Aminated slag-based regular porous ball as well as preparation method and adsorption application thereof

Abstract

The invention relates to an aminated slag-based regular porous ball as well as a preparation method and adsorption application thereof, and belongs to the technical field of solid waste recycling and sewage adsorption materials. The method solves the problems that an existing slag-based adsorption material is irregular in shape and influences engineering application, and a functionalization method is low in efficiency and limited in adsorption performance. According to the technical scheme, the preparation method comprises the following steps: mixing slag, an alkali activator, water and a dispersant into slurry, adding chitosan and a foaming agent, injecting into a spherical mold, and curing to obtain a regular porous precursor; and carrying out hydrothermal reaction on the precursor in a specific amino compound aqueous solution to finally obtain the product. According to the method, the regular sphere shape of the material is guaranteed through mold forming, engineering use is facilitated, high-density amino active sites are introduced into the material through hydrothermal reaction, and the adsorption performance is improved. The prepared porous ball is mainly used for adsorbing and removing pollutants in a water body.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid waste resource utilization and sewage adsorption materials, and specifically relates to an aminated slag-based regular porous sphere and a preparation method and adsorption application thereof. BACKGROUND

[0002] Industrial waste slag (such as slag) resource utilization and water pollution control are important topics in the field of environmental engineering. Geopolymers are widely studied as adsorption matrices due to their three-dimensional network structure and simple preparation characteristics. However, traditional geopolymer adsorption materials face two major bottlenecks: First, the adaptability of morphology and structure is poor. Most studies prepare materials into irregular particles or blocks, which have uneven shape and size, and are prone to cause bed pressure drop increase, channeling short circuit, and even blockage in actual dynamic adsorption processes (such as fixed bed, flow bed), which seriously limits their engineering application potential. Although individual studies have attempted to granulate, they often lack coordinated control of spherical regularity, particle size uniformity, and internal porous structure.

[0003] Second, the adsorption function is single and the capacity is limited. In order to improve the adsorption capacity of specific pollutants (such as heavy metals), functional components (such as chitosan) are often introduced by physical doping or simple mixing. However, this method has low functionalization efficiency, limited number of active groups (such as amino groups) introduced, and easy blockage of original pores of the material, resulting in a decrease in specific surface area. For example, the prior art (CN202511001473.8) improves performance by introducing magnetic components and harsh hydrothermal conditions, but the process is complex, the cost is high, and the problem of simultaneous regulation of morphology and high efficiency of function has not been solved.

[0004] Therefore, it is of great significance to develop a slag-based adsorption material that can simultaneously realize regular spherical macro-morphology, developed pore microstructure, and high-density specific active sites, and to support a simple and efficient preparation process, for promoting the application of adsorption materials in continuous and high-efficiency sewage treatment. SUMMARY

[0005] An object of the present application is to solve at least the above-mentioned drawbacks and to provide at least the advantages that will be mentioned later.

[0006] The present application provides an aminated slag-based regular porous sphere and a preparation method and adsorption application thereof, which aims to solve the problems of irregular shape of existing slag-based geopolymer adsorption materials leading to difficulties in engineering application, and low functionalization efficiency and limited adsorption performance of physical doping method.

[0007] The present application provides a preparation method of an aminated slag-based regular porous sphere, comprising the following steps: (1) Mix slag, alkali activator and water, add dispersant and stir evenly to obtain basic slurry; then add chitosan and foaming agent and continue stirring to obtain uniform slurry; wherein the chitosan accounts for 15% to 25% of the total mass of slag and chitosan; (2) The slurry is injected into a spherical mold and cured to obtain a slag-based regular porous spherical precursor; (3) The slag-based regular porous sphere precursor is placed in a solution containing an amino compound and subjected to a hydrothermal reaction. After the reaction, it is washed and dried to obtain the aminated slag-based regular porous sphere. The amino compound is selected from N-(2-hydroxyethyl)ethylenediamine, N,N′-bis(2-hydroxyethyl)ethylenediamine, N-(2-hydroxypropyl)ethylenediamine or N-(2-hydroxypropyl)-1,3-propanediamine.

[0008] Preferably, the foaming agent is hydrogen peroxide, and its addition amount is 0.8%-1.2% of the slag mass.

[0009] Preferably, the dispersant is sodium dodecyl sulfate, and its addition amount is 0.2%-0.5% of the slag mass.

[0010] Preferably, the alkali activator is water glass with a modulus of 1.0-2.0, and the mass ratio of the total mass of the alkali activator and water to the mass of the slag is (0.9-1.2):1. The modulus refers to the molar ratio of SiO2 to Na2O in the water glass.

