A method for preparing an adsorbent using clay minerals and carbide slag

Abstract

The application discloses a method for preparing an adsorbent from clay minerals and carbide slag, and belongs to the technical field of deep processing of natural non-metallic minerals and preparation of heavy metal adsorption functional materials. The method uses natural clay and carbide slag as raw materials, and prepares a composite adsorption material containing multiple metal active sites through a solid phase reaction, and is suitable for efficient removal of high and low concentration heavy metal ions. The raw materials are cheap and easy to obtain, the preparation process is simple and efficient, the product has excellent performance, is widely applied, and has a broad prospect.

Description

Technical Field

[0001] The invention relates to a method for preparing an adsorbent by utilizing clay minerals and carbide slag, and belongs to the technical field of deep processing of natural non-metallic minerals, high-value utilization of resources and preparation of adsorption materials. Background Art

[0002] Heavy metals such as lead, nickel, cadmium, and chromium are essential in industries such as electronics, metallurgy, batteries, and new energy. However, their production and disposal can lead to serious environmental pollution, threatening water and soil safety. These metals are highly toxic and difficult to degrade, accumulating in the environment and spreading through the food chain.

[0003] In recent years, despite the development of a variety of heavy metal pollution treatment technologies, the removal methods and efficiency for low-concentration but highly harmful heavy metal pollutants are still limited. Adsorption is considered to be an effective means of treating heavy metal-contaminated wastewater in the future because it can completely remove heavy metals in water without causing secondary pollution, and is particularly suitable for low-concentration pollutants. However, existing adsorbents are difficult to strike a balance between adsorption capacity and efficiency, especially for the removal of low-concentration heavy metal ions. The high cost limits their widespread application. Therefore, it is crucial to develop new adsorbent materials that are low-cost, efficient, and suitable for heavy metal ions of different concentrations.

[0004] In nature, clay minerals (such as kaolinite, halloysite, and montmorillonite) are natural nano-silicate minerals characterized by fine particle size, stable structure, and large specific surface area. They are key components in the self-purification of heavy metals in the natural environment and possess excellent adsorption properties. Western my country boasts abundant attapulgite clay resources, with reserves reaching billions of tons. Its excellent adsorption properties make it suitable for use as an adsorption material. However, due to the paragenesis or association of these minerals with other minerals, the adsorption capacity of natural clays is limited, resulting in high purification and separation costs and hindering large-scale application.

[0005] To this end, the present invention proposes a technique for synthesizing porous adsorbent materials using the synergistic conversion of natural clay and solid waste. This technology converts low-reactivity minerals and solid waste into highly active mineral components, producing a new material with excellent heavy metal adsorption properties. This material not only retains the low-cost and environmentally friendly characteristics of clay minerals and mineral-based solid waste, but also significantly enhances adsorption performance, making it a new green and environmentally friendly material. Currently, research on the preparation of high-performance composite adsorbent materials by reacting natural clay and carbide slag with borates is still underdeveloped and holds great promise for development. Summary of the Invention

[0006] To address the challenge of purifying both high- and low-concentration heavy metal pollutants, the present invention provides a method for synergistically converting natural clay minerals and carbide slag solid waste into a porous heavy metal adsorbent. This method aims to utilize clay minerals and carbide slag, which are abundant and inexpensive in nature, to produce an environmentally friendly adsorbent with high efficiency for removing both high- and low-concentration heavy metal ions, effectively purifying heavy metal pollutants such as lead from various water bodies. This not only addresses the problem of heavy metal pollution but also opens up new avenues for the high-value utilization of clay mineral resources and the recycling of solid waste.

[0007] Heavy metal adsorbents are widely used in environmental protection, chemical engineering, energy, agriculture and animal husbandry, food and medicine, and the nuclear industry, and hold broad market potential. Existing adsorbent materials primarily include activated carbon, zeolites, and oxides. However, activated carbon and zeolites have limited adsorption capacity for low-concentration heavy metal ions and rapidly lose effectiveness after use. Oxide adsorbents also have low removal rates for low-concentration heavy metals. In contrast, mineral-based silicate composites offer the highest cost-performance ratio due to their readily available and inexpensive raw materials, simple preparation methods, environmentally friendly production processes, and excellent adsorption performance.

