Method and system for determining the remaining adsorption capacity of a pollution adsorbent particle

Abstract

The application discloses a kind of pollution adsorbent particle residual adsorption amount determination method and system, it is related to pollution adsorbent particle desorption research technical field.The application constructs improved Lan* desorption kinetics model;Based on origin software and desorption kinetics experimental data, the coefficient in improved Lan* desorption kinetics model is fitted, and residual adsorption amount prediction model of pollution adsorbent particle is obtained;Target desorption time is substituted into residual adsorption amount prediction model of pollution adsorbent particle, and the residual adsorption amount of unit mass pollution adsorbent particle at target desorption time is determined.The application can quickly complete the prediction of the residual adsorption amount of adsorbate of unit mass adsorbent at any desorption time by introducing solid-liquid ratio to construct improved Lan* desorption kinetics model.

Description

Technical Field

[0001] This invention relates to the field of pollution particle desorption research technology, and in particular to a method and system for determining the remaining adsorption capacity of pollution adsorbent particles. Background Technology

[0002] Currently, research on the adsorption and desorption of pollutants by particles largely focuses on adsorption isotherms, with relatively little attention paid to kinetics. However, adsorption isotherms alone cannot fully describe the adsorption and desorption phenomena; both adsorption and desorption processes need to be considered. Desorption refers to the phenomenon at the solid-liquid interface where the adsorbate is released from the solid phase, resulting in an increase in its concentration in the solution and a corresponding decrease in its concentration on the solid phase. Desorption kinetics refers to the process by which adsorbates (oil pollutants, heavy metals, nutrients (such as nitrogen or phosphorus), or toxic organic compounds) adsorbed on the particulate phase (such as soil or sediment) are released back into the liquid phase. It is a crucial factor in studying the changes in the concentration (or desorption amount) of particulate pollutants over time.

[0003] Currently, desorption kinetic models for adsorbates in the particulate phase include the Elovich kinetic model, the pseudo-first-order (PFO) kinetic model, and the pseudo-second-order (PSO) kinetic model. The formulas for each model are as follows:

[0004] The Elovich dynamic model is:

[0005] The pseudo-first-order dynamic model is as follows:

[0006] The pseudo-second-order dynamic model is as follows:

[0007] in, The amount of adsorbate desorbed per unit mass of adsorbent at time t, expressed in mg / kg; , represents the amount of adsorbate desorbed per unit mass of adsorbent at desorption equilibrium, in mg / kg; a and b are Elovich adsorption kinetic model constants; t is the adsorption time in seconds; K1 is the pseudo-first-order reaction kinetic rate constant in 1 / s; K2 is the pseudo-second-order reaction kinetic rate constant in kg / (mg·s).

[0008] Studies have found that the kinetic models applicable to the adsorption and desorption processes of oil pollutants, heavy metals, nitrogen and phosphorus pollutants, or organic matter in sediments (or soils) of different types (or sources) are not consistent under different conditions. Most kinetic models include multiple adjustable parameters and can interpret experimental data well, but they lack a theoretical basis, cannot reflect the mechanism of desorption, and the fitted parameters change with experimental conditions, limiting the further application of these models. Allen et al. and Febrianto et al. found that the rate constant of the PFO kinetic model in different systems is closely related to the solute concentration. The kinetic rate constant of the PSO kinetic model is related to operating conditions such as solution pH, initial ion concentration, temperature, and oscillation rate. Research on kinetic formulas is mainly based on statistical data and empirical formulas, lacking a systematic and comprehensive understanding of the applicability and simulation mechanism of various adsorption-desorption kinetic models. Some studies treat adsorption-desorption as a rapid non-equilibrium process, using first-order or reversible nonlinear kinetic formulas to describe adsorption and desorption, thus oversimplifying the adsorption-desorption mechanism.

[0009] The Elovich model is an empirical model without clearly defined physical meaning and cannot provide important information about mass transfer mechanisms. Originally used to study adsorption and desorption at the gas-solid interface, it has limitations for liquid-solid interface adsorption and desorption. The derivation of the PFO and PSO models fails to consider mass conservation and the influence of the solid-liquid ratio on kinetic parameters, which is also unreasonable. The PFO kinetic model can only describe the initial stage of the kinetic process. The good fit of the PFO and PSO models to experimental data is merely a result of mathematical and experimental condition selection. The Elovich, PFO, and PSO kinetic models do not include external experimental conditions, such as particulate concentration or dry bulk density (solid-liquid ratio), rendering these models incapable of predictive calculations. Summary of the Invention

[0010] The purpose of this invention is to provide a method and system for determining the remaining adsorption capacity of pollutant adsorbent particles. By introducing a solid-liquid ratio into the Lan* desorption kinetic model, an improved Lan* desorption kinetic model is constructed, which can quickly predict the remaining adsorbate capacity per unit mass of adsorbent at any desorption time.

[0011] To achieve the above objectives, the present invention provides the following solution:

[0012] A method for determining the residual adsorption capacity of pollutant adsorbent particles, comprising:

[0013] Obtain experimental data on the desorption kinetics of the same pollutant adsorbent particles;

[0014] An improved Lan* desorption kinetic model was constructed; the improved Lan* desorption kinetic model was obtained by introducing the solid-liquid ratio into the Lan* desorption kinetic model.

