A high-efficiency defluorination agent suitable for photovoltaic wastewater and its preparation process

Abstract

The present invention discloses a highly efficient defluorination agent suitable for photovoltaic wastewater and its preparation process, which specifically relates to the field of photovoltaic wastewater treatment, including an outer polymer barrier and an inner core drug release barrier, wherein the outer polymer barrier is coated on the outside of the inner core drug release barrier, a drug release region 1 is formed between the outer polymer barrier and the inner core drug release barrier, and the inner cavity of the inner core drug release barrier is a drug release region 2; the outer polymer barrier is composed of polyvinylidene fluoride, polyethylene terephthalate and chitosan, and the outer polymer barrier dissolves under the action of electric current or ultraviolet rays. By designing the structure of the outer polymer barrier and the inner core drug release barrier, the function of gradually releasing the agent under a specific environment is achieved, the outer polymer barrier dissolves under the action of electric current or ultraviolet rays, and the inner core drug release barrier is gradually hydrolyzed through an alkaline environment, which optimizes the action time and effect of the agent and avoids the problem of unstable efficiency caused by too fast release in traditional defluorination agents.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic wastewater treatment, and more specifically, to a high-efficiency defluorination agent suitable for photovoltaic wastewater and a preparation process thereof. Background Art

[0002] In the existing photovoltaic wastewater treatment, defluorination agents usually rely on physical or chemical adsorbents, such as activated alumina, aluminum hydroxide and other materials. Although these agents have certain defluorination capabilities, they often face problems such as unstable release control, short action time, and decreased agent efficiency in actual applications. Especially in complex industrial wastewater environments, it is difficult to balance the reaction time of the agent and the defluorination efficiency, resulting in complex operations and large fluctuations in the defluorination effect.

[0003] The defect of too-rapid release of defluoridation agents is particularly prominent in actual use. Due to the lack of control over the release of the agents, the agents often dissolve quickly after being added, causing excessive or insufficient local reactions, resulting in unstable wastewater treatment effects and inability to maintain long-term and efficient defluoridation capabilities. Summary of the invention

[0004] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a high-efficiency fluorine removal agent suitable for photovoltaic wastewater and a preparation process thereof. Through the structure of an outer polymer barrier and an inner core drug-releasing barrier, the function of gradually releasing the agent under a specific environment is achieved. The outer polymer barrier dissolves under the action of electric current or ultraviolet rays, while the inner core drug-releasing barrier gradually hydrolyzes through an alkaline environment to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a highly efficient defluorination agent suitable for photovoltaic wastewater, comprising an outer polymer barrier and an inner core drug release barrier, wherein the outer polymer barrier is coated on the outside of the inner core drug release barrier, a drug release region 1 is formed between the outer polymer barrier and the inner core drug release barrier, and the inner cavity of the inner core drug release barrier is a drug release region 2;

[0006] The outer polymer barrier is composed of 40% to 60% polyvinylidene fluoride, 20% to 30% polyethylene terephthalate and 10% to 20% chitosan, and the outer polymer barrier dissolves under the action of electric current or ultraviolet light;

[0007] The polyvinylidene fluoride of the outer polymer barrier decomposes under the action of electric current or electric field. The reaction is stimulated by the electric field, which breaks the CF bond in the polyvinylidene fluoride molecular chain, releases by-products ethylene and hydrogen, and triggers the release of the agent. The reaction formula is:

[0008] C2H2F2+H2O+E→F - +H2+C2H4

[0009] The polyethylene terephthalate of the outer polymer barrier is photolyzed under the action of ultraviolet HV, and the reaction formula is:

[0010] C 10 H8O4+hv→C5H4O2+C5H4O2

[0011] The composition of the inner core release barrier includes 50% to 60% polycaprolactone, 20% to 25% gelatin, 5% to 10% silicon dioxide, and 10% to 15% calcium chloride;

[0012] The polycaprolactone of the inner core drug release barrier is hydrolyzed in an alkaline environment, and the reaction formula is:

[0013] C6H 10 O2+OH - →C5H8O4+H2O

[0014] The first drug release area includes a pH regulator, which includes 30% to 40% of sodium bicarbonate, 20% to 30% of boric acid and 10% to 20% of sodium hexametaphosphate, and the sodium hexametaphosphate is used to adjust the pH value of the water body after the outer polymer barrier is dissolved;

[0015] Drug release area 1 uses sodium bicarbonate to neutralize the acidity in the water and adjust the pH value. The reaction formula is as follows:

[0016] NaHCO3+H + →Na + +CO2+H2O

[0017] Subsequently, the alkalinity of the water body is adjusted by a buffering reaction between boric acid and hydroxide ions, and the reaction formula is as follows:

[0018]

[0019] Sodium hexametaphosphate in the pH regulator is used to inhibit premature reaction by complexing with calcium ions in the water. The reaction formula is as follows:

[0020] NaPO 36 +Ca 2+ → Complex

[0021] The second drug release area includes a defluoridation component, which is released after the inner core drug release barrier dissolves. The defluoridation component includes 5% to 10% calcium carbonate; 40% to 50% aluminum hydroxide; 20% to 25% calcium phosphate; and 10% to 15% polycaprolactone.

[0022] The aluminum hydroxide in the defluorination component reacts with fluoride ions to form fluoroaluminate precipitate:

[0023] AlOH3+3F - →AlF3+3OH-

[0024] Calcium ions and fluoride ions form calcium fluoride precipitate:

[0025] Ca 2+ +2F - →CaF2 (precipitation).