[0008] This invention addresses the shortcomings of existing adsorption materials and, by combining research on the driving force for high-concentration heavy metal adsorption and the mass transfer efficiency of deep adsorption of low-concentration heavy metals, successfully prepared a composite adsorbent with ultra-high adsorption capacity and extreme purification capabilities for common heavy metal ions (such as Pb(II), Cu(II), Cd(II), and Zn(II)) through the synergistic conversion of clay minerals / solid waste and borates. Notably, this adsorbent exhibits exceptional performance in treating both high and low concentrations of heavy metals, a feat unmatched by existing adsorption materials. It offers significant cost-effectiveness and broad market prospects.

[0009] A method for preparing an adsorbent using clay minerals and carbide slag, the main preparation method comprising the following steps:

[0010] (1) After crushing and grinding natural clay minerals, natural clay mineral powder with a particle size of less than 80 mesh is obtained; carbide slag and gasification slag that do not contain harmful heavy metals are selected as raw materials for preparing adsorbents;

[0011] (2) mixing the above-mentioned natural clay mineral powder, carbide slag powder and a small amount of gasification slag fine powder to obtain a mineral powder composition, then adding borate solid and continuing to stir and mix;

[0012] (3) Evenly spraying an aqueous solution containing a surfactant, which accounts for 10% to 25% of the total mass of the solid powder, into the obtained mixture, stirring it thoroughly to obtain a semi-wet mixture;

[0013] (4) The semi-wet mixture is continuously rolled 3-5 times with a double roller machine under the condition of a double roller spacing of 0.5-1 mm to obtain a flake product. This process further mixes the solids and causes some materials to undergo mechanochemical reaction, thereby increasing the reactivity of the reactants.

[0014] (5) calcining the above-mentioned flaky product at 400-900°C for 0.5-4h;

[0015] (6) The calcined product is cooled, crushed, and packaged to obtain the finished product.

[0016] In a possible embodiment, the natural clay mineral contains one or more minerals including attapulgite, illite, chlorite, montmorillonite, illite-montmorillonite, kaolinite, quartz, calcite, feldspar, mica, etc.

[0017] In a possible embodiment, in the composition of natural clay ore powder + carbide slag + gasified slag, the mass fraction of natural clay ore powder is 50% to 70%, the mass fraction of carbide slag is 25% to 45%, and the mass fraction of gasified slag is 5% to 25%.

[0018] In one possible embodiment, the borate includes at least one of sodium metaborate and sodium tetraborate.

[0019] In one possible embodiment, the surfactant is at least one of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, sodium lauryl sulfate, and sodium lauryl sulfonate, and its usage is 0.5% to 2% of the mass of the natural clay mineral powder + carbide slag + gasified slag composition.

[0020] In one possible embodiment, the amount of the borate is 10% to 60% of the total mass of the natural clay mineral powder + carbide slag + gasified slag composition.

[0021] In one possible embodiment, the heating rate of the calcination process is 5-20°C / min.

[0022] In a possible embodiment, the carbon content in the gasified slag is not less than 15%.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention prepares high-performance porous silicate adsorption materials by synergistically transforming natural clay and mineral-based solid waste (calcium carbide slag, gasification slag, etc.), achieving the three major goals of high-value utilization of complex clay minerals, resource utilization of solid waste, and development of high-performance adsorption materials. This not only effectively solves the problem of heavy metal water pollution, but also provides a new technology for the efficient utilization of low-quality clay minerals and solid waste resources.

[0025] (2) Under the induction of borate, the present invention achieves the synergistic transformation of calcium, aluminum, and iron components in clay minerals and carbide slag, and prepares borate-silicate composite adsorption materials. During the mineral transformation process, the inert Si-O-Si bonds break to form a large number of active Si-O- groups, which significantly enhances the material's chemical complexation, electrostatic adsorption, and ion exchange capabilities for heavy metals, and improves the adsorption driving force and mass transfer efficiency. Therefore, the adsorption capacity of the adsorption material for Pb(II), Cd(II), Co(II), and Ni(II) reached 6.34 times, 6.51 times, 13.71 times, and 16.48 times that of natural clay minerals, and 16.34 times, 24.70 times, 18.12 times, and 11.66 times that of commercially available activated carbon, respectively.

