A computing method, device and storage medium for evaluating migration potential of microplastics in porous media

Abstract

The application discloses a kind of evaluation microplastics in porous medium migration potential calculation method, device and storage medium, belong to environmental monitoring and simulation technical field.For solve the problem that existing technology uses spherical hypothesis to lead to inaccurate evaluation, the method of the present application includes: using parameterized mathematical model to quantize the three-dimensional profile of microplastics, to continuously describe its geometric form;Based on the three-dimensional profile, by surface element integration etc. Method will microplastics surface be discretized into multiple surface units, and the interaction of all surface units and porous medium is integrated or summed to calculate total interaction energy barrier;Compare the energy barrier with the energy barrier of preset reference geometric body under the same condition, obtain standardized migration potential criterion.The present application overcomes the limitation of traditional spherical hypothesis, can continuously, quantitatively evaluate the migration potential of microplastics of different shapes, significantly improve the accuracy and reliability of prediction.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring and simulation technology, and in particular to a calculation method, apparatus and storage medium for evaluating the migration potential of microplastics in porous media. Background Technology

[0002] Microplastics, as a novel pollutant, have attracted global attention due to their widespread presence in environmental media such as soil and groundwater. The migration capacity of microplastics in porous media (such as soil and aquifers) is a key factor determining their environmental risk and fate. Accurately assessing the migration potential of microplastics is crucial for predicting their pollution extent and developing effective groundwater protection strategies.

[0003] Currently, research methods for assessing the migration potential of microplastics mainly include laboratory column simulation experiments and computational predictions based on theoretical models. Among them, computational models based on the extended DLVO (Derjaguin-Landau-Verwey-Overbeek) theory are widely used to predict the retention or migration behavior of microplastics by analyzing the interaction energy between microplastics and media particles.

[0004] However, existing technologies commonly suffer from a fundamental flaw when applying theoretical models for calculations: the "sphericity assumption." To simplify calculations, existing models typically approximate microplastics of various shapes (such as fibers, fragments, and irregular particles) as ideal spheres. This simplification deviates significantly from reality, as microplastics in the real environment exhibit extremely diverse geometries, and their shape is a key factor influencing their hydrodynamic behavior and how they interact with the medium.

[0005] Due to the limitations of the "spherical assumption," existing methods cannot accurately quantify the impact of shape on the migration process. For example, microplastics of different shapes exhibit significant differences in their orientation in fluids, effective contact area with porous media, and response under specific water chemistry conditions (such as the presence of divalent cations). These differences are precisely the core determinants of their final migration distance and distribution pattern. Therefore, existing technologies lack an assessment framework that can effectively integrate the true and continuous geometric characteristics of microplastics, leading to significant discrepancies between their predictions and field observation data, making it difficult to reliably assess the environmental risks of microplastics. Summary of the Invention

[0006] To address the technical problem in existing technologies where the "spherical assumption" prevents accurate assessment of the migration potential of microplastics with irregular shapes, this invention provides a calculation method, apparatus, and storage medium for evaluating the migration potential of microplastics in porous media. This method quantitatively considers the continuous geometric characteristics of microplastics, thereby significantly improving the accuracy of migration potential assessment.

[0007] This invention provides a computational method for evaluating the migration potential of microplastics in porous media, comprising the following steps: quantifying the three-dimensional profile of the microplastic using a parametric mathematical model, wherein the parametric mathematical model uses a set of parameters to continuously describe the geometry of the microplastic; based on the three-dimensional profile, discretizing the surface of the microplastic into multiple surface units, and integrating or summing the interactions between all surface units and the porous media to calculate the total interaction energy barrier between the microplastic and the porous media; comparing the total interaction energy barrier with the energy barrier of a preset reference geometry under the same conditions to obtain a standardized migration potential criterion. Through the above steps, this invention transforms the complex geometry of microplastics into calculable parameters, calculates the energy barrier that reflects the influence of shape, and finally obtains a universal criterion through standardization, achieving an accurate and quantitative evaluation of the migration potential of non-spherical microplastics.