[0015] Based on Origin software and desorption kinetics experimental data, the coefficients in the improved Lan* desorption kinetics model were fitted to obtain a prediction model for the remaining adsorption capacity of pollutant adsorbent particles.

[0016] Obtain the target desorption time;

[0017] Substitute the target desorption time into the prediction model for the remaining adsorption capacity of the pollutant adsorbent particles to determine the remaining adsorption capacity of a unit mass of pollutant adsorbent particles at the target desorption time.

[0018] Optionally, the desorption kinetic experimental data includes the remaining adsorption amount per unit mass of pollutant adsorbent particles at different desorption times, determined through desorption kinetic experiments.

[0019] Optionally, the improved Lan* desorption kinetic model includes:

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] Among them, Q t Let be the amount of adsorbate adsorbed per unit mass of adsorbent at time t during the desorption of adsorbent particles, q be the first intermediate variable, p be the second intermediate variable, R be the third intermediate variable, e be the base of the natural logarithm, and C be the third intermediate variable. t Let be the concentration of the adsorbate in the liquid phase at time t during the desorption of the adsorbent particles, Q0 be the initial adsorption amount per unit mass of adsorbent, S be the adsorbent concentration, and r be the adsorbent concentration. s This is the dry bulk density of the adsorbent.

[0026] Optionally, the improved Lan* desorption kinetic model further includes:

[0027]

[0028]

[0029] Among them, Q t→∞ C represents the equilibrium adsorption capacity per unit mass of adsorbent during the desorption of adsorbent particles. t→∞This represents the equilibrium concentration of the adsorbate in the liquid phase during the desorption of pollutant adsorbent particles.

[0030] A system for determining the residual adsorption capacity of pollutant adsorbent particles, comprising:

[0031] The desorption kinetics experimental data acquisition module is used to acquire desorption kinetics experimental data of the same pollutant adsorbent particles;

[0032] An improved Lan* desorption kinetics model building module is used to construct an improved Lan* desorption kinetics model; the improved Lan* desorption kinetics model is obtained by introducing a solid-liquid ratio into the Lan* desorption kinetics model.

[0033] The module for determining the prediction model of the remaining adsorption capacity of pollutant adsorbent particles is used to fit the coefficients in the improved Lan* desorption kinetic model based on Origin software and desorption kinetic experimental data to obtain the prediction model of the remaining adsorption capacity of pollutant adsorbent particles.

[0034] The target desorption time determination module is used to obtain the target desorption time;

[0035] The residual adsorption capacity prediction module for pollutant particles is used to substitute the target desorption time into the residual adsorption capacity prediction model for pollutant adsorbent particles to determine the residual adsorption capacity of a unit mass of pollutant adsorbent particles at the target desorption time.

[0036] Optionally, the desorption kinetic experimental data includes the remaining adsorption amount per unit mass of pollutant adsorbent particles at different desorption times, determined through desorption kinetic experiments.

[0037] Optionally, the improved Lan* desorption kinetic model includes:

[0038]

[0039]

[0040]

[0041]

[0042]

[0043] Among them, Q t Let be the amount of adsorbate adsorbed per unit mass of adsorbent at time t during the desorption of adsorbent particles, q be the first intermediate variable, p be the second intermediate variable, R be the third intermediate variable, e be the base of the natural logarithm, and C be the third intermediate variable. t Let be the concentration of the adsorbate in the liquid phase at time t during the desorption of the adsorbent particles, Q0 be the initial adsorption amount per unit mass of adsorbent, S be the adsorbent concentration, and r be the adsorbent concentration. sThis is the dry bulk density of the adsorbent.

[0044] Optionally, the improved Lan* desorption kinetic model further includes:

[0045]

[0046]

[0047] Among them, Q t→∞ C represents the equilibrium adsorption capacity per unit mass of adsorbent during the desorption of adsorbent particles. t→∞ This represents the equilibrium concentration of the adsorbate in the liquid phase during the desorption of pollutant adsorbent particles.

[0048] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0049] This invention provides a method and system for determining the remaining adsorption capacity of pollutant adsorbent particles, comprising: acquiring desorption kinetic experimental data of the same pollutant adsorbent particles; constructing an improved Lan* desorption kinetic model; the improved Lan* desorption kinetic model is obtained by introducing a solid-liquid ratio into the Lan* desorption kinetic model; fitting the coefficients in the improved Lan* desorption kinetic model based on Origin software and desorption kinetic experimental data to obtain a prediction model for the remaining adsorption capacity of pollutant adsorbent particles; obtaining a target desorption time; and substituting the target desorption time into the prediction model for the remaining adsorption capacity of pollutant adsorbent particles to determine the remaining adsorption capacity per unit mass of pollutant adsorbent particles at the target desorption time. This invention, by introducing a solid-liquid ratio into the Lan* desorption kinetic model to construct an improved Lan* desorption kinetic model, can quickly predict the remaining adsorbate adsorption capacity per unit mass of adsorbent at any desorption time. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a flowchart of the method for determining the remaining adsorption capacity of pollutant adsorbent particles in Embodiment 1 of the present invention;

[0052] Figure 2 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of heavy oil from sediments under different initial adsorption amounts in Example 2 of the present invention;

[0053] Figure 3This is a schematic diagram of the Lan-rs* equation fitting for the desorption of heavy oil from sediments under different salinities in Example 2 of the present invention;

[0054] Figure 4 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of heavy oil from sediments of different particle sizes in Example 2 of the present invention;

[0055] Figure 5 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of heavy oil from sediments at different temperatures in Example 2 of the present invention;

[0056] Figure 6 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of heavy metals by the four adsorbents in Example 2 of the present invention;

[0057] Figure 7 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of PCP (pentachlorophenol) from gray powdery sand at different temperatures in Example 2 of the present invention.