[0026] A preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater, comprising:

[0027] Firstly, aluminum hydroxide and calcium phosphate are mixed to form a suspension or slurry in deionized water, then calcium carbonate is added to the formed suspension or slurry, and then the mixture is converted into solid particles by spray drying or freeze drying. Then, the dried defluorination particles are mixed with molten polycaprolactone to obtain defluorination particles coated with polycaprolactone;

[0028] The treated fluorine removal component particles are added to the melt of the inner core drug release barrier, and the temperature of the melt of the inner core drug release barrier is maintained at 80° C. to 100° C. The melt of the inner core drug release barrier is prepared by mixing polycaprolactone, gelatin, calcium chloride and silicon dioxide, and then adding the fluorine removal particles to the mixture and stirring.

[0029] The molten core drug-releasing barrier is coated on the outside of the defluorination component particles, and after cooling, the defluorination component-coated particles are obtained;

[0030] The coated core drug release barrier particles are placed in a drum mixer, and sodium bicarbonate, boric acid and sodium hexametaphosphate are gradually added as pH adjusters; the pH adjusters are attached to the surface of the particles by physical adsorption;

[0031] Dissolving polyvinylidene fluoride, polyethylene terephthalate and chitosan in an organic solvent and heating and stirring to 60°C to 70°C; then coating the solution on the surface of the particles containing the pH regulator by rotary spraying to form a complete outer polymer barrier; the outer polymer barrier is gradually dissolved under microcurrent or ultraviolet conditions;

[0032] The composite particles containing the defluorination component, the inner core drug release barrier and the outer layer polymer barrier are placed in a vacuum drying oven, dried until the residual solvent in the particles evaporates, and finally the particles are formed by granulation or tableting to obtain defluorination agent particles;

[0033] After obtaining the defluorination agent particles, unprocessed particle data of the defluorination agent particles are obtained by using a spectral reflectance sensor and a laser particle size analyzer, the unprocessed particle data including the optical reflectance and particle size distribution of the particles, and the unprocessed particle data are standardized to obtain standardized particle data;

[0034] The standardized particle data is used as input values ​​and input into the K-means clustering algorithm for processing;

[0035] When processing standardized particle data, the K-means clustering algorithm first sets the initial cluster center of optical reflectance and particle size distribution, and through multiple iterations, assigns each defluorination agent particle to the nearest cluster center and continuously updates the center position;

[0036] By adjusting the number of clusters K, the number of iterations, and the distance metric, uniformity deviations are detected and marked;

[0037] Based on the K-means clustering results, the particle distribution information of the defluorination agent is fed back in real time to monitor the optical reflectivity and particle size distribution of the particles. By identifying the deviation between the reflectivity and the particle size, the mixing and coating process parameters in the preparation process are adjusted.

[0038] In a preferred embodiment, the optical reflectivity parameters include spectral reflectance ratio, reflection spectrum width and relative refractive index; the proposed spectral reflectance ratio is SRR; the proposed reflection spectrum width is RSW; the proposed relative refractive index is RI;

[0039] The spectral reflectance ratio SRR is used to measure the reflectivity of the particle surface to incident light. The calculation formula is:

[0040]

[0041] Among them I reflected is the reflected light intensity; I incident is the incident light intensity;

[0042] The reflection spectrum width RSW is used to measure the reflection performance of particles in different wavelength ranges and reflect the surface roughness. The calculation formula is:

[0043] RSW=λ max -λ min

[0044] where λ max is the upper wavelength of the reflection peak; min Indicates the lower wavelength of the reflection peak;

[0045] The relative refractive index RI is used to describe the difference in refractive index between the granular material and the medium. The calculation formula is:

[0046]

[0047] where n particle is the refractive index of the particle; n medium is the refractive index of the medium.

[0048] In a preferred embodiment, the particle size distribution parameters include particle size variation coefficient, optical anisotropy and volume particle size distribution, the proposed particle size variation coefficient is CVD, the proposed optical anisotropy is OA, and the proposed volume particle size distribution is VDD;

[0049] The coefficient of variation of particle size, CVD, is used to indicate the degree of dispersion of particle size distribution. CVD is expressed as:

[0050]

[0051] where σ particle is the particle size standard deviation; d avg represents the average particle size;

[0052] Optical anisotropy OA is used to measure the difference in optical behavior of particles in different directions. The formula is:

[0053]

[0054] Where R ∥ is the reflectivity in the parallel direction, R ⊥ is the vertical reflectivity;

[0055] Volume particle size distribution VDD is used to express the distribution relationship between volume and particle size. The formula is:

[0056]

[0057] Where V i Indicates the volume fraction of a specific particle size; d i Indicates the value of the particle size.

[0058] In a preferred embodiment, the spectral reflectance ratio, reflectance spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy and volume particle size distribution in the unprocessed particle data are standardized;

[0059] The proposed standardized processing formula is:

[0060]

[0061] Where Z i is the normalized data point; X i are the original six parameter data; μ i is the mean of each parameter, σ i is the standard deviation of each parameter; through standardization, data of different dimensions can be processed within the same range.

[0062] In a preferred embodiment, when setting the cluster centers, first initialize K cluster centers C1, C2, ..., C KEach cluster center corresponds to six dimensions, which represent spectral reflectance ratio, reflectance spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy and volume particle size distribution. The initial values ​​are:

[0063] C j =[SRR j ,RSW j ,RI j ,CVD j ,OA j ,VDD j ]

[0064] Among them C j represents the jth cluster center; SRR j 、RSW j , RI j 、CVD j OA j 、VDD j They represent the initial values ​​of the cluster center in six dimensions: spectral reflectance ratio, reflection spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy, and volume particle size distribution.

