A method for designing an antifouling agent and an antifouling agent

Abstract

This invention proposes a method for designing scale inhibitors and a scale inhibitor thereof. The method includes calculating the binding energy between several organic monomers and calcium scale crystals, determining the first target organic monomer by combining the electrostatic potential energy diagrams of each organic monomer, and then calculating the binding energy between the molecular pairs and the ternary system and the calcium scale crystals step by step. This is combined with the corresponding electrostatic potential energy diagrams, the ESP extreme points of each group, and AIM analysis of the electron density ρ and Laplace electron density at the extreme points to finally obtain the first target ternary scale inhibitor system. This method is simple, reliable, and efficient, avoiding the use of phosphorus-containing elements or other harmful chemicals. The scale inhibitor obtained by this method has high and stable scale inhibition performance, does not contain phosphorus or other harmful chemicals, and is environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a method for designing a scale inhibitor and the scale inhibitor itself. Background Technology

[0002] Scaling has always been a serious challenge in industrial circulating cooling water systems, especially in environments with high temperatures and high scale ion content, where scale deposition and accumulation are more significant, severely threatening the stability and efficiency of industrial production. Existing scale inhibition methods mainly include physical and chemical methods. Physical scale inhibition methods include coating, ultrasonic, magnetic treatment, and electro-treatment, while chemical scale inhibition methods include adding acid, injecting CO2, and adding scale inhibitors. Among these methods, the most widely used and simplest to employ is adding scale inhibitors to the water.

[0003] Traditional scale inhibitors primarily work by affecting the solubility and crystal growth of hardness ions in water, thereby preventing or slowing down scale formation. Patents CN108996717A, CN108439618A, CN108439618A, and CN1526663A have proposed scale inhibitors suitable for industrial high-temperature water systems. However, it is worth noting that traditional scale inhibitors often contain environmentally harmful components such as phosphates, chromates, and nitrates, posing a certain pollution risk to water bodies and the environment. With increasingly stringent environmental regulations and standards, the design and development of efficient and environmentally friendly scale inhibitors has become an urgent priority.

[0004] However, the design and application of scale inhibitors still face some challenges. For example, little is known about the molecular-level relationships between scale inhibitors and water, scale, and metal surfaces; and there is a lack of in-depth understanding of the interactions and synergistic effects among different scale inhibitors. As a result, the design of scale inhibitors is usually based solely on experience and trial-and-error experimental screening. This approach to scale inhibitor design lacks systematicity and scientific rigor, and requires significant human and material resources, thus having certain limitations.

[0005] In recent years, with the rapid development of computer technology, the inventors of this application have introduced quantum chemistry and molecular dynamics simulation technology into the design of scale inhibitors, and proposed an efficient, green, economical and practical design method for scale inhibitors, scale inhibitors and their preparation methods, providing an innovative solution to the problem of calcium carbonate and calcium sulfate scale in industrial circulating cooling systems. Summary of the Invention

[0006] In view of this, this application proposes a scale inhibitor design method and a scale inhibitor. Through precise quantum chemical calculations and analysis, efficient and green scale inhibitors can be screened to address the problem of calcium carbonate and calcium sulfate scale at high temperatures in industrial circulating cooling systems.

[0007] To achieve the above technical objectives, this invention proposes a method for designing scale inhibitors, which includes the following steps:

[0008] (1) Calculate the binding energy of several organic monomers with calcium scale crystals respectively, and determine the first target organic monomer by combining the electrostatic potential energy diagram of each organic monomer.

[0009] (2) Combine the monomers in the first target organic monomer in pairs to obtain several molecular pairs; calculate the binding energy of the molecular pairs with the calcium scale crystals, the ESP extreme points of each group, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis, combined with the electrostatic potential energy diagram of the molecular pairs, determined the second target organic monomer;

[0010] (3) Combine the monomers in the second target organic monomer into several ternary systems; calculate the binding energy of the ternary system with the calcium scale crystal, the ESP extreme points of each group in the ternary system, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis yielded the first target ternary scale inhibitor system.

[0011] In the above technical solution, by gradually optimizing organic monomers, pairwise combinations of organic monomers, and triadic combinations of organic monomers from the atomic and molecular level, a scale inhibitor composition with better interaction between organic monomers and between monomers and calcium scale crystals is selected. Specifically, the first target organic monomer selected in step (1) not only has high binding energy and affinity, but also exhibits excellent scale inhibition performance under high temperature conditions; in step (2), the monomers in the first target organic monomer are combined in pairs and further optimized, and the second target organic monomer selected exhibits stronger affinity in the interaction with calcium scale crystals; subsequently, in step (3), the ESP extreme points of the groups in each ternary system are analyzed and AIM analysis is performed on them to determine the electron density ρ and Laplace electron density at the extreme points. By determining the binding energy between the system and calcium scale crystals, the first target ternary scale inhibitor system is obtained, thereby obtaining a scale inhibitor suitable for industrial circulating cooling water systems.

[0012] The above technical solution provides an efficient and green method for designing scale inhibitors, which has important practical application value for solving the scaling problem in industrial circulating cooling systems.

