Method and system for determining adsorbate adsorption capacity of an adsorbent

Abstract

The present invention relates to a method and system for determining the adsorbate adsorption capacity of an adsorbent. The method includes: conducting an adsorption kinetics experiment on an adsorbent sample to obtain multiple sets of experimental data; fitting a Lan-rs adsorption kinetics model based on the experimental data to determine the model coefficients of the Lan-rs adsorption kinetics model corresponding to the adsorbent, and obtaining a Lan-rs adsorption kinetics model with known coefficients; using the Lan-rs adsorption kinetics model with known coefficients to determine the adsorbate adsorption capacity of the adsorbent at any adsorption time. Based on the Lan kinetics model, the present invention considers the solid-liquid ratio, especially a high solid-liquid ratio, improves the Lan kinetics model, and obtains the Lan-rs adsorption kinetics model of the present invention. It can be unrestricted by the solid-liquid ratio, better simulate the adsorption kinetics process, and achieve high-precision calculation of the adsorbate adsorption capacity of an adsorbent with a relatively high solid-liquid ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of soil pollution determination, and particularly to a method and system for determining the adsorbate adsorption amount of an adsorbent. Background Art

[0002] Compared with the research on adsorption isotherms, less attention has been paid to the research on adsorption kinetics. The adsorption phenomenon cannot be fully described by only adsorption isotherms, and the adsorption process needs to be considered. Some studies regard the adsorption of adsorbates by sediments as a rapid non-equilibrium process, and use first-order or reversible non-linear kinetic equations to describe adsorption and desorption, and the adsorption mechanism is overly simplified.

[0003] When studying the pollutant adsorption process, adsorption kinetic models such as Elovich, PFO (Pseudo-first-order), and PSO (Pseudo-second-order) are widely used. The forms of the model equations are as follows:

[0004] Elovich adsorption kinetic model:

[0005] Q t =aln(bt + 1)

[0006] PFO adsorption kinetic model:

[0007]

[0008] PSO adsorption kinetic model:

[0009]

[0010] Wherein, Q t is the adsorption amount of the adsorbate per unit mass of the adsorbent at time t, mg / kg; Q e is the adsorption amount of the adsorbate per unit mass of the adsorbent at adsorption equilibrium, mg / kg; a and b are constants of the Elovich adsorption kinetic model; t is the adsorption time, s; K1 is the pseudo-first-order reaction kinetic rate constant, 1 / s; K2 is the pseudo-second-order reaction kinetic rate constant, kg / (mg·s).

[0011] However, the Elovich adsorption kinetic model is an empirical model without a clear physical meaning and cannot provide important information about the mass transfer mechanism.

[0012] The PFO adsorption kinetic model is only valid in the initial stage of adsorption. In the whole adsorption process, the correlation between the PFO model and experimental data is poor.

[0013] The PSO adsorption kinetic model does not consider the existence of reverse reactions. Almost all adsorption reactions involve physical adsorption and covalent bond reactions, etc. It is theoretically inappropriate to ignore desorption. Moreover, in the derivation process of the PFO and PSO adsorption kinetic models, mass conservation is not applied, and the influence of the solid-liquid ratio on the adsorption kinetic parameters is not considered, which is obviously unreasonable.

[0014] Previous studies have pointed out that the PFO and PSO adsorption kinetic models assume that the adsorbate concentration is relatively constant. Therefore, these two models theoretically require that the initial liquid phase concentration of the adsorbate be high enough. However, too high an initial concentration will make it difficult to accurately determine the adsorption capacity because the adsorption capacity is calculated based on the change in the liquid phase concentration.

[0015] Huang Suiliang and Huang combined the initial conditions and derived an adsorption kinetic model (abbreviated as the Lan model in this invention) based on the rate term and the law of mass conservation in the process of deriving the Langmuir-type adsorption isotherm. However, in this model, it actually targets the case of a small solid-liquid ratio, that is, the particulate matter concentration S of the adsorbent and the dry bulk density r of the adsorbent particles s are very small compared to each other (such as in natural waters), or rather, the influence of the volume occupied by solid particles in the solution is not considered, and it is not applicable to the case where S / r s is not very small, such as adsorption occurring in adsorbents with a high solid-water ratio. SUMMARY OF THE INVENTION

[0016] In view of this, the present invention provides a method and system for determining the adsorbate adsorption capacity of an adsorbent to achieve high-precision calculation of the adsorbate adsorption capacity of the adsorbent.