[0011] Preferably, in step (1), the slag is powder and its particle size is not less than 150 mesh; in step (2), the curing is carried out at 50-90℃ for 6-24 hours; in step (3), the temperature of the hydrothermal reaction is 160-200℃ and the reaction time is 3-8 hours.

[0012] Preferably, in step (3), the mass fraction of the amino compound in the aqueous solution is 6%-12%.

[0013] The present invention also provides an aminated slag-based regular porous sphere, which has a macroscopic spherical structure and a microscopic internal pore surface modified with regular leaf-like nanostructures, and is prepared by the above-described preparation method.

[0014] The present invention also provides the application of the above-mentioned aminated slag-based regular porous spheres in the adsorption and removal of organic pollutants and / or heavy metal ions in water.

[0015] Preferably, the organic pollutant is neutral red, and the heavy metal ion is Pb. 2+ .

[0016] Preferably, the amination-modified slag-based regular porous spheres undergo a color change after adsorbing metal ions, and this color change is used to identify Pb in the water. 2+ Ag + or Cu 2+ .

[0017] The present invention has at least the following beneficial effects: First, using industrial slag as the main raw material reduces material costs and provides an effective way to utilize solid waste resources.

[0018] Secondly, the regular spherical shape obtained by molding has controllable size and good uniformity, which is beneficial for filling in continuous processes such as fixed bed and fluidized bed, and can reduce bed pressure drop and avoid channeling or clogging problems.

[0019] Third, a hydrothermal reaction using hydroxyl-containing amino compounds forms a regular leaf-like nanostructure within the material, increasing the specific surface area and stabilizing the introduction of high-density amino active sites, thereby enhancing the resistance to dyes (such as neutral red) and heavy metal ions (such as Pb). 2+ Adsorption capacity of ).

[0020] Fourth, the material undergoes a significant color change after adsorbing specific metal ions (such as Pb adsorption). 2+ or Ag + It turns black afterward, having adsorbed Cu. 2+ (It turns green afterward) and can be used for rapid and intuitive identification of target metals in water.

[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0022] Figure 1 The image shows a photograph of the slag / chitosan composite porous spheres (Slag / CS(20%)-PS) prepared in Example 1 of this invention. The spheres are pale yellow in color.

[0023] Figure 2 The image shows a comparison of the infrared spectra of slag / chitosan composite porous spheres (Slag / CS(20%)-PS) and blank slag porous spheres (Slag-PS). In the image, 3467 cm⁻¹... -1 The peak at 2928 cm⁻¹ represents the stretching vibrations of OH and NH in chitosan. -1 This is a CH stretching vibration; 1644 cm -1 The amide I band exhibits C=O vibration; 1473 cm⁻¹ -1 The point is characterized by CN bond stretching vibration; 979 cm. -1The presence of characteristic peaks for COC and Si-O-Al / Si-O-Si at this point proves that chitosan has been successfully introduced.

[0024] Figure 3 The image shows the X-ray diffraction pattern of slag / chitosan composite porous spheres (Slag / CS(20%)-PS). Characteristic diffraction peaks of chitosan crystals appear at 2θ = 19.8° and 29.3°, further confirming the introduction of chitosan.

[0025] Figure 4 The image shows a scanning electron microscope image of a slag / chitosan composite porous sphere (Slag / CS(20%)-PS), which reveals a uniform porous structure with relatively smooth pore surfaces.

[0026] Figure 5 This is a scanning electron microscope (SEM) image of slag / chitosan composite porous spheres after hydrothermal modification with N-(2-hydroxyethyl)ethylenediamine (AEEDA) (Slag / CS(20%)-PS-AEEDA). Abundant and regular leaf-like nanostructures can be seen growing on the surface of the pores after modification.

[0027] Figure 6 The image shows a physical sample of Slag / CS(20%)-PS-AEEDA, which appears grayish-white in sunlight. After amination, its strength is found to increase.

[0028] Figure 7 The images show a comparison of scanning electron microscope (SEM) images of porous spheres modified with different amino compounds in Comparative Example 1. The images show that hydroxylamine compounds (such as AEEDA, BAEEDA, HPEDA, and HPPDA) can form regular leaf-like structures, while the others have rough or irregular structures. The analysis suggests that the hydroxylamine compounds and chitosan in the porous spheres act as templates, inducing molecular rearrangement in the porous spheres at high temperatures, forming regular leaf-like nanostructures on the inner surface of the pores. This also regulates the pore size of the porous spheres, which can further increase their surface area.