[0065] In a preferred embodiment, the distance from the particle to the cluster center is calculated, and the data x of each particle is calculated. i The distance to each cluster center is calculated using the Euclidean distance formula;

[0066] x i =[SRR i ,RSW i ,RI i ,CVD i ,OA i ,VDD i ]

[0067]

[0068] Where d(x i ,C j ) is the particle x i To cluster center C j The distance of x ik Is particle x i The value of the kth parameter; C jk is the cluster center C j At the kth parameter coordinate, each particle is assigned to a nearby cluster center by calculating the distance;

[0069] Then update the cluster center. When all particles are allocated, update the position of each cluster center:

[0070]

[0071] Among them C j is the new position of the j-th cluster center; n j is the number of particles assigned to the jth class; x i are particles belonging to this cluster.

[0072] In a preferred embodiment, the clustering effect is optimized by adjusting the clustering parameters, which include the number of clusters K, the upper limit of the number of iterations T, and the distance measurement method.

[0073] The cluster number K means that by testing different cluster numbers K, the cluster number reflecting the uniformity of particles is found; the upper limit of the number of iterations T is used to avoid excessive iterations affecting the efficiency of the algorithm; the distance measurement method means that in addition to the Euclidean distance, the Manhattan distance is used for testing, and the formula is:

[0074]

[0075] SRR i is the spectral reflectance ratio of the i-th particle, which represents the ratio of incident light to reflected light and measures the surface smoothness; RSW i is the width of the reflection spectrum, which indicates the reflection distribution of particles in different wavelength ranges; RI i is the relative refractive index, describing the difference in refraction between the granular material and the medium; CVD i is the coefficient of variation of particle size, reflecting the degree of dispersion of particle size distribution; OA i is optical anisotropy, which characterizes the difference in optical properties of particles in different directions; VDD i It is the volume particle size distribution, which shows the relationship between particle volume and particle size.

[0076] Technical effects and advantages of the present invention:

[0077] 1. The present invention realizes the function of gradually releasing the agent under a specific environment by designing the structure of the outer polymer barrier and the inner core drug release barrier. The outer polymer barrier dissolves under the action of electric current or ultraviolet rays, while the inner core drug release barrier gradually hydrolyzes in an alkaline environment, thereby ensuring the sequential release of the pH regulator and the defluorination component, optimizing the action time and effect of the agent, and avoiding the problem of unstable efficiency caused by too fast release in traditional defluorination agents;

[0078] 2. The present invention achieves precise adjustment of the pH value of the water body by adding pH regulators such as sodium bicarbonate, boric acid and sodium hexametaphosphate in the drug release area 1. Sodium hexametaphosphate delays the reaction by complexing calcium ions, while sodium bicarbonate and boric acid play a neutralizing and buffering role respectively, ensuring that the pH value of the water body is stable within the optimal range, that is, 6.5 to 8, which provides a good chemical environment for the subsequent defluorination reaction;

[0079] 3. Using spectral reflectance and particle size distribution data, the present invention introduces a K-means clustering algorithm to monitor the distribution of defluorination agent particles in real time. Through standardized data, the system can identify the optical and physical property deviations of the particles and adjust the mixing and coating process parameters in the production process according to the feedback information. This method improves the uniformity and consistency of the particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 It is a flow chart of the preparation process of the present invention. DETAILED DESCRIPTION

[0081] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0082] Refer to the instruction manual Figure 1 , an embodiment of the present invention is a highly efficient defluorination agent suitable for photovoltaic wastewater, comprising an outer polymer barrier and an inner core drug release barrier, wherein the outer polymer barrier is coated on the outside of the inner core drug release barrier, a drug release region 1 is formed between the outer polymer barrier and the inner core drug release barrier, and the inner cavity of the inner core drug release barrier is a drug release region 2;

[0083] The outer polymer barrier comprises 40% to 60% polyvinylidene fluoride, 20% to 30% polyethylene terephthalate and 10% to 20% chitosan. -3 A to 10 -2 A. Dissolved under the action of ultraviolet light with a wavelength of 280 to 320 nm present in electric fields or photovoltaic wastewater;

[0084] The polyvinylidene fluoride of the outer polymer barrier decomposes under the action of microcurrent or electric field. The reaction is stimulated by the electric field, which breaks the CF bond in the polyvinylidene fluoride molecular chain, releases byproducts ethylene and hydrogen, and triggers the release of the drug. The reaction formula is:

[0085] C2H2F2+H2O+E→F - +H2+C2H4

[0086] The polyethylene terephthalate of the outer polymer barrier is photolyzed under the action of ultraviolet light hv, where h is Planck's constant, v is the frequency of light, and hv represents the photon energy or light radiation in the photochemical reaction. The reaction formula is:

[0087] C 10H8O4+hv→C5H4O2+C5H4O2

[0088] The composition of the inner core drug release barrier includes 50% to 60% polycaprolactone as a sustained-release material, 20% to 25% gelatin for controlling the dissolution time, 5% to 10% silicon dioxide as a filler to adjust the mechanical strength and dissolution rate of the inner core, and 10% to 15% calcium chloride, which helps control the drug release process under microcurrent or photovoltaic environment;

[0089] The polycaprolactone of the inner core drug release barrier is hydrolyzed in an alkaline environment, and the reaction formula is:

[0090] C6H 10 O2+OH - →C5H8O4+H2O

[0091] Polycaprolactone is a degradable polymer that undergoes hydrolysis under alkaline conditions. - It will attack the ester bond of polycaprolactone, causing the polymer chain to break, generating small molecular products such as hydroxycarboxylic acid C5H8O4 and water. Through this reaction, polycaprolactone can slowly dissolve, thereby controlling the release rate of the agent. This reaction is gradually carried out in the alkaline environment of the water body, ensuring that the fluoride removal component in the second drug release area can be gradually released after the pH adjustment is completed, thus ensuring the effectiveness and timing of the agent.