[0017] To achieve the above object, the present invention provides the following solutions:

[0018] A method for determining the adsorbate adsorption capacity of an adsorbent, the method comprising the following steps:

[0019] Conduct an adsorption kinetic experiment on an adsorbent sample to obtain multiple sets of experimental data; the multiple sets of experimental data include the adsorbate adsorption capacity per unit mass of the adsorbent and the liquid phase adsorbate concentration at different preset adsorption times;

[0020] Based on the experimental data, perform Lan-rs adsorption kinetic model fitting to determine the model coefficients of the Lan-rs adsorption kinetic model corresponding to the adsorbent, and obtain the Lan-rs adsorption kinetic model with known coefficients; the model coefficients include: the adsorption rate coefficient K L1 、the desorption rate coefficient K L2 and the saturated adsorption capacity Q of the adsorbent per unit mass m ; the Lan-rs adsorption kinetic model is an improved Lan adsorption kinetic model by introducing the solid-liquid ratio;

[0021] Determine the adsorbate adsorption amount of the adsorbent at any adsorption time using the known Lan-rs adsorption kinetics model.

[0022] Optionally, conduct an adsorption kinetics experiment on the adsorbent sample to obtain multiple sets of experimental data, specifically including:

[0023] Load the adsorbent sample and the adsorbate solution into a headspace vial;

[0024] Conduct a constant-temperature oscillation experiment on the headspace vial;

[0025] When the preset adsorption time is reached, place the headspace vial after constant-temperature oscillation in a centrifuge for solid-liquid separation operation, and extract the supernatant after centrifugation;

[0026] Measure the supernatant using ultraviolet spectrophotometry to obtain the liquid-phase adsorbate concentration at the preset adsorption time;

[0027] Based on the law of conservation of mass, calculate the adsorbate adsorption amount per unit mass of the adsorbent at the preset adsorption time according to the liquid-phase adsorbate concentration at the preset adsorption time.

[0028] Optionally, the Lan-rs adsorption kinetics model includes the following formula:

[0029]

[0030]

[0031]

[0032] Among them, Q t is the adsorption amount of the adsorbate per unit mass of the adsorbent at time t, q, p, and R are the first intermediate variable, the second intermediate variable, and the third intermediate variable respectively, e is the base of the natural logarithm, C t is the liquid-phase adsorbate concentration at time t, C0 is the initial liquid-phase adsorbate concentration, S is the adsorbent concentration, r s is the dry bulk density of the adsorbent.

[0033] Optionally, the Lan-rs adsorption kinetics model also includes the following formula:

[0034]

[0035]

[0036] Among them, Q t→∞ is the equilibrium adsorption amount of the adsorbate per unit mass of the adsorbent, C t→∞ is the equilibrium concentration of the liquid-phase adsorbate.

[0037] An adsorbate adsorption capacity determination system for an adsorbent, the system comprising:

[0038] An experimental data acquisition module, configured to perform an adsorption kinetics experiment on an adsorbent sample to obtain multiple sets of experimental data; the multiple sets of experimental data include the adsorbate adsorption capacity per unit mass of the adsorbent and the liquid-phase adsorbate concentration at different preset adsorption times;

[0039] A model fitting module, configured to perform Lan-rs adsorption kinetics model fitting based on the experimental data to determine the model coefficients of the Lan-rs adsorption kinetics model corresponding to the adsorbent, and obtain a Lan-rs adsorption kinetics model with known coefficients; the model coefficients include: the adsorption rate coefficient K L1 , the desorption rate coefficient K L2 and the saturated adsorption capacity Q of the adsorbent per unit mass m ; The Lan-rs adsorption kinetics model is an improved Lan adsorption kinetics model by introducing the solid-liquid ratio.

[0040] An adsorbate adsorption capacity acquisition module, configured to use the Lan-rs adsorption kinetics model with known coefficients to determine the adsorbate adsorption capacity of the adsorbent at any adsorption time.

[0041] Optionally, the experimental data acquisition module obtains experimental data by the following specific steps:

[0042] Load the adsorbent sample and the adsorbate solution into a headspace bottle;

[0043] Perform a constant-temperature oscillation experiment on the headspace bottle;

[0044] When the preset adsorption time is reached, place the headspace bottle after constant-temperature oscillation in a centrifuge for solid-liquid separation operation, and extract the supernatant after centrifugation;

[0045] Measure the supernatant by ultraviolet spectrophotometry to obtain the liquid-phase adsorbate concentration at the preset adsorption time;

[0046] Based on the law of conservation of mass, calculate the adsorbate adsorption capacity per unit mass of the adsorbent at the preset adsorption time according to the liquid-phase adsorbate concentration at the preset adsorption time.

