Method for preparing RM / Ni(OH)2 nanomaterial based on red mud and application

Abstract

The application relates to a method for preparing RM / Ni(OH)2 nanometer material based on red mud and application, and aims to utilize solid waste red mud (RM), slowly hydrolyze Na2O and CaO in the RM, take metal oxides such as Fe2O3, Al2O3 and TiO2 as supporting materials, in-situ grow Ni(OH)2 nanometer sheets on the RM surface through a one-step hydrothermal method, and prepare RM / Ni(OH)2 nanometer adsorption material. The adsorbent RM / Ni(OH)2 has the characteristics of high adsorption capacity, low cost and simple manufacturing process, can effectively adsorb dye wastewater, realizes resource utilization of the RM, provides a new idea for water dye pollution treatment and RM resource utilization, combines the advantages of high specific surface area and rich surface functional groups of the red mud and Ni(OH)2, and makes up for the shortage of limited adsorption capacity of the two. The raw material source is rich, the RM is not subjected to traditional acid-base treatment in the use process, secondary pollution caused by acid-base waste liquid to the environment is reduced, and the true "waste treatment with waste" is realized.

Description

Technical Field

[0001] This invention relates to the field of adsorption technology for organic pollutants, specifically to a method for preparing RM / Ni(OH)2 nanomaterials based on red mud and its application. Background Technology

[0002] As we all know, water resources are essential for human survival and development. With the acceleration of industrialization, many industries use large quantities of chemical dyes to provide products with various stable colors, such as textiles, printing, food processing, and cosmetics. More than 1.6 million tons of artificial dyes are produced annually, frequently used for dyeing different colors to enhance their aesthetic value. One ton of textiles requires 15 tons of water for printing and dyeing, of which 80-90% is wasted. Among different types of dyes, azo dyes account for 60-70% of all dyes used in the textile industry, widely used due to their chemical stability and versatility. Azo dyes contain at least one azo group in their chemical structure, where the azo group is usually linked to one or more aromatic ring systems, forming a conjugated system that serves as the chromophore of the dye. Congo Red (CR) is a well-known and widely used azo dye, consisting of two azo groups (-N=N-) as chromophores in its molecular structure. During use, approximately 15% of CR dyes enter industrial wastewater without proper treatment. Due to its high water solubility, high toxicity, high color intensity, and poor biodegradability, CR (chromium ore) has become one of the most difficult industrial wastewaters to treat, severely damaging the ecological environment and posing a significant threat to human health. Removing CR dyes from wastewater and water bodies is an important task.

[0003] Adsorption is a reliable technique for removing carbon dioxide (CR) due to its low cost, simple operation, and high removal efficiency. However, commonly used adsorbents still suffer from drawbacks such as relatively cumbersome synthesis routes, harsh preparation conditions, and high production costs, hindering their practical application. Therefore, developing adsorbents with low cost and high adsorption efficiency is of great significance. In recent years, the creation of functional materials from waste through effective strategies to achieve waste treatment has attracted increasing attention. Currently, methods such as calcination pyrolysis, hydrothermal synthesis, sol-gel, coprecipitation, and ball milling are commonly used to transform waste (such as biological waste, electronic waste, and industrial waste) into functional materials for wastewater purification.

[0004] Red mud (RM) is an alkaline solid waste generated during alumina production. Global RM reserves exceed 4 billion tons, with an annual cumulative total of 175.5 million tons. 90% of RM originates from Australia and China. It is estimated that China has approximately 480-870 million tons of untreated red mud, with only about 4% being reused; the majority is stored in stockpiles. The large-scale generation of RM and its strong alkalinity (pH 11-13) cause significant environmental pollution (groundwater contamination, soil alkalization, and air pollution from dust). Therefore, reducing environmental pollution caused by RM is of significant research value. Because RM contains abundant oxides (such as Fe₂O₃, Al₂O₃, TiO₂, Na₂O, and CaO), it can be used as a supporting material to prevent the aggregation of nano-adsorbents, improve the adsorption performance of loaded adsorbents, and remove antibiotics, metal ions, and dyes from wastewater.

[0005] Recently, Ni(OH)₂, a typical 2D transition metal hydroxide, has attracted widespread interest in dye adsorption processes due to its easy availability and relatively high efficiency. Here, Ni is added to utilize the abundant oxides in RM (such as Fe₂O₃, Al₂O₃, TiO₂, Na₂O, and CaO). +2 In this study, Ni(OH)₂ nanosheets were hydrothermally grown on the surfaces of oxides such as Fe₂O₃, Al₂O₃, and TiO₂ through the slow hydrolysis of Na₂O and CaO, thus preparing RM / Ni(OH)₂ adsorbent materials for the removal of dye wastewater. This achieves the goal of turning waste into treasure and treating waste with waste. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. This method utilizes the abundant oxides in RM (such as Fe2O3, Al2O3, TiO2, Na2O, and CaO), and adds Ni... +2 In this process, Ni(OH)2 nanosheets are grown hydrothermally on the surfaces of oxides such as Fe2O3, Al2O3, and TiO2 through the slow hydrolysis of Na2O and CaO, thus preparing RM / Ni(OH)2 adsorbent materials.

[0007] This invention is achieved through the following technical solution:

[0008] Step 1: Place the raw red mud into an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve;

[0009] Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 min;

[0010] Step 3: Add (3-6g) RM to the above solution and stir for 6 hours;

[0011] Step 4: Conduct a hydrothermal experiment on the above solution at a temperature of 140–220°C for 12 hours.

[0012] Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry it at 60℃ for 12 hours to obtain RM / Ni(OH)2 adsorbent material.

[0013] Application of RM / Ni(OH)2 adsorbent material in adsorbing Congo red in wastewater.