[0013] In another aspect of the present invention, a scale inhibitor obtained by the above-described scale inhibitor design method is provided.

[0014] In a further example of the present invention, the scale inhibitor may be a copolymer scale inhibitor MA-IA-VS or MA-HA-VS.

[0015] This invention discloses a scale inhibitor design method based on the interaction between organic monomers, molecular pairs, ternary systems, and calcium scale crystals, and the electrostatic potential energy diagram to screen scale inhibitors suitable for industrial circulating water cooling systems in high-temperature environments. This method is simple, reliable, and efficient, and can avoid the use of phosphorus-containing elements or other harmful chemicals. The scale inhibitor obtained by this method has high and stable scale inhibition performance, does not contain phosphorus elements or other harmful chemicals, and is green and environmentally friendly. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 The energy values ​​(kcal / mol) and electrostatic potential diagrams of the final conformations of molecular models containing unsaturated organic monomers with different functional groups in Example 2 are shown, wherein (c) maleic acid (MA), (d) itaconic acid (IA), (e) acrylic acid (AcA), (f) hydroxypropyl acrylate (HA), (g) vinyl acetate (VA), (h) sodium vinyl sulfonate (VS), (i) sodium methacrylate (MS), and (j) sodium p-styrene sulfonate (PS);

[0018] Figure 2 The energy values ​​(kcal / mol) of the final geometric conformation of the organic monomer molecular model with scale phase in Example 2 are shown.

[0019] Figure 3 The energy values ​​(kcal / mol) and electrostatic potential diagrams of the final conformations of the molecular-pair molecular model in Example 2 are shown, where (k)MA-IA, (l)AcA-VS, (m)HA-VS, (n)IA-AcA, (o)IA-VS, and (p)MA-HA.

[0020] Figure 4 The energy values ​​and final geometric conformation (kcal / mol) of the molecular pair model with scale phase in Example 2 are shown.

[0021] Figure 5 The diagram shows the stable configuration and electrostatic potential energy of the system in Example 2 where the molecular pair interacts with CaCO3, as well as the electron density ρ and Laplace electron density at the electrostatic potential energy extrema.

[0022] Figure 6 The diagram shows the stable configuration and electrostatic potential energy of the system in Example 2 where the molecular pair interacts with CaSO4, as well as the electron density ρ and Laplace electron density at the electrostatic potential energy extrema.

[0023] Figure 7The energy values ​​(kcal / mol) and electrostatic potential diagrams of the final conformation of the molecular model of the ternary system in Example 2 are shown, where (q)MA-IA-VS and (r)MA-HA-VS;

[0024] Figure 8 The energy values ​​and interaction energies (kcal / mol) of the final conformation between the ternary system and the calcium scale crystals in Example 2 are shown.

[0025] Figure 9 The stable configuration and electrostatic potential energy diagram of the MA-IA-VS interacting system with CaCO3 in Example 2 are shown, along with the electron density ρ and Laplace electron density at the electrostatic potential energy extremum.

[0026] Figure 10 The diagram shows the IRI scattering and isosurface of (a) MA-IA-VS-CaCO3 and MA-HA-VS-CaCO3, and (b) IRI scattering and isosurface of MA-IA-VS-CaSO4 and MA-HA-VS-CaSO4.

[0027] Figure 11 The following diagrams show the IGMH scattering and isosurface plots of MA-IA-VS and MA-HA-VS with CaCO3 in Example 3 (a); and the IGMH scattering and isosurface plots of MA-IA-VS and MA-HA-VS with CaSO4 in Example 3 (b).

[0028] Figure 12 The synthetic route of the scale inhibitor MA-IA-VS shown in Example 4 is illustrated.

[0029] Figure 13 The scale inhibition rates of (a) maleic acid-based scale inhibitors, (b) itaconic acid-based scale inhibitors, (c) the effect of initiator dosage on scale inhibition rate, (d) the effect of reaction temperature on scale inhibition rate, and (e) the effect of reaction time on scale inhibition rate are shown in Example 4.

[0030] Figure 14 This shows the effect of the dosage of scale inhibitor MA-IA-VS on the scale inhibition rate of CaCO3 and CaSO4;

[0031] Figure 15 The images show (a) the infrared spectrum of MA-IA-VS; (b) the thermogravimetric curve of MA-IA-VS; (c) SEM images of CaCO3 without MA-IA-VS and (d) with MA-IA-VS; (e) and (f) SEM images of CaCO3 without MA-IA-VS and with MA-IA-VS; (g) XRD pattern of CaCO3 with MA-IA-VS; and (h) XRD patterns of CaSO4 without MA-IA-VS and with MA-IA-VS.

[0032] Figure 16 The final adsorption configurations of scale inhibitor MA-IA-VS are shown in (a): CaCO3 (104) facet and (b): (110) facet, and in (c): CaSO4 (010) facet and (d): (100) facet. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more comprehensive description will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., not intended to limit the scope of protection of the invention.

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. To better illustrate the present invention and facilitate understanding of its technical solution, typical but non-limiting embodiments of the present invention are as follows.