[0047] Optionally, the Lan-rs adsorption kinetics model includes the following formula:

[0048]

[0049]

[0050]

[0051] Wherein, Q tis the adsorption amount of adsorbate per unit mass of adsorbent at time t, q, p, and R are the first intermediate variable, the second intermediate variable, and the third intermediate variable respectively, e is the base of the natural logarithm, C t is the liquid-phase adsorbate concentration at time t, C0 is the initial liquid-phase adsorbate concentration, S is the adsorbent concentration, r s is the dry bulk density of the adsorbent.

[0052] Optionally, the Lan-rs adsorption kinetic model further includes the following formula:

[0053]

[0054]

[0055] wherein, Q t→∞ is the equilibrium adsorption amount of adsorbate per unit mass of adsorbent, C t→∞ is the equilibrium concentration of liquid-phase adsorbate.

[0056] According to the specific embodiments provided by the present invention, the following technical effects are disclosed:

[0057] The present invention discloses a method and a system for determining the adsorption amount of adsorbate of an adsorbent. The method includes: conducting an adsorption kinetics experiment on an adsorbent sample to obtain multiple sets of experimental data; fitting a Lan-rs adsorption kinetic model based on the experimental data to determine the model coefficients of the Lan-rs adsorption kinetic model corresponding to the adsorbent, and obtaining a Lan-rs adsorption kinetic model with known coefficients; using the Lan-rs adsorption kinetic model with known coefficients to determine the adsorption amount of adsorbate of the adsorbent at any adsorption time. Based on the Lan kinetic model, the present invention considers the solid-liquid ratio, especially a high solid-liquid ratio, improves the Lan kinetic model, and obtains the Lan-rs adsorption kinetic model of the present invention, which can be not limited by the solid-liquid ratio, better simulate the adsorption kinetics process, and realize the high-precision calculation of the adsorption amount of adsorbate of an adsorbent with a high solid-liquid ratio. Description of the Drawings

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0059] Figure 1 is a flowchart of a method for determining the adsorption amount of adsorbate of an adsorbent provided in Embodiment 1 of the present invention;

[0060] Figure 2It is a graph showing the change of the total amount of organic matter adsorbed by the soil sample over time obtained from the adsorption kinetics experiment provided in Embodiment 2 of the present invention; Figure 2 In (a), (b), (c) and (d) are graphs showing the change of the total amount of organic matter adsorbed by soil samples X1-1, X1-2, C1-1 and C1-2 over time respectively;

[0061] Figure 3 It is a schematic diagram of the fitting result of the experimental data obtained from the adsorption kinetics experiment provided in Embodiment 2 of the present invention and the Lan-rs adsorption kinetics model; Figure 3 In (a), (b), (c) and (d) are schematic diagrams of the fitting results of the experimental data of soil samples X1-1, X1-2, C1-1 and C1-2 and the Lan-rs adsorption kinetics model respectively;

[0062] Figure 4 It is a schematic diagram of the fitting result of the adsorption kinetics data obtained from the literature provided in Embodiment 3 of the present invention and the Lan-rs adsorption kinetics model; Figure 4 In (a), (b), (c), (d) and (e) are schematic diagrams of the fitting results of the adsorption kinetics data of different adsorbents for different adsorbates and the Lan-rs adsorption kinetics model respectively;

[0063] Figure 5 It is a comparison graph of the fitting effects of the Lan-rs adsorption kinetics model and the Lan adsorption kinetics model provided in Embodiment 4 of the present invention. Detailed implementation manners

[0064] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0065] The purpose of the present invention is to provide a method and system for determining the adsorbate adsorption amount of an adsorbent to achieve high-precision calculation of the adsorbate adsorption amount of the adsorbent.

[0066] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0067] Embodiment 1

[0068] Embodiment 1 of the present invention provides a method for determining the adsorbate adsorption amount of an adsorbent. The adsorption amount includes the liquid phase concentration of the adsorbate. The method includes the following steps:

[0069] Step 101: Conduct adsorption kinetics experiments on the adsorbent sample to obtain multiple sets of experimental data. The multiple sets of experimental data include the adsorbate adsorption amount per unit mass of the adsorbent and the liquid-phase adsorbate concentration at different preset adsorption times.