[0014] Compared with the prior art, the present invention has the following superior effects:

[0015] This invention discloses a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The preparation process does not require traditional acid-base activation pretreatment of the red mud raw material, thus avoiding secondary pollution of the environment by the waste acid and alkali solutions generated from acid-base treatment.

[0016] By utilizing the strong alkalinity of RM and the slow hydrolysis of Na2O and CaO in RM, ultrathin Ni(OH)2 nanosheets were successfully grown in situ on the surface of metal oxides such as Fe2O3, Al2O3 and TiO2 of RM. This resulted in the RM / Ni(OH)2 adsorbent material having a large specific surface area, thereby achieving efficient removal of dye wastewater.

[0017] The resulting RM / Ni(OH)2 nanomaterials have excellent adsorption effects on Congo red in wastewater, while solving the problem of large-scale accumulation of solid waste red mud. This turns solid waste red mud into a valuable resource, realizing the resource utilization of solid waste red mud, while avoiding secondary pollution from waste acid and alkali caused by traditional acid and alkali pretreatment, thus achieving the goal of turning waste into treasure and treating waste with waste. Attached Figure Description

[0018] Figure 1 This is a basic roadmap of the RM / Ni(OH)2 adsorbent material obtained in this invention;

[0019] Figure 2 The diagram shows the adsorption performance of the RM / Ni(OH)2 adsorbent material obtained in this invention. Detailed Implementation

[0020] To enhance understanding of the present invention, the present invention will be further described below with reference to specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be used to limit the scope of protection of the present invention.

[0021] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud, comprising the following steps:

[0022] Step 1: Place the raw material red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add (3-6 g) RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at a temperature of (140-220℃) and a holding time of 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0023] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0024] Implementation Case 1:

[0025] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0026] Step 1: Place the raw red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 3 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 140℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0027] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 2 hours. Take samples every 10 minutes in the first hour and every 30 minutes in the next 3 hours. Use a UV-Vis spectrophotometer to test its adsorption.

[0028] Implementation Case 2:

[0029] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0030] Step 1: Dry the raw red mud in an oven at 60℃ for 12 hours, then grind it for 30 minutes and sieve it through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 3 g RM to the above solution and stir for 6 hours; Step 4: Perform a hydrothermal experiment on the above solution at 180℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry it at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0031] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0032] Implementation Case 3:

[0033] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0034] Step 1: Place the raw material red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 3 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 220℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0035] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 2 hours. Take samples every 10 minutes in the first hour and every 30 minutes in the next 2 hours. Use a UV-Vis spectrophotometer to test its adsorption.

[0036] Implementation Case 4:

[0037] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0038] Step 1: Place the raw red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 4.5 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 140℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0039] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0040] Implementation Case 5:

[0041] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0042] Step 1: Place the raw material red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 4.5 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 180℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0043] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0044] Implementation Case 6:

[0045] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0046] Step 1: Place the raw material red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 4.5 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 220℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0047] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0048] Implementation Case 7:

[0049] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0050] Step 1: Place the raw red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 6 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 140℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0051] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0052] Implementation Case 8:

[0053] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0054] Step 1: Place the raw material red mud in an oven to dry at 60℃ for 12 hours, then grind for 30 minutes and sieve through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 6 g RM to the above solution and stir for 6 hours; Step 4: Conduct a hydrothermal experiment on the above solution at 180℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0055] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

[0056] Implementation Case 9:

[0057] This invention relates to a method and application for preparing RM / Ni(OH)2 nanomaterials based on red mud. The specific steps are as follows:

[0058] Step 1: Dry the raw red mud in an oven at 60℃ for 12 hours, then grind it for 30 minutes and sieve it through a 200-mesh sieve; Step 2: Add 0.01 mol NiCl2·6H2O to 100 mL of deionized water and stir for 30 minutes; Step 3: Add 6 g RM to the above solution and stir for 6 hours; Step 4: Perform a hydrothermal experiment on the above solution at 220℃ for 12 hours; Step 5: Wash the hydrothermal product three times each with deionized water and anhydrous ethanol, and dry it at 60℃ for 12 hours to obtain the RM / Ni(OH)2 adsorbent material.

[0059] Take 0.02g of RM / Ni(OH)2 nanomaterial and put it into 80mL of 200mg / L Congo red solution. Stir magnetically in the dark for 3h. Take samples every 10min for the first hour and every 30min for the next 2h. Use a UV-Vis spectrophotometer to test its adsorption.

Claims

1. A method for preparing RM / Ni(OH)2 nanomaterials based on red mud, characterized by, It comprises the following steps: Step 1, red mud RM drying, grinding, sieving, wherein the drying temperature is 60 DEG C, drying time 12 h, grinding 30 min, 200 mesh sieving; Step 2, a certain amount of NiCl2·6H2O is added to deionized water, stirred and dissolved to form a solution; the amount of NiCl2·6H2O is 0.01 mol, the amount of deionized water added is 100 mL, and the stirring time is 30 min; Step 3, a certain amount of sieved red mud RM is added to the solution of step 2, stirred to homogenize, and a mixed solution is formed; the amount of red mud added is 3-6 g, and the stirring time is 6 h; Step 4, the mixed solution of step 3 is moved to a polytetrafluoroethylene liner for hydrothermal treatment, the hydrothermal temperature is 140-220 DEG C, and the holding time is 12 h; Step 5, the hydrothermal product is washed with deionized water and anhydrous ethanol for 3 times respectively, centrifuged, and the precipitate is obtained, dried at 60 DEG C for 12 h, and RM / Ni(OH)2 adsorption material is obtained.

2. The application of the RM / Ni(OH)2 nanomaterial prepared based on red mud prepared by the method of claim 1 in the adsorption removal of Congo red dye in wastewater.

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