[0008] In one specific implementation, the parameterized mathematical model is a hyperellipsoidal model, and the set of parameters includes principal semi-axis and shape index. The hyperellipsoidal model can flexibly and continuously describe various three-dimensional morphologies, from cubes to octahedrons and from sharp to rounded shapes, by adjusting a few parameters such as the shape index. It is well-suited for uniformly quantifying microplastics with diverse morphologies, such as particles, fragments, and fibers.

[0009] Furthermore, the integration or summation of the interactions between all surface units and the porous medium is achieved through the surface element integration method. This method decomposes the complex interaction problem between non-spherical bodies into the summation of interactions between a large number of "point-to-surface" or "surface-to-surface" units, thereby enabling the accurate calculation of the total interaction energy between a microplastic of any given shape and the medium surface.

[0010] Specifically, the interactions can include at least one of van der Waals forces, electrostatic double-layer forces, and Lewis acid-base forces. Comprehensive consideration of these major interfacial interactions ensures that the calculated total interaction energy barrier more closely matches physicochemical realities, thereby improving the accuracy of the assessment.

[0011] Optionally, the preset reference geometry is a sphere with an equivalent volume or surface area to the microplastic. Using an equivalent sphere as a benchmark can make the calculated migration potential criterion dimensionless, eliminating the influence of factors such as particle size, and providing a unified and directly comparable evaluation standard for the migration potential of microplastics of different shapes and sizes.

[0012] To further improve the accuracy of the assessment, the method of the present invention may further include: calculating the orientation of the microplastics in the flow field based on fluid dynamics, and introducing an orientation correction factor to correct the total interaction energy barrier. This step considers the influence of the dynamic attitude changes of non-spherical particles during the flow process on their interaction with the medium, making the model closer to real migration scenarios.

[0013] Furthermore, the method of the present invention also includes classifying the migration potential of microplastics into multiple levels based on the value of the standardized migration potential criterion. This classification approach transforms complex calculation results into intuitive and easy-to-understand risk levels, facilitating rapid decision-making by environmental managers.

[0014] For example, the multiple levels may include: when the value of the standardized migration potential criterion is less than 1, the migration potential is determined to be at a severe inhibition level; when the value of the standardized migration potential criterion is greater than or equal to 1 and less than or equal to 2, the migration potential is determined to be at a moderate inhibition level; and when the value of the standardized migration potential criterion is greater than 2, the migration potential is determined to be at a limited inhibition level. These specific numerical thresholds are derived based on extensive calculations and experimental data verification, providing clear judgment criteria for risk assessment.

[0015] Furthermore, the method of the present invention may also include: constructing a shape index-dependent two-site migration prediction model based on the relationship between the migration potential criterion and shape parameters, for predicting the penetration curve of microplastics in porous media. This enables the present invention not only to assess the "potential" of migration, but also to further predict its dynamic migration process in porous media over time and space, providing richer and more detailed prediction information.

[0016] To assess the impact of specific environmental factors, the method of this invention may further include: using the concentration of divalent cations as a hydrochemical condition parameter when calculating the total interaction energy barrier; and outputting a quantitative assessment result of the retention effect of the divalent cations on microplastics of different shapes based on the standardized migration potential criterion. This enables the present invention to serve as a shape-sensitive assessment tool for predicting differences in the migration risk of microplastics of different shapes in calcium- and magnesium-rich hard water or soil environments.

[0017] Accordingly, the present invention also provides a computational device for evaluating the migration potential of microplastics in porous media, comprising: a profile quantization module for quantifying the three-dimensional profile of the microplastic using a parametric mathematical model; an energy calculation module for calculating the total interaction energy barrier between the microplastic and the porous media based on the three-dimensional profile; and a criterion construction module for comparing the total interaction energy barrier with the energy barrier of a preset reference geometry to obtain a standardized migration potential criterion. This device can automatically execute the above method, achieving efficient evaluation of the migration potential of microplastics.

[0018] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method as described in any of the preceding claims.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: First, this invention is the first to propose using a parametric mathematical model (such as a hyperellipsoidal model) to continuously and quantitatively describe the three-dimensional profile of microplastics, and combining this with methods such as surface element integrals to calculate their interaction energy, completely breaking free from the constraints of the traditional "spherical assumption." This allows the assessment of the migration potential of microplastics to truly reflect the influence of their geometric morphology, greatly improving the accuracy and reliability of predictions.

