Material for removing heavy metal ions in wastewater and preparation method thereof

Abstract

The invention discloses a material for removing heavy metal ions in wastewater and a preparation method of the material, Mg-doped ZnO quantum dots are loaded on a porous material carrier by adopting a deposition-precipitation method, agglomeration of the ZnO quantum dots is inhibited by utilizing a rich pore channel structure of a porous material, and the heavy metal ions in the wastewater are removed by utilizing the characteristics of small particle size, high activity and the like of the ZnO quantum dots. The adsorption performance of the porous material on heavy metal ions is effectively enhanced. Through Mg doping, the activity of the ZnO quantum dots is improved, and the stability of the ZnO quantum dots is enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of groundwater pollution remediation materials, and particularly relates to a material for removing heavy metal ions in wastewater and a preparation method thereof. Background Art

[0002] Industrial activities will produce a large amount of wastewater containing heavy metals (Cr, Pb, Cd, As, etc.). If not treated in time, it will cause serious environmental pollution and endanger the natural environment and human health.

[0003] Common methods for treating heavy metal wastewater include chemical precipitation, solution extraction, biological methods, adsorption, etc. Among them, adsorption is widely used due to its advantages such as high efficiency, environmental friendliness, and low cost.

[0004] In recent years, a variety of technologies for preparing adsorption materials for heavy metals in wastewater have been disclosed in the art. Chinese invention patent CN118874417A discloses a formula and preparation method for a low-concentration heavy metal wastewater adsorbent. The invention uses edible fungus waste as the main raw material, supplemented with polyvinyl alcohol, sodium alginate and other ingredients, and forms hydrogel particles with good adsorption properties and mechanical strength through a specific preparation process. Chinese invention patent CN118874443A discloses a heavy metal adsorption material and its preparation method and application. The invention mixes biomass with thiosulfate, performs pyrolysis, and obtains modified biochar. The modified biochar is then mixed with magnesium chloride and sintered to obtain a heavy metal adsorption material. However, in the prior art, heavy metal adsorption materials still have problems such as low mechanical strength and poor adsorption properties. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in response to the technical problems existing in the prior art, the present invention provides a material for removing heavy metal ions in wastewater and a preparation method thereof.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] A material for removing heavy metal ions in wastewater comprises raw materials including porous material, zinc acetate, magnesium acetate and cerium nitrate, wherein the mass ratio of zinc acetate, magnesium acetate and cerium nitrate is 85:10:5 to 80:15:5.

[0008] As a further improvement of the above technical solution:

[0009] In the above technical solution, the porous material is one of sepiolite, attapulgite, kaolin, and biochar.

[0010] The present invention also provides a method for preparing a material for removing heavy metal ions from wastewater, which is used to prepare the above-mentioned material, comprising the following steps:

[0011] Step S1, weighing a porous material, zinc acetate, magnesium acetate, and cerium nitrate, adding them to anhydrous ethanol or methanol, stirring in a water bath at 60-90° C. for 2-4 hours, and cooling to obtain a mixed solution;

[0012] Step S2, slowly adding anhydrous ethanol or methanol solution to the mixed solution of step S1, stirring at room temperature for 4 to 8 hours, transferring to a hydrothermal kettle, hydrothermally crystallizing at 140 to 180° C. for 8 to 15 hours, cooling, washing three times with deionized water, filtering, and drying to obtain Mg-Ce-ZnO / porous material powder;

[0013] Using porous materials as carriers, Mg and Ce-doped ZnO quantum dots are loaded on the carriers through deposition and precipitation. ZnO quantum dots can effectively enhance the adsorption performance of porous materials for heavy metals, and the porous structure of the carrier can effectively inhibit the agglomeration of ZnO quantum dots.

[0014] Step S3: adding Mg-Ce-ZnO / porous material powder to inorganic binder and glass fiber, mixing evenly, placing in a granulator, and preparing small balls with a diameter of 3 to 8 mm.

[0015] In the above technical solution, in step S1, Mg-Ce-ZnO accounts for 0.1-1 wt% of the mass of the porous material.

[0016] In the above technical solution, in step S2, the anhydrous ethanol is anhydrous ethanol containing KOH.

[0017] In the above technical solution, in step S3, the inorganic binder is one of Al2O3, SiO2, pseudo-boehmite, and TiO2.

[0018] In the above technical solution, in step S3, the mass fraction of Mg-Ce-ZnO / porous material is 85-95%, the mass fraction of inorganic binder is 1-10%, and the mass fraction of glass fiber is 1-10%.

