without substituent.

[0017] Optionally, the quaternary ammonium salt containing one and / or two long carbon chains is selected from at least one of the compounds having the structure of Formula II,

[0018]

[0019] wherein X - is an ion with one negative charge; at least one of R1, R2 is selected from C6-C 20 alkane and / or arene with or without substituent.

[0020] Optionally, in Formula II, at least one of R1, R2 is selected from C8-C 18 alkane and / or arene with or without substituent.

[0021] Optionally, the X is halogen.

[0022] Optionally, the X is selected from at least one of F, Cl, Br.

[0023] Optionally, R1 is selected from C8-C 18 alkane with or without substituent; R2 is selected from C8-C 18 arene with or without substituent.

[0024] Optionally, R1 is selected from C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 or C 18 alkane with or without substituent.

[0025] Optionally, R2 is selected from C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 or C 18 arene with or without substituent.

[0026] Optionally, R1 is selected from C8to C 18 alkanes.

[0027] Optionally, R1 is C n H 2n+1 wherein n = 8, 10, 12, 14, 16 or 18.

[0028] Optionally, R2 is selected from C8to C 18 aromatics containing substituents.

[0029] Optionally, R2 is selected from C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 aromatics containing substituents.

[0030] Optionally, R2 is selected from arylsulphenyl containing substituents or not containing substituents, aryl, heterocyclyl, C5to C 12 fused bicycloalkyl, C5to C 12 benzo-fused carbocyclyl, C5to C 12 benzo-fused heterocyclyl, aryloxy, C5to C 12 fused bicycloalkyloxy, C5to C 12 benzo-fused carbocyclyloxy, C5to C 12 benzo-fused heterocyclyloxy, aryl-C1to C8alkyl, aryl-C1to C8alkoxy, aryloxy-C1to C8alkyl, aryloxy-C1to C8alkoxy, C1to C8alkoxyaryloxy, C1to C8alkylaryl, C1to C8alkoxyaryl or heterocyclyloxy.

[0031] Optionally, the substituents include C1to C8alkyl, C3to C8cycloalkyl, C1to C8alkoxy, C1to C8alkylamino, C1to C8alkylsulphenyl, cycloalkyloxy, C3to C8cycloalkyl-C1to C8alkyl, C3to C8cycloalkyl-C1to C8alkoxy, C3to C8cycloalkyloxy-C1to C8alkyl, C1to C8alkoxy-C1to C8alkyl, C1to C8alkoxy-C1to C8alkoxy, C1to C8alkoxy-C1to C8alkyl, C1to C8alkyl-C3to C8cycloalkyloxy or C1to C8alkyl-C3to C8cycloalkyl.

[0032] Optionally, R2 is selected from at least one of benzyl, ethylbenzene, dimethylbenzene, trimethylbenzene, tetramethylbenzene, phenylpropyl, naphthalene, biphenyl, terphenyl.

[0033] Optionally, the mass content of the long carbon chain quaternary ammonium salt in the modified porous material is 10% to 20%.

[0034] Optionally, the mass content of the long carbon chain quaternary ammonium salt in the modified porous material is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between any two of the values.

[0035] Optionally, the long carbon chain quaternary ammonium salt is fixed in the form of agglomerates or chemical bonds inside the porous material.

[0036] Optionally, the long chain quaternary ammonium salt is inside the porous material through hydrophobic interaction, so that the molecules are agglomerated, and the aggregate size is increased.

[0037] Optionally, the modified porous material releases long carbon chain quaternary ammonium salt in water in an amount of ≤ 100 ppm.

[0038] Optionally, the modified porous material releases long carbon chain quaternary ammonium salt in water in an amount of 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, or any value between any two of the values.

[0039] Preferably, the modified porous material releases long carbon chain quaternary ammonium salt in water in an amount of ≤ 50 ppm.

[0040] Preferably, the modified porous material releases long carbon chain quaternary ammonium salt in water in an amount of ≤ 15 ppm.

[0041] Since the quaternary ammonium salt molecules are adsorbed into the pores, the adsorbed and concentrated quaternary ammonium salt molecules are agglomerated by hydrophobic groups inside the pores, forming large-size agglomerates, which exceed the pore entrance size of the porous material, and thus it is difficult to desorb from the pores of the porous material.