[0058] Figure 8 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of petroleum from silty clay and silt in Embodiment 2 of the present invention;

[0059] Figure 9 This is a schematic diagram of the Lan-rs* equation fitting for soil desorption of PCP (pentachlorophenol) at different temperatures in Example 2 of the present invention;

[0060] Figure 10 This is a schematic diagram of the Lan-rs* equation fitting for soil desorption of PCP (pentachlorophenol) under different salinities in Example 2 of the present invention;

[0061] Figure 11 This is a schematic diagram of the Lan-rs* equation fitting for soil desorption of PCP (pentachlorophenol) at different pH levels in Example 2 of the present invention;

[0062] Figure 12 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of benzo[a]pyrene by silt in Example 2 of the present invention;

[0063] Figure 13 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of MCPA (4-chloro-2-methylphenoxyacetic acid) in red soil in Example 2 of the present invention;

[0064] Figure 14 This is a schematic diagram of the Lan* and Lan-rs* equation fitting for the desorption of MCPA (4-chloro-2-methylphenoxyacetic acid) in Rhodic red soil in Example 2 of the present invention;

[0065] Figure 15This is a schematic diagram of the Lan* and Lan-rs* equation fitting for the desorption of MCPA (4-chloro-2-methylphenoxyacetic acid) in Haplic red soil in Example 2 of the present invention;

[0066] Figure 16 This is a schematic diagram of the Lan* and Lan-rs* equation fitting for the desorption of MCPA (4-chloro-2-methylphenoxyacetic acid) by Paddy red soil in Example 2 of the present invention;

[0067] Figure 17 This is a schematic diagram of the Lan-rs* equation fitting for the desorption of SMZ (sulfamethoxazole) in three types of soil in Example 2 of the present invention;

[0068] Figure 18 This is a schematic diagram of the fitting of the Lan* and Lan-rs* equations for the desorption of SMZ (sulfamethoxazole) in meadow black soil in Example 2 of the present invention;

[0069] Figure 19 This is a schematic diagram of the Lan* and Lan-rs* equation fitting for the desorption of SMZ (sulfamethoxazole) by alkaline soil in Example 2 of the present invention;

[0070] Figure 20 This is a schematic diagram of the fitting of the Lan* and Lan-rs* equations for the desorption of SMZ (sulfamethoxazole) in dark brown soil in Example 2 of the present invention;

[0071] Figure 21 This is a schematic diagram of fitting the Lan* and Lan-rs* equations for the desorption of fluorene by silty clay in Example 2 of the present invention. Detailed Implementation

[0072] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0073] The purpose of this invention is to provide a method and system for determining the remaining adsorption capacity of pollutant adsorbent particles. By introducing a solid-liquid ratio into the Lan* desorption kinetic model, an improved Lan* desorption kinetic model is constructed, which can quickly predict the remaining adsorbate capacity per unit mass of adsorbent at any desorption time.

[0074] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0075] Example 1

[0076] like Figure 1 As shown in the figure, this embodiment provides a method for determining the remaining adsorption capacity of pollutant adsorbent particles, including:

[0077] Step 101: Obtain desorption kinetics experimental data for the same pollutant adsorbent particles. The desorption kinetics experimental data includes the remaining adsorption capacity per unit mass of pollutant adsorbent particles at different desorption times, determined through desorption kinetic experiments.

[0078] Step 102: Constructing an improved Lan* desorption kinetic model; the improved Lan* desorption kinetic model is obtained by introducing a solid-liquid ratio into the Lan* desorption kinetic model. In the Lan* desorption kinetic model, 1-S / r in the equation... s The concentration is approximately 1. Clearly, for high solid-liquid ratio conditions, such as soil systems, this treatment will introduce significant errors (S is the adsorbent concentration, r...). s (This refers to the dry bulk density of the adsorbent).

[0079] The improved Lan* desorption kinetics model includes:

[0080]

[0081]

[0082]

[0083]

[0084]

[0085] Among them, Q t Let be the amount of adsorbate adsorbed per unit mass of adsorbent at time t during the desorption of adsorbent particles, q be the first intermediate variable, p be the second intermediate variable, R be the third intermediate variable, e be the base of the natural logarithm, and C be the third intermediate variable. t Let be the concentration of the adsorbate in the liquid phase at time t during the desorption of the adsorbent particles, Q0 be the initial adsorption amount per unit mass of adsorbent, S be the adsorbent concentration, and r be the adsorbent concentration. s This is the dry bulk density of the adsorbent.

[0086] The improved Lan* desorption kinetics model also includes:

[0087]

[0088]

[0089] Among them, Q t→∞ C represents the equilibrium adsorption capacity per unit mass of adsorbent during the desorption of adsorbent particles. t→∞ This represents the equilibrium concentration of the adsorbate in the liquid phase during the desorption of pollutant adsorbent particles.