[0070] The step 101 of conducting adsorption kinetics experiments on the adsorbent sample to obtain multiple sets of experimental data specifically includes: loading the adsorbent sample and the adsorbate solution into a headspace bottle; conducting a constant-temperature shaking experiment on the headspace bottle; when the preset adsorption time is reached, placing the headspace bottle after constant-temperature shaking in a centrifuge for solid-liquid separation operation, and extracting the supernatant after centrifugation; measuring the supernatant by ultraviolet spectrophotometry to obtain the liquid-phase adsorbate concentration at the preset adsorption time; and calculating the adsorbate adsorption amount per unit mass of the adsorbent at the preset adsorption time based on the law of conservation of mass according to the liquid-phase adsorbate concentration at the preset adsorption time.

[0071] Step 102: Based on the experimental data, perform Lan-rs adsorption kinetics model fitting to determine the model coefficients of the Lan-rs adsorption kinetics model corresponding to the adsorbent, and obtain the Lan-rs adsorption kinetics model with known coefficients. The model coefficients include: adsorption rate coefficient K L1 , desorption rate coefficient K L2 and the saturated adsorption amount Q per unit mass of the adsorbent m ; The Lan-rs adsorption kinetics model is the Lan adsorption kinetics model improved by introducing the solid-liquid ratio.

[0072] Step 102 is specifically as follows:

[0073] Let Q t be the adsorption amount of the adsorbate per unit mass of the adsorbent at time t, mg / kg; C t be the liquid-phase adsorbate concentration at time t, mg / L; Q m be the saturated adsorption amount per unit mass of the adsorbent, mg / kg; K L1 be the adsorption rate coefficient, L / (mg·s); K L2 be the desorption rate coefficient, 1 / s; S be the adsorbent concentration, 10 3 kg / m 3 ; rs be the dry bulk density of the adsorbent, 10 3 kg / m 3 ; V be the volume of the water-adsorbent-adsorbate mixture, mL; Q0 be the initial adsorption amount of the adsorbate per unit mass of the adsorbent, mg / kg; C0 be the initial liquid-phase adsorbate concentration, mg / L; Q t→∞ be the equilibrium adsorption amount of the adsorbate per unit mass of the adsorbent, mg / kg; C t→∞ be the equilibrium concentration of the liquid-phase adsorbate.

[0074] According to the rate term in the derivation process of the Langmuir adsorption isotherm, the adsorption kinetic equation can be set as:

[0075]

[0076] According to the law of conservation of mass, the sum of the masses of the adsorbate in the liquid phase and the solid phase in the reactor (headspace vial) is a constant value:

[0077] Q t SV+(1-S / r s )VC t =Q0SV+(1-S / r s )VC0 (2)

[0078] Let: M=Q0S+(1-S / r s )C0

[0079] From equation (2), we can get:

[0080]

[0081] For the adsorption problem, it can be assumed that the initial adsorption amount of the adsorbate per unit mass of the adsorbent is 0, that is, the initial condition is:

[0082] Q0=0 (4)

[0083] Substitute equation (4) into equation (3), we can get:

[0084]

[0085] Substitute equation (5) into equation (1), we can get:

[0086]

[0087] Let:

[0088] R=K L1 Q m C0 (7)

[0089]

[0090]

[0091] Substitute (7), (8), (9) into equation (6), we can get:

[0092]

[0093] Combine the initial conditions (when t=0):

[0094] Q t =Q0

[0095] Integrating equation (10) gives:

[0096]

[0097] Let:

[0098]

[0099] Combining equations (4) and (12), equation (11) can be simplified to:

[0100]

[0101] Simplifying (13) gives:

[0102]

[0103] Substituting equation (12) into equation (14), the Lan-rs adsorption kinetic equation (15) can be obtained:

[0104]

[0105] Where, R = K L1 Q m C0.

[0106] Substituting equation (15) into equation (5) gives:

[0107]

[0108] The above two equations can calculate the concentrations of the adsorbate in the solid phase (equation (15)) and the liquid phase (equation (16)) at any adsorption time during the adsorption process.

[0109] When adsorption reaches equilibrium, the calculation formulas for the equilibrium concentration in the particle phase (i.e., the equilibrium adsorption amount of the adsorbate per unit mass of the adsorbent) and the equilibrium concentration in the liquid phase (i.e., the equilibrium concentration of the adsorbate in the liquid phase) can be obtained by taking the limit of equations (15) and (16) with respect to time, as shown in equations (17) and (18).