[0042] According to another aspect of the present application, a method for preparing the modified porous material as described in any of the above is provided, wherein the porous material and the long carbon chain quaternary ammonium salt are mixed at a temperature of 5°C to 50°C for 2h to 24h to obtain the modified porous material.

[0043] Optionally, the temperature can be 5℃, 6℃, 7℃, 8℃, 9℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 30℃, 40℃, 50℃, or any value between any two of the values.

[0044] Optionally, the preparation method comprises: mixing the porous material and the long carbon chain quaternary ammonium salt solution at a temperature of 5℃ to 50℃ for 2h to 24h to obtain the modified porous material.

[0045] Optionally, in the long carbon chain quaternary ammonium salt solution, the mass content of the long carbon chain quaternary ammonium salt is 1% to 10%.

[0046] Optionally, in the long carbon chain quaternary ammonium salt solution, the mass content of the long carbon chain quaternary ammonium salt is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between any two of the values.

[0047] Optionally, the solid-liquid ratio of the porous material and the long carbon chain quaternary ammonium salt solution is 1g:40mL to 60mL.

[0048] Optionally, the solid-liquid ratio of the porous material and the long carbon chain quaternary ammonium salt solution is 1g:40mL, 1g:41mL, 1g:42mL, 1g:43mL, 1g:44mL, 1g:45mL, 1g:46mL, 1g:47mL, 1g:48mL, 1g:49mL, 1g:50mL, 1g:51mL, 1g:52mL, 1g:53mL, 1g:54mL, 1g:55mL, 1g:56mL, 1g:57mL, 1g:58mL, 1g:59mL, 1g:60mL, or any ratio between any two of the ratios.

[0049] Optionally, the reaction includes static stirring or shaking.

[0050] The stirring or shaking is to mix the quaternary ammonium salt and the porous material uniformly, so that the reaction is more complete.

[0051] Optionally, the preparation method further comprises filtering and drying.

[0052] Optionally, the unbound quaternary ammonium salt and other impurities are filtered, so that a product with higher purity is obtained in subsequent operations.

[0053] Specifically, the mixture after the reaction is dried.

[0054] Optionally, the drying conditions are 50℃ to 70℃, and the drying time is 10h to 20h.

[0055] Preferably, drying is performed at 60℃ for 12h.

[0056] Optionally, the preparation method further comprises water washing.

[0057] Optionally, the water washing is rinsing the dried mixture with water. The purpose is to remove the long carbon chain quaternary ammonium salt combined on the surface of the porous material. The long carbon chain quaternary ammonium salt is weakly combined with the surface of the porous material, and is easy to be removed by water washing.

[0058] According to another aspect of the present application, a solid disinfectant is provided, which comprises the modified porous material according to any one of the above.

[0059] Optionally, the germicidal rate of the solid disinfectant is 89.99% to 99.99%.

[0060] Optionally, the germicidal rate of the solid disinfectant is 95% to 99.99%.

[0061] Optionally, the germicidal rate of the solid disinfectant is 95%, 96%, 97%, 98%, 99%, 99.99%, or any value between any two values.

[0062] According to another aspect of the present application, the use of the solid disinfectant as described above in water bodies to kill bacteria / fungi and inactivate viruses is provided.

[0063] Optionally, the water bodies include swimming pool water, domestic water, drinking water, tap water, and secondary water supply.

[0064] Compared with the prior art, the present application has the following beneficial effects:

[0065] (1) The present application provides a modified porous material. The long carbon chain quaternary ammonium salt is combined with the porous material, adsorbed into the interior of the porous material, and forms agglomerates, thereby being stably fixed in the interior of the porous material, reducing the residue in the water body. When sterilizing and disinfecting in water, this process can be transferred to the interior of the porous material, i.e., the porous material adsorbs the pollutants or microorganisms in the water, and the long carbon chain quaternary ammonium salt disinfects these pollutants, both of which cooperate with each other, making the sterilization and disinfection of the pollutants in the water more thorough, and having high efficiency in purifying water quality, etc. In addition, since the long carbon chain quaternary ammonium salt is in the form of agglomerates in the interior of the porous material, compared with other conventional disinfectants, the residue in the water is extremely small, avoiding the generation of disinfection by-products (DBPs), reducing the reprocessing of water quality, and reducing energy consumption and saving costs.