[0026] (3) The preparation method of the present invention is simple, the raw materials are widely available and low-cost, it is environmentally friendly, suitable for large-scale industrial production, and has broad application prospects.

[0027] (4) The product has excellent performance and good environmental compatibility. It is suitable for the adsorption and purification of heavy metal ions in various fresh water and sea water. It can not only be used to treat heavy metal-containing wastewater, but also can fix heavy metals in the soil and control their migration. It has a wide range of applications and broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, without paying any creative work, other related drawings can be obtained based on these drawings, which also fall within the scope of protection of the present application.

[0029] Figure 1 These are the XRD patterns of natural clay and the heavy metal adsorbent MMA-1 prepared using the technology of the present invention.

[0030] Figure 2 SEM images of natural clay (left) and heavy metal adsorbent MMA-1 (right) prepared using the technology of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be further described below with reference to the embodiments, which should not be construed as limiting the technical solution.

[0032] The present invention provides a method for preparing a high-performance heavy metal adsorbent by synergistically transforming natural clay and carbide slag solid waste. The method comprises the following steps: subjecting natural clay, carbide slag, gasified slag fines and borates to mechanical rolling treatment to improve mixing uniformity and the reactivity of each component; and then subjecting the natural clay, carbide slag and gasified slag to a heat treatment to promote the reaction of clay minerals, carbide slag and gasified slag with borates to form a porous silicate-borate composite adsorption material. During this process, a large number of active Si-O groups are formed on the surface of the mineral structure during transformation. At the same time, the surface charge becomes more negative, the specific surface area increases, and the ion exchange capacity is enhanced, thereby exhibiting excellent adsorption and fixation capabilities for high and low concentration heavy metal ions. The present invention prepares a composite heavy metal adsorbent by treating clay and solid waste, which are abundant in reserves but complex in composition, with the process described above. The composite heavy metal adsorbent has significantly better performance than adsorption materials such as natural clay and commercially available activated carbon, and can be widely used for the adsorption, removal or passivation of toxic heavy metal ions in water and soil.

[0033] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0034] Example 1

[0035] Natural clay minerals (sourced from Hangjin Banner, Inner Mongolia Autonomous Region, with the main mineral components including attapulgite, illite, chlorite, quartz, and calcite) were crushed and pulverized to obtain natural clay powder with a particle size of less than 80 mesh. Carbide slag and fumed slag (carbon content ≥15%), which do not contain harmful heavy metals, were selected as raw materials for preparing the adsorbent. 50 kg of natural clay powder, 45 kg of carbide slag powder, and 5 kg of fumed slag fine powder were mixed to obtain a mineral powder composition. Then, 60 kg of sodium tetraborate solid was added and stirred until thoroughly mixed. A 25 kg aqueous solution containing 0.5 kg of the surfactant cetyltrimethylammonium bromide was evenly sprayed into the resulting mixture and stirred thoroughly to obtain a semi-wet mixture. The semi-wet mixture was then rolled five times continuously on a double-roller mill with a gap of 0.5 mm between the rollers to obtain a flake product. This process further mixed the solids and caused some of the materials to undergo a mechanochemical reaction, increasing the reactivity of the reactants. The flake product was calcined at 700°C for 0.5 h at a heating rate of 5°C / min. The calcined product was cooled, crushed, and packaged to obtain the finished product. Product number: MMA-1.