[0110]

[0111]

[0112] It can be seen that compared with the Lan adsorption kinetic model, the present Lan-rs adsorption kinetic model takes into account the influence of the volume S / r occupied by the particulate matter s and is more complete and more universal.

[0113] Combining (7), (8), (9), (17), and (18) gives:

[0114]

[0115] Wherein: K L = K L1 / K L2

[0116] Equation (19) is the Langmuir adsorption isotherm.

[0117] Step 103, use the Lan-rs adsorption kinetic model with known coefficients to determine the adsorbate adsorption amount of the adsorbent at any adsorption time.

[0118] Example 2

[0119] Example 2 of the present invention verifies the effect of the method in Example 1 of the present invention based on the adsorption kinetic experiment of soil samples adsorbing organic matter:

[0120] Soils X1-1 and X1-2 were collected from the campus woodland of Nankai University in Tianjin, with particle sizes of 0.125 - 0.250 mm and 0.075 - 0.125 mm respectively, and were not contaminated by petroleum hydrocarbons; soils C1-1 and C1-2 were collected from a petroleum hydrocarbon contaminated site in Hangzhou, Zhejiang Province, with particle sizes of 0.125 - 0.250 mm and 0.075 - 0.125 mm respectively. Weigh 1 g and 2 g of soil samples X1-1, X1-2, C1-1, and C1-2 respectively, place them in a 40 mL headspace bottle, inject the petroleum hydrocarbon solution without leaving a headspace. In this example, the soil sample is the adsorbent and the petroleum hydrocarbon solution is the organic matter or adsorbate. After sealing the headspace bottle, place it in a constant temperature shaking incubator at 25 °C and 150 rpm. At the 0th min, 1st min, 2nd min, 5th min, 7th min, 15th min, 20th min, 30th min, 40th min, 60th min, 90th min, 120th min, 180th min, 5 h, 8 h, 12 h, 24 h, and 48 h, place the shaken headspace bottle in a centrifuge at 2000 rpm for solid-liquid separation operation. Take 35 mL of the centrifuged supernatant and use ultraviolet spectrophotometry to measure the content of petroleum hydrocarbons in the liquid phase. Through calculation, the adsorption kinetic experiment data (adsorbate adsorption amount per unit mass of adsorbent and liquid phase adsorbate concentration) can be obtained.

[0121] Figure 2 In (a), (b), (c), and (d) are the graphs of the total organic matter adsorption of 4 soil samples (X1-1, X1-2, C1-1, C1-2) changing with time. When the adsorption equilibrium is reached (t → ∞), with the increase of the solid-liquid ratio, the total adsorption amount of the 4 soil samples increases, while the organic matter adsorption amount per unit weight (mass) of the soil decreases.

[0122] Use the Lan-rs adsorption kinetic model to fit 8 groups of kinetic experiment data, and the fitting results are shown inFigure 3 and Table 1.

[0123] Table 1 Fitting parameters of the experimental results of the adsorption of organic matter by soil particles using the Lan-rs adsorption kinetic model

[0124]

[0125]

[0126] Among them, TOM is the organic matter content of the soil sample.

[0127] From Figure 3 It can be seen that at the adsorption equilibrium (t → ∞), under the condition of a high solid-liquid ratio, the adsorption amount per unit mass of soil particles is smaller than that under the condition of a low solid-liquid ratio.

[0128] Previous studies have also explained the negative correlation between the unit adsorption amount and the solid-liquid ratio from different perspectives. In the state of a high solid-liquid ratio, due to the aggregation of a large amount of adsorbate, the adsorption sites easily obtained on the adsorbent per unit mass are reduced; secondly, under the condition of a high solid-liquid ratio, the collision between adsorbents is more frequent and desorption is more likely to occur. The phenomenon that the adsorption capacity decreases significantly with the increase of the solid concentration appears in various combinations of adsorbents and adsorbates. The Lan-rs adsorption kinetic model of the embodiment of the present invention can correctly reflect the change of the solid-liquid ratio.

[0129] It was found in this experiment that in the experiments with different solid-liquid ratios, the four parameters (the saturated adsorption amount Q of the adsorbent per unit mass m , the adsorption rate coefficient K L1 , the desorption rate coefficient K L2 , and the adsorption-desorption rate constant K L ) fitted by the Lan-rs adsorption kinetic model are not very different. Because these four parameters are all related to the properties of the adsorbent and the adsorbate themselves and the physical and chemical conditions of the system, and the relationship with the adsorbent concentration S is included in the Lan-rs adsorption kinetic equation through mass conservation.