[0090] Step 103: Based on Origin software and desorption kinetic experimental data, fit the coefficients in the improved Lan* desorption kinetic model to obtain a prediction model for the remaining adsorption capacity of pollutant adsorbent particles.

[0091] Step 104: Obtain the target desorption time.

[0092] Step 105: Substitute the target desorption time into the prediction model for the remaining adsorption capacity of pollutant adsorbent particles to determine the remaining adsorption capacity per unit mass of pollutant adsorbent particles at the target desorption time.

[0093] Example 2

[0094] This embodiment provides a method for determining the remaining adsorption capacity of pollutant adsorbent particles, including the following steps:

[0095] Step 1: Collect experimental data on desorption kinetics from relevant literature. This data includes the adsorbate adsorption capacity per unit mass of adsorbent at different preset desorption times. Specifically, experimental data on the desorption kinetics of pollutant particles were collected from nine articles, covering kinetic studies of heavy metals and toxic organic compounds desorbed from adsorbents in soil and sediments. The timescales included both short-term and long-term desorption studies. The specific sources of the desorption kinetic data are as follows:

[0096] 1. A batch sampling method with timed intervals was employed. 0.200 g of heavy oil-contaminated sediment sample was accurately weighed, 50 ml of artificial seawater was added, the mixture was kept at a constant temperature and shaken, and samples were taken at timed intervals. After centrifugation, the supernatant was collected. A certain volume of the supernatant was extracted with n-hexane, and the concentration of heavy oil in the supernatant was determined by ultraviolet spectrophotometry to calculate the amount of heavy oil desorbed from the sediment. Using heavy oil as the target pollutant, the desorption kinetics of heavy oil from the sediment were studied, considering factors such as the initial heavy oil loading, the salinity of the solution, the particle size of the sediment, and the temperature.

[0097] 1.1: Desorption kinetics of heavy oil at 24.85℃ with initial loadings of 20000 mg / kg and 40000 mg / kg sediment.

[0098] 1.2: Desorption kinetics of sediments with heavy oil pollution intensity of 40000 mg / kg in artificial seawater (ASW), diluted artificial seawater (DASW), and distilled water (DW) media, with media salinity ASW>DASW>DW.

[0099] 1.3: Desorption kinetics of sediments smaller than 61 μm and sediments between 61 μm and 180 μm with heavy oil pollution intensity of 40,000 mg / kg.

[0100] 1.4: Desorption kinetics of sediments with heavy oil contamination intensity of 40,000 mg / kg in ASW medium at 9.85℃, 14.85℃, 19.85℃, 24.85℃ and 28.85℃.

[0101] 2. Sediment samples taken from the Yellow River were sieved into clay, fine silt, coarse silt, and fine sand as desorption experimental media. Deionized water was used for the desorption experiments. Due to the extremely low cadmium concentration in the original Yellow River sediment samples, cadmium was artificially added to the original sediment samples for the desorption experiments. During the experiment, the water temperature was maintained between 24℃ and 25℃, the pH between 6 and 7, and the solid-liquid ratio was 1:100. During sampling, the sediment in the container was kept in suspension by stirring. At regular intervals, 10 ml of liquid was taken, filtered through a 0.5 mm membrane, and the cadmium ion concentration in the filtrate was measured.

[0102] 3. The soil was gray silty sand free of PCP (pentachlorophenol). PCP-contaminated soil was prepared using pure PCP powder and acetone. Three soil samples were analyzed, yielding an average soil concentration of 48.800 mg / kg and a standard deviation of 1.800 mg / kg. 0.500 g of soil was weighed and placed in 15 ml brown glass bottles. Approximately 15 ml of sodium perchlorate solution was added to each bottle, ensuring no headspace in the bottles. The batch temperatures for the five soil sample groups were 30℃, 45℃, 60℃, 75℃, and 90℃. The PCP concentration in the soil phase was obtained by subtracting the mass of PCP in the residual aqueous phase, and the original soil concentration for each bottle was calculated. The calculated average original soil concentration was 37.200 mg / kg, with a standard deviation of 12.900 mg / kg.

[0103] 4. The experiment used uncontaminated silty clay and silt from the groundwater level fluctuation zone of the contaminated site as the experimental medium. Petroleum-contaminated media were prepared using petroleum reserve fluid and sterilized silty clay and silt. The solid-liquid ratio for the desorption experiment was 1:2.5, the rotation speed was 120 rpm, and the experimental water was uncontaminated groundwater from the vicinity of the site. Based on the characteristics of the groundwater environment and actual measurement results, the experimental environment was set to be shaded and at a temperature of 12℃. At the beginning of the experiment, and at 1h, 3h, 6h, 12h, 24h, 48h, and 72h, 2ml of the supernatant in a brown bottle was collected and filtered through a 0.22μm filter membrane to test the concentration of petroleum hydrocarbons. A static desorption experiment of petroleum hydrocarbon pollutants was conducted.