[0020] Second, this invention constructs a standardized, dimensionless migration potential criterion by comparing the energy barrier of the target microplastic with the energy barrier of a reference geometry (such as an equivalent sphere). This criterion is universal and comparable, and experiments have shown that it exhibits a perfect monotonically negative correlation with the experimental retention coefficient of the microplastic, proving its effectiveness as the "gold standard" for migration potential.

[0021] Third, this invention provides a scalable computational framework that can easily incorporate factors such as hydrodynamic effects (e.g., orientation correction) and complex water chemistry conditions (e.g., divalent cation concentration). For example, this invention can quantitatively reveal the significant differences in the retention effects of divalent cations on microplastics of different shapes, providing a shape-sensitive and accurate tool for microplastic risk assessment in specific environments (e.g., hard water areas).

[0022] Fourth, this invention not only assesses migration potential but also enables the construction of more advanced dynamic migration models (such as shape index-dependent two-site migration prediction models) to predict the complete penetration behavior of microplastics in porous media. This establishes a quantitative bridge between microscopic interfacial mechanisms and macroscopic pollutant migration patterns, providing strong scientific support for in-depth research and precise control of microplastic pollution. Attached Figure Description

[0023] Figure 1This is a schematic diagram illustrating the core concept of an embodiment of the present invention.

[0024] Figure 2 The overall flowchart of the evaluation method provided in the embodiments of the present invention is shown.

[0025] Figure 3 This is a schematic diagram illustrating the principle of calculating the interaction energy barrier using surface element integrals, as provided in an embodiment of the present invention.

[0026] Figure 4 This diagram illustrates the correlation between the standardized migration potential criterion and experimental measurement results provided in this embodiment of the invention.

[0027] Figure 5 This is a schematic diagram illustrating the quantitative comparison of the effects of divalent cations on the retention effect of microplastics of different shapes, provided in an embodiment of the present invention.

[0028] Figure 6 A system block diagram of a computing device provided in an embodiment of the present invention. Detailed Implementation

[0029] To address the problem that existing technologies for assessing microplastic migration potential often simply categorize microplastics into fibers, fragments, particles, etc., ignoring the significant differences in the geometric contours of microplastics within the same category, leading to inaccurate assessment results, this invention provides a novel computational method. Existing models are mostly based on the idealized assumption of sphericity, making them difficult to apply directly to microplastic samples with diverse morphologies in the field, thus limiting their application value in real-world environmental risk assessment. This invention aims to establish a quantitative link between the actual distribution patterns of microplastics in the environment and their interfacial retention mechanisms by introducing continuous shape descriptors, thereby achieving accurate and rapid screening of microplastic migration potential.

[0030] In the technical solution of this invention, to achieve accurate description of the complex three-dimensional contours of microplastics, the concept of a "parametric mathematical model" is introduced. This parametric mathematical model is a mathematical model capable of continuously and quantitatively describing geometric morphology using a set of adjustable parameters, overcoming the limitations of traditional discrete classification methods. A preferred example is the hyperellipsoidal model, which, through parameters such as principal semi-axis and shape index, can describe continuous morphological changes from cube to octahedron, from sharp to rounded. Figure 1 As shown, microplastics of various shapes in the real environment, such as fibers, fragments, and particles, can be accurately mathematically represented using this model, and their quantified shape indices can be extracted. This quantification lays a solid foundation for subsequent mechanical calculations.

[0031] To calculate the interaction between non-spherical microplastics and the environmental medium, this invention proposes the concept of a "total interaction energy barrier." This refers to the total energy barrier that microplastics need to overcome during migration, formed by the combined effects of various interfacial forces between them and the porous medium. The size of this energy barrier directly determines how easily microplastics are captured or retained by the porous medium. Due to the irregular shape of microplastics, traditional calculation methods based on macroscopic geometry are no longer applicable. Therefore, this invention discretizes the continuous surface of the microplastic into multiple tiny area units, i.e., surface units 11, and integrates or sums the interaction forces of each unit to accurately calculate the total energy barrier.