[0130] The study also found that the distribution coefficient in the adsorption reaction is independent of the solid concentration and is mainly affected by the soil organic matter content. The organic matter content is the most important variable to explain the adsorption differences of different soil samples. It was found in this experiment that the higher the soil organic matter content, the larger the fitted K L (K L : X1-2 > X1-1 > C1-2 > C1-1).

[0131] The correlation coefficient R of the fitting of the Lan-rs adsorption kinetic model to 8 groups of experimental data 2All are above 0.900 (Table 1), indicating a good fitting effect. Therefore, the Lan-rs adsorption kinetic model derived based on the rate term and mass conservation law during the derivation of the Langmuir adsorption isotherm and combined with the initial conditions meets the requirements for the fitting accuracy of the experimental data.

[0132] Example 3

[0133] In Example 3 of the present invention, the adsorption kinetic data of the reference literature is used to verify the effect of Example 1 of the present invention.

[0134] Collect the adsorption kinetic data in the relevant literature and use the Lan-rs adsorption kinetic model for fitting. The fitting results are shown in Figure 4 and Table 2.

[0135] Table 2 Fitting parameters of the Lan-rs adsorption kinetic model for the adsorption kinetic experimental data in the literature

[0136]

[0137] In Table 2, the parameters No. 1 and No. 2 are from the literature "Study on the Adsorption Behavior of Diesel and Gasoline on Loess by Biochar and Humic Acid" (Wang Shulun 2013); the parameters No. 3, No. 4 and No. 5 are from the literature "Study on the Adsorption-Desorption of Typical Heavy Metal Pollutants by River Sediments" (He Mengqi 2014); the parameter No. 6 is from the literature "pyrene by Chernozem and carbonaceous sorbents: comparison of kinetics and interaction mechanisms" (Minkina et al. 2022); the parameter No. 7 is from the literature "Study on the Adsorption Characteristics and Adsorption Kinetics of Modified Bentonite on Cd(Ⅱ) in Wastewater" (Yang Xiumin et al. 2022); the parameters No. 8 and No. 9 are from the literature "Study on the Adsorption Equilibrium, Kinetics and Mechanism of Copper and Nickel in Water by Fly Ash" (Yu Zheng et al. 2022).

[0138] The fitting parameter R of the Lan-rs adsorption kinetic model for each experimental data 2 All are around 0.900. The Lan-rs adsorption kinetic model can not only fit the organic matter adsorption process, but also be applicable to the heavy metal adsorption process.

[0139] Example 4

[0140] In Example 4 of the present invention, the fitting effects of the Lan-rs adsorption kinetic model and the Lan adsorption kinetic model are compared:

[0141] In Example 4 of the present invention, the soil sample X1-1 (C0 = 5.320·mg L -1 , rs = 0.924×10 3 kg·m -3 ), the parameters K L1 , K L2 , Q m are respectively K L1 = 437.672*10-7L·(mg·s) -1 , K L2 = 2.300*10 - 3 s -1 , Q m = 443.930mg·kg -1 ; The parameters of the Lan equation are: K L1 = 437.526*10 -7 L·(mg·s) -1 , K L2 = 2.350*10 -3 ·s -1 , Q m = 443.930mg·kg -1 , combining the Lan-rs equation and the Lan equation to calculate the adsorption amount Q t→∞ at equilibrium under different soil sample concentrations S (different solid-liquid ratios) Figure 5 As shown 3 , when S is at 500 kg / m 3 , the equilibrium adsorption amount of the Lan-rs adsorption kinetic model is about 95% less than that of the Lan adsorption kinetic model. Since the solid particle content in a general soil system is much greater than 600 kg / m s s s , it can be seen that when S (or S / r

[0142] Example 5

[0143] Example 5 of the present invention provides a system for determining the adsorbate adsorption amount of an adsorbent, and the system includes:

[0144] An experimental data acquisition module, configured to perform an adsorption kinetics experiment on an adsorbent sample to obtain multiple sets of experimental data; the multiple sets of experimental data include the adsorbate adsorption amount per unit mass of the adsorbent and the liquid-phase adsorbate concentration at different preset adsorption times.