[0066] (2) The application uses a long carbon chain quaternary ammonium salt and a porous material internally physically combined method, which can fix the long carbon chain quaternary ammonium salt in the pore of the porous material. Through the adsorption of the porous material, the combination process is spontaneously formed. That is, the modification method of the application is relatively mild, the required reaction conditions are simple, a small amount of quaternary ammonium salt can achieve the modification effect, the cost can be significantly reduced, there is no side effect, and large-scale application can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 is the adsorption-desorption isotherm graph of the modified porous material and activated carbon prepared in Example 1 and Example 2 of the application; the abscissa is the relative pressure, unit: p / p0; the ordinate is the adsorption amount, unit: cm 3 ·g -1 .

[0068] Figure 2 is the pore structure graph of the modified porous material and activated carbon prepared in Example 1 and Example 2 of the application; the abscissa is the pore size, unit: nm; the ordinate is the differential pore volume of the adsorption amount to the pore size, unit: cm 3 / g·nm; (a) complete graph; (b) partial enlarged view of the dashed line part in (a).

[0069] Figure 3 is the simulation effect diagram of BAC placed in the micropore of the modified porous material in a manual manner; (a) shows water molecules; (b) hides water molecules.

[0070] Figure 4 is the simulation effect diagram of BAC placed in the micropore of the modified porous material in a manual manner for 1 ns; (a) is a perspective view; (b) is a front view.

[0071] Figure 5 is the simulation effect diagram of BAC placed in the micropore of the modified porous material in a manual manner for 2 ns; (a) is a perspective view; (b) is a front view.

[0072] Figure 6 is the simulation effect diagram of BAC placed in the micropore of the modified porous material in a random manner; (a) is a perspective view; (b) is a front view.

[0073] Figure 7 is the simulation effect diagram of BAC placed in the micropore of the modified porous material in a random manner for 1 ns; (a) is a perspective view; (b) is a front view.

[0074] Figure 8 is the simulation effect diagram of BAC placed in the micropore of the modified porous material in a manual manner; (a) is a perspective view; (b) is a front view.

[0075] Figure 9is a simulated effect diagram of BAC placed in the pores of the modified porous material in a random manner; (a) perspective view; (b) front view.

[0076] Figure 10 is a simulated effect diagram of BAC placed in the pores of the modified porous material in a random manner; (a) perspective view; (b) front view.

[0077] Figure 11 is a simulated effect diagram of BAC placed in the pores of the modified porous material in a random manner; (a) perspective view; (b) front view.

[0078] Figure 12 is a content curve diagram of the modified porous material prepared in Embodiments 1-2 of the present application releasing BAC in water; the abscissa is time, in h; the ordinate is mass concentration, in ppm.

[0079] Figure 13 is a sterilization effect diagram of the modified porous material prepared in Embodiments 1-2 of the present application and activated carbon, BAC solution; the abscissa is time, in h; the ordinate is sterilization rate, in %. DETAILED DESCRIPTION

[0080] The specific embodiments of the present application will be described below with reference to the accompanying drawings.

[0081] In the present application, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by a person skilled in the art. And the reagents, materials and operation steps used herein are all widely used reagents, materials and conventional steps in the corresponding field.

[0082] It should be noted that the application modes presented in the following examples are only preferred application modes for the materials, the examples described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. In addition, if not specifically stated, all reagents used in the following examples are commercially available or can be synthesized according to the methods described herein or known methods, and the reaction conditions not listed are also easily obtained by a person skilled in the art. The operation methods not specified in the following examples are usually carried out under conventional conditions, or under the conditions recommended by the manufacturer.

[0083] Activated carbon: columnar activated carbon prepared by Ningxia Wangdake Coal Industry Co., Ltd. using Ningxia anthracite as raw material;

[0084] Benzalkonium chloride (BAC, 80wt%) solution was purchased from Shanghai Maikelin Biochemical Co., Ltd., Lot number: C11726906;

[0085] Water bath constant temperature oscillator: SHZ-B type, Beijing Yidecheng Trade Co., Ltd.

[0086] Circulating water type multi-purpose vacuum pump: SHB-III type, Shanghai Zhenjie Experimental Equipment Co., Ltd.

[0087] Example 1

[0088] Long carbon chain quaternary ammonium salt: benzalkonium chloride (CAS number: 63449-41-2, abbreviated as BAC), the structural formula is:

[0089]

[0090] Among them, R: 68% is C12, 32% is C14.