[0032] To ensure comparability of evaluation results for microplastics of different shapes and sizes, this invention further constructs a "standardized migration potential criterion." This criterion compares the total interaction energy barrier of the target microplastic under specific environmental conditions with the energy barrier of a "pre-defined reference geometry" (e.g., a sphere of equal volume) under the same conditions, resulting in a dimensionless index. This index eliminates the scale effect of absolute energy values, enabling researchers to uniformly compare and evaluate the migration potential across different experimental conditions and microplastic types. The construction of this criterion is crucial for achieving high-throughput screening and risk ranking of a large number of field-tested microplastic samples.

[0033] The technical solution of the present invention will be described in detail below. For example... Figure 2 As shown, in one aspect of the present invention, a computational method for evaluating the migration potential of microplastics in porous media is provided. The core framework of this method includes three key steps. First, in step S102, a parametric mathematical model is used to quantify the three-dimensional profile of the microplastic. This parametric mathematical model uses a set of parameters to continuously describe the geometry of the microplastic. This step solves the problem that the prior art cannot quantitatively describe the continuous shape changes of microplastics. Next, in step S103, based on the three-dimensional profile obtained in the previous step, the surface of the microplastic is discretized into multiple surface units, and the interaction between all surface units and the porous media is integrated or summed to calculate the total interaction energy barrier between the microplastic and the porous media. This step overcomes the limitations of the traditional spherical assumption and can accurately calculate the interaction energy of microplastics of arbitrary shapes. Finally, in step S105, the calculated total interaction energy barrier is compared with the energy barrier of a preset reference geometry under the same conditions (calculated in step S104) to obtain a standardized migration potential criterion, and the migration potential level can be output in step S106. These three steps together form a complete logical chain from shape quantification to energy calculation and then to standardized assessment, providing a systematic solution for accurately assessing the risk of microplastic migration.

[0034] Furthermore, based on the above scheme, the parameterized mathematical model is preferably a hyperellipsoidal model. This model is defined by a mathematical equation, whose Cartesian coordinate form can be expressed as: (x / a)^n + (y / b)^n + (z / c)^r = 1. In this equation, x, y, and z are spatial coordinates; a, b, and c are the lengths of the principal semi-axes of the microplastic in the three principal axis directions, which together determine its size and aspect ratio; while n and r are two dimensionless shape indices, which control the geometric shape of the microplastic in the equatorial and meridional planes, respectively. For example, by adjusting the values ​​of the shape indices n and r (e.g., in the range of 0 to 6), various transitional shapes from sharp octahedrons to rounded spheres, or from square cross-sections to circular cross-sections, can be continuously generated. Through this model, different types of microplastics such as fibers, fragments, and particles observed in the field can be mapped to specific shape index n values. For example, experiments have found that the median shape index n value for PE fibers is approximately 4.28, for fragments it is approximately 2.90, and for particles it is approximately 1.95. This continuous parametric description method makes the shape characteristics of microplastics no longer a vague qualitative classification, but a precise input that can be used for quantitative calculations and model building.

[0035] In a preferred embodiment, the step of integrating or summing the interactions of all surface units with the porous medium is implemented using a surface element integration method. For example... Figure 3 As shown, this method first meshes the surface of the microplastic 10, defined by the hyperellipsoidal model, discretizing it into a large number of surface units 11. Then, for each surface unit 11, the interaction force between it and the porous medium surface 20 is precisely calculated. This interaction force is the resultant force of various interfacial forces, specifically including van der Waals forces F_vdW, electrostatic double-layer forces F_EDL, Lewis acid-base interactions, and in some high-precision calculations, Born repulsion, etc. By numerically integrating or summing the interaction energy of all surface units on the entire microplastic surface, a total interaction energy barrier dependent on the precise shape of the microplastic and its spatial orientation is finally obtained. This method fundamentally solves the problem of calculating the interactions of non-spherical objects, and its calculation accuracy is far higher than that of traditional spherical or ellipsoidal approximation models.