[0035] Example 1

[0036] A method for designing scale inhibitors, comprising the following steps:

[0037] (1) Calculate the binding energy of several organic monomers with calcium scale crystals respectively, and determine the first target organic monomer by combining the electrostatic potential energy diagram of each organic monomer.

[0038] This embodiment identifies the organic monomer with the greatest scale inhibition potential based on the binding energy between the organic monomer and calcium scale crystals and the electrostatic potential energy diagram of the organic monomer. Optionally, the organic monomer is an unsaturated organic monomer containing different functional groups. Further optionally, the functional group includes one or more of carboxyl, ester, and sulfonic acid groups.

[0039] Optionally, the calcium scale crystals may comprise calcium carbonate and / or calcium sulfate.

[0040] Optionally, quantum mechanical simulations can be used to calculate the binding energy between the organic monomer and the calcium scale crystal, as well as the electrostatic potential energy diagram of the organic monomer.

[0041] Further, optionally, when performing quantum mechanical simulation calculations, the organic monomers are structurally optimized and their frequencies are calculated based on density functional theory and GAUSSIAN software; even further, the density functional theory is selected from the B3LYP method and the 6-311G(d,p) basis set in density functional theory.

[0042] Alternatively, the binding energy is calculated from ΔE, and a compensation method is used to correct the basis set superposition error (BSSE) using the formula shown in the figure. corrected As shown: AE = E 钙垢 / 阻垢剂体系 -(E阻垢剂 +E 钙垢 ) and E corrected =ΔE+E BSSE In the formula, ΔE represents the interaction energy between the scale inhibitor and the scaling system, E 钙垢 / 阻垢剂体系 E represents the total energy of the system with the scale inhibitor and calcium carbonate or calcium sulfate in the most stable configuration. 阻垢剂 E represents the energy of the most stable configuration of the scale inhibitor. 钙垢 E represents the energy of the most stable configuration of calcium carbonate and / or calcium sulfate. corrected E represents the corrected calculated interaction energy. BSSE The representative used a compensation method to compensate for the basis set error.

[0043] (2) Combine the monomers in the first target organic monomer in pairs to obtain several molecular pairs; calculate the binding energy of the molecular pairs with the calcium scale crystals, the ESP extreme points of each group, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis, combined with the electrostatic potential energy diagram of the molecular pairs, identified the second target organic monomer.

[0044] Optionally, this step also employs quantum mechanical simulations to calculate the binding energy between the molecular pairs and the calcium scale crystals, as well as the electrostatic potential energy diagram of the molecular pairs.

[0045] It should be noted that the atoms (AIM) in the molecule are a model for topological analysis of electron density in quantum chemistry. AIM is based on the electron density ρ at the bond critical point (BCP) and the Laplace electron density. To quantify the chelating effect of electron cloud concentration on metal ions.

[0046] It should be noted that in the actual design process of scale inhibitors, the influence of organic monomers on the physicochemical properties (such as solubility) of scale inhibitors can also be considered to determine a suitable second target organic monomer.

[0047] (3) Combine the monomers in the second target organic monomer into several ternary systems; calculate the binding energy of the ternary system with the calcium scale crystal, the ESP extreme points of each group in the ternary system, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis revealed the first target ternary scale inhibitor system, which is a scale inhibitor suitable for industrial circulating cooling water systems.

[0048] Optionally, this step also employs quantum mechanical simulations to calculate the binding energy between the ternary system and the calcium scale crystal, as well as the electrostatic potential energy diagram of the ternary system.

[0049] Further optional, in the specific scale inhibitor design process, in order to select a scale inhibitor type that better meets the requirements from the first target ternary scale inhibitor system containing multiple ternary systems, the scale inhibitor design method of this embodiment also includes step (4): performing interaction region indicator function analysis and independent gradient model electron density gradient analysis on the ternary system in the target ternary scale inhibitor system to select a second target scale inhibitor system, thereby selecting a scale inhibitor type with better performance based on the first target scale inhibitor system and according to specific requirements.

[0050] It should be noted that this refers to the Interaction Region Indicator Function (IRI) analysis. IRI examines chemical bonds and weak interactions in chemical systems and is an important tool for studying intermolecular interactions. The definition of IRI is shown in the following equation:

[0051]

[0052] Where ρ is the electron density; λ is the Laplace electron density. The IRI analysis plot is a 2D plot of IRI against sin(λ2)ρ, where λ2 is the second derivative of the electron density in the direction perpendicular to the bond.

[0053] The independent gradient model electron density gradient (IGMH) analysis describes a method for showcasing custom inter- and intra-fragment interactions, primarily utilizing isosurfaces of δg and its variants to represent interactions within chemical systems. For the three-dimensional case, g, g_IGM, and δg are defined as follows: bold r is the coordinate vector, i cycles through all atoms, the || symbol represents taking the modulus of the inner vector, ▽ is the vector differential operator, and ρi represents the electron density of atom i.

[0054] δg(r)=g IGM (r)-g(r)

[0055]

[0056]

[0057] δg can represent the interactions between all atoms in the current system. In order to focus on representing the interactions between specific interfragments and within specific fragments, the user-defined fragments in loop A can be defined with δg_inter and δg_intra respectively, as shown below.