[0019] The material for removing heavy metal ions from wastewater and the preparation method thereof provided by the present invention have the following advantages over the prior art:

[0020] (1) The material for removing heavy metal ions from wastewater of the present invention uses Mg and Ce doped ZnO quantum dots as adsorption activity enhancing materials. Compared with ZnO, Mg and Ce doped ZnO quantum dots have the advantages of small particles, high surface energy, multiple active sites, and high reaction activity. At the same time, Mg and Ce doping will further improve the activity and stability of ZnO quantum dots, and can further enhance the adsorption activity of active materials for heavy metals. Non-doped CeO2 can also provide active adsorption sites for anions.

[0021] (2) The method for preparing a material for removing heavy metal ions from wastewater of the present invention utilizes the rich pore structure of the porous material to inhibit the agglomeration of ZnO quantum dots. The small particle size and high activity of the ZnO quantum dots are utilized to effectively enhance the adsorption performance of the porous material for heavy metal ions. Mg doping improves the activity and stability of the ZnO quantum dots. The material has strong mechanical properties and permeability, making it suitable for long-term use. The overall preparation process is simple and the cost is low, making it convenient for large-scale preparation and application. DETAILED DESCRIPTION

[0022] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0023] Example 1

[0024] Weigh sepiolite, zinc acetate, magnesium acetate, and cerium nitrate, add them to anhydrous ethanol, and stir in a 90°C waterbath for 2 hours. After cooling, slowly add a solution of KOH in anhydrous ethanol, stir at room temperature for 4 hours, then transfer to a hydrothermal reactor and crystallize at 140°C for 15 hours. After cooling, wash three times with deionized water, filter, and dry to obtain Mg-Ce-ZnO / sepiolite powder. Weigh the Mg-Ce-ZnO / sepiolite powder, add Al2O3 and glass fiber, mix thoroughly, and place in a granulator to produce pellets with a diameter of 3 mm.

[0025] The molar ratio of zinc acetate, magnesium acetate, and cerium nitrate is 85:10:5. The amount of KOH is 2.5 times the total amount of zinc acetate and magnesium acetate. Mg-Ce-ZnO accounts for 0.1 wt% of the sepiolite.

[0026] The material composition is as follows: the mass fraction of Mg-Ce-ZnO / sepiolite powder is 85%, the mass fraction of Al2O3 is 10%, and the mass fraction of glass fiber is 5%.

[0027] Example 2

[0028] Attapulgite, zinc acetate, magnesium acetate, and cerium nitrate were weighed and added to methanol. The mixture was stirred in a 60°C waterbath for 4 hours. After cooling, a methanolic solution of potassium hydroxide was slowly added and stirred at room temperature for 8 hours. The mixture was then transferred to a hydrothermal reactor and hydrothermally crystallized at 180°C for 8 hours. After cooling, the mixture was washed three times with deionized water, filtered, and dried to obtain Mg-Ce-ZnO / attapulgite powder. The Mg-Ce-ZnO / attapulgite powder was weighed, SiO2 and glass fiber were added, and the mixture was mixed thoroughly. The mixture was then placed in a pelletizer to produce pellets with a diameter of 8 mm.

[0029] The molar ratio of zinc acetate, magnesium acetate, and cerium nitrate is 80:15:5. The molar ratio of KOH is four times the combined molar ratio of zinc acetate and magnesium acetate. Mg-Ce-ZnO accounts for 1 wt% of the attapulgite.

[0030] The material composition is as follows: the mass fraction of Mg-Ce-ZnO / attapulgite powder is 95%, the mass fraction of SiO2 is 2%, and the mass fraction of glass fiber is 3%.

[0031] Example 3

[0032] Kaolin, zinc acetate, magnesium acetate, and cerium nitrate were weighed and added to anhydrous ethanol. Stirred in an 80°C waterbath for 3 hours. After cooling, a KOH solution in anhydrous ethanol was slowly added and stirred at room temperature for 6 hours. The mixture was then transferred to a hydrothermal reactor and hydrothermally crystallized at 160°C for 10 hours. After cooling, the mixture was washed three times with deionized water, filtered, and dried to obtain Mg-Ce-ZnO / kaolin powder. The Mg-Ce-ZnO / kaolin powder was weighed, pseudo-boehmite and glass fiber were added, mixed thoroughly, and placed in a granulator to produce pellets with a diameter of 5 mm.