[0036] In another embodiment, to construct a standardized criterion, the preset reference geometry is set as a sphere with an equivalent volume or surface area to the microplastic. A sphere is chosen as the reference because it is the simplest geometrically and most uniformly shaped form, and its interaction theory with the environment is the most mature and well-established. By calculating the energy barrier of an ideal sphere with the same volume or surface area as the target microplastic under identical environmental conditions (such as water chemistry, porous media properties, etc.) and using it as a benchmark, the influence of size and environmental factors on the absolute value of the energy barrier can be effectively eliminated. Thus, the standardized migration potential criterion, which can be calculated using the formula Φ=V_barrier / V_barrier(sphere), becomes a dimensionless index that purely reflects shape and orientation effects, greatly enhancing the comparability between different research results.

[0037] To more closely approximate real physical processes, the method of this invention may further include an orientation correction step. In pore flow within porous media, non-spherical microplastics do not migrate in a fixed posture but rather rotate and orient themselves due to hydrodynamic effects. This orientation change significantly affects their effective contact area and interaction strength with the porous media surface. Therefore, this embodiment first simulates the orientation trajectory of microplastics in a specific flow field (e.g., a flow field at a specific velocity in a column experiment filled with quartz sand) based on hydrodynamic calculations, such as solving the Jeffery equation in finite element software. Based on the simulated dominant orientation distribution, an orientation correction factor can be calculated, which is a function of the aspect ratio and shape index of the microplastic. Finally, this correction factor is applied to the total interaction energy barrier calculated above, thereby obtaining a more accurate energy barrier value that considers the dynamic orientation effect in the flow field. This design makes the model's predictions more consistent with actual physical transport processes.

[0038] This invention also provides a method for interpreting and applying assessment results. After calculating a standardized migration potential criterion, the method further includes a step of classifying the migration potential of microplastics into multiple levels based on the value of the criterion. This classification makes the assessment results more intuitive and facilitates risk decision-making for environmental managers. As a specific classification scheme, the multiple levels may include: when the value of the standardized migration potential criterion is less than 1, the migration potential is determined to be at a severe inhibition level, indicating that microplastics of this shape are extremely easily retained compared to spheres of equal volume; when the value of the standardized migration potential criterion is greater than or equal to 1 and less than or equal to 2, the migration potential is determined to be at a moderate inhibition level; when the value of the standardized migration potential criterion is greater than 2, the migration potential is determined to be at a limited inhibition level, indicating that microplastics of this shape have a relatively high migration capacity. This clear numerical threshold classification provides a clear operational guide for risk assessment.

[0039] To bridge the gap from static migration potential assessment to dynamic migration process prediction, the method of this invention may further include the step of constructing a prediction model. Specifically, the method further includes: constructing a shape index-dependent two-site migration prediction model based on the quantitative relationship between the standardized migration potential criterion and shape parameters (such as shape index). This model is a mathematical model that considers two different retention mechanisms (e.g., reversible and irreversible retention), and its key parameters (such as retention coefficients) are no longer empirical constants but are directly related to the shape index or standardized migration potential criterion calculated by this invention. In this way, once the shape index of the microplastic is determined, its penetration curve in porous media can be directly predicted using this model. Experimental verification shows that the prediction model constructed using this method has an extremely high fit with experimental data, with a coefficient of determination greater than 0.99, thereby achieving accurate dynamic prediction of microplastic transport behavior.

[0040] Considering the complex ionic composition of real groundwater environments, the method of this invention specifically incorporates a step to address the influence of divalent cations. This method includes using the concentration of divalent cations (such as Ca²⁺) as a key input parameter for water chemistry conditions when calculating the total interaction energy barrier. Since divalent cations can effectively compress the electrostatic double layer and potentially enhance particle adhesion through ion bridging, their impact on microplastic retention cannot be ignored. The method of this invention can systematically calculate and output changes in the standardized migration potential criterion values ​​for microplastics of different shapes (such as particles, fragments, and fibers) by varying the input Ca²⁺ concentration. Based on this, a quantitative assessment of the retention effect of divalent cations on microplastics of different shapes can be achieved. For example, studies have found that the enhancing effect of Ca²⁺ on retention exhibits a significant shape dependence, with the enhancing effect ranked as follows: particles > fragments > fibers. Under specific conditions, the difference in retention effect between particles and fibers can reach as high as 61.56%. This function provides a shape-sensitive and accurate tool for microplastic risk assessment in Ca²⁺-rich groundwater environments (such as karst areas).