[0145] The experimental data acquisition module obtains experimental data by the following specific steps: loading the adsorbent sample and the adsorbate solution into a headspace bottle; conducting a constant-temperature oscillation experiment on the headspace bottle; when the preset adsorption time is reached, placing the headspace bottle after constant-temperature oscillation in a centrifuge for solid-liquid separation operation, and extracting the supernatant after centrifugation; measuring the supernatant by ultraviolet spectrophotometry to obtain the liquid-phase adsorbate concentration at the preset adsorption time; based on the law of conservation of mass, calculating the adsorbate adsorption amount per unit mass of the adsorbent at the preset adsorption time according to the liquid-phase adsorbate concentration at the preset adsorption time.

[0146] The model fitting module is used to perform Lan-rs adsorption kinetics model fitting based on the experimental data, determine the model coefficients of the Lan-rs adsorption kinetics model corresponding to the adsorbent, and obtain the Lan-rs adsorption kinetics model with known coefficients; the model coefficients include: adsorption rate coefficient K L1 , desorption rate coefficient K L2 and the saturated adsorption amount Q of per unit mass of the adsorbent m ; the Lan-rs adsorption kinetics model is the Lan adsorption kinetics model improved by introducing the solid-liquid ratio.

[0147] The Lan-rs adsorption kinetics model includes the following formula:

[0148]

[0149]

[0150]

[0151] where Q t is the adsorption amount of per unit mass of the adsorbent for the adsorbate at time t, q, p, and R are the first intermediate variable, the second intermediate variable, and the third intermediate variable respectively, e is the base of the natural logarithm, C t is the liquid-phase adsorbate concentration at time t, C0 is the initial liquid-phase adsorbate concentration, S is the adsorbent concentration, r s is the dry bulk density of the adsorbent.

[0152] The Lan-rs adsorption kinetics model also includes the following formula:

[0153]

[0154]

[0155] where Q t→∞ is the equilibrium adsorption amount of the adsorbate per unit mass of the adsorbent, C t→∞ is the equilibrium concentration of the liquid-phase adsorbate.

[0156] An adsorbate adsorption amount acquisition module, configured to determine the adsorbate adsorption amount of the adsorbent at any adsorption time by using the Lan-rs adsorption kinetic model with known coefficients.

[0157] According to the specific embodiments provided by the present invention, the following technical effects are disclosed:

[0158] The present invention discloses a method and a system for determining the adsorbate adsorption amount of an adsorbent. The method includes: conducting an adsorption kinetics experiment on an adsorbent sample to obtain multiple groups of experimental data; performing Lan-rs adsorption kinetic model fitting based on the experimental data to determine the model coefficients of the Lan-rs adsorption kinetic model corresponding to the adsorbent, and obtaining a Lan-rs adsorption kinetic model with known coefficients; and determining the adsorbate adsorption amount of the adsorbent at any adsorption time by using the Lan-rs adsorption kinetic model with known coefficients. Based on the Lan kinetic model, the present invention considers the solid-liquid ratio, especially a high solid-liquid ratio, improves the Lan kinetic model to obtain the Lan-rs adsorption kinetic model of the present invention, which can be unrestricted by the solid-liquid ratio, better simulate the adsorption kinetics process, and achieve high-precision calculation of the adsorbate adsorption amount of an adsorbent with a high solid-liquid ratio.

[0159] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0160] Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the control method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for determining the adsorbate adsorption capacity of an adsorbent, characterized in that, The method includes the following steps: Perform adsorption kinetics experiments on the adsorbent sample to obtain multiple sets of experimental data; the multiple sets of experimental data include the adsorbate adsorption amount per unit mass of the adsorbent and the liquid-phase adsorbate concentration at different preset adsorption times; Based on the experimental data, perform fitting of the Lan-rs adsorption kinetic model, determine the model coefficients of the Lan-rs adsorption kinetic model corresponding to the adsorbent, and obtain the Lan-rs adsorption kinetic model with known coefficients; the model coefficients include: the adsorption rate coefficient K L1 , the desorption rate coefficient K L2 , and the saturated adsorption capacity Q of the adsorbent per unit mass m ; the Lan-rs adsorption kinetic model is the Lan adsorption kinetic model improved by introducing the solid-liquid ratio Use the Lan-rs adsorption kinetics model with known coefficients to determine the adsorbate adsorption amount of the adsorbent at any adsorption time.