[0036] Example 2

[0037] A natural clay mineral (from Hangjin Banner, Inner Mongolia Autonomous Region, main mineral components include attapulgite, illite, chlorite, quartz, calcite) is crushed and ground to obtain a natural clay mineral powder with a particle size of less than 80 mesh. Select calcium carbide slag and gasification slag (carbon content ≥ 15%) without harmful heavy metals as raw materials for preparing the adsorbent. Mix 70 kg of natural clay mineral powder, 25 kg of calcium carbide slag powder and 5 kg of gasification slag fine powder uniformly to obtain a mineral powder composition. Then add 10 kg of sodium tetraborate solid and continue to stir and mix uniformly; uniformly spray 10 kg of an aqueous solution containing 2 kg of surfactant octadecyltrimethylammonium bromide into the obtained mixture, stir uniformly, and obtain a semi-wet mixture; continuously roll the semi-wet mixture 3 times with a double roller with a roller spacing of 1 mm to obtain a sheet-shaped product, which further mixes the solids uniformly and causes part of the materials to undergo a mechanochemical reaction, thereby increasing the reactivity of the reactants; calcine the sheet-shaped product at a temperature of 400°C and a temperature rising rate of 10°C / min for 4 h; cool the calcined product, crush it, and package it to obtain the finished product. The product number is MMA-2.

[0038] Example 3

[0039] A natural clay mineral (from Linze County, Zhangye City, Gansu Province, main mineral components include attapulgite, illite, quartz, calcite, feldspar, mica) is crushed and ground to obtain a natural clay mineral powder with a particle size of less than 80 mesh. Select calcium carbide slag and gasification slag (carbon content ≥ 15%) without harmful heavy metals as raw materials for preparing the adsorbent. Mix 50 kg of natural clay mineral powder, 25 kg of calcium carbide slag powder and 25 kg of gasification slag fine powder uniformly to obtain a mineral powder composition. Then add 25 kg of sodium tetraborate solid and continue to stir and mix uniformly; uniformly spray 20 kg of an aqueous solution containing 1 kg of surfactant sodium dodecyl sulfate into the obtained mixture, stir uniformly, and obtain a semi-wet mixture; continuously roll the semi-wet mixture 4 times with a double roller with a roller spacing of 1 mm to obtain a sheet-shaped product, which further mixes the solids uniformly and causes part of the materials to undergo a mechanochemical reaction, thereby increasing the reactivity of the reactants; calcine the sheet-shaped product at a temperature of 900°C and a temperature rising rate of 20°C / min for 1 h; cool the calcined product, crush it, and package it to obtain the finished product. The product number is MMA-3.

[0040] Example 4

[0041] Natural clay minerals (sourced from Shangsi County, Guangxi, with the main mineral components including illite, montmorillonite, kaolinite, quartz, and calcite) were crushed and pulverized to obtain natural clay powder with a particle size of less than 80 mesh. Carbide slag and fumed slag (carbon content ≥ 15%), which do not contain harmful heavy metals, were selected as raw materials for preparing the adsorbent. 60 kg of natural clay powder, 30 kg of carbide slag powder, and 10 kg of fumed slag fine powder were mixed to obtain a mineral powder composition. Then, 30 kg of sodium tetraborate solid was added and stirred until thoroughly mixed. A 20 kg aqueous solution containing 1.5 kg of the surfactant dodecyltrimethylammonium bromide was evenly sprayed into the resulting mixture and stirred thoroughly to obtain a semi-wet mixture. The semi-wet mixture was then rolled three times continuously on a double-roller mill with a gap of 1 mm between the rollers to obtain a flake product. This process further mixed the solids and caused some of the materials to undergo a mechanochemical reaction, increasing the reactivity of the reactants. The flake product was calcined at 750°C for 2 hours at a heating rate of 15°C / min. The calcined product was cooled, crushed, and packaged to obtain the finished product. Product number: MMA-4.

[0042] Example 5

[0043] Natural clay minerals (sourced from Hangjin Banner, Inner Mongolia Autonomous Region, with the main mineral components including attapulgite, illite, chlorite, quartz, and calcite) were crushed and pulverized to obtain natural clay powder with a particle size of less than 80 mesh. Carbide slag and fumed slag (carbon content ≥15%), which do not contain harmful heavy metals, were selected as raw materials for preparing the adsorbent. 70 kg of natural clay powder, 15 kg of carbide slag powder, and 15 kg of fumed slag fine powder were mixed to obtain a mineral powder composition. Then, 40 kg of sodium tetraborate solid was added and stirred until thoroughly mixed. 18 kg of an aqueous solution containing 1 kg of the surfactant sodium dodecylsulfonate was evenly sprayed into the resulting mixture and stirred thoroughly to obtain a semi-wet mixture. The semi-wet mixture was then rolled five times continuously on a double-roller mill with a gap of 0.5 mm between the rollers to obtain a flake product. This process further mixed the solids and caused some of the materials to undergo a mechanochemical reaction, increasing the reactivity of the reactants. The flake product was calcined at 800°C for 1 hour at a heating rate of 10°C / min. The calcined product was cooled, crushed, and packaged to obtain the finished product. Product number: MMA-5.