[0092] Calcium chloride is very easy to dissolve in water, generating calcium ions and chloride ions. Calcium ions further combine with fluoride ions in the water to form insoluble calcium fluoride precipitates. This reaction is crucial to the defluoridation process. Calcium ions can quickly combine with fluoride ions in the drug release area 2 to generate stable precipitates, thereby effectively reducing the fluoride ion concentration in the water. The dissolution of calcium chloride will not affect the pH of the water, ensuring the stability of pH regulation.

[0093] CaCl2→Ca 2+ +2Cl -

[0094] Silicon dioxide is mainly used as a filler and sustained-release regulator in this system. Although it does not participate in chemical reactions, nor does it dissolve or react with other ingredients, its presence can improve the mechanical strength of the drug release barrier and prevent the barrier from dissolving too quickly under external stimuli. In addition, silicon dioxide helps to regulate the rate of drug release, ensuring that the drug can be gradually released throughout the process without being drastically affected by external conditions, thus ensuring the smooth progress of the entire reaction process.

[0095] The first drug release area includes a pH regulator, which includes 30% to 40% of sodium bicarbonate, 20% to 30% of boric acid and 10% to 20% of sodium hexametaphosphate. The sodium hexametaphosphate is used to adjust the pH value of the water body to a range of 6.5 to 8 after the outer polymer barrier is dissolved;

[0096] Drug release area 1 uses sodium bicarbonate to neutralize the acidity in the water and adjust the pH value. The reaction formula is as follows:

[0097] NaHCO3+H + →Na + +CO2+H2O

[0098] Subsequently, the alkalinity of the water body is adjusted by a buffering reaction between boric acid and hydroxide ions, and the reaction formula is as follows:

[0099]

[0100] Sodium hexametaphosphate in the pH regulator is used to inhibit premature reaction by complexing with calcium ions in the water. The reaction formula is as follows:

[0101] NaPO 36 +Ca 2+ → Complex

[0102] The second drug release area includes a defluoridation component, which is released after the inner core drug release barrier dissolves. The defluoridation component includes 5% to 10% calcium carbonate; 40% to 50% aluminum hydroxide; 20% to 25% calcium phosphate; and 10% to 15% polycaprolactone.

[0103] The aluminum hydroxide in the defluorination component reacts with fluoride ions to form fluoroaluminate precipitate:

[0104] AlOH3+3F - →AlF3+3OH -

[0105] Calcium ions and fluoride ions form calcium fluoride precipitate:

[0106] Ca 2+ +2F - →CaF2 (precipitation).

[0107] A preparation process of a highly efficient defluorination agent suitable for photovoltaic wastewater:

[0108] First, aluminum hydroxide and calcium phosphate are mixed to form a suspension or slurry in deionized water, and then calcium carbonate is added to the formed suspension or slurry to stabilize the mixture to ensure that the two are evenly distributed, and then the mixture is converted into solid particles by spray drying or freeze drying. Then, the dried defluorination particles are mixed with molten polycaprolactone to ensure that the surface of the particles is evenly coated with polycaprolactone to obtain defluorination particles coated with polycaprolactone;

[0109] The treated fluorine removal component particles are added to the melt of the inner core drug release barrier, and the temperature of the melt of the inner core drug release barrier is maintained at 80° C. to 100° C. The melt of the inner core drug release barrier is prepared by mixing polycaprolactone, gelatin, calcium chloride and silicon dioxide, and then adding the fluorine removal particles to the mixture and stirring.

[0110] The molten core drug-releasing barrier is coated on the outside of the defluorination component particles, and after cooling, the defluorination component-coated particles are obtained;

[0111] The coated core drug release barrier particles are placed in a drum mixer, and sodium bicarbonate, boric acid and sodium hexametaphosphate are gradually added as pH adjusters; the pH adjusters are attached to the surface of the particles by physical adsorption and are evenly distributed. This step ensures that after the outer layer is dissolved, the pH adjusters can quickly adjust the pH value of the water body;

[0112] Dissolving polyvinylidene fluoride, polyethylene terephthalate and chitosan in an organic solvent and heating and stirring to 60°C to 70°C; then coating the solution on the surface of the particles containing the pH regulator by rotary spraying to form a complete outer polymer barrier; the outer polymer barrier is gradually dissolved under microcurrent or ultraviolet conditions;

[0113] The composite particles containing the defluorination component, the inner core drug release barrier and the outer layer polymer barrier are placed in a vacuum drying oven, the temperature is controlled at 50°C to 70°C, and dried for 4 to 6 hours until the residual solvent in the particles is completely volatilized, and finally the particles are formed by granulation or tableting process to obtain defluorination agent particles;

[0114] After obtaining the defluorination agent particles, unprocessed particle data of the defluorination agent particles are obtained by using a spectral reflectance sensor and a laser particle size analyzer, the unprocessed particle data including the optical reflectance and particle size distribution of the particles, and the unprocessed particle data are standardized to obtain standardized particle data;

[0115] The standardized particle data is used as input values ​​and input into the K-means clustering algorithm for processing;

[0116] When processing standardized particle data, the K-means clustering algorithm first sets the initial cluster center of optical reflectance and particle size distribution, and through multiple iterations, assigns each defluorination agent particle to the nearest cluster center and continuously updates the center position;

[0117] By adjusting the number of clusters K, the maximum number of iterations, and the distance metric, the defluorination agent particles are reasonably distributed in different categories, and uniformity deviations are detected and marked.