[0029] Figure 8 The images show a comparison of scanning electron microscope (SEM) images of porous spheres with different chitosan contents in Comparative Example 2 after undergoing the same amination treatment. The images show that the leaf-like structure is the most dense and regular when the chitosan content is 20%.

[0030] Figure 9 The image shows scanning electron microscopy (SEM) images of porous spheres obtained after hydrothermal reaction in AEEDA solutions of different concentrations in Comparative Example 3. The images show that the foliated structure is optimal when the concentration of amino compounds is in the range of 6%-12%.

[0031] Figure 10 The image shows scanning electron microscopy (SEM) images of porous spheres obtained at different hydrothermal reaction times in Comparative Example 4, indicating that the structure is fully developed after 5 hours of reaction.

[0032] Figure 11 The image shows scanning electron microscope (SEM) images of porous spheres obtained at different hydrothermal reaction temperatures in Comparative Example 5, indicating that 180 °C is the optimal reaction temperature.

[0033] Figure 12 The image shows a comparison of the infrared spectra of porous spheres modified with two amino compounds, AEEDA and BAEEDA, indicating that they both have similar spectra at 1473 cm⁻¹. -1 They all exhibit significant CN bond absorption peaks and have similar structures.

[0034] Figure 13 The X-ray diffraction comparison of porous spheres modified with two amino compounds, AEEDA and BAEEDA, shows that the original crystalline peaks of chitosan disappear and a new crystalline phase appears, indicating that structural reorganization occurs during the amination process.

[0035] Figure 14 The curve shows the effect of solution pH on the adsorption of neutral red by Slag / CS(20%)-PS-AEEDA.

[0036] Figure 15 A bar chart comparing the adsorption capacity of porous spheres with different compositions and whether they are modified for neutral red.

[0037] Figure 16 The curve shows the effect of adsorption time on the adsorption of neutral red by Slag / CS(20%)-PS-AEEDA.

[0038] Figure 17 The isothermal adsorption curves of neutral red dye adsorbed by Slag / CS(20%)-PS-AEEDA and the fitting curves of the Langmuir and Freundlich models are shown.

[0039] Figure 18 Slag / CS(20%)-PS-AEEDA for different metal ions (Pb 2+ Hg 2+ Ni 2+ Mn 2+ Cu 2+ Ag + A comparison chart of adsorption capacities.

[0040] Figure 19 The effect of solution pH on the adsorption of Pb by Slag / CS(20%)-PS-AEEDA 2+ The influence curve.

[0041] Figure 20 The adsorption time of Pb adsorption by Slag / CS(20%)-PS-AEEDA 2+ The influence curve.

[0042] Figure 21 For different Pb 2+ The effect of initial concentration on the adsorption performance of Slag / CS(20%)-PS-AEEDA, and the isothermal adsorption fitting results.

[0043] Figure 22 Slag / CS(20%)-PS-AEEDA adsorption of Pb 2+ Ag + Cu 2+ Before and after color change comparison chart.

[0044] Figure 23 This is a flowchart illustrating the preparation process of the present invention. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0046] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available unless otherwise specified. The alkaline activator used in this invention is water glass (i.e., sodium silicate aqueous solution), with a modulus of 1.5, meaning that the molar ratio of SiO2 to Na2O is 1.5. The aminated slag-based regular porous spheres of this invention have dual regular characteristics: firstly, their macroscopic morphology, formed by a spherical mold, presents a spherical shape with basically uniform size; secondly, their microstructure, after hydrothermal modification with amino compounds, forms a regular leaf-like nanostructure on the surface of the internal pores. The pore size of the spherical mold can be selected within a wide range, typically 0.3-3.0 cm, preferably 0.5 cm, to adapt to the particle size requirements of different adsorption scenarios. In actual operation, the volume of slurry injected into a single mold cavity (i.e., the amount added) can be flexibly adjusted to control the particle size of the formed porous sphere precursor under the same mold specification (e.g., a mold pore size of 0.5 cm). When the amount of material added is small, the particle size of the formed spheres is smaller; when the amount added is sufficient to fill the cavity, the spheres are closer to the theoretical aperture size of the mold. The average particle size of the final product can be easily adjusted within a certain range (e.g., 0.2-0.5 cm) to meet different application requirements.

[0047] The slag used in this invention was provided by Beihai Chengde Zongwei New Materials Co., Ltd. The chemical composition and content of the slag are shown in Table 1.