[0041] To more clearly illustrate the technical solution of the present invention, a detailed description is provided below in conjunction with the accompanying drawings and specific embodiments. Figure 2 As shown, this invention provides a basic flowchart of a computational method for evaluating the migration potential of microplastics in porous media. In a basic embodiment, the method receives a digital three-dimensional model of an irregular microplastic and a set of environmental parameters as input, corresponding to step S101. First, in step S102, the system uses a general parametric mathematical model, such as a polynomial surface or radial basis function network, to fit and quantify the profile of the microplastic, obtaining a set of parameters that can describe its geometry.

[0042] Next, in step S103, based on the three-dimensional profile described by the parameterized model, the surface of the microplastic is discretized into multiple surface units. Then, according to general interaction theories, such as the classical DLVO theory, the interaction energy between each surface unit and the collector surface representing the porous medium is calculated, and the energy contributions of all surface units are summed to obtain the total interaction energy barrier of the microplastic under a given environment. This process does not depend on any specific shape assumptions and has wide applicability.

[0043] Finally, in steps S104 and S105, the system defines a preset reference geometry, such as an ellipsoid with the same equivalent volume as the target microplastic. Under identical environmental parameters, the energy barrier of this reference ellipsoid is calculated. By dividing the total interaction energy barrier of the target microplastic by the energy barrier of the reference ellipsoid, a standardized ratio is obtained; this ratio is the standardized migration potential criterion. This criterion reflects the difference in migration ability of the target microplastic relative to the standard geometry due to its specific shape, thereby achieving a quantitative assessment of its migration potential. This basic embodiment establishes the core technical idea of ​​the invention: evaluating the migration potential of microplastics of arbitrary shapes through a process of "parameterization quantization - discrete integral calculation - standardized comparison".

[0044] Based on the above embodiments, a more preferred implementation specifies the contour quantization and energy calculation steps. For example... Figure 1 As shown, this embodiment explicitly employs a hyperellipsoidal model as the parameterized mathematical model. After obtaining the microplastic contour data, the contour quantization step S102 uses the hyperellipsoidal equation to fit the three-dimensional morphology. Through optimization algorithms, the optimal principal semi-axes a, b, c and shape indices n, r can be determined for each microplastic sample. For example, studies have found that with increasing soil depth, the shape index n of microplastics exhibits a significant increasing trend from 1.73 to 3.00, revealing the shaping effect of environmental screening on microplastic morphology.

[0045] Building upon this, energy calculation step S103 employs a more refined surface integral method, combined with an extended DLVO theory. This theory, based on the classical DLVO theory, incorporates considerations of Lewis acid-base interactions. For example... Figure 3As shown, when calculating the interaction between each surface element 11 and the porous medium surface 20, van der Waals forces F_vdW, electrostatic double-layer forces F_EDL, and Lewis acid-base interactions are calculated separately. The calculation of these forces depends on the local geometric position, normal vector, and material properties of the element. By numerically integrating all elements across the entire hyperellipsoidal surface, a highly accurate total interaction energy barrier that depends on both shape and orientation can be obtained. This embodiment, by introducing a hyperellipsoidal model and surface element integration methods, significantly improves the accuracy and physical realism of shape description and energy calculation.

[0046] To ensure the comparability and practicality of the evaluation results, another embodiment explicitly defines the reference geometry and criterion classification. In this embodiment, the preset reference geometry in step S104 is strictly set as a perfect sphere with an equivalent volume to the target microplastic. After calculating its energy barrier, a standardized migration potential criterion is constructed in step S105. The effectiveness of this criterion has been strongly validated by experiments. Figure 4 As shown, the values ​​of the standardized migration potential criterion for a series of microplastics of different shapes calculated by the method of this invention are compared with the actual retention coefficients measured by column experiments. A perfect monotonically negative correlation is found between the two, with a Kendall rank correlation coefficient reaching -1.00. This indicates that the smaller the value of the standardized migration potential criterion, the stronger the actual retention of the microplastic and the lower the migration potential, thus demonstrating the extreme effectiveness and reliability of this criterion as an indicator of migration potential.