[0104] 5. Regarding the desorption process, when the PCP (pentachlorophenol) pollution level in the soil is 8500 mg / kg, the desorption rate of PCP is relatively high, and the air-drying effect of the contaminated soil sample is also better at this time. Therefore, a contaminated soil sample with a PCP concentration of 8500 mg / kg was used to study the desorption kinetics of PCP. The solid-liquid ratio in the desorption experiment was 1:10. The kinetics of PCP desorption from contaminated soil were studied based on system temperature, salinity, and pH. A certain mass of contaminated soil sample with a PCP content of 8500 mg / kg was weighed into a centrifuge tube, distilled water was added for desorption, the tube was sealed, and the mixture was kept at a constant temperature and protected from light by shaking. Samples were taken periodically, and the sample was centrifuged at 4000 rpm for 10 min. After centrifugation, the supernatant was filtered, its absorbance was measured, and the amount of PCP desorbed from the soil was calculated.

[0105] 5.1: The tests were conducted at 0℃, 5℃, 10℃, 15℃, 20℃ and 25℃ respectively.

[0106] 5.2: Desorption kinetics experiments were conducted on contaminated soil samples by adding different concentrations of NaCl (sodium chloride) solution (concentration range of 0.100 mol / L to 0.500 mol / L) to centrifuge tubes.

[0107] 5.3: In the experiment, the pH of the desorption solvent (distilled water) was adjusted using 0.100 mol / L HCl (hydrochloric acid) solution and 0.100 mol / L NaOH (sodium hydroxide) solution, with pH values ​​of 5, 6, 7, 8 and 9 respectively, before being added to the soil sample and shaken.

[0108] 6: Silty sand (natural background pollution of benzo[a]pyrene was 12 μg / kg, below the detection limit of 50 μg / kg). Desorption experiments were conducted with benzo[a]pyrene. 4 ml of polycyclic aromatic hydrocarbon standard was mixed with 16 ml of deionized water to obtain the stock solution for pollution treatment. By adding the stock solution to the silty sand, silty sand contaminated with benzo[a]pyrene at a concentration of 0.483 mg / kg was prepared. 15 ml of the aqueous solution and 1.5 g of anthropogenically contaminated soil were added to a sealed tube, and desorption experiments were conducted on a shaker at 4.85℃.

[0109] 7. The experimental materials were MCPA (4-chloro-2-methylphenoxyacetic acid) and three types of iron-aluminate soil (latysodies) from Haikou City, China, at depths ranging from 0 to 20 cm. For each soil type, 2 g of soil was mixed with 10 ml of calcium chloride solution (5.000 mg / L MCPA) for adsorption studies. Desorption studies were conducted immediately after the adsorption experiment. After removing all supernatant, 10 ml of calcium chloride solution was added, and the desorption was carried out in the dark at 25°C and 200 rap / min. Samples were taken at different time points, centrifuged at 6000 rap / min for 10 min, and the MCPA concentration in the supernatant was analyzed by high-performance liquid chromatography (HPLC).

[0110] 8. The experimental materials were SMZ (sulfamethoxazole) and three types of soil samples. Soil samples were taken from the top 0–20 cm layer. Meadow black soil was taken from Jilin Agricultural University, albic soil from Yongji County, Jilin Province, and dark brown soil from Changbai Mountain, Jilin Province. After the adsorption experiment, the supernatant was discarded after centrifugation, and desorption was performed. 10 ml of 0.010 mol / L CaCl2 background electrolyte solution was added, with a solid-liquid ratio of 1:2.5. The samples were shaken at 200 rap / min at 25℃ in the dark. Samples were taken at 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h, and 24 h, and centrifuged at 4000 rap / min for 10 min. The supernatant was filtered through a 0.22 μm filter membrane, and the SMZ content in the liquid phase was determined by HPLC.

[0111] 9. The dynamic desorption behavior and characteristics of fluorene in soil were revealed using a soil column (14 cm inner diameter, 30 cm height). The column was filled layer by layer with silty clay to ensure that each layer had the same mass and a specific gravity of 1.410 g / cm³. 3 An adsorption experiment was first conducted using a soil column saturated with distilled water, followed by an adsorption experiment using a 10.000 mg / L fluorene washing solution at a flow rate of 2000 ml / d. After adsorption, a desorption experiment was performed using a washing solution containing only CaCl2, NaN3, and NaHCO3 at room temperature (20 ± 3 °C) for 30 days, with the solution collected daily at the column outlet. The sample was then analyzed to determine the amount of fluorene desorbed in the liquid phase.

[0112] Step 2: Based on the experimental data, using Origin software, the improved Lan* desorption kinetic model is fitted to the data to determine the model coefficients of the improved Lan* desorption kinetic model corresponding to the adsorbent, thus obtaining an improved Lan* desorption kinetic model with known coefficients; the model coefficients include: adsorption rate coefficient K. L1 Desorption rate coefficient K L2 And the saturated adsorption capacity Q per unit mass of adsorbent m The improved Lan* desorption kinetic model is a Lan* desorption kinetic model improved by introducing a solid-liquid ratio.