[0091] Modified porous material preparation method:

[0092] Prepare a benzalkonium chloride solution with a mass fraction of 2wt% (solvent is water), according to the solid-liquid ratio of 1g (activated carbon sample): 50ml (benzalkonium chloride solution), take 3g of activated carbon sample and dimethyl diallyl ammonium chloride solution into a conical flask, and place the conical flask in a water bath oscillator (160rpm / min) at room temperature (25℃); the mixed solution is filtered, and the solid sample obtained by filtration is dried in an oven at 60℃ for 12h, to obtain a modified porous material AC-BAC-2, wherein the mass content of benzalkonium chloride in the modified porous material is 15.4%.

[0093] Example 2

[0094] As in Example 1, only the mass fraction of benzalkonium chloride solution in Example 1 is changed to 1%, 5%, 7%, respectively, to obtain modified porous materials AC-BAC-1 (mass content of benzalkonium chloride is 13.5%), AC-BAC-5 (mass content of benzalkonium chloride is 16.2%), and AC-BAC-7 (mass content of benzalkonium chloride is 16.7%).

[0095] Example 3

[0096] As in Example 1, the reaction time in Example 1 is changed to 2h, 4h, 6h, 8h, 12h, respectively, to obtain modified porous materials AC-BAC-2h, AC-BAC-4h, AC-BAC-6h, AC-BAC-8h, and AC-BAC-12h.

[0097] Example 4

[0098] As in Example 1, only the quaternary ammonium salt in Example 1 is changed to:

[0099]

[0100] Modified porous materials AC-a, AC-b were obtained respectively.

[0101] The modified porous materials AC-a, AC-b have the same properties as the modified porous material obtained in Example 1.

[0102] Example 5

[0103] As in Example 1, only the activated carbon in Example 1 was replaced with: biochar, molecular sieve, diatomite, activated carbon fiber, respectively, to obtain modified porous materials B-BAC-2, MS-BAC-2, D-BAC-2, ACF-BAC-2. The modified porous materials have the same properties as the modified porous material obtained in Example 1. Due to space limitations, only the modification of activated carbon is tested.

[0104] Comparative Example 1

[0105] Only coal-based activated carbon, no changes.

[0106] Performance analysis

[0107] 1. The pore volume distribution and BET specific surface area of the modified porous materials prepared in the examples and Comparative Example 1 were determined. The pore structure parameters of AC and its modified samples were determined using a gas adsorption analyzer (Micromeritics, ASAP 2020Plus). Before analysis, these samples were first degassed at 100°C until the pressure was less than 0.01 torr. Through DFT analysis of helium adsorption, free space analysis data of the sample were obtained, which were used to measure the specific surface area and pore volume distribution of the sample. The results are shown in Figure 1 and Figure 2 .

[0108] From Figure 1 it can be found that the nitrogen adsorption-desorption isotherm of activated carbon belongs to the IUPAC (International Union of Pure and Applied Chemistry) specified type I isotherm, which shows that activated carbon is mainly composed of micropores, which is consistent with the characteristics of activated carbon prepared from anthracite. After modification of activated carbon, the adsorption performance of activated carbon decreases significantly, and the decrease is proportional to the concentration of activated carbon. From Figure 2 pore size distribution, it can be seen that activated carbon contains a large amount of micropores (≤2 nm) and a small amount of mesopores (2-5 nm), and these micropores and mesopores decrease or even disappear after BAC modification. It shows that the anthracite-based activated carbon has strong adsorption capacity for BAC molecules, and the adsorbed BAC molecules will block part of the micropores and mesopores of the activated carbon.

[0109] 2. Molecular simulation of the modified porous materials prepared in the examples.

[0110] It is difficult to reveal the behavior of BAC molecules in the pores of activated carbon by traditional experimental methods. In this paper, molecular dynamics simulation method was used to explore the behavior pattern of BAC molecules at the molecular level.