[0047] Based on this reliable criterion, the migration potential classification in step S106 is implemented. According to the aforementioned classification criteria, when the calculated value of the standardized migration potential criterion is less than 1, the microplastic is labeled as "severely inhibited"; when its value is between 1 and 2 (inclusive), it is labeled as "moderately inhibited"; and when its value is greater than 2, it is labeled as "limitedly inhibited". This series of specific implementation steps, from precise reference settings to strong correlation verification with experimental results, and then to clear classification applications, together constitute a complete and practical evaluation system.

[0048] Considering that microplastics are not stationary in porous media but move and rotate under fluid influence, a more refined implementation introduces orientation correction. In real groundwater environments, a long, thin fibrous microplastic tends to have its long axis parallel to the streamline direction, while a disc-shaped fragment may tumble. These dynamic behaviors affect the probability and force of collisions with the pore walls. Therefore, this embodiment adds a sub-step in step S103: solving the Jeffery equation describing the rotation of non-spherical particles in shear flow using finite element software to obtain the probabilistic orientation distribution of the microplastics under a specific flow field. Based on this distribution, a comprehensive orientation correction factor is calculated and used to correct the initially calculated total interaction energy barrier. By introducing fluid dynamics effects, this embodiment makes the calculated energy barrier results more consistent with the actual situation in dynamic transport processes, further improving the prediction accuracy of the model.

[0049] The method of this invention can also be used to quantify the impact of complex hydrochemical conditions on the migration behavior of microplastics of different shapes. In a specific application scenario, researchers wanted to assess the impact of Ca²⁺-rich agricultural irrigation return water on the retention risk of microplastics of different shapes in soil. This embodiment uses a series of different Ca²⁺ concentrations as hydrochemical input parameters and runs the complete computational process of this invention on three typical microplastic morphologies (particulate, fragmented, and fibrous). The calculation results are as follows: Figure 5 As shown, the enhanced retention effect of Ca²⁺ is clearly shape-dependent. With increasing Ca²⁺ concentration, the normalized migration potential criterion values ​​for all microplastic shapes decrease (enhanced retention), but the decrease is most dramatic for particulate microplastics, followed by fragments, and finally fibers. Under certain conditions, the enhanced retention effect induced by Ca²⁺ can produce a difference of up to 61.56% between particles and fibers. This quantitative result reveals and confirms for the first time the synergistic effect between divalent cations and microplastic shape, providing crucial scientific evidence for developing risk management strategies targeting specific water quality and pollution patterns.

[0050] like Figure 6 As shown, the present invention also provides a computing device 100 for evaluating the migration potential of microplastics in porous media. This device can be a computer, a server, or an embedded system in hardware, and its core includes a processor 140 and a memory 150. The memory 150 stores computer program instructions, which, when executed by the processor 140, enable the evaluation method of the present invention. These program instructions logically constitute multiple functional modules, including a profile quantization module 110, an energy calculation module 120, and a criterion construction module 130, and may further include a migration prediction module.

[0051] In a complete end-to-end workflow, the user first submits the sample data to be analyzed through the device's input interface, such as microscopic images or 3D scan data of microplastic samples collected on-site, along with corresponding hydrochemical parameters. After the data is input, the device automatically begins calculations. The contour quantization module 110 is activated, calling a hyperellipsoidal model to fit the image of each microplastic sample, automatically extracting key parameters such as its principal semi-axis and shape index.

[0052] Subsequently, the energy calculation module 120 takes over the processing. Based on the shape parameters output by the contour quantization module 110 and the hydrochemical parameters input by the user, it invokes an algorithm based on surface integrals and combines it with an orientation correction factor to accurately calculate the total interaction energy barrier of each microplastic under each hydrochemical scenario. This module is the computational core of the entire device, ensuring the accurate simulation of the physical processes.

[0053] Next, the criterion construction module 130 begins operation. It first calculates the energy barrier of a sphere with the same volume as each microplastic in the corresponding water chemistry scenario as a benchmark, and then divides the two to obtain a standardized migration potential criterion. Based on the value of this criterion, the module further classifies the criterion according to preset thresholds and outputs the results.