[0044] Comparative Example 1

[0045] Natural clay minerals (sourced from Hangjin Banner, Inner Mongolia Autonomous Region, with the main mineral components including attapulgite, illite, chlorite, quartz, and calcite) were crushed and pulverized to obtain natural clay powder with a particle size of less than 80 mesh. Carbide slag and fumed slag (carbon content ≥15%), which do not contain harmful heavy metals, were selected as raw materials for preparing the adsorbent. 50 kg of natural clay powder, 45 kg of carbide slag powder, and 5 kg of fumed slag fine powder were mixed to obtain a mineral powder composition. The resulting mixture was evenly sprayed with 25 kg of an aqueous solution containing 0.5 kg of the surfactant cetyltrimethylammonium bromide, and thoroughly stirred to obtain a semi-wet mixture. The semi-wet mixture was then continuously rolled five times using a double-roller mill with a gap of 0.5 mm between the rollers to obtain a flake product. This process further mixed the solids and caused some of the materials to undergo a mechanochemical reaction, increasing the reactivity of the reactants. The flake product was then calcined at 700°C for 0.5 h at a heating rate of 5°C / min. The calcined product was cooled, crushed, and packaged to obtain the finished product. Product number: DBL-1.

[0046] Comparative Example 2

[0047] Natural clay minerals (sourced from Hangjin Banner, Inner Mongolia Autonomous Region, with the main mineral components including attapulgite, illite, chlorite, quartz, and calcite) were crushed and pulverized to obtain natural clay powder with a particle size of less than 80 mesh. Calcium carbide slag and fumed slag (carbon content ≥15%), which do not contain harmful heavy metals, were selected as raw materials for preparing the adsorbent. Weigh 100 kg of natural clay mineral powder, add 60 kg of sodium tetraborate solid, and continue stirring to mix thoroughly. Evenly spray 25 kg of an aqueous solution containing 0.5 kg of the surfactant cetyltrimethylammonium bromide into the resulting mixture and stir thoroughly to obtain a semi-wet mixture. The semi-wet mixture is then rolled five times continuously on a double-roller mill with a gap of 0.5 mm between the rollers to obtain a flaky product. This process further mixes the solids and causes some of the materials to undergo a mechanochemical reaction, increasing the reactivity of the reactants. The flaky product is then calcined at 700°C for 0.5 h at a heating rate of 5°C / min. The calcined product is cooled, crushed, and packaged to obtain the finished product. Product number: DBL-2.

[0048] Comparative Example 3

[0049] Natural clay minerals (sourced from Hangjin Banner, Inner Mongolia Autonomous Region, with the main mineral components including attapulgite, illite, chlorite, quartz, and calcite) were crushed and pulverized to obtain natural clay powder with a particle size of less than 80 mesh. Carbide slag and fumed slag (carbon content ≥15%), which do not contain harmful heavy metals, were selected as raw materials for preparing the adsorbent. 50 kg of natural clay powder, 45 kg of carbide slag powder, and 5 kg of fumed slag fine powder were mixed to obtain a mineral powder composition. Then, 60 kg of sodium tetraborate solid was added and stirred until thoroughly mixed. 25 kg of water was evenly sprayed into the resulting mixture and stirred thoroughly to obtain a semi-wet mixture. The semi-wet mixture was continuously rolled five times using a double-roller mill with a gap of 0.5 mm between the rollers to obtain a flaky product. This process further mixed the solids and caused some of the materials to undergo a mechanochemical reaction, increasing the reactivity of the reactants. The flaky product was calcined at 700°C for 0.5 h at a heating rate of 5°C / min. The calcined product was cooled, crushed, and packaged to obtain the finished product. Product number: DBL-3.