[0111] The specific process is as follows: (1) model establishment: in order to simplify the simulation process, graphene sheets were used instead of graphite sheets (as the pore structure of activated carbon prepared from anthracite is mainly slit pores formed by irregular accumulation of graphite sheets, so it can be simplified), the distance between graphene sheets was controlled to simulate the micropores and mesopores of activated carbon; 10×10 nm 2 graphene structure was obtained by VMD (Visual Molecular Dynamics, a molecular visualization software); OPLS-AA force field of graphene was obtained by x2top function of GROMACS; the force constants of bond, bond angle and dihedral angle were set to 400000, 600 and 150 respectively; OPLS-AA force field of BAC cation was obtained by LigParGen; 100 BAC molecules were placed in a 10×10×10 nm 3 periodic box by random (the number density of one molecule is 10 nm 3 ) or artificial way, the concentration of BAC in the model system was 6.8wt%; the middle of the box was separated by two graphene layers with a size of 10×10 nm 2 ; in addition, the shortest distance between BAC molecules and graphene layers was set to 0.3 nm. 28000 water molecules were added to the box as solvent, and the force field of water was TIP4P. Finally, 100 Cl - ions were added to make the solution neutral. (2) energy minimization: after the model was established, the system energy of the model was minimized; first, the graphene layers in the model were fixed, then the PME method was used for long-range electrostatic interaction. The above process makes the energy of the established model minimum, and the convergence standard is that the maximum force in the system is less than 1000 kJ / mol / nm. (3) molecular dynamics simulation: molecular dynamics simulation under NVT ensemble was carried out, the temperature was set to 300 K, the adjustment mode was thermostat with random term, the integration time step was 2 fs, the simulation time was 200 ps, and the system reached equilibrium; the sampling process was similar to the equilibrium process, but the simulation time was 1 ns and 2 ns respectively.

[0112] The distance between graphene layers was controlled to simulate the slit pore structure of activated carbon. When the distance between graphene layers is 2 nm, the micropore structure of activated carbon is close to the micropore structure of activated carbon, and the distance between graphene layers is controlled to simulate the mesopore structure of activated carbon. Then the behavior of BAC molecules in the constructed micropores and mesopores was simulated by molecular dynamics method.

[0113] (i) Explore the behavior change of BAC molecules inside and outside the micropore: the BAC molecules are arranged in the box in a artificial way, as shown in Figure 3 . Figure 3 (a) The distance between the black graphene layers is set to 2 nm to simulate activated carbon. The gray particles represent water molecules in the model system; in order to more clearly observe the behavior trajectory of BAC, the water molecules in the system can be hidden, as shown in Figure 3 (b). After running the model system for 1 ns and 2 ns, the behavior change of BAC molecules inside and outside the micropore is shown in Figure 4 .

[0114] As shown in Figure 4 (a) and Figure 4 (b), after running the system for 1 ns, the originally arranged BAC molecules have undergone great positional changes. The BAC molecules tend to aggregate, and the BAC molecules distributed outside the graphene layer have a greater degree of aggregation. After running the system for 2 ns, as shown in Figure 5 (a) and Figure 5 (b), the number of free BAC molecules is greatly reduced, and the BAC molecules are more aggregated. In addition, the BAC molecules are crisscrossed in the micropore. From the above simulation results, it can be inferred that the main reason for the immobilization of BAC molecules in the micropore. BAC molecules contain large-sized long-chain alkyl groups, and these long-chain alkyl groups are crisscrossed and aggregated in a small range in the activated carbon micropore. Due to the agglomeration, the size of the BAC molecules becomes large, and it is difficult to desorb from the activated carbon micropore, resulting in the phenomenon of micropore immobilization of BAC molecules.

[0115] (ii) Explore the behavior change of BAC molecules inside and outside the micropore: the BAC molecules are arranged in the box in a random way, as shown in Figure 6 ; Figure 6 The distance between the black graphene layers is set to 2 nm to simulate activated carbon. After running the model system for 1 ns, the behavior change of BAC molecules inside and outside the micropore is shown in Figure 7 .

[0116] As can be seen from Figure 6 and 7 , the behavior change of BAC molecules in this model is basically consistent with the model of artificially placing BAC molecules. As shown in 7(a) and Figure 7 (b), outside the pore, a small amount of BAC molecules are combined with the activated carbon surface parallel to the graphene layer, while more BAC molecules aggregate and tend to form agglomerates, even micelles. The BAC molecules are horizontally or vertically aggregated in a small range in the micropore, but due to the limited space, it is difficult for the BAC molecules in the micropore to form large aggregates.

[0117] (ii) Explore the behavior of BAC molecules in the mesopore: BAC molecules are arranged in the box in a manual and random manner, respectively, as shown in Figure 8 and Figure 9 . Figure 8 and Figure 9 The distance between the black graphene layers in the mesopore is set to 4 nm to simulate activated carbon. After running the established model system for 1 ns and 2 ns, the behavior of BAC molecules in the micropore and mesopore is shown in Figure 10 and Figure 11 .