[0118] Based on the K-means clustering results, the defluorination agent particle distribution information is fed back in real time to monitor the optical reflectivity and particle size distribution of the particles. By identifying the deviation between the reflectivity and the particle size, the mixing and coating process parameters in the preparation process are adjusted to ensure that the surface characteristics and size of the particles are consistent, thereby optimizing the release effect of the defluorination agent and the uniformity of the particles.

[0119] The optical reflectivity parameters include spectral reflectance ratio, reflection spectrum width and relative refractive index; the proposed spectral reflectance ratio is SRR; the proposed reflection spectrum width is RSW; the proposed relative refractive index is RI;

[0120] The spectral reflectance ratio SRR is used to measure the reflectivity of the particle surface to incident light. The calculation formula is:

[0121]

[0122] Among them I reflected is the reflected light intensity; I incident is the incident light intensity;

[0123] The reflection spectrum width RSW is used to measure the reflection performance of particles in different wavelength ranges and reflect the surface roughness. The calculation formula is:

[0124] RSW=λ max -λ min

[0125] where λ max is the upper wavelength of the reflection peak, that is, the position of the highest value of the reflectivity change within the wavelength range; min Indicates the lower wavelength of the reflection peak, that is, the position of the lowest value of the reflectivity change within the wavelength range;

[0126] The relative refractive index RI is used to describe the difference in refractive index between the granular material and the medium. The calculation formula is:

[0127]

[0128] where n particle is the refractive index of the particle; n medium is the refractive index of the medium.

[0129] The particle size distribution parameters include particle size variation coefficient, optical anisotropy and volume particle size distribution. The particle size variation coefficient is proposed to be CVD, the optical anisotropy is proposed to be OA, and the volume particle size distribution is proposed to be VDD.

[0130] The coefficient of variation of particle size, CVD, is used to indicate the degree of dispersion of particle size distribution. CVD is expressed as:

[0131]

[0132] where σ particle is the particle size standard deviation; d avg represents the average particle size;

[0133] Optical anisotropy OA is used to measure the difference in optical behavior of particles in different directions. The formula is:

[0134]

[0135] Where R ∥ is the reflectivity in the parallel direction, R ⊥ is the vertical reflectivity;

[0136] Volume particle size distribution VDD is used to express the distribution relationship between volume and particle size. The formula is:

[0137]

[0138] Where V i Indicates the volume fraction of a specific particle size; d i Indicates the value of the particle size.

[0139] The spectral reflectance ratio, reflectance spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy and volume particle size distribution in the unprocessed particle data were standardized;

[0140] The proposed standardized processing formula is:

[0141]

[0142] Where Z i is the normalized data point; X i are the original six parameter data, such as spectral reflectance ratio, relative refractive index, etc.; μ i is the mean of each parameter, σ i is the standard deviation of each parameter; through standardization, data of different dimensions can be processed within the same range.

[0143] When setting the cluster center, first initialize K cluster centers C1, C2, ..., C KEach cluster center corresponds to six dimensions, which represent spectral reflectance ratio, reflectance spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy and volume particle size distribution. The initial values ​​are:

[0144] C j =[SRR j ,RSW j ,RI j ,CVD j ,OA j ,VDD j ]

[0145] Among them C j represents the jth cluster center; SRR j 、RSW j , RI j 、CVD j OA j 、VDD j They represent the initial values ​​of the cluster center in six dimensions: spectral reflectance ratio, reflection spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy, and volume particle size distribution.

[0146] Calculate the distance from the particle to the cluster center and calculate the data x of each particle i The distance to each cluster center is calculated using the Euclidean distance formula;

[0147] x i =[SRR i ,RSW i ,RI i ,CVD i ,OA i ,VDD i ]

[0148]

[0149] Where d(x i ,C j ) is the particle x i To cluster center C j The distance of x ik Is particle x i The value of the kth parameter; C jk is the cluster center C j At the coordinate of the kth parameter, each particle is assigned to a nearby cluster center, that is, to the nearest cluster center, by calculating the distance;

[0150] Then update the cluster center. When all particles are allocated, update the position of each cluster center:

[0151]

[0152] Among them C j is the new position of the j-th cluster center; n j is the number of particles assigned to the jth class; x i is the particle belonging to the cluster; through this formula, the average value of each cluster is recalculated and the cluster center is updated until the cluster center no longer changes.

[0153] According to the specific application, the clustering effect is optimized by adjusting the clustering parameters, which include the number of clusters K, the upper limit of the number of iterations T, and the distance measurement method.

[0154] The cluster number K means that by testing different cluster numbers K, the cluster number that best reflects the uniformity of particles is found; the upper limit of the iteration number T is the maximum number of iterations, which is used to avoid excessive iterations affecting the efficiency of the algorithm; the distance measurement method means that in addition to the Euclidean distance, the Manhattan distance is used for testing, and the formula is:

[0155]

[0156] This approach is suitable for providing a robust distance metric when the optical and particle size parameters vary greatly;

[0157] SRR i is the spectral reflectance ratio of the i-th particle, which represents the ratio of incident light to reflected light and measures the surface smoothness; RSW i is the width of the reflection spectrum, which indicates the reflection distribution of particles in different wavelength ranges; RI i is the relative refractive index, describing the difference in refraction between the granular material and the medium; CVD i is the coefficient of variation of particle size, reflecting the degree of dispersion of particle size distribution; OA i is optical anisotropy, which characterizes the difference in optical properties of particles in different directions; VDD i It is the volume particle size distribution, which shows the relationship between particle volume and particle size.