[0054] Finally, as an optional advanced feature, the migration prediction module can be activated. This module utilizes a pre-built shape index-dependent two-site migration prediction model, taking the value of the standardized migration potential criterion output by the criterion construction module 130 or the shape index n output by the contour quantization module 110 as input, to directly predict and output the penetration curve of the microplastic in a specific porous medium. The entire process achieves fully automated processing from raw images to final risk level and dynamic behavior prediction, enabling efficient screening of massive samples and complex environmental scenarios, providing an unprecedentedly powerful tool for environmental risk assessment of microplastics.

[0055] Those skilled in the art will understand that all or part of the steps of the above methods can be implemented by a computer program instructing related hardware, and the computer program can be stored in a computer-readable storage medium. Accordingly, the present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps described in any of the foregoing method embodiments. The storage medium can be ROM, RAM, magnetic disk, or optical disk, etc. This form allows the technical solution of the present invention to be conveniently distributed, installed, and deployed on various computing platforms in the form of a software product.

Claims

1. A calculation method for evaluating the migration potential of microplastics in porous media, characterized in that, Includes the following steps: A parametric mathematical model is used to quantify the three-dimensional profile of microplastics. The parametric mathematical model uses a set of parameters to continuously describe the geometry of microplastics. Based on the three-dimensional profile, the surface of the microplastic is discretized into multiple surface units, and the interaction between all surface units and the porous medium is integrated or summed to calculate the total interaction energy barrier between the microplastic and the porous medium. The total interaction energy barrier is compared with the energy barrier of a preset reference geometry under the same conditions to obtain a standardized migration potential criterion. Based on the value of the standardized migration potential criterion, the migration potential of microplastics is divided into multiple levels; The multiple levels include: when the value of the standardized migration potential criterion is less than 1, the migration potential is determined to be a severe inhibition level; When the value of the standardized migration potential criterion is greater than or equal to 1 and less than or equal to 2, the migration potential is determined to be at a moderate inhibition level; when the value of the standardized migration potential criterion is greater than 2, the migration potential is determined to be at a limited inhibition level.

2. The method according to claim 1, characterized in that, The parameterized mathematical model is a hyperellipsoidal model, and the set of parameters includes the principal semi-axis and the shape index.

3. The method according to claim 1, characterized in that, The integration or summation of the interactions between all surface units and the porous medium is achieved through the surface unit integration method; the interactions include at least one of van der Waals forces, electrostatic double layer forces, and Lewis acid-base forces.

4. The method according to claim 1, characterized in that, The preset reference geometry is a sphere with an equivalent volume or surface area to the microplastic.

5. The method according to claim 1, characterized in that, The method further includes: The orientation of microplastics in the flow field is calculated based on fluid dynamics, and an orientation correction factor is introduced to correct the total interaction energy barrier.

6. The method according to claim 1, characterized in that, The method further includes: Based on the relationship between the migration potential criterion and the shape parameter, a shape index-dependent two-site migration prediction model is constructed to predict the penetration curve of microplastics in porous media.

7. The method according to claim 1, characterized in that, The method further includes: In calculating the total interaction energy barrier, the concentration of divalent cations is used as a parameter of the water chemistry conditions; and Based on the standardized migration potential criterion, a quantitative evaluation result of the retention effect of the divalent cation on microplastics of different shapes is output.

8. A computational device for evaluating the migration potential of microplastics in porous media, characterized in that, include: The contour quantization module is used to quantify the three-dimensional contour of microplastics using a parametric mathematical model, wherein the parametric mathematical model uses a set of parameters to continuously describe the geometry of the microplastics. An energy calculation module is used to discretize the surface of the microplastic into multiple surface units based on the three-dimensional contour, and to integrate or sum the interactions between all surface units and the porous medium in order to calculate the total interaction energy barrier between the microplastic and the porous medium. The criterion construction module is used to compare the total interaction energy barrier with the energy barrier of a preset reference geometry under the same conditions to obtain a standardized migration potential criterion. Based on the value of the standardized migration potential criterion, the migration potential of microplastics is divided into multiple levels; The multiple levels include: when the value of the standardized migration potential criterion is less than 1, the migration potential is determined to be a severe inhibition level; When the value of the standardized migration potential criterion is greater than or equal to 1 and less than or equal to 2, the migration potential is determined to be at a moderate inhibition level; when the value of the standardized migration potential criterion is greater than 2, the migration potential is determined to be at a limited inhibition level.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 7.

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