[0033] The molar ratio of zinc acetate, magnesium acetate, and cerium nitrate is 82:13:5. The amount of KOH is three times the total amount of zinc acetate and magnesium acetate. Mg-Ce-ZnO accounts for 0.5 wt% of the kaolin.

[0034] The material composition is as follows: the mass fraction of Mg-Ce-ZnO / kaolin powder is 90%, the mass fraction of pseudo-boehmite is 5%, and the mass fraction of glass fiber is 5%.

[0035] Example 4

[0036] Biochar, zinc acetate, magnesium acetate, and cerium nitrate were weighed and added to anhydrous ethanol. Stirred in a 70°C waterbath for 2 hours. After cooling, a solution of KOH in anhydrous ethanol was slowly added and stirred at room temperature for 5 hours. The mixture was then transferred to a hydrothermal reactor and hydrothermally crystallized at 150°C for 12 hours. After cooling, the mixture was washed three times with deionized water, filtered, and dried to obtain Mg-Ce-ZnO / biochar powder. The Mg-Ce-ZnO / biochar powder was weighed, Al2O3 and glass fiber were added, mixed thoroughly, and placed in a pelletizer to produce pellets with a diameter of 4 mm.

[0037] The molar ratio of zinc acetate, magnesium acetate, and cerium nitrate is 90:5:5. The molar ratio of KOH is four times the combined molar ratio of zinc acetate and magnesium acetate. Mg-Ce-ZnO accounts for 0.8 wt% of the biochar.

[0038] The material composition is: the mass fraction of Mg-Ce-ZnO / biochar powder is 85%, the mass fraction of Al2O3 is 5%, and the mass fraction of glass fiber is 10%.

[0039] Example 5

[0040] Biochar, zinc acetate, magnesium acetate, and cerium nitrate were weighed and added to anhydrous ethanol. Stirred in an 80°C waterbath for 3 hours. After cooling, a solution of KOH in anhydrous ethanol was slowly added and stirred at room temperature for 4 hours. The mixture was then transferred to a hydrothermal reactor and hydrothermally crystallized at 180°C for 10 hours. After cooling, the mixture was washed three times with deionized water, filtered, and dried to obtain Mg-Ce-ZnO / biochar powder. The Mg-Ce-ZnO / biochar powder was weighed, TiO2 and glass fiber were added, mixed thoroughly, and placed in a pelletizer to produce pellets with a diameter of 6 mm.

[0041] The molar ratio of zinc acetate, magnesium acetate, and cerium nitrate is 83:12:5. The amount of KOH is 2.5 times the combined amount of zinc acetate and magnesium acetate. Mg-Ce-ZnO accounts for 0.3 wt% of the biochar.

[0042] The material composition is: the mass fraction of Mg-Ce-ZnO / biochar powder is 90%, the mass fraction of TiO2 is 7%, and the mass fraction of glass fiber is 3%.

[0043] Comparative Example 1

[0044] Weigh sepiolite powder, add Al2O3 and glass fiber, mix well, and place in a granulator to prepare small balls with a diameter of 3 mm.

[0045] The material composition is as follows: the mass fraction of sepiolite powder is 85%, the mass fraction of Al2O3 is 10%, and the mass fraction of glass fiber is 5%.

[0046] Comparative Example 2

[0047] Attapulgite and zinc acetate were weighed and added to anhydrous ethanol. Stirred in a 60°C waterbath for 4 hours. After cooling, a solution of KOH in anhydrous ethanol was slowly added and stirred at room temperature for 8 hours. The mixture was then transferred to a hydrothermal reactor and hydrothermally crystallized at 180°C for 8 hours. After cooling, the mixture was washed three times with deionized water, filtered, and dried to obtain ZnO / attapulgite powder. The ZnO / attapulgite powder was weighed, SiO2 and glass fiber were added, and the mixture was mixed thoroughly. The mixture was then placed in a granulator to produce pellets with a diameter of 8 mm.

[0048] The amount of KOH is 4 times the total amount of zinc acetate and magnesium acetate. ZnO accounts for 1 wt% of the mass of the attapulgite.

[0049] The material composition is as follows: the mass fraction of ZnO / attapulgite powder is 95%, the mass fraction of SiO2 is 2%, and the mass fraction of glass fiber is 3%.