[0048] Table 1: The following is in conjunction with the appendix Figures 1-23 The technical solution and effects of the present invention will be described in detail.

[0049] Example 1: Preparation of slag / chitosan composite porous spheres (Slag / CS(20%)-PS) precursor Weigh 12g of slag powder (passed through a 200-mesh sieve), 0.04g of sodium dodecyl sulfate (SDS) as a dispersant, 8.2g of water glass with a modulus of 1.5, and 4g of deionized water. Place them in a container and mechanically stir at 250 rpm for 2 minutes to ensure uniform mixing. Then, add 3.0g of chitosan (20% of the total mass of slag and chitosan) and 0.4g of a 30% hydrogen peroxide solution (equivalent to 1% of the slag mass, used as a foaming agent). Continue stirring at the same speed for 2 minutes to obtain a uniform slurry. Load the slurry into a syringe and drip it dropwise into a spherical rubber mold with a pore size of 0.5cm. Then, place the mold in a 70℃ oven for 12 hours to cure. After curing, demold to obtain slag / chitosan composite porous spheres (labeled Slag / CS(20%)-PS). The actual product is shown below. Figure 1 As shown, it is pale yellow.

[0050] The infrared spectrum of the composite porous sphere ( Figure 2 The figure shows that at 3467cm -1 The characteristic peak of chitosan appears at 2928 cm⁻¹, which is attributed to the stretching vibrations of OH and NH. -1 This refers to the CH stretching vibration in the chitosan molecular chain; 1644 cm⁻¹ -1 The C=O stretching vibration of the acetyl group (amide I band); 1473 cm⁻¹ -1 The absorption peak at 979 cm⁻¹ is the CN bond stretching vibration peak. -1 The presence of characteristic peaks for COC, Si-O-Al, and Si-O-Si at this location confirms the successful integration of chitosan into the geopolymer framework. X-ray diffraction pattern ( Figure 3 The appearance of a chitosan crystal diffraction peak at 2θ = 19.8° further confirms the introduction of chitosan. (Scanning electron microscopy) Figure 4 This indicates that it has a uniform porous structure.

[0051] Example 2: Preparation of ammoniated slag-based regular porous spheres (Slag / CS(20%)-PS-AEEDA) 2g of N-(2-hydroxyethyl)ethylenediamine (AEEDA) was weighed and placed in a polytetrafluoroethylene liner. 20mL of deionized water was added to dissolve it, preparing a solution with an AEEDA mass fraction of approximately 9.1% (w / w). Subsequently, 2g of Slag / CS(20%)-PS precursor was added to this solution, and the mixture was sealed in a high-pressure reactor and subjected to a hydrothermal reaction at 180℃ for 5 hours. After the reaction, the reactor was allowed to cool naturally to room temperature. The product was then removed, and the spheres were repeatedly washed with a large amount of tap water until the washing solution was neutral to remove unreacted amino compounds. Finally, the washed product was dried in a 70℃ oven to constant weight to obtain ammoniated slag-based regular porous spheres (labeled as Slag / CS(20%)-PS-AEEDA). The actual product is shown in the image. Figure 6 As shown, the color is lighter than that of the Slag / CS(20%)-PS ball, appearing grayish-white.

[0052] The molecular formula of AEEDA is shown below: .

[0053] Scanning electron microscope (SEM) Figure 5 The infrared spectrum shows that abundant leaf-like nanostructures have grown on the surface of its internal pores. Figure 12 ) at 1473cm -1 A significant CN bond absorption peak appears nearby, XRD pattern ( Figure 13 The new crystal diffraction peaks indicate that the original crystal structure of chitosan has been disrupted and that it has chemically reacted with amino compounds to form a new crystalline phase. BET specific surface area measurements (as shown in Table 2) show that the specific surface area of ​​the amination-treated material increased from 47.106 m² / s². 2 / g increased to 73.646m 2 / g, a significant increase.

[0054] Table 2. Specific surface area of ​​Slag / CS-PS after hydrothermal reaction in different amino compounds. Product physical and structural performance characterization: The ammoniated slag-based regular porous spheres (Slag / CS(20%)-PS-AEEDA) prepared in Example 2 are macroscopically spherical with a basically uniform particle size, with an average particle size of 0.2-0.5 cm (which is essentially unchanged compared to the size of the precursor). Figure 5Scanning electron microscopy reveals that its core microscopic feature lies in the abundant and regular leaf-like nanostructures grown on the surface of its internal pores. Determined using the national standard GB / T1966-1996, this material exhibits high porosity (approximately 70%-85%) and a large specific surface area, providing ample space for the diffusion and adsorption of pollutant molecules. Furthermore, through hydrothermal modification with amino compounds, the material not only acquires a high density of amino active sites but also exhibits enhanced mechanical strength, maintaining structural integrity during conventional adsorption operations.