[0050] Experimental part

[0051] Experiment 1

[0052] The surface areas and pore parameters of the composite heavy metal adsorbents MMA-1, MMA-2, MMA-3, MMA-4, and MMA-5 prepared in Examples 1-5 and the natural clay were measured. The results are shown in Table 1.

[0053] Table 1 Specific surface area and pore parameters of natural clay and borosilicate composite heavy metal adsorbents

[0054]

[0055] As can be seen from Table 1, the specific surface area of ​​the composite heavy metal adsorbent prepared by the present invention is greatly improved compared with natural clay, and the pore volume and average pore diameter are also significantly increased, which is more conducive to the exposure of the adsorption sites inside the composite heavy metal adsorbent and the diffusion of the adsorbate inside the material.

[0056] Experiment 2

[0057] A high concentration solution with a Pb(II), Cd(II), Co(II), and Zn(II) ion concentration of ≥200 mg / L was prepared, and natural clay (particle size ≤177 μm), the adsorbents DBL-1 (particle size ≤177 μm), DBL-2 (particle size ≤177 μm), and DBL-3 (particle size ≤177 μm) prepared in Comparative Examples 1-3, the composite heavy metal adsorbents MMA-1 (particle size ≤177 μm), MMA-2 (particle size ≤177 μm), MMA-3 (particle size ≤177 μm), MMA-4 (particle size ≤177 μm), and MMA-5 (particle size ≤177 μm) prepared in Examples 1-5, and commercially available activated carbon (particle size ≤177 μm) were respectively added to the above solution, and the mixture was fully stirred or shaken to allow the adsorption to reach equilibrium. The adsorbent was separated by filtration, and the concentration of heavy metal ions in the filtrate was determined. The saturated adsorption capacity was calculated based on the concentration difference of heavy metal ions in the solution before and after adsorption and the mass of the adsorbent. The results are shown in Table 2.

[0058] Table 2 Saturated adsorption capacity of clay and adsorbent for high concentrations of Pb(II), Cd(II), Co(II), and Zn(II) ions

[0059]

[0060] As shown in Table 2, the saturated adsorption capacity of the composite heavy metal adsorbent prepared in the present invention for Pb(II), Cd(II), Co(II), and Zn(II) ions is significantly higher than that of natural clay minerals and commercially available activated carbon. The adsorption capacity of the adsorbent is significantly higher than that of comparative examples DBL-1 (without borate), DBL-2 (without carbide slag and gasification slag), and DBL-3 (without surfactant).

[0061] Experiment 3

[0062] A low-concentration solution with a Pb(II), Cd(II), Co(II), and Zn(II) ion concentration of ≤1000 μg / L was prepared. Natural clay (particle size ≤177 μm), adsorbents DBL-1 (particle size ≤177 μm), DBL-2 (particle size ≤177 μm), and DBL-3 (particle size ≤177 μm) prepared in Comparative Examples 1-3, composite heavy metal adsorbents MMA-1 (particle size ≤177 μm), MMA-2 (particle size ≤177 μm), MMA-3 (particle size ≤177 μm), MMA-4 (particle size ≤177 μm), and MMA-5 (particle size ≤177 μm) prepared in Examples 1-5, and commercially available activated carbon (particle size ≤100 μm) were added to the solution. The mixture was stirred or shaken thoroughly to allow adsorption to reach equilibrium. The solution was separated by filtration, and the residual heavy metal ions in the filtrate were measured. The results are shown in Table 3.

[0063] Table 3 Residual amounts of low-concentration Pb(II), Cd(II), Co(II), and Zn(II) ions after treatment with clay and adsorbent (initial concentration: 1000 μg / L)

[0064]

[0065] As shown in Table 3, the composite heavy metal adsorbent prepared by the present invention can reduce the concentrations of Pb(II), Cd(II), Co(II), and Zn(II) ions in solutions with an initial concentration of 1000 μg / L to a minimum of 3.12, 1.8, 1.73, and 4.26 μg / L, respectively, meeting WHO drinking water standards. Its overall adsorption performance significantly outperforms commercially available activated carbon and control samples (DBL-1, DBL-2, and DBL-3). The borosilicate composite adsorbent can reduce the concentrations of all four ions from approximately 1000 μg / L to less than 10 μg / L, making it suitable for removing low-concentration heavy metals in water.