[0118] As can be seen from Figure 10 and Figure 11 , the change of BAC molecules in the mesopore is similar to that in the micropore. The difference is that the interlayer distance of the mesopore in graphene is larger than that of the micropore, and the mesopore space is larger, so the aggregation of BAC molecules in the mesopore is more obvious. Similarly, due to the limitation of the mesopore size of activated carbon, it is also difficult for BAC molecules to leave the pore because the aggregation of molecules makes the size of the aggregate larger.

[0119] As can be seen from the above, BAC molecules in the solution are adsorbed into the pores of AC, and the concentration of BAC in the pores increases. The adsorbed and concentrated BAC molecules form large aggregates through the hydrophobic groups in the pores, and the formed large aggregates are difficult to desorb from the micropore and mesopore. However, BAC molecules have a critical micelle concentration, and the size of the formed aggregates will not always increase. In addition, as is well known to those skilled in the art, the pore shape of activated carbon prepared by steam activation is close to the shape of an ink bottle, i.e. the entrance of the pore is small and the space inside the pore is large; the size of the aggregates formed by these BAC molecules is difficult to exceed the size of the large pore, but it is easy to be larger than the size of the entrance, which also makes it difficult for these BAC molecules to desorb; therefore, from the above it can be known that the change of long-chain quaternary ammonium salt in the modified porous material, and it is given that the change can significantly reduce the release amount of long-chain quaternary ammonium salt in water.

[0120] 3. Measure the release amount of BAC in water of the modified porous material prepared in the example.

[0121] The content of BAC in water is determined by ultraviolet spectrophotometry, as follows:

[0122] (1) Obtain the standard curve: prepare BAC standard solutions of different concentrations, and determine the absorbance of the above different concentration standard solutions by visible ultraviolet spectrophotometer (Thermofisher, Genesys 180), wavelength is 263 nm, according to the abscissa is the concentration, ordinate is the absorbance to draw the standard curve.

[0123] (2) Water washing of modified porous materials: 2 g of modified porous materials prepared in Example 1 and Example 2 were placed in a suction funnel, and 1000 ml, 1500 ml, 2000 ml of deionized water were used to wash the modified porous materials, respectively. After washing, the materials were filtered, and the solid and filtrate were separated. The concentration of BAC in the filtrate was determined by UV spectrophotometer to determine whether the BAC molecules weakly bound to the surface of the activated carbon were effectively removed. The test results are shown in Table 1.

[0124] During the modification process, many BAC molecules are adsorbed into the pores of the activated carbon, and a small number of BAC molecules are bound to the surface of the activated carbon. The binding of these BAC molecules to the surface of the activated carbon changes the surface charge distribution and hydrophobicity of the activated carbon. At the same time, it also proves the weak binding of BAC molecules to the surface of AC. Therefore, before exploring whether the pores of the activated carbon can immobilize the activated carbon molecules, it is necessary to eliminate the influence of these BAC molecules adsorbed on the surface of the activated carbon. The purpose of washing the modified AC with deionized water is to remove the BAC molecules that are not firmly bound to the surface of the AC. During the washing process, the BAC content of the filtrate needs to be closely monitored to determine whether the BAC molecules on the surface of the activated carbon have been effectively removed, and the results are shown in Table 1.

[0125] Table 1 BAC content released by different modified porous materials in water

[0126]

[0127] As can be seen from Table 1, after washing the modified AC sample with 1500 ml of deionized water, the residual BAC concentration in the filtrate is less than 10 ppm. The concentration is close to the detection limit of the UV spectrophotometer, and it can be approximately considered that the BAC molecules on the surface of the AC have been removed. However, in order to ensure that the BAC molecules on the surface of the activated carbon are removed and to reduce the impact on subsequent experiments, 2000 ml of deionized water was used to wash the activated carbon sample in the experiment.

[0128] (3) Measurement of BAC content in water: The modified porous materials washed with water above and 2000 ml of deionized water were mixed in a conical flask, with a solid-liquid ratio of 1:50 g / ml, and then placed in a water bath bottle at a frequency of 80 r / min and a temperature of 25 degrees. After a period of time (2 h, 4 h, 6 h, 8 h, 12 h, 24 h), the oscillation was stopped, the sample was filtered, and the BAC concentration in the filtrate was determined by UV spectrophotometer. The results are shown in Figure 12 .