[0158] This scheme designs a highly efficient defluorination agent suitable for photovoltaic wastewater, and ensures its highly efficient defluorination ability in the photovoltaic wastewater environment by configuring components and preparing processes; the agent is mainly composed of an outer polymer barrier, an inner core drug release barrier, a defluorination component and a pH regulator; the outer polymer barrier is composed of polyvinylidene fluoride, polyethylene terephthalate and chitosan; the main purpose of this material combination is to ensure the stability of the agent and its gradual release under specific conditions;

[0159] Among them, polyvinylidene fluoride is a material with strong chemical corrosion resistance. It can remain stable under the condition of no current or ultraviolet light, but it begins to gradually degrade under the action of electric field or ultraviolet light. In practical applications, such as photovoltaic wastewater treatment, the outer layer can be triggered to dissolve due to the possible current or sunlight in the wastewater, so that the agent can be released on demand; the addition of polyethylene terephthalate is mainly a response to the ultraviolet band. Under ultraviolet light, the molecular structure of polyethylene terephthalate begins to change, causing it to disintegrate, thereby accelerating the degradation of the outer polymer barrier; chitosan is used to enhance the structural strength of the outer barrier. At the same time, because of its good sustained-release properties, it can ensure that the drug will not suddenly release the drug during the dissolution process, but can be released smoothly and gradually. The selection and combination of this multi-layer material ensures that the dissolution and release timing of the drug can be accurately controlled in the complex photovoltaic wastewater environment;

[0160] The design of the inner core drug release barrier is to further control the release of the drug. The inner core is mainly composed of polycaprolactone, gelatin, calcium chloride and silicon dioxide. Polycaprolactone is a commonly used biodegradable material with sustained release characteristics, especially in an alkaline environment. Its decomposition rate is relatively slow. This is very critical because when the drug is released into the water body, the pH value of the water body usually changes gradually, especially under the action of the pH regulator, gradually tending to an alkaline environment. Polycaprolactone can gradually hydrolyze in this environment, ensuring that the fluoride removal components contained in the inner core can be slowly released to avoid The role of gelatin is to further enhance the sustained-release function. After combining with polycaprolactone, it forms a network structure, making the drug release process more controllable and stable. Calcium chloride is not only a part of the drug structure, but also provides the necessary calcium ions for the defluorination process. Calcium ions combine with fluoride ions in water during the defluorination reaction to form calcium fluoride precipitation, thereby reducing the concentration of fluoride ions in the water. Silicon dioxide is used as a filler to enhance the mechanical strength of the drug to ensure that the drug will not be released prematurely due to mechanical action during transportation, storage or in water.

[0161] The defluorination component is the core of the whole agent, which mainly includes aluminum hydroxide, calcium phosphate, calcium carbonate and a small amount of polycaprolactone. Aluminum hydroxide is a widely used defluorination material. It combines with fluoride ions in water to form insoluble fluoroaluminate, which then precipitates out to reduce the fluoride content in the water. Calcium phosphate, as an inorganic material, releases calcium ions and combines with fluoride ions to form calcium fluoride precipitation, which is another key defluorination pathway. The addition of calcium phosphate not only improves the defluorination efficiency of the agent, but also reacts with other ions in the water to further stabilize the defluorination process. The role of calcium carbonate is not limited to adjusting pH, it also acts as a buffer in the entire defluorination process to prevent drastic fluctuations in the pH value of the water body, thereby affecting the defluorination effect. A small amount of polycaprolactone is introduced into the defluorination component to further ensure that the defluorination component can be slowly released, which can extend the action time of the agent and ensure that the defluorination reaction can continue for a longer period of time, avoiding the loss of efficacy caused by a one-time rapid reaction.

[0162] The preparation process ensures that these components can be combined and coated to eventually form a stable granular medicine. First, the defluorination component is prepared. Aluminum hydroxide and calcium phosphate are mixed in deionized water to form a suspension. The mixture is stabilized by adding calcium carbonate. This step ensures that the mixture will not cause particle aggregation or sedimentation due to unstable components. The mixture is converted into solid particles by spray drying or freeze drying. The dried particles are not only uniform in size, but also able to maintain their chemical activity. The size and distribution of the particles are very critical for the coating of the medicine. Particles that are too large or too small will affect the subsequent coating process and the release behavior of the medicine. In this process, the particle size can be further accurately controlled by screening equipment to ensure that each particle has the same characteristics in the subsequent coating.

[0163] The dried defluorination particles are then mixed with molten polycaprolactone and coated at a temperature of 80°C to 100°C. The melting temperature of polycaprolactone is very important. Too high a temperature will cause the material to decompose, while too low a temperature will affect the uniformity of the coating. The stirring speed also needs to be precisely controlled to ensure that each particle can be evenly coated with polycaprolactone, thereby ensuring that the release time of the agent is consistent. If the stirring is not sufficient, the coating on the particle surface will be uneven, causing some particles to release the defluorination component prematurely, affecting the effect of the entire agent.