[0113] Step 2 is as follows:

[0114] Let Q t C represents the amount of adsorbate adsorbed per unit mass of adsorbent at time t, expressed in mg / kg. t Q represents the concentration of the liquid phase adsorbate at time t, in mg / L. m K represents the saturated adsorption capacity per unit mass of adsorbent, expressed in mg / kg. L1 K is the adsorption rate coefficient, with units of L / (mg·s);L2 S is the desorption rate coefficient, in units of 1 / s; S is the adsorbent concentration, in units of 10. 3 kg / m 3 ;r s This is the dry bulk density of the adsorbent, in units of 10. 3 kg / m 3 V represents the volume of the water-adsorbent-adsorbate mixture, in ml; Q0 represents the initial adsorption capacity of adsorbate per unit mass of adsorbent, in mg / kg; C0 represents the initial concentration of adsorbate in the liquid phase, in mg / L; Q t→∞ The equilibrium adsorption capacity per unit mass of adsorbent is expressed in mg / kg; C t→∞ Let be the equilibrium concentration of the adsorbate in the liquid phase. Based on the rate term derived from the Langmuir adsorption isotherm, the desorption kinetics formula can be set as:

[0115]

[0116] According to the law of conservation of mass, the sum of the masses of the adsorbates in the liquid and solid phases of the reactor is a constant value:

[0117] Q t SV+(1-S / r s )VC t =Q0SV+(1-S / r s )VC0 (2)

[0118] Let: M = Q0S + (1 - S / r) s )C0

[0119] From formula (2), we can obtain:

[0120]

[0121] For the desorption problem, we can assume that the initial concentration of the adsorbate in the liquid phase is 0, that is, the initial conditions are:

[0122] C0=0 (4)

[0123] Substituting formula (4) into formula (3), we get:

[0124]

[0125] Substituting formula (5) into formula (1), we get:

[0126]

[0127] make:

[0128]

[0129]

[0130]

[0131] Substituting formulas (7), (8), and (9) into formula (6), we get:

[0132]

[0133] Combine the initial conditions (at t = 0):

[0134] C t =C0=0

[0135] From the integral formula (10), we can obtain:

[0136]

[0137] Let the intermediate variable A be:

[0138]

[0139] Combining formulas (4) and (12), formula (11) can be simplified to:

[0140]

[0141] Simplifying (13) yields:

[0142]

[0143] Substituting equation (12) into equation (14), we obtain the Lan-rs* desorption kinetics equation (15):

[0144]

[0145] in,

[0146] Substituting formula (15) into formula (5), we get:

[0147]

[0148] Based on formulas (15) and (16), the concentrations of adsorbates in the solid phase (formula (15)) and liquid phase (formula (16)) at any desorption time during the desorption process of the pollutant adsorbent particles can be calculated.

[0149] When desorption reaches equilibrium, the equilibrium concentration of the particulate phase adsorbate (i.e., the equilibrium adsorption amount of adsorbate per unit mass of adsorbent) and the equilibrium concentration of the liquid phase adsorbate (i.e., the equilibrium concentration of the liquid phase adsorbate) can be calculated by taking the limit of time from formulas (15) and (16), as shown in formulas (17) and (18).

[0150]

[0151]

[0152] It can be seen that, compared with the Lan* desorption kinetic model, the improved Lan* desorption kinetic model takes into account the volume S / r occupied by particulate matter. s The impact is more comprehensive and has a wider reach.

[0153] Combining equations (7), (8), (9), (17), and (18), we can obtain the Langmuir adsorption isotherm:

[0154]

[0155] Where: K L =K L1 / K L2 .

[0156] Step 3: Determine the adsorbate adsorption amount of the adsorbent at any desorption time using an improved Lan* desorption kinetic model with known coefficients.

[0157] Specifically, the desorption kinetic data in the references are used to verify the effectiveness of Embodiment 1 of the present invention.

[0158] Desorption kinetic data from relevant literature were collected, and the data were fitted using an improved Lan* desorption kinetic model in Origin software. The fitting results are shown in Table 1. Figures 2-21 In the figure, Lan-rs*kinetic represents the Lan-rs* kinetic equation; Q0 represents the initial adsorption capacity of the adsorbent; Q t 1 represents the adsorption capacity of the adsorbent at any given time; ASW, DASW, and DW represent artificial seawater, diluted artificial seawater, and distilled water, respectively; PCP represents pentachlorophenol; MCPA represents 4-chloro-2-methylphenoxyacetic acid; and SMZ represents sulfamethoxazole.

[0159] Table 1. Fitting parameters of the improved Lan* desorption kinetics model to experimental data from the literature.

[0160]

[0161]

[0162] In Table 1, heavy oil + sediment 1: Q0 = 20000 mg·kg -1 Heavy oil + sediment 2: Q0 = 40000 mg·kg -1Heavy oil + sediment 3: saline medium is ASW; Heavy oil + sediment 4: saline medium is DASW; Heavy oil + sediment 5: saline medium is DW. Heavy oil + sediment 6: sediment grain size <61μm; Heavy oil + sediment 7: sediment grain size 61~180μm; Heavy oil + sediment 8: temperature 9.85℃; Heavy oil + sediment 9: temperature 14.85℃; Heavy oil + sediment 10: temperature 19.85℃; Heavy oil + sediment 11: temperature 24.85℃; Heavy oil + sediment 12: temperature 28.85℃.