[0066] Structural characterization and performance of the product of the present invention: The structure of the MMA-1 adsorbent was confirmed by X-ray powder diffraction (XRD) analysis, and the morphology of the MMA-1 adsorbent was confirmed by scanning electron microscopy (SEM) analysis. Figure 1 As can be seen in the figure, characteristic diffraction peaks of quartz at 2θ = 26.7°, calcite at 2θ = 29.40°, attapulgite at 2θ = 7.82°, and illite at 2θ = 8.45° are observed in the clay sample. The diffraction peak of calcium borate is also visible in the XRD pattern of the composite adsorbent MMA-1, indicating that calcium borate phases can also form in the presence of a large amount of clay, transforming the quartz, attapulgite, and illite components of the clay mineral into new silicates.

[0067] From the attached Figure 2 The presence of rod-shaped, flaky, and massive particles in natural clay (sourced from Hangjin Banner, Inner Mongolia Autonomous Region) indicates the presence of various mineral particle forms, consistent with the characteristics of naturally mixed clay. Through the preparation process described herein, the rod-shaped and flaky minerals are transformed into a uniform granular adsorbent, forming a borosilicate composite heavy metal adsorbent.

[0068] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A method for preparing an adsorbent using clay minerals and carbide slag, characterized in that: The following steps are involved: (1) crushing and grinding natural clay minerals to obtain natural clay mineral powder with a particle size of less than 80 mesh; Carbide slag and gasification slag that do not contain harmful heavy metals are selected as raw materials for preparing adsorbents; (2) Mix the above-mentioned natural clay mineral powder, carbide slag powder and gasification slag fine powder, then add borate solid and continue stirring and mixing; (3) evenly spraying an aqueous solution containing a surfactant in an amount of 10% to 25% of the total mass of the solid powder into the mixture obtained in step (2), stirring the mixture evenly to obtain a semi-wet mixture; (4) The semi-wet mixture is continuously rolled 3-5 times with a double roller machine under the condition of a double roller spacing of 0.5-1 mm to obtain a sheet product; (5) calcining the flake product at 400-900°C for 0.5-4h; (6) Cooling, crushing, and packaging the calcined product to obtain the finished product; In the composition of natural clay ore powder + carbide slag + gasified slag, the mass fraction of natural clay ore powder is 50% to 70%, the mass fraction of carbide slag is 25% to 45%, and the mass fraction of gasified slag is 5% to 25%; The amount of the borate is 10% to 60% of the total mass of the natural clay mineral powder, carbide slag and gasified slag composition.

2. The method for preparing an adsorbent using clay minerals and carbide slag according to claim 1, wherein: The natural clay minerals contain one or more minerals, including attapulgite, illite, chlorite, montmorillonite, illite-montmorillonite, kaolinite, quartz, calcite, feldspar, and mica.

3. The method for preparing an adsorbent using clay minerals and carbide slag according to claim 1, wherein: The borate is selected from at least one of sodium metaborate and sodium tetraborate.

4. The method for preparing an adsorbent using clay minerals and carbide slag according to claim 1, wherein: The surfactant is at least one of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, sodium lauryl sulfate, and sodium lauryl sulfonate, and its usage is 0.5% to 2% of the mass of the natural clay mineral powder + carbide slag + gasified slag composition.

5. The method for preparing an adsorbent using clay minerals and carbide slag according to claim 1, wherein: In step (5), the heating rate of the calcination process is 5-20°C / min.

6. The method for preparing an adsorbent using clay minerals and carbide slag according to claim 1, wherein: The carbon content in the gasified slag is not less than 15%.

7. An adsorbent prepared by the method for preparing an adsorbent using clay minerals and carbide slag according to any one of claims 1 to 6.

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