[0055] The amination process of this invention is not a simple physical mixing or impregnation. Under hydrothermal conditions, the selected hydroxyl-containing amino compound (such as AEEDA) interacts with components such as chitosan in the spherical framework, inducing their in-situ growth and rearrangement on the pore surface, thereby forming a regular and well-developed leaf-like nanostructure. This process simultaneously achieves two key effects: firstly, it provides secondary regulation of pores at the micro-nano scale, further increasing the specific surface area of ​​the material and providing more contact sites for pollutants; secondly, it chemically introduces and modifies high-density amino (-NH2) active groups onto the enlarged pore surface. These amino groups can bind to dye molecules (such as neutral red) in water through electrostatic attraction, hydrogen bonding, and other interactions, and can also bind to heavy metal ions (such as Pb). 2+ Coordination or ion exchange occurs.

[0056] Comparative Example 1: Effect of different amino compounds Following the steps of Example 2, only the amino compound AEEDA was replaced by N,N′-bis(2-hydroxyethyl)ethylenediamine (BAEEDA), N-(2-hydroxypropyl)ethylenediamine (HPEDA), N-(2-hydroxypropyl)-1,3-propanediamine (HPPDA), diethylenetriamine (DETA), urea, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (KH-602), and 2,5-diaminobenzenesulfonic acid (2,5-DASA), the names and molecular formulas of which are shown in Table 3.

[0057] Table 3. Different modified amino compounds and their molecular formulas Scanning electron microscopy results ( Figure 5 , Figure 7 The results show that the hydroxylamine-containing compounds (AEEDA, BAEEDA, HPEDA, HPPDA) selected in this invention can form regular and well-developed leaf-like structures within the pores; while compounds with other structures (such as DETA, urea, etc.) produce products with coarse, irregular, or no significant changes in structure. Because AEEDA and BAEEDA modification forms this unique, well-ordered nanostructure, the specific surface area of ​​the material is significantly increased (Table 2), ultimately exhibiting the highest pollutant adsorption capacity.Figure 15 It is evident that compounds with specific structures of AEEDA, BAEEDA, HPEDA, and HPPDA play a unique role in the formation of regular nanostructures.

[0058] Comparative Example 2: Effect of different chitosan contents Following the preparation method of Example 1, only the amount of chitosan added was changed to prepare precursors with chitosan contents (as a percentage of the mass of slag and chitosan) of 0%, 5%, 10%, and 20% (labeled as Slag / CS(0%)-PS, Slag / CS(5%)-PS, etc., respectively). These precursors were uniformly amination-treated with AEEDA under the same conditions.

[0059] Scanning electron microscope (SEM) Figure 8 The results showed that when the chitosan content was 20%, the foliated structure formed after amination was the most dense and regular. Adsorption performance tests also indicated that the adsorption capacity was highest at this level. This demonstrates that the chitosan content has a significant impact on the formation of the subsequent amination structure, with an optimal content of 20% (corresponding to a mass ratio of 1:5).

[0060] Comparative Example 3: Effect of amino compound concentration Solutions of AEEDA in deionized water with mass fractions of 6%, 9%, 12%, 15%, and 18% were prepared. Other conditions were the same as in Example 2. SEM ( Figure 9 This indicates that when the concentration is between 6% and 12%, the foliated structure of the product is uniform and regular, while excessively high concentrations lead to structural adhesion and irregularities. This suggests that the concentration of amino compounds needs to be controlled within an appropriate range.

[0061] Comparative Example 4: Effect of hydrothermal reaction time The hydrothermal reaction times were set to 2, 3, 5, and 8 hours, respectively, with other conditions the same as in Example 2. SEM ( Figure 10 The results showed that the structure was fully developed after 5 hours of reaction, and there was little change in structure after further extending the reaction time.

[0062] Comparative Example 5: Effect of Hydrothermal Reaction Temperature The hydrothermal reaction temperatures were set to 150℃, 180℃, and 200℃, respectively, with other conditions the same as in Example 2. SEM ( Figure 11 The data shows that the leaf-like structure is regular and abundant at 180℃, which is the optimal reaction temperature. If the temperature is too low, the structure will not develop fully, while if the temperature is too high, it may lead to the degradation of chitosan and the destruction of the structure.