[0058] δg inter ((r)=g lGM,inter (r)-g inter (r)

[0059]

[0060]

[0061] δg intra (r)=δg(r)-δg inter (r)

[0062] Example 2

[0063] This embodiment is based on the scale inhibitor design method shown in Embodiment 1, and demonstrates the scale inhibitor design process under specific working conditions. It should be noted that this embodiment is only a preferred embodiment and does not limit the scope of protection of this application.

[0064] A method for designing scale inhibitors, comprising the following steps:

[0065] Step (1): Calculate the binding energy between several organic monomers and calcium scale crystals, and determine the first target organic monomer by combining the electrostatic potential energy diagram of each organic monomer. In this embodiment, the organic monomers to be screened include unsaturated organic monomers containing carboxyl groups MA, IA, and AcA, unsaturated organic monomers containing ester groups HA and VA, and unsaturated organic monomers containing sulfonic acid groups VS, MS, and PS.

[0066] This implementation is based on density functional theory (DFT) and uses GAUSSIAN 09 software. The B3LYP / 6-311G(d,p) basis set is used to optimize the structure and calculate the frequency of the monomers. The optimal structure and the most stable configuration energy are obtained according to the principle of energy minimization. By drawing the van der Waals surface electrostatic potential energy diagram of each substance, the reaction sites of each substance are preliminarily determined, which provides a basis for the structural optimization of the interacting system.

[0067] Figure 1 The most stable configurations and energies of the organic monomers are shown, with the maximum value on the color chart being 0.144321 and the minimum value being -0.076682. Figure 1 In the electrostatic potential energy diagram of organic monomers, red indicates regions where positive charges accumulate, and blue indicates regions where negative charges accumulate. In carboxylic acids, the O, C=O, and HO groups near the carboxyl groups, and in sulfonic acids, the S=O group near the carboxyl groups, are covered by blue (-) isosurfaces. This is a result of the presence of isolated electron pairs and conjugated structures with high electron density. However, in CaCO3 and CaSO4, Ga... 2+ And sodium sulfonate + A red (+) isosurface is easily observed nearby, corresponding to a low electron density and a positive charge (electron-deficient region). After combining with the scaling system, analyzing the change in electron cloud density compared to the organic monomer itself allows us to determine its charge transfer, i.e., electronic transitions.

[0068] Figure 2This is a diagram showing the interaction energies between organic monomers and molecular pairs in a system interacting with calcium scale. A smaller calculated interaction energy indicates a lower system energy than the monomer energy, signifying greater system stability and stronger chelation. In the interaction between monomers and calcium scale crystals, geometric optimization was used to achieve the most stable conformation. Among carboxyl-containing monomers, MA exhibits good chelating ability for CaCO3 (ΔEI = -29.18 kcal·mol⁻¹) and CaSO4 (ΔEI = -31.41 kcal·mol⁻¹). HA, containing an ester group, shows even stronger chelating ability for CaCO3 (ΔEI = -37.91 kcal·mol⁻¹) and CaSO4 (ΔEI = -39.50 kcal·mol⁻¹). Although the interaction energy of VS with CaCO3 (ΔEI = -17.66 kcal·mol-1) and CaSO4 (ΔEI = -17.71 kcal·mol-1) is weaker than that of monomers containing carboxyl and ester groups, the introduction of sulfonic acid groups can make the designed product soluble in water, and the interaction energy of VS with sulfonic acid groups is greater than that of PS and MS.

[0069] Therefore, in this embodiment, the first target organic monomer includes MA, IA, AcA, VS, and HA.

[0070] Step (2): Combine the monomers in the first target organic monomers in pairs to obtain several molecular pairs; calculate the binding energy of the molecular pairs with the calcium scale crystals, the ESP extreme points of each group, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis, combined with the electrostatic potential energy diagram of the molecular pairs, identified the second target organic monomer.

[0071] Figures 3-4 Electrostatic potential diagrams and binding energies of the MA-IA, AcA-VS, HA-VS, IA-AcA, IA-VS, and MA-HA molecules with calcium scale crystals are shown. Comparative analysis of the interaction energies of acrylic acid monomers with calcium sulfate and calcium carbonate (-13.75 and -15.73 kcal / mol) and the interaction energies of the paired models IA-AcA and AcA-VS (-27.63 and -33.51 kcal / mol) suggests that acrylic acid does not provide a significant benefit in capturing divalent ions.

[0072] Comparative analysis Figures 5-6 Electron density ρ and Laplace electron density were calculated for the electrostatic potential extrema of the interaction system between the middle molecular pair and CaCO3 and CaSO4, as well as the extrema around the AIM pair group. The analysis of extreme points reveals maxima and minima. Maximum points correspond to regions of high electron cloud density. Compared to the molecular pairs exhibiting AcA, other molecular pairs show denser electron clouds within their regions, characterized by numerous and high electron density maxima, increased local potential, and enhanced chelation. It is important to note that functional groups within the molecular pairs are enriched in these regions, often due to Ca... 2+ It can have strong electron cloud overlap with these dense electron cloud regions, making it easier to interact with Ca. 2+ Chelation occurs, leading to enhanced Ca2+. 2 + Chelation effect. Simultaneously, the arrangement and spatial configuration of the groups make it difficult for the groups to effectively surround and coordinate Ca. 2+ The chelating ability is limited. For example, AcA-IA and MA-IA molecular pairs, which both contain only carboxyl groups, show lower affinity, which is indicated by a lower binding energy.