2. The method for determining the adsorbate adsorption amount of the adsorbent according to claim 1, characterized in that The performing of adsorption kinetics experiments on the adsorbent sample to obtain multiple sets of experimental data specifically includes: Load the adsorbent sample and the adsorbate solution into a headspace vial; Perform a constant-temperature shaking experiment on the headspace vial; When the preset adsorption time is reached, place the headspace vial after constant-temperature shaking in a centrifuge for solid-liquid separation operation, and extract the supernatant after centrifugation; Measure the supernatant by ultraviolet spectrophotometry to obtain the liquid-phase adsorbate concentration at the preset adsorption time; Based on the law of conservation of mass, calculate the adsorbate adsorption amount per unit mass of the adsorbent at the preset adsorption time according to the liquid-phase adsorbate concentration at the preset adsorption time.

3. The method for determining the adsorbate adsorption amount of the adsorbent according to claim 1, characterized in that, The Lan-rs adsorption kinetics model includes the following formula: R = K L1 Q m C0; Among them, Q t is the adsorption amount of adsorbate per unit mass of adsorbent at time t, q, p, and R are the first intermediate variable, the second intermediate variable, and the third intermediate variable respectively, e is the base of the natural logarithm, C t is the liquid-phase adsorbate concentration at time t, C0 is the initial liquid-phase adsorbate concentration, S is the adsorbent concentration, r s is the dry bulk density of the adsorbent.

4. The method for determining the adsorbate adsorption amount of the adsorbent according to claim 3, characterized in that, The Lan-rs adsorption kinetics model also includes the following formula: Among them, Q t→∞ is the equilibrium adsorption amount of the adsorbate per unit mass of the adsorbent, and C t→∞ is the equilibrium concentration of the adsorbate in the liquid phase.

5. An adsorbate adsorption amount determination system for an adsorbent, characterized in that, The system includes: An experimental data acquisition module for performing adsorption kinetics experiments on the adsorbent sample to obtain multiple sets of experimental data; the multiple sets of experimental data include the adsorbate adsorption amount per unit mass of the adsorbent and the liquid-phase adsorbate concentration at different preset adsorption times; A model fitting module, which is used to perform Lan-rs adsorption kinetic model fitting based on the experimental data, determine the model coefficients of the Lan-rs adsorption kinetic model corresponding to the adsorbent, and obtain the Lan-rs adsorption kinetic model with known coefficients; the model coefficients include: adsorption rate coefficient K L1 , desorption rate coefficient K L2 and saturated adsorption capacity Q of the adsorbent per unit mass m ; the Lan-rs adsorption kinetic model is the Lan adsorption kinetic model improved by introducing the solid-liquid ratio; An adsorbate adsorption amount acquisition module for using the Lan-rs adsorption kinetics model with known coefficients to determine the adsorbate adsorption amount of the adsorbent at any adsorption time.

6. The adsorbate adsorption amount determination system of the adsorbent according to claim 5, characterized in that, The experimental data acquisition module obtains experimental data by the following specific steps: Load the adsorbent sample and the adsorbate solution into a headspace vial; Perform a constant-temperature shaking experiment on the headspace vial; When the preset adsorption time is reached, place the headspace vial after constant-temperature shaking in a centrifuge for solid-liquid separation operation, and extract the supernatant after centrifugation; Measure the supernatant by ultraviolet spectrophotometry to obtain the liquid-phase adsorbate concentration at the preset adsorption time; Based on the law of conservation of mass, calculate the adsorbate adsorption amount per unit mass of the adsorbent at the preset adsorption time according to the liquid-phase adsorbate concentration at the preset adsorption time.

7. The adsorbate adsorption amount determination system of the adsorbent according to claim 5, characterized in that The Lan-rs adsorption kinetics model includes the following formula: R = K L1 Q m C0; Among them, Q t is the adsorption amount of adsorbate per unit mass of adsorbent at time t, q, p, and R are the first intermediate variable, the second intermediate variable, and the third intermediate variable respectively, e is the base of the natural logarithm, C t is the liquid-phase adsorbate concentration at time t, C0 is the initial liquid-phase adsorbate concentration, S is the adsorbent concentration, r s is the dry bulk density of the adsorbent.

8. The adsorbate adsorption amount determination system of the adsorbent according to claim 7, characterized in that, The Lan-rs adsorption kinetics model also includes the following formula: Among them, Q t→∞ is the equilibrium adsorption amount of the adsorbate per unit mass of the adsorbent, and C t→∞ is the equilibrium concentration of the adsorbate in the liquid phase.

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