[0063] Example of effect: Adsorption performance test The adsorption performance of the ammoniated slag-based regular porous spheres (taking Slag / CS(20%)-PS-AEEDA as an example) prepared by the method of this invention was verified in detail through the following series of adsorption tests.

[0064] Experiment 1: Effect of solution pH on adsorption performance To determine the optimal adsorption acidity, six 20 mL aliquots of 150 mg / L neutral red dye solution were prepared. The pH of each dye solution was adjusted using 0.1 M hydrochloric acid and 0.1 M NaOH solution (alkaline conditions were not tested because the properties of neutral red solution change at pH > 6.8). 20 mg of Slag / CS(20%)-PS-AEEDA adsorption beads were accurately added to each solution. The mixture was placed in a 25°C constant-temperature shaker and adsorbed at 150 rpm for 12 hours. After adsorption, the residual dye concentration in the solution was measured, and the adsorption capacity was calculated. The results are as follows: Figure 14 As shown, the material achieves optimal adsorption of neutral red dye at pH 5.5.

[0065] Similarly, examine its effect on Pb 2+ Adsorption: Prepare a Pb concentration of 100 mg / L 2+ The solution, with a volume of 50 mL, was adjusted to a pH of 2-6 using 0.1 M nitric acid. 20 mg of adsorption beads were added to each solution, and the mixture was shaken and adsorbed for 12 hours at 25 °C and 150 rpm. Test results showed that adsorption of Pb at pH=4 was effective. 2+ The adsorption capacity is the largest (see Figure 19 middle).

[0066] Experiment 2: Effect of material composition on amination modification To systematically evaluate the contribution of material composition and modification steps, a 100 mg / L neutral red solution was prepared, with each 20 mL aliquot. 20 mg of different control materials were added to the solution: blank slag porous spheres (Slag-PS), composite porous spheres with chitosan contents of 5%, 10%, and 20% (Slag / CS(5%)-PS, Slag / CS(10%)-PS, Slag / CS(20%)-PS), and porous spheres modified with AEEDA or BAEEDA (Slag / CS(20%)-PS-AEEDA, Slag / CS(20%)-PS-BAEEDA). All samples were placed in a 30°C shaker for 12 hours for adsorption. The results are as follows: Figure 15 As shown, the adsorption capacity of the blank slag balls was the lowest; after the introduction of chitosan, the adsorption capacity increased with the increase of chitosan content; after amination modification with AEEDA or BAEEDA, the adsorption capacity reached the highest value. This directly proves the necessity and synergistic enhancement effect of introducing chitosan into the slag matrix and further modifying it with hydrothermal compounds containing hydroxylamine for significantly improving the adsorption capacity of the material.

[0067] Experiment 3: Adsorption Kinetics A 25 mL solution of neutral red dye with a concentration of 20 mg / L was prepared and placed in a constant temperature environment at 25 °C. 20 mg of Slag / CS(20%)-PS-AEEDA adsorption beads were added to the solution, and the mixture was magnetically stirred at 150 rpm. Samples were taken at different time intervals to determine the solution concentration and calculate the adsorption capacity. The results are as follows: Figure 16 As shown, the adsorption process basically reached equilibrium within 90 minutes, indicating a relatively fast adsorption rate. Further fitting of the data using pseudo-first-order and pseudo-second-order kinetic models is performed (Table 4). The fitting results show that the correlation coefficient (R²) of the pseudo-second-order kinetic model is relatively high. 2 The value is higher (>0.99), indicating that the adsorption process is mainly chemical adsorption.

[0068] Table 4: Kinetic parameters of neutral red adsorption by Slag / CS(20%)-PS-AEEDA As shown in Table 4, the calculated equilibrium adsorption capacity (q2 = 18.08 mg / g) of the pseudo-second-order kinetic model agrees well with the experimentally measured value (q = 19.9 mg / g), and their correlation coefficient (R²) is also consistent. 2 The value >0.99 is significantly higher than that of the pseudo-first-order model. This indicates that the adsorption kinetics of neutral red by Slag / CS(20%)-PS-AEEDA is more consistent with the pseudo-second-order model, and the adsorption rate is mainly controlled by the chemical interaction between the amino active sites on the adsorbent surface and the dye molecules. The large fitting deviation of the pseudo-first-order model further illustrates that simple physical diffusion is not the main mechanism. This result is consistent with the design goal of this invention, which is to functionalize the material by introducing high-density amino groups. It can be seen that hydrothermal modification has successfully endowed the material with abundant specific chemisorption sites.