[0073] like Figures 5-6 In the lower part of the coordinate axis, the minimum value appears in the region of low molecular electron cloud density. Except for molecules containing AcA, most exhibit relatively few sparse electron cloud regions. Lower electron cloud density also means that the electron cloud distribution in the region is not very dense, making it difficult to correlate with Ca. 2+ A strong overlap of electron clouds occurs. Negative values ​​indicate a reduced electron density distribution and uneven distribution of group compactness and charge density in the molecular pair, which facilitates chelation between scale inhibitors and metal ions, reduces electron cloud repulsion, exposes chelation sites, and promotes interactions. In the interaction between MA-IA and CaCO3... A value close to -2.10E+08 indicates a high electron cloud density in the region, and Ca... 2+ It exhibits strong interactions with the carboxyl group or oxygen atom in the molecule. In molecular pairs where AcA appears... Most values ​​are close to -1.90E+01, indicating a relatively low electron cloud density and weak interactions in the region; consistent with the binding energy results, AcA does not provide a significant benefit in capturing divalent ions.

[0074] In this embodiment, the second target organic monomers include MA, IA, VS, and HA.

[0075] Step (3): Combine the monomers in the second target organic monomer into several ternary systems; calculate the binding energy between the ternary system and the calcium scale crystal, the ESP extreme points of each group in the ternary system, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis yielded the first target ternary scale inhibitor system. Several ternary systems constructed in this embodiment include MA-IA-VS, MA-HA-VS, MA-IA-HA, and IA-VS-HA.

[0076] like Figure 7 The electrostatic potential energy diagram shown indicates that the red region represents a positive charge accumulation area, and the blue region represents a negative charge accumulation area. In carboxylic acids, the O, C=O, and HO groups near the carboxyl groups, and in sulfonic acids, the S=O group near the carboxyl groups, are covered by blue (-) isosurfaces. This is a result of the presence of isolated electron pairs and conjugated structures with high electron density. However, in CaCO3 and CaSO4, Ga... 2+ Furthermore, red (+) isosurface coverage is easily observed near Na+ in sodium sulfonate, corresponding to low electron density and positive charge (electron-deficient region); the interaction system combined with calcium scale crystals is analyzed to determine the change in electron cloud density compared to the monomer itself, thus identifying charge transfer, i.e., electronic transition.

[0077] like Figure 8 As shown, the interaction energy between the scale inhibitor and the calcium scale crystals was calculated using the aforementioned interaction energy formula. These two ternary systems exhibited excellent binding energies in their interaction with the calcium scale crystals CaCO3 and CaSO4, which were -87.49 and -88.62 kcal / mol (MA-IA-VS) and -62.01 and -67.43 kcal / mol (MA-HA-VS), respectively. The high binding energy values ​​enabled them to effectively inhibit the growth of calcium scale crystals.

[0078] Further analysis of the extreme points of the electrostatic potential energy diagram, such as... Figure 9 As shown, the electron density at these extreme points is lower than that of molecular pairs ( Figures 5-6 The electron cloud density within the region increases significantly, as reflected in the electrostatic potential energy diagram of the groups and Ca. 2+ The white isosurfaces formed by the binding of molecules also represent strong interactions between them. In contrast, combinations of molecular pairs exhibit lower electron densities and Laplace electron densities, as well as weaker interactions. Furthermore, the reduction in minimum values ​​further strengthens the interaction strength between MA-IA-VS and MA-HA-VS.

[0079] In this embodiment, the first target ternary scale inhibitor system includes MA-IA-VS and MA-HA-VS.

[0080] Example 3

[0081] Based on the scale inhibitor design method shown in Example 2, this example further screens the types of scale inhibitors in the obtained first target ternary scale inhibitor system. Specifically, this example includes performing interaction region indicator function analysis and independent gradient model electron density gradient analysis on the ternary system in the target ternary scale inhibitor system to screen out the second target scale inhibitor system.

[0082] Figure 10 (a) illustrates the chemical systems of MA-IA-VS and MA-HA-VS with CaCO3, which involve not only chemical bonds but also intramolecular or intermolecular interactions. Within the interaction systems of MA-IA-VS and MA-HA-VS with CaCO3, the IRI clearly shows the interaction between the scale inhibitor molecules and the calcium scale crystals. The region near CaCO3 shows partial steric effects, indicated by the orange mapping color, while the green portion of the IRI isosurface signifies an attractive dispersion effect.