[0163] PCP + gray silty sand 1: temperature 30℃; PCP + gray silty sand 2: temperature 45℃; PCP + gray silty sand 3: temperature 60℃; PCP + gray silty sand 4: temperature 75℃; PCP + gray silty sand 5: temperature 90℃; PCP + soil 1: temperature 25℃; PCP + soil 2: NaCl concentration 0 mol·L⁻¹ -1 PCP + Soil 3: NaCl concentration is 0.1 mol·L⁻¹ -1 PCP + Soil 4: NaCl concentration is 0.2 mol·L⁻¹ -1 PCP + Soil 5: NaCl concentration is 0.5 mol·L⁻¹ -1 PCP + Soil 6: pH = 6, PCP + Soil 7: pH = 7, PCP + Soil 8: pH = 8, PCP + Soil 9: pH = 9.

[0164] MCPA+Rhodic ferralsol 1: Soil is Rhodic ferralsol; MCPA+Rhodic ferralsol 2: Soil is Haplic ferralsol; MCPA+Rhodic ferralsol 3: Soil is Paddy ferralsol.

[0165] In Table 1, parameters 1.1, 1.2, 1.3, and 1.4 are from the literature "Study on the Adsorption and Desorption Behavior of Heavy Oil on Sediments in Jiaozhou Bay and Its Influencing Factors" (Han Hui 2011); parameter 2 is from the literature "Investigation of cadmium desorption from different-sized sediments" (Huang 2003b); parameter 3 is from the literature "Desorption kinetics of PCP-contaminated soil: effect of temperature" (Kenand Lo 2002); parameter 4 is from the literature "Study on the Migration and Transformation Law of Petroleum Hydrocarbon Pollutants in Groundwater Level Fluctuation Zones" (Lin Guangyu 2014); parameters 5.1, 5.2, and 5.3 are from the literature "Study on the Adsorption-Desorption Kinetics of PCP in Wetland Soil" (Cheng Fangfang 2012); and parameter 6 is from the literature "Desorption of polycyclic aromatic hydrocarbons from soil in the presence of dissolved organic matter: Effect of solution composition and aging" (…). -Knabner et al. 2000); parameter 7 is from the literature "Influence of dissolved organic matter on sorption and desorption of MCPAinferralsol" (Wu et al. 2018); parameter 8 is from the literature "Study on the adsorption / desorption characteristics of sulfamethoxazole in different types of soil" (Wang Xinshuang 2017); parameter 9 is from the literature "Study of dynamic sorption and desorption of polycyclic aromatic hydrocarbons in silty-clay soil" (Yang et al. 2013).

[0166] Analysis of low solid-liquid ratio (S / r) s<5.000E-02), the fitting results of the Lan-rs* and Lan* desorption kinetic formulas to the kinetic data. As can be seen from the fitting parameters of groups 1 to 6 in Table 1, the correlation coefficients of both the Lan-rs* and Lan* desorption kinetic formulas are between 0.728 and 0.982. In 16 out of 33 desorption kinetic experiments, the correlation coefficients are above 0.900. This indicates that both desorption kinetic formulas can describe the desorption kinetics of different particles relative to different adsorbates under low solid-liquid ratio conditions.

[0167] Analysis of higher solid-liquid ratios (S / r) s >5.000E-02), the fitting results of Lan-rs* and Lan* desorption kinetic formulas to the kinetic data. As can be seen from the fitting parameters in groups 7 to 9 of Table 1, the correlation coefficients of the Lan-rs* desorption kinetic formula are all higher than those of the Lan* formula (0.974>0.959, 0.908>0.898, 0.966>0.948, 0.781>0.727, 0.868>0.708, 0.876>0.809, 1.000>0.942). In 6 out of the 7 experimental groups, the correlation coefficient of the Lan-rs* formula is above 0.850, indicating that the Lan-rs* formula can better describe the desorption kinetic process under high solid-liquid ratio conditions compared to the Lan* desorption kinetic formula. This is because Lan-rs* considers the volume occupied by particulate matter (S / r). s The effect of the Lan-rs* formula is more general and can better describe desorption under high solid-liquid ratio conditions. Compared to the Lan* desorption kinetic formula, the Lan-rs* formula shows a higher degree of overlap between the fitting curves and the experimental data points. In summary, the Lan-rs* desorption kinetic formula is more applicable than the Lan* formula for desorption processes under high solid-liquid ratio conditions.

[0168] Example 3

[0169] To perform the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a system for determining the remaining adsorption capacity of pollutant adsorbent particles is provided below, comprising:

[0170] The desorption kinetics experimental data acquisition module is used to acquire desorption kinetics experimental data for the same pollutant adsorbent particles. The desorption kinetics experimental data includes the remaining adsorption capacity per unit mass of pollutant adsorbent particles at different desorption times, determined through desorption kinetic experiments.

[0171] An improved Lan* desorption kinetics model building module is used to construct an improved Lan* desorption kinetics model; the improved Lan* desorption kinetics model is obtained by introducing a solid-liquid ratio into the Lan* desorption kinetics model.

[0172] The improved Lan* desorption kinetics model includes:

[0173]

[0174]

[0175]

[0176]

[0177]

[0178] Among them, Q t Let be the amount of adsorbate adsorbed per unit mass of adsorbent at time t during the desorption of adsorbent particles, q be the first intermediate variable, p be the second intermediate variable, R be the third intermediate variable, e be the base of the natural logarithm, and C be the third intermediate variable. t Let be the concentration of the adsorbate in the liquid phase at time t during the desorption of the adsorbent particles, Q0 be the initial adsorption amount per unit mass of adsorbent, S be the adsorbent concentration, and r be the adsorbent concentration. s This is the dry bulk density of the adsorbent.