[0069] Experiment 4: Adsorption isotherm and maximum capacity Neutral red dye solutions with different initial concentrations (ranging up to 800 mg / L) were prepared, each with a volume of 20 mL. 10 mg of Slag / CS(20%)-PS-AEEDA adsorption beads were added to each solution, and the solutions were placed in constant-temperature shakers at 15℃, 30℃, and 45℃, respectively, and shaken at 150 rpm for 120 minutes for adsorption. The absorbance of the supernatant was measured using a UV-Vis spectrophotometer, and the equilibrium adsorption capacity was calculated. The results are shown below. Figure 17 As shown in Figure a, when the initial dye concentration was 800 mg / L and the temperature was 45℃, the measured equilibrium adsorption capacity reached 489.1 mg / g. The experimental data were fitted using the Langmuir model. Figure 17 (b) The results show that the model can describe the adsorption behavior well, and the calculated theoretical maximum adsorption capacity (q) is accurate. mThe theoretical value was 541.07 mg / g (Table 5). This theoretical value is higher than the measured maximum value, indicating that the adsorption was not completely saturated under the experimental conditions, and the material has a higher adsorption potential. Both models showed good fit, indicating that the adsorption process simultaneously includes characteristics of monolayer adsorption and surface heterogeneous adsorption.

[0070] Table 5: Isotherm fitting parameters for neutral red dye adsorption by Slag / CS(20%)-PS-AEEDA Experiment 5: Selective adsorption of various metal ions Prepare solutions of various metal ions (such as Pb) at a concentration of 100 mg / L. 2+ Mn 2+ Cu 2+ Ag + Hg 2+ Each 50 mL aliquot of the solution was prepared. 20 mg of Slag / CS(20%)-PS-AEEDA adsorption spheres were added to each aliquot, and the solutions were placed in a 25°C constant-temperature shaker at 150 rpm for 24 hours. After adsorption, the concentration of residual metal ions in the solution was determined using inductively coupled plasma optical emission spectrometry (ICP-OES), and the adsorption capacity was calculated. The results are as follows: Figure 18 As shown, this material adsorbs a variety of metal ions, but not Pb. 2+ It has the highest adsorption capacity and exhibits good selectivity.

[0071] Experiment 6: For Pb 2+ Specialized Adsorption Performance Research Systematic study on the adsorption characteristics of Pb²⁺ by Slag / CS(20%)-PS-AEEDA: pH effect: Preparation of Pb at a concentration of 100 mg / L 2+ The solution (50 mL) was adjusted to pH 2-6 with 0.1 M nitric acid. 20 mg of adsorption beads were added, and the mixture was shaken at 25°C and 150 rpm for 12 hours before the adsorption was measured. Figure 19 .

[0072] Kinetics: Preparation of Pb at a concentration of 100 mg / L 2+ Add 20 mg of adsorption beads to a 50 mL solution, shake at 25 °C and 150 rpm, and take samples at different time points to determine the adsorption capacity. Figure 20 .

[0073] Isothermal adsorption: Preparation of Pb at different initial concentrations (50-1200 mg / L) 2+Add 20 mg of adsorption beads to a 50 mL solution, and incubate at 25 °C and 150 rpm for 12 hours with shaking. Measure the adsorption amount. Figure 21 a.

[0074] All tests were conducted under constant temperature conditions of 25℃. The overall results are as follows: Figure 21 And as shown in Table 6. This material is effective against Pb. 2+ The adsorption of [the substance] is optimal at pH=4, reaching adsorption equilibrium in approximately 80 minutes. The theoretical maximum adsorption capacity (q) was calculated by fitting the isothermal adsorption data to the Langmuir model. m The concentration of Pb was 956.7 mg / g (Table 6). Under the experimental conditions (Pb... 2+ With an initial concentration of 1000 mg / L, the maximum equilibrium adsorption capacity was measured to be 880.5 mg / g. The theoretical value is higher than the measured value, indicating that the material has a higher adsorption potential. The correlation coefficient R0 of the Langmuir model fitting is [value missing]. 2 =0.9832, indicating that the adsorption process is more consistent with monolayer adsorption characteristics. In the Freundlich model, 1 / n = 0.2966 (less than 1), indicating that the adsorbent's effect on Pb is... 2+ Adsorption is beneficial.

[0075] During the above adsorption experiment, we observed a visual phenomenon: the porous sphere adsorbed Pb. 2+ After ionization, the sphere changed from grayish-white to black. When testing the effect of adsorption at different times, the black color deepened with the extension of adsorption time.