[0083] Specifically, in MA-IA-VS, the hydrogen bonds formed intramolecularly by groups such as carboxyl and sulfonic acid groups are clearly visible, and the three-dimensional regions resulting from their close contact are also clearly visible on the red isosurface. In CaCO3, Ca... 2+ The bonding regions are well revealed on the corresponding green-blue IRI isosurfaces. The absence of blue mapping points in the IRI of MA-HA-VS indicates a stronger binding force between MA-IA-VS and CaCO3. This observation is consistent with the large binding energy calculated by quantum chemical methods. Several green peaks appear in sign(λ²)ρ within the range of -0.025 to 0.00 au, corresponding to the weak interaction between MA-IA-VS and CaCO3. Several blue peaks also appear in the region below -0.25 au, corresponding to the isosurfaces. Figure 10 The two blue circular areas in (a) indicate that there is a strong interaction in this area.

[0084] Similarly, Figure 10 (b) The IRI scattering and isosurface plots of MA-IA-VS and MA-HA-VS with CaSO4 show that, within this geometry, there are significant van der Waals interactions between MA-IA-VS and MA-HA-VS and CaSO4, as well as within the two molecules. Furthermore, MA-IA-VS exhibits stronger interactions than the MA-HA-VS system, as evidenced by the blue isosurface plots and the IRI scattering diagrams. Therefore, IRI is extremely useful for studying chemical systems. IRI analysis can ideally reveal the smooth transitions between weak interactions and chemical bonds, clarifying the chemical bonds and weak interactions in MA-IA-VS and MA-HA-VS with CaSO4.

[0085] To avoid the influence of intramolecular interactions and further elucidate the interaction between the scale inhibitor and calcium scale crystals, this study used the IGMH method to reveal the weak interactions in the molecular system fragments. MA-IA-VS is a ternary copolymer containing carboxyl and sulfonic acid groups. IGMH analysis was performed on two systems containing CaCO3 and CaSO4, and δg was plotted with sign(λ2)ρ coloring. inter Scattering plots and isosurface plots, the results are as follows Figure 11 As shown. Note that, in order to reveal the interactions between the closely packed configurations in this molecule to the greatest extent possible, MA-IA-VS and MA-HA-VS, as well as CaCO3 and CaSO4, were defined as separate segments in the calculation.

[0086] As can be seen from the isosurface plot, several thin and wide isosurfaces appear between the two defined segments, ideally representing π-π packing interactions. As indicated by the red arrows, some regions on the isosurface appear dark blue, seemingly indicating a strong attractive interaction, due to the δg defined by IGMH. inter The isosurface clearly shows Ca 2+ The interactions with surrounding oxygen atoms, as shown by the light blue areas on the isosurface, indicate that the electron density in these regions is significantly higher than in typical diffuse interaction regions, thus demonstrating that the interaction between MA-IA-VS and calcium scale crystals is better than that between MA-HA-VS. The IGMH diagram clearly reveals the actual major interaction regions between the guest and host molecules; the green areas on the isosurface indicate very low electron density in these regions, meaning that the interaction is entirely dispersion-dominated. Furthermore, the green and orange areas on some atoms in the CaCO3 and CaSO4 molecules, respectively, vividly highlight the atoms that contribute significantly to host-guest recombination.

[0087] The second target scale inhibitor system obtained by the scale inhibitor design method in this embodiment includes MA-IA-VS.

[0088] Example 4

[0089] This embodiment demonstrates a method for preparing a scale inhibitor based on the scale inhibitor design method of Example 3. Specifically, the method for preparing the scale inhibitor includes the following steps:

[0090] S1, maleic acid, itaconic acid, and sodium vinyl sulfonate are dissolved in 30 ml of deionized water and heated under an inert atmosphere;

[0091] S2, when the temperature is heated to 82-85℃, ammonium persulfate initiator is added; the amount of initiator added is 8%-10% of the total mass of maleic acid, itaconic acid and sodium vinyl sulfonate added;

[0092] S3 was then reacted at 82-85℃ for 3.5-4 hours to obtain the copolymer scale inhibitor maleic acid-itaconic acid-vinyl sulfonic acid.

[0093] The synthetic route of the scale inhibitor MA-IA-VS is as follows: Figure 12 As shown, the preparation process includes: generating sulfate radicals by heating and decomposing the initiator ammonium persulfate; the free radicals attack the double bonds in maleic acid, itaconic acid, or sodium vinyl sulfonate molecules, thereby opening the double bonds and forming new free radicals; chain growth: the newly formed free radicals continue to attack the double bonds of other monomer molecules, repeating the process to increase the polymer chain; termination: when two free radicals meet, they will eliminate each other to form stable copolymer molecules, which is the termination reaction.