[0179] The improved Lan* desorption kinetics model also includes:

[0180]

[0181]

[0182] Among them, Q t→∞ C represents the equilibrium adsorption capacity per unit mass of adsorbent during the desorption of adsorbent particles. t→∞ This represents the equilibrium concentration of the adsorbate in the liquid phase during the desorption of pollutant adsorbent particles.

[0183] The module for determining the prediction model of the remaining adsorption capacity of pollutant adsorbent particles is used to fit the coefficients in the improved Lan* desorption kinetic model based on Origin software and desorption kinetic experimental data to obtain the prediction model of the remaining adsorption capacity of pollutant adsorbent particles.

[0184] The target desorption time determination module is used to obtain the target desorption time.

[0185] The residual adsorption capacity prediction module for pollutant particles is used to input the target desorption time into the residual adsorption capacity prediction model for pollutant adsorbent particles to determine the residual adsorption capacity per unit mass of pollutant adsorbent particles at the target desorption time.

[0186] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0187] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for determining the remaining adsorption capacity of pollutant adsorbent particles, characterized in that, include: Obtain experimental data on the desorption kinetics of the same pollutant adsorbent particles; Building and improving LAN Desorption kinetics model; improved LAN The desorption kinetic model is based on Lan The desorption kinetics model was obtained by introducing the solid-liquid ratio. The improved Lan The desorption kinetic model includes: ； ； ； ； ； in, This represents the amount of adsorbate adsorbed per unit mass of adsorbent at time t during the desorption of pollutant adsorbent particles. As the first intermediate variable, As the second intermediate variable, As the third intermediate variable, is the base of the natural logarithm. Let t represent the concentration of the adsorbate in the liquid phase at time t during the desorption of the adsorbent particles, and Q0 represent the initial adsorption capacity per unit mass of adsorbent. The adsorbent concentration is... The dry bulk density of the adsorbent; The improved Lan The desorption kinetic model also includes: ； in, This refers to the equilibrium adsorption capacity per unit mass of adsorbent during the desorption of pollutant adsorbent particles. The equilibrium concentration of the adsorbate in the liquid phase during the desorption of pollutant adsorbent particles; Based on Origin software and desorption kinetic experimental data, an improved Lan By fitting the coefficients in the desorption kinetics model, a prediction model for the remaining adsorption capacity of the pollutant adsorbent particles is obtained. Obtain the target desorption time; Substitute the target desorption time into the prediction model for the remaining adsorption capacity of the pollutant adsorbent particles to determine the remaining adsorption capacity of a unit mass of pollutant adsorbent particles at the target desorption time.

2. The method for determining the remaining adsorption capacity of pollutant adsorbent particles according to claim 1, characterized in that, The desorption kinetics experimental data include the remaining adsorption amount per unit mass of pollutant adsorbent particles at different desorption times, determined through desorption kinetics experiments.

3. A system for determining the remaining adsorption capacity of pollutant adsorbent particles, characterized in that, include: The desorption kinetics experimental data acquisition module is used to acquire desorption kinetics experimental data of the same pollutant adsorbent particles; Improved Lan The desorption kinetics model building module is used to build improved LAN Desorption kinetics model; improved LAN The desorption kinetic model is based on Lan The desorption kinetics model was obtained by introducing the solid-liquid ratio. The improved Lan The desorption kinetic model includes: ； ； ； ； ； in, This represents the amount of adsorbate adsorbed per unit mass of adsorbent at time t during the desorption of pollutant adsorbent particles. As the first intermediate variable, As the second intermediate variable, As the third intermediate variable, is the base of the natural logarithm. Let t represent the concentration of the adsorbate in the liquid phase at time t during the desorption of the adsorbent particles, and Q0 represent the initial adsorption capacity per unit mass of adsorbent. The adsorbent concentration is... The dry bulk density of the adsorbent; The improved Lan The desorption kinetic model also includes: ； in, This refers to the equilibrium adsorption capacity per unit mass of adsorbent during the desorption of pollutant adsorbent particles. The equilibrium concentration of the adsorbate in the liquid phase during the desorption of pollutant adsorbent particles; A module for predicting the residual adsorption capacity of pollutant adsorbent particles is used to determine the model for improving LAN based on Origin software and desorption kinetic experimental data. By fitting the coefficients in the desorption kinetics model, a prediction model for the remaining adsorption capacity of the pollutant adsorbent particles is obtained. The target desorption time determination module is used to obtain the target desorption time; The residual adsorption capacity prediction module for pollutant particles is used to substitute the target desorption time into the residual adsorption capacity prediction model for pollutant adsorbent particles to determine the residual adsorption capacity of a unit mass of pollutant adsorbent particles at the target desorption time.

4. The system for determining the remaining adsorption capacity of pollutant adsorbent particles according to claim 3, characterized in that, The desorption kinetics experimental data include the remaining adsorption amount per unit mass of pollutant adsorbent particles at different desorption times, determined through desorption kinetics experiments.

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