[0050] Test Example 1

[0051] Prepare a 200 mg / L Pb(II) solution by adding the pellets and Pb(II) solution at a dosage of 1 g / L to a conical flask. Place the conical flask in a shaker at 25°C and 180 rpm for 5 hours. Measure the Pb(II) concentration in the solution using an inductively coupled plasma spectrometer, and calculate the Pb(II) removal rate.

[0052] Table 1 Pb(Ⅱ) removal rate of different materials

[0053] Residual Pb(Ⅱ) concentration (mg / L) Pb(Ⅱ) removal rate (%) Example 1 0.1 99.9 Example 2 0.09 99.9 Example 3 0.08 99.9 Example 4 0.05 99.9 Example 5 0.09 99.9 Comparative Example 1 74.31 62.8 Comparative Example 2 51.25 74.4

[0054] Test Example 2

[0055] Prepare a 100 mg / L Cd(II) solution by adding pellets and the Cd(II) solution at a dosage of 1 g / L to a conical flask. Place the conical flask in a shaker at 25°C and 180 rpm for 10 hours. Determine the Cd(II) concentration in the solution using an inductively coupled plasma spectrometer, and calculate the Cd(II) removal rate.

[0056] Table 2 Removal rate of Cd(Ⅱ) of different materials

[0057] Residual Cd(Ⅱ) concentration (mg / L) Cd(Ⅱ) removal rate (%) Example 1 0 100 Example 2 0 100 Example 3 0 100 Example 4 0 100 Example 5 0.01 99.9 Comparative Example 1 41.98 58.0 Comparative Example 2 23.54 76.5

[0058] Test Example 3

[0059] Prepare a 20 mg / L As(V) solution by adding the pellets and As(V) solution at a dosage of 1 g / L to a conical flask. Place the conical flask in a shaker at 25°C and 180 rpm for 12 hours. Measure the As(V) concentration in the solution using an inductively coupled plasma spectrometer, and calculate the As(V) removal rate.

[0060] Table 2 As(V) removal rates of different materials

[0061] Residual As(V) concentration (mg / L) As(V) removal rate (%) Example 1 0.04 99.8 Example 2 0.03 99.8 Example 3 0.05 99.8 Example 4 0.04 99.9 Example 5 0.01 99.9 Comparative Example 1 12.92 35.4 Comparative Example 2 8.32 58.4

[0062] The above examples are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, they are not intended to limit the present invention. Therefore, any simple modifications, equivalent variations, and modifications to the above examples that do not depart from the technical solution of the present invention and are based on the technical essence of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A material for removing heavy metal ions from wastewater, characterized in that: The raw materials include porous material, zinc acetate, magnesium acetate and cerium nitrate, wherein the mass ratio of zinc acetate, magnesium acetate and cerium nitrate is 85:10:5 to 80:15:

5.

2. The material for removing heavy metal ions from wastewater according to claim 1, characterized in that The porous material is one of sepiolite, attapulgite, kaolin and biochar.

3. A preparation method for removing heavy metal ions from wastewater, characterized in that: The method for preparing the material according to claim 1 or 2 comprises the following steps: Step S1, weighing a porous material, zinc acetate, magnesium acetate, and cerium nitrate, adding them to anhydrous ethanol or methanol, stirring in a water bath at 60-90° C. for 2-4 hours, and cooling to obtain a mixed solution; Step S2, slowly adding anhydrous ethanol or methanol solution to the mixed solution of step S1, stirring at room temperature for 4 to 8 hours, transferring to a hydrothermal kettle, hydrothermally crystallizing at 140 to 180° C. for 8 to 15 hours, cooling, washing three times with deionized water, filtering, and drying to obtain Mg-Ce-ZnO / porous material powder; Step S3: adding Mg-Ce-ZnO / porous material powder to inorganic binder and glass fiber, mixing evenly, placing in a granulator, and preparing small balls with a diameter of 3 to 8 mm.

4. The preparation method according to claim 3, characterized in that In the step S1, Mg-Ce-ZnO accounts for 0.1-1 wt% of the porous material.

5. The preparation method according to claim 3, characterized in that In the step S2, the anhydrous ethanol is anhydrous ethanol containing KOH.

6. The preparation method according to claim 3, characterized in that In step S3, the inorganic binder is one of Al2O3, SiO2, pseudo-boehmite, and TiO2.

7. The preparation method according to claim 3, characterized in that In step S3, the mass fraction of Mg-Ce-ZnO / porous material is 85-95%, the mass fraction of inorganic binder is 1-10%, and the mass fraction of glass fiber is 1-10%.