[0094] In an optional embodiment of this example, the amounts of reactants (molar ratio of components), reaction time, reaction temperature, and initiator dosage were optimized experimentally, such as... Figure 13 As shown, specifically: Figure 13 (a) At a reaction temperature of 353 K, a reaction time of 4 h, and an initiator dosage of 8% of the total mass fraction, five sets of experiments were set up with MA:IA:VS molar ratios of 1:1:0.25, 2:1:0.25, 3:1:0.25, 4:1:0.25, and 5:1:0.25 to show the scale inhibition rate of scale inhibitors with different maleic acid ratios; Figure 13 (b) At a reaction temperature of 353 K, a reaction time of 4 h, and an initiator dosage of 8% of the total mass fraction, five sets of experiments were set up with MA:IA:VS molar ratios of 3:1:0.25, 3:2:0.25, 3:3:0.25, 3:4:0.25, and 3:5:0.25 to show the scale inhibition rate of scale inhibitors with different itaconic acid ratios; Figure 13 (c) Five sets of experiments were conducted under the conditions of ensuring a reaction temperature of 353K, a reaction time of 4h, and a MA:IA:VS molar ratio of 3:3:0.25, with the initiator dosage being 4%, 6%, 8%, 10%, and 12% of the total monomer mass, respectively, to show the effect of initiator dosage on scale inhibition rate. Figure 13 (d) Based on (c), with ammonium persulfate accounting for 10% of the total mass of the monomer, five sets of experiments were set up with reaction temperatures of 70℃, 75℃, 80℃, 85℃ and 90℃ respectively, showing the effect of reaction temperature on scale inhibition rate. Figure 13 (e) Under the premise of ensuring that the amount of initiator is 10% of the total mass of monomers, the reaction temperature is 85℃, and the molar ratio is 3:3:0.25, five sets of experiments were set with reaction times of 3h, 3.5h, 4h, 4.5h, and 5h to show the effect of reaction time on scale inhibition rate.

[0095] Comparative analysis confirms that in this embodiment, the molar ratio of scale inhibitor MA:IA:VS can be selected as 3:3:0.25; the initiator dosage can be selected as 10%; the reaction temperature can be selected as 85℃; and the reaction time can be selected as 4h. Based on these results, this embodiment further measures the scale inhibition performance of the scale inhibitor (MA-IA-VS).

[0096] Specifically: Solution A and solution B are prepared using deionized water. Solution A has the following composition: C NaCl =18.75g / L, C CaCl2·H2O =27.75 g / L, solution B has the following composition: C NaCl =18.75g / L, C Na2SO4 =26.65 g / L; Add 130 ml of distilled water, 50 ml of solution A, a certain amount of scale inhibitor, and 50 ml of solution B to a 250 ml volumetric flask, and shake well; then dilute with distilled water to the mark, cap, and invert to mix. At the same time, a blank control group without scale inhibitor will also be prepared.

[0097] The solution in the 250 ml volumetric flask was then transferred to an Erlenmeyer flask. The Erlenmeyer flask was first kept at the set temperature for 0.5 h. After temperature equilibrium was achieved, the gas was released, the cap was tightened, and the solution was kept at the set temperature for 16 h. After the solution cooled to room temperature, the clear solution was filtered out, and the Ca2+ in the solution was titrated with disodium ethylenediaminetetraacetate. 2+ Content. Ca content in each group. 2+ The content was titrated three times, and the arithmetic mean of the parallel determinations was taken as the test result.

[0098] Ca 2+ The concentration is calculated using the following formula: Scale inhibition rate obtained: Plot the scale inhibition rate of the sample as a function of concentration. Figure 14 It can be confirmed that the scale inhibitor MA-IA-VS prepared in this embodiment can achieve high scale inhibition performance. When the dosage is 30 mg / L, the scale inhibition rate of CaCO3 can reach more than 99%; when the dosage is 7 mg / L, the scale inhibition rate of CaSO4 can reach more than 99%.

[0099] Furthermore, the structure and purity of the scale inhibitor MA-IA-VS prepared in this embodiment were tested.

[0100] Specifically: Weigh an appropriate amount of the final product, maleic acid-itaconic acid-sodium vinyl sulfonate copolymer scale inhibitor, prepared in this embodiment, and compress it into KBr mixed tablets. Analyze the tablets using a Nicoletti S20 Fourier transform infrared spectroscopy spectrometer (Thermo Scientific, USA) at 4000 cm⁻¹. -1 -400cm -1 The scale inhibitor samples were scanned within the specified range.

[0101] from Figure 15 (a) The infrared spectrum of MA-IA-VS shows that the chemical shifts of each functional group are consistent with the target product, indicating that the final product was obtained; the thermal stability of the scale inhibitor was analyzed using a thermogravimetric differential thermal analyzer (Hitachi TG / DTA6300), such as... Figure 15 As shown in (b), thermogravimetric analysis revealed that the scale inhibitor has good thermal stability at 120°C.

[0102] A scanning electron microscope, model MIRALMS, manufactured by Tescan in the Czech Republic, was used to observe, for example... Figure 15 (cf) The surface morphology of calcium carbonate and calcium sulfate in the blank and after adding scale inhibitors is shown in the experiment. The instrument used was an X-ray diffractometer, model SmartlabSE, manufactured by Rigaku, Japan. Figure 15 (gh) shows the XRD spectra of CaCO3 and CaSO4 crystals after the addition of MA-IA-VS. These diffraction peaks after the addition of MA-IA-VS correspond to the characteristic peaks of aragonite, calcite, and aragonite, indicating that MA-IA-VS can distort the orientation of calcium carbonate crystals and change the crystal structure. These results are consistent with the SEM results, proving the scale inhibition effect of MA-IA-VS.