[0164] After coating the inner core drug release barrier, the particles are physically adsorbed with pH regulators (sodium bicarbonate, boric acid and sodium hexametaphosphate); the role of the pH regulator is to adjust the pH of the water body to keep it in the best defluoridation reaction environment; sodium bicarbonate can quickly neutralize the acidity in the water, boric acid plays a buffering role to prevent drastic fluctuations in the pH value, and sodium hexametaphosphate complexes calcium ions to prevent them from reacting with fluoride ions too early, thereby delaying the reaction; the combination of these three regulators can ensure that the agent can work effectively under different water quality conditions;

[0165] Finally, the coated particles are placed in a vacuum drying oven at a temperature of 50°C to 70°C for 4 to 6 hours to ensure that the residual solvent in the particles is completely volatilized; this step is to prevent the solvent from remaining in the drug and affecting the stability and effect of the drug; after drying, the particles are granulated or tableted to form stable drug particles, which not only have good storage stability, but also can maintain their physical and chemical properties in actual use;

[0166] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An efficient defluorination agent suitable for photovoltaic wastewater, comprising an outer polymer barrier and an inner core drug release barrier, wherein the outer polymer barrier is coated on the outside of the inner core drug release barrier, characterized in that: The outer polymer barrier and the inner core drug release barrier form a drug release region 1, and the inner cavity of the inner core drug release barrier is a drug release region 2; The outer polymer barrier is composed of 40% to 60% polyvinylidene fluoride, 20% to 30% polyethylene terephthalate and 10% to 20% chitosan, and the outer polymer barrier dissolves under the action of electric current or ultraviolet light; The polyvinylidene fluoride of the outer polymer barrier decomposes under the action of electric current or electric field. The reaction is stimulated by the electric field, which breaks the CF bond in the polyvinylidene fluoride molecular chain, releases by-products ethylene and hydrogen, and triggers the release of the agent. The reaction formula is: C2H2F2+H2O+E→F - +H2+C2H4 The polyethylene terephthalate of the outer polymer barrier is photolyzed under the action of ultraviolet HV, and the reaction formula is: C 10 H8O4+hv→C5H4O2+C5H4O2 The composition of the inner core release barrier includes 50% to 60% polycaprolactone, 20% to 25% gelatin, 5% to 10% silicon dioxide, and 10% to 15% calcium chloride; The polycaprolactone of the inner core drug release barrier is hydrolyzed in an alkaline environment, and the reaction formula is: C6H 10 O2+OH - →C5H8O4+H2O The first drug release area includes a pH regulator, which includes 30% to 40% of sodium bicarbonate, 20% to 30% of boric acid and 10% to 20% of sodium hexametaphosphate, and the sodium hexametaphosphate is used to adjust the pH value of the water body after the outer polymer barrier is dissolved; Drug release area 1 uses sodium bicarbonate to neutralize the acidity in the water and adjust the pH value. The reaction formula is as follows: NaHCO3+H + →Na + +CO2+H2O Subsequently, the alkalinity of the water body is adjusted by a buffering reaction between boric acid and hydroxide ions, and the reaction formula is as follows: Sodium hexametaphosphate in the pH regulator is used to inhibit premature reaction by complexing with calcium ions in the water. The reaction formula is as follows: NaPO 36 +Ca 2+ → Complex The second drug release area includes a defluoridation component, which is released after the inner core drug release barrier dissolves. The defluoridation component includes 5% to 10% calcium carbonate; 40% to 50% aluminum hydroxide; 20% to 25% calcium phosphate; and 10% to 15% polycaprolactone. The aluminum hydroxide in the defluorination component reacts with fluoride ions to form fluoroaluminate precipitate: <h2 style=";text-align:left;direction:ltr">AlOH3+3F<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> →AlF3+3OH<h2 style=";text-align:left;direction:ltr"> - Calcium ions and fluoride ions form calcium fluoride precipitate: Ca 2+ +2F - →CaF2 (precipitation).

2. A preparation process of a highly efficient defluorination agent suitable for photovoltaic wastewater, characterized in that: Firstly, aluminum hydroxide and calcium phosphate are mixed to form a suspension or slurry in deionized water, then calcium carbonate is added to the formed suspension or slurry, and then the mixture is converted into solid particles by spray drying or freeze drying. Then, the dried defluorination particles are mixed with molten polycaprolactone to obtain defluorination particles coated with polycaprolactone; The treated fluorine removal component particles are added to the melt of the inner core drug release barrier, and the temperature of the melt of the inner core drug release barrier is maintained at 80° C. to 100° C. The melt of the inner core drug release barrier is prepared by mixing polycaprolactone, gelatin, calcium chloride and silicon dioxide, and then adding the fluorine removal particles to the mixture and stirring. The molten core drug-releasing barrier is coated on the outside of the defluorination component particles, and after cooling, the defluorination component-coated particles are obtained; The coated core drug release barrier particles are placed in a drum mixer, and sodium bicarbonate, boric acid and sodium hexametaphosphate are gradually added as pH adjusters; the pH adjusters are attached to the surface of the particles by physical adsorption; Dissolving polyvinylidene fluoride, polyethylene terephthalate and chitosan in an organic solvent and heating and stirring to 60°C to 70°C; then coating the solution on the surface of the particles containing the pH regulator by rotary spraying to form a complete outer polymer barrier; the outer polymer barrier is gradually dissolved under microcurrent or ultraviolet conditions; The composite particles containing the defluorination component, the inner core drug release barrier and the outer layer polymer barrier are placed in a vacuum drying oven, dried until the residual solvent in the particles evaporates, and finally the particles are formed by granulation or tableting to obtain defluorination agent particles; After obtaining the defluorination agent particles, unprocessed particle data of the defluorination agent particles are obtained by using a spectral reflectance sensor and a laser particle size analyzer, the unprocessed particle data including the optical reflectance and particle size distribution of the particles, and the unprocessed particle data are standardized to obtain standardized particle data; The standardized particle data is used as input values ​​and input into the K-means clustering algorithm for processing; When processing standardized particle data, the K-means clustering algorithm first sets the initial cluster center of optical reflectance and particle size distribution, and through multiple iterations, assigns each defluorination agent particle to the nearest cluster center and continuously updates the center position; By adjusting the number of clusters K, the number of iterations, and the distance metric, uniformity deviations are detected and marked; Based on the K-means clustering results, the particle distribution information of the defluorination agent is fed back in real time to monitor the optical reflectivity and particle size distribution of the particles. By identifying the deviation between the reflectivity and the particle size, the mixing and coating process parameters in the preparation process are adjusted.