[0129] As Figure 12As shown, only a small amount of BAC molecules was released from the pores of the AC sample into the water, and the BAC concentration in the water remained relatively stable and did not significantly increase with the extension of time. Moreover, the number of BAC molecules released from different AC samples into the water was basically close. In summary, the released BAC molecules in the AC sample were negligible in ppm, and these BAC molecules were independent of time. Therefore, it is considered that the pore structure of the AC has a good fixation effect on the BAC molecules.

[0130] Antibacterial performance research

[0131] Escherichia coli dry powder was purchased from Guangdong Huanke Microbial Technology Co., Ltd.

[0132] (1) Culturing Escherichia coli and measuring the growth curve.

[0133] The liquid medium was prepared as follows: 1.2 grams of beef extract, 4 grams of peptone and 5 grams of sodium chloride were respectively dissolved in 1000 milliliters of deionized water, stirred and dissolved, the pH value was adjusted to 7.0-7.2 with 1 mol / L NaOH solution, and then they were respectively put into four 250ml conical flasks and sterilized in a high-pressure sterilization pot for 0.5 hours. Take an appropriate amount of freeze-dried powder and put it into the sterilized medium for activation. 2.5ml of Escherichia coli strain solution was transferred to the conical flask containing the liquid medium, and placed in a shaking bed at 25℃, 170r / min for different time; then 5ml of liquid was taken out from the medium after different shaking time, and its OD 600nm (absorbance value at 600nm wavelength) was measured by ultraviolet spectrophotometer. The experiment was repeated three times, and the growth curve of Escherichia coli was drawn.

[0134] (2) Bactericidal performance of AC modified with different concentrations of BAC on Escherichia coli.

[0135] Preparation of nutrient agar medium: 20g agar powder, 4g peptone, 5g NaCl and 1.2g beef extract were dissolved in 1000ml deionized water, the pH value of the solution was adjusted to 7.0-7.2 with 0.1mol / L NaOH or HCl solution, and then the solution was placed in a conical flask and cooled and sterilized, and then poured into a flat plate.

[0136] Preparation of diluent: adjust the pH value of 0.85% NaCl physiological saline to 7.0-7.2 with 0.1mol / L NaOH or HCl solution, add 2ml Tween 80, then put it into a conical flask and sterilize.

[0137] Obtaining the solution containing E. coli: 10 ml of the above E. coli strain solution in the logarithmic growth phase was cultured in a conical flask containing 1000 ml of liquid medium, shaken at 25°C, 170 rpm for 10 hours until the E. coli grew to the logarithmic phase (OD 600nm = 0.5), then 30 ml of the strain solution was taken out from the conical flask into a 50 ml centrifuge tube and centrifuged at 400 r / min for 10 minutes; after centrifugation, the supernatant was poured out, 30 ml of the diluent Tween 80 was added to the centrifuge tube, then it was centrifuged under the same conditions for 10 minutes, and the operation was repeated twice.

[0138] By repeating the above process several times, a plurality of centrifuge tubes containing E. coli were obtained.

[0139] Antibacterial test: 0.6 g of modified AC (AC-BAC-1, AC-BAC-2, AC-BAC-5, AC-BAC-7) and unmodified activated carbon (AC) with different BAC concentrations and 2% BAC solution (BAC-2) not fixed on activated carbon were added into the above centrifuge tubes respectively, and they were placed on a shaking table at 170 r / min, 25°C, to detect the antibacterial performance of the modified AC on E. coli. 0.5 ml samples were taken from the centrifuge tubes at 0 hour, 0.5 hour, 1 hour, 1.5 hours and 2 hours respectively, and the obtained 0.5 ml samples were diluted with a series of gradients (diluted by 10 6 , 10 7 and 10 8 times respectively). 100 ul of each of the above dilutions was taken and spread on sterilized agar plates, and cultured in a 37°C incubator for 12 hours. The concentration of E. coli was obtained by observation and counting, and the results are shown in Figure 13 .