[0076] Table 6: Isotherm fitting parameters for Pb²⁺ adsorption by Slag / CS(20%)-PS-AEEDA Experiment 7: Research on Visual Recognition of Metal Ions Based on Color Changes Selectivity: Preparation of Pb at a concentration of 100 mg / L 2+ Solution (50 mL), simultaneously prepared with different metal ions (Hg) 2+ Ni 2 + Mn 2+ Cu 2+ Ag + The mother liquor was diluted to a concentration of 100 mg / L, and then one Slag / CS(20%)-PS-AEEDA adsorption ball was added to each. The mixture was shaken at 25℃ and 150 rpm, and the color change was observed. A color change was also observed in experiment 5. In the adsorption of metal ions, it was found that the porous ball adsorbed Pb. 2+ and Ag + It later turned black, Cu 2+It later turns green, but does not change color when adsorbing other metal ions, thus demonstrating that the porous sphere is effective against Pb. 2+ The adsorption is selective and visible; the color change before and after adsorption is as follows: Figure 22 .

[0077] In actual adsorption experiments, no sphere breakage was observed in any tests using Slag / CS(20%)-PS-AEEDA porous spheres. The spheres remained intact during post-adsorption recovery, and their structure remained stable even after repeated rinsing with tap water and drying at 70°C, demonstrating that the material possesses the mechanical strength required for engineering applications.

[0078] This invention utilizes a technical approach of "preparing a slag-based regularly spherical precursor and then hydrothermally functionalizing it with hydroxylamine-containing compounds" to successfully fabricate ammoniated slag-based regularly porous spheres with a regularly spherical macroscopic morphology, a well-developed porous microstructure, and a high density of amino active sites. This material is resistant to dyes (such as neutral red) and heavy metal ions (especially Pb). 2+ It exhibits high adsorption capacity, rapid kinetics and good selectivity, making it suitable for continuous flow wastewater treatment processes and showing significant potential for engineering applications.

[0079] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Further modifications can be readily implemented by those skilled in the art.

Claims

1. A method for preparing ammoniated slag-based regular porous spheres, characterized in that, Includes the following steps: (1) Mix slag, alkali activator and water, add dispersant, and stir evenly to obtain basic slurry; then add chitosan and foaming agent, and continue stirring to obtain uniform slurry; wherein the mass fraction of chitosan in the total mass of slag and chitosan is 15%-25%; (2) The slurry is injected into a spherical mold and cured to obtain a slag-based regular porous spherical precursor; (3) The slag-based regular porous sphere precursor is placed in a solution containing an amino compound and subjected to a hydrothermal reaction. After the reaction, it is washed and dried to obtain the aminated slag-based regular porous sphere. The amino compound is selected from N-(2-hydroxyethyl)ethylenediamine, N,N′-bis(2-hydroxyethyl)ethylenediamine, N-(2-hydroxypropyl)ethylenediamine or N-(2-hydroxypropyl)-1,3-propanediamine.

2. The preparation method according to claim 1, characterized in that, The foaming agent is hydrogen peroxide, and its addition amount is 0.8%-1.2% of the slag mass.

3. The preparation method according to claim 1, characterized in that, The dispersant is sodium dodecyl sulfate, and its addition amount is 0.2%-0.5% of the slag mass.

4. The preparation method according to claim 1, characterized in that, The alkaline activator is water glass with a modulus of 1.0-2.0, where the modulus is the molar ratio of SiO2 to Na2O, and the mass ratio of the total mass of the alkaline activator and water to the mass of the slag is (0.9-1.2):

1.

5. The preparation method according to claim 1, characterized in that, In step (1), the slag is powder and its particle size is not less than 150 mesh when sieved; in step (2), the curing is carried out at 50-90℃ for 6-24 hours; in step (3), the temperature of the hydrothermal reaction is 160-200℃ and the reaction time is 3-8 hours.

6. The preparation method according to claim 1, characterized in that, In step (3), the mass fraction of the amino compound in the aqueous solution is 6%-12%.

7. An aminated slag-based regular porous sphere, characterized in that, It is prepared by any one of claims 1 to 6.

8. The application of the aminated slag-based regular porous spheres as described in claim 7 in the adsorption and removal of organic pollutants and / or heavy metal ions in water.

9. The application according to claim 8, characterized in that, The organic pollutant is neutral red, and the heavy metal ion is Pb. 2+ .

10. The application according to claim 8 or 9, characterized in that, The aminated slag-based regular porous spheres undergo a color change after adsorbing metal ions, and this color change can be used to identify Pb in water. 2+ Ag + or Cu 2+ .

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