3. The preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater according to claim 2, characterized in that: The optical reflectivity parameters include spectral reflectance ratio, reflection spectrum width and relative refractive index; the proposed spectral reflectance ratio is SRR; the proposed reflection spectrum width is RSW; the proposed relative refractive index is RI; The spectral reflectance ratio SRR is used to measure the reflectivity of the particle surface to incident light. The calculation formula is: Among them I reflected is the reflected light intensity; I incident is the incident light intensity; The reflection spectrum width RSW is used to measure the reflection performance of particles in different wavelength ranges and reflect the surface roughness. The calculation formula is: RSW=λ max -l min where λ max is the upper wavelength of the reflection peak; min Indicates the lower wavelength of the reflection peak; The relative refractive index RI is used to describe the difference in refractive index between the granular material and the medium. The calculation formula is: where n particle is the refractive index of the particle; n medium is the refractive index of the medium.

4. The preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater according to claim 3, characterized in that: The particle size distribution parameters include particle size variation coefficient, optical anisotropy and volume particle size distribution. The particle size variation coefficient is proposed to be CVD, the optical anisotropy is proposed to be OA, and the volume particle size distribution is proposed to be VDD. The coefficient of variation of particle size, CVD, is used to indicate the degree of dispersion of particle size distribution. CVD is expressed as: where σ particle is the particle size standard deviation; d avg represents the average particle size; Optical anisotropy OA is used to measure the difference in optical behavior of particles in different directions. The formula is: Where R ∥ is the reflectivity in the parallel direction, R ⊥ is the vertical reflectivity; Volume particle size distribution VDD is used to express the distribution relationship between volume and particle size. The formula is: Where V i Indicates the volume fraction of a specific particle size; d i Indicates the value of the particle size.

5. The preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater according to claim 4, characterized in that: The spectral reflectance ratio, reflectance spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy and volume particle size distribution in the unprocessed particle data were standardized; The proposed standardized processing formula is: Where Z i is the normalized data point; X i are the original six parameter data; μ i is the mean of each parameter, σ i is the standard deviation of each parameter; through standardization, data of different dimensions can be processed within the same range.

6. The preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater according to claim 5, characterized in that: When setting the cluster center, first initialize K cluster centers C1, C2, ..., C K Each cluster center corresponds to six dimensions, which represent spectral reflectance ratio, reflectance spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy and volume particle size distribution. The initial values ​​are: C j [SRR j ,RSW j ,RI j ,CVD j ,OA j ,VDD j ] Among them C j represents the jth cluster center; SRR j 、RSW j , RI j , CVD j OA j 、VDD j They represent the initial values ​​of the cluster center in six dimensions: spectral reflectance ratio, reflection spectrum width, relative refractive index, particle size variation coefficient, optical anisotropy, and volume particle size distribution.

7. The preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater according to claim 6, characterized in that: Calculate the distance from the particle to the cluster center and calculate the data x of each particle i The distance to each cluster center is calculated using the Euclidean distance formula; x i =[SRR i ,RSW i ,RI i ,CVD i ,OA i ,VDD i ] Where d(x i ,C j ) is the particle x i To cluster center C j The distance of x ik Is particle x i The value of the kth parameter; C jk is the cluster center C j At the kth parameter coordinate, each particle is assigned to a nearby cluster center by calculating the distance; Then update the cluster center. When all particles are allocated, update the position of each cluster center: Among them C j is the new position of the j-th cluster center; n j is the number of particles assigned to the jth class; x i are particles belonging to this cluster.

8. The preparation process of a high-efficiency defluorination agent suitable for photovoltaic wastewater according to claim 7, characterized in that: The clustering effect is optimized by adjusting the clustering parameters, which include the number of clusters K, the upper limit of iterations T, and the distance measurement method. The cluster number K means that by testing different cluster numbers K, the cluster number reflecting the uniformity of particles is found; the upper limit of the number of iterations T is used to avoid excessive iterations affecting the efficiency of the algorithm; the distance measurement method means that in addition to the Euclidean distance, the Manhattan distance is used for testing, and the formula is: Where SRR i is the spectral reflectance ratio of the i-th particle, which represents the ratio of incident light to reflected light and measures the surface smoothness; RSW i is the width of the reflection spectrum, which indicates the reflection distribution of particles in different wavelength ranges; RI i is the relative refractive index, describing the difference in refraction between the granular material and the medium; CVD i is the coefficient of variation of particle size, reflecting the degree of dispersion of particle size distribution; OA i is optical anisotropy, which characterizes the difference in optical properties of particles in different directions; VDD i It is the volume particle size distribution, which shows the relationship between particle volume and particle size.

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