[0140] As Figure 13As shown, the germicidal performance of the modified ACs with different BAC concentrations is different. Specifically, AC-BAC-2 produces a better germicidal effect, and the time is the shortest, reaching 97.8% at 0.5 h and 98.56% at 2 h. However, the sample with the highest germicidal rate at 2 h is AC-BAC-1, with a germicidal rate of 98.95%. With the increase of the BAC concentration in the modified porous material, the germicidal performance of the modified porous material decreases. For example, the germicidal performance of AC-BAC-5 is obviously higher than that of AC-BAC-7 before 1.5 h. However, when the time increases to 2 h, the germicidal rates of AC-BAC-5 and AC-BAC-7 are close to 95.47% and 95.04%, respectively. Although the germicidal rates are lower than those of AC-BAC-1 and AC-BAC-2, they are at a relatively high level. If any of the substances is used alone, i.e., the unmodified activated carbon or the 2% BAC solution used for modifying the activated carbon, the germicidal performance (the germicidal rates are 50%-60% and 70%-80%, respectively) is general, which is far lower than the germicidal rate (≥95%) of the modified activated carbon.

[0141] As can be seen from the above, the combination of the two general germicidal ACs and BAC, i.e., the fixation of BAC in the AC, can significantly improve the germicidal effect. In the sterilization process, the activated carbon adsorbs and concentrates the E. coli in the water body into the pores, and the BAC in the pores kills the E. coli, thereby significantly improving the sterilization effect.

[0142] Benzalkonium chloride is a disinfectant with double functions, which can kill bacteria and fungi and inactivate viruses. Direct use of BAC can effectively kill microorganisms in water, but the residual BAC is difficult to separate from water and can cause secondary pollution to the human environment. The porous material has a strong adsorption capacity for BAC molecules, and the adsorbed BAC molecules enter the narrow pores of the porous material and form larger agglomerates through hydrophobic groups, so that the BAC molecules are difficult to desorb from the narrow pores of the porous material. The amount of BAC released by the modified porous material is ppm level, which can be ignored. Therefore, the modified porous material prepared in the application can not only kill bacteria and viruses, but also avoid the disadvantages of traditional chlorine disinfection, thereby being better applied to the purification of microorganisms in water.

[0143] In the present application, only part of the structures are selected as representatives in the experimental examples to illustrate the preparation method and effect of the present application, and the structures not listed have similar effects.

[0144] The monomers used in the experimental examples can be purchased or prepared simply, and the preparation process is also a prior art, so it is not described in detail in the specification.

[0145] It should be noted that the applicant has done a lot of tests on the series structure, and sometimes in order to better compare with the existing system, there is more than one test on the same structure and system, so there may be some errors in different tests.

[0146] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0147] The preferred specific embodiments and examples of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the concept of the present application.

Claims

1. A method for producing a modified porous material, characterized by, The porous material and the long carbon chain quaternary ammonium salt solution are mixed for 24 hours at a temperature of 5-50℃, the mass content of the long carbon chain quaternary ammonium salt in the long carbon chain quaternary ammonium salt solution is 1-10%, and the solid-liquid ratio of the porous material and the long carbon chain quaternary ammonium salt solution is 1g:40-60mL; the modified porous material is obtained; The preparation method comprises filtering and drying, and further comprises water washing; the water washing is washing the mixture after drying with water; The porous material is a porous carbon material; The mass content of the long carbon chain quaternary ammonium salt in the modified porous material is 10-20%; The amount of the long carbon chain quaternary ammonium salt released by the modified porous material in water is ≤15ppm; The long carbon chain quaternary ammonium salt is fixed in the form of agglomerates in the porous material; The long carbon chain quaternary ammonium salt is benzalkonium chloride BAC; The long carbon chain quaternary ammonium salt is fixed in the pores of the porous material; The size of the agglomerates of the long carbon chain quaternary ammonium salt formed by hydrophobic interaction is larger than the entrance of the pores of the porous material; The sterilization rate of the modified porous material to water is ≥95%.

2. The method of claim 1, wherein the modified porous material is prepared by a method comprising: The porous material comprises at least one of biochar, activated carbon and activated carbon fiber.

3. A solid disinfectant, characterized by, The solid disinfectant comprises the modified porous material prepared in any one of claims 1-2, and the sterilization rate of the solid disinfectant is 95-99.99%.

4. Use of the solid disinfectant according to claim 3 for killing bacteria / fungi, inactivating viruses in water bodies, characterized in that, The water body comprises swimming pool water, household water and secondary water supply. The porous material comprises at least one of biochar, activated carbon and activated carbon fiber. The solid disinfectant comprises the modified porous material prepared in any one of claims 1-2, and the sterilization rate of the solid disinfectant is 95-99.99%. The water body comprises swimming pool water, household water and secondary water supply.

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