[0103] Furthermore, this embodiment uses molecular dynamics simulations to demonstrate the interaction between the scale inhibitor MA-IA-VS and calcium carbonate and calcium sulfate crystals.

[0104] Specifically, the adsorption process of the scale inhibitor MA-IA-VS on two crystal faces of two types of calcium scale crystals was calculated using kinetic calculation methods, and the results are as follows: Figure 16 As shown; it should be noted that water molecules have been hidden in the figure to better observe the adsorption configuration of the scale inhibitor on the crystal surface.

[0105] The final adsorption configuration shows that the scale inhibitor is adsorbed onto the crystal facets. This alters the surface characteristics of the crystals, distorting the surface and thus making it unsuitable for further crystal growth, thereby achieving the purpose of scale inhibition. Interaction energy E interaction and binding energy E bin E is calculated using the following formula interaction =E total -(E surface +E polymer+water ) and E bin =-E interaction Table 1 shows the binding energy (kcal / mol) between the scale inhibitor MA-IA-VS and the surface of calcium scale crystals at 353 K.

[0106] Table 1

[0107]

[0108]

[0109] Table 1 confirms that all binding energies are positive, indicating that the bonding process between the scale inhibitor and the crystal is exothermic. This suggests that the scale inhibitor easily adsorbs onto the crystal, thus affecting or even preventing crystal growth. Deformation energy ΔE deform ΔE can be calculated using the following formula: deform =ΔE polymer-bin -E polymer Table 2 shows the ΔE of MA-IA-VS and the crystal surface at 353K. deform (kcal / mol).

[0110] Table 2

[0111]

[0112] Combination Figure 16 It can be confirmed that the crystal deforms when the scale inhibitor interacts with the crystal face. Calculations based on Tables 1-2 show that the scale inhibitors adsorbed on the crystal face are all distorted, but the absolute value of the non-bonded interaction energy is much greater than the corresponding deformation energy of the scale inhibitor. Therefore, both scale inhibitors can overcome their own deformation on both crystal faces of the two crystals and then tightly bond with the crystal surface, thereby affecting the normal growth of the crystal and achieving the purpose of scale inhibition.

[0113] It should be noted that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the present invention to these descriptions; the dimensional data in this embodiment do not necessarily limit the technical solution, but merely illustrate one specific working condition. For those skilled in the art, various simple improvements and modifications can be made without departing from the concept of the present invention, and all such improvements and modifications should be considered to fall within the scope of protection of the present invention.

Claims

1. A method of scale inhibitor design, characterized by, Includes the following steps: (1) Calculate the binding energy of several organic monomers with calcium scale crystals respectively, and determine the first target organic monomer by combining the electrostatic potential energy diagram of each organic monomer. (2) two-by-two combination of monomers in the first target organic monomer to obtain several molecular pairs; calculate the binding energy of the molecular pairs with calcium scale crystals, the ESP extreme points of each group, and perform AIM analysis of the electron density p and Laplace electron density at the extreme points analysis, determine the second target organic monomer in combination with the electrostatic potential energy diagram of the molecular pair; (3) Combine the monomers in the second target organic monomer into several ternary systems; calculate the binding energy of the ternary system with the calcium scale crystal, the ESP extreme points of each group in the ternary system, and perform AIM analysis on the electron density ρ and Laplace electron density at the extreme points. Analysis yielded the first target ternary scale inhibitor system.

2. The scale inhibitor design method according to claim 1, characterized in that, The organic monomers are unsaturated organic monomers containing different functional groups.

3. The scale inhibitor design method according to claim 2, characterized in that, The different functional groups include one or more of carboxyl, ester, and sulfonic acid groups.

4. The scale inhibitor design method according to claim 1, characterized in that, The calcium scale crystals include calcium carbonate and / or calcium sulfate.

5. The scale inhibitor design method according to claim 1, characterized in that, Quantum mechanics simulations were used to calculate the binding energy between organic monomers, molecular pairs, ternary systems and calcium scale crystals, as well as the electrostatic potential energy diagrams of organic monomers, molecular pairs and ternary systems.

6. The scale inhibitor design method according to claim 5, characterized in that, When using quantum mechanical simulation calculations, structural optimization and frequency calculations are performed based on density functional theory and GAUSSIAN software.

7. The scale inhibitor design method according to claim 6, characterized in that, The density functional theory is selected from the B3LYP method and the 6-311G(d,p) basis set in density functional theory.

8. The scale inhibitor design method according to claim 1, characterized in that, It also includes performing interaction region indicator function analysis and independent gradient model electron density gradient analysis on the ternary system in the target ternary scale inhibitor system to screen out the second target scale inhibitor system.

9. The scale inhibitor obtained by the scale inhibitor design method according to any one of claims 1-8.

10. The scale inhibitor prepared by the scale inhibitor design method according to claim 9, characterized in that, The scale inhibitor is a copolymer scale inhibitor MA-IA-VS or MA-HA-VS.

Images