Preparation of bismuth sulfide inorganic / organic composite material and application of bismuth sulfide inorganic / organic composite material in removal of hexavalent chromium in industrial wastewater

Abstract

The invention discloses preparation of a bismuth sulfide inorganic / organic composite material and application of the bismuth sulfide inorganic / organic composite material to removal of hexavalent chromium in industrial wastewater, and relates to the technical field of composite materials and adsorption separation and reduction of heavy metals. The preparation method comprises the following steps: 1, respectively dissolving a bismuth source and a sulfur source in an ethylene glycol solvent, performing ultrasonic treatment, stirring and dispersing uniformly, adding the bismuth source into the sulfur source, and stirring uniformly to obtain a reaction precursor solution; the simple solvothermal and room-temperature stirring method is adopted, the reaction condition is mild, the operation process is simple, the requirement for a reaction device is low, reproducibility is good, and the method is more suitable for large-scale production. The bismuth sulfide inorganic / organic composite material is synthesized through in-situ growth of dopamine on the surface of bismuth sulfide and chemical grafting of polyethyleneimine. The bismuth sulfide inorganic / organic composite material obtained by the invention shows excellent performance of removing Cr (VI) in industrial wastewater.

Description

Technical Field

[0001] The invention belongs to the technical field of adsorption separation and reduction of composite materials and heavy metals, and specifically relates to the preparation of a bismuth sulfide inorganic / organic composite material and the application of the composite material in removing hexavalent chromium from industrial wastewater. Background Art

[0002] With the progress and development of industry, the application of metallic chromium has gradually increased. Chromium is one of the seven heavy metals. Due to its high hardness and excellent corrosion resistance, chromium is widely used in electroplating, leather, textile and other fields. The chromium commonly used in industry is mainly Cr(III) and Cr(VI). The toxicity of Cr(VI) is more than 100 times higher than that of Cr(III). Even trace amounts of Cr(VI) can pose a great threat to human health. Cr(VI) is not only cytotoxic, genotoxic and carcinogenic, but also exists stably in the natural environment for a long time, is difficult to reduce spontaneously, and can cause great environmental pollution. Chromium-containing wastewater is produced in the electroplating, textile and leather industries. Among these three types of wastewater, the Cr(VI) concentration in electroplating wastewater is much higher than that in the other two types, and the large amount of coexisting anions and cations in electroplating wastewater will significantly affect the removal of Cr(VI). Therefore, it is very difficult to remove Cr(VI) in real electroplating wastewater.

[0003] The ultimate goal of treating electroplating wastewater containing chromium is to separate Cr(VI) from the actual wastewater and convert it into low-toxic Cr(III). However, it is difficult for the single treatment technologies reported so far to simultaneously achieve efficient separation and conversion of Cr(VI), and multiple methods need to be coordinated to achieve in-depth treatment of Cr(VI). Adsorption is widely used to separate Cr(VI) due to its advantages such as high efficiency, simplicity, and low cost. However, adsorption Cr(VI) cannot be converted into Cr(III), and it needs to be combined with photocatalysis, electrocatalysis and other reduction methods to more effectively remove Cr(VI). Therefore, it is very necessary to design a material with both high adsorption capacity and strong reduction capacity to remove Cr(VI) from industrial electroplating wastewater.

[0004] Bismuth sulfide has been proven to be a material with both adsorption performance and photocatalytic activity. However, the adsorption capacity of bismuth sulfide for Cr(VI) is currently limited, which in turn affects its photocatalytic ability and limits its application in industrial chromium-containing wastewater. Therefore, it is necessary to introduce substances with specific groups into bismuth sulfide to enhance its adsorption effect on Cr(VI). Therefore, it is of great research and application value to design and synthesize a bismuth sulfide inorganic / organic composite material with both high adsorption performance and strong reduction performance to achieve deep removal of industrial chromium-containing wastewater.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a preparation method of a bismuth sulfide inorganic / organic composite material and its application in removing hexavalent chromium from industrial wastewater, and solve the problems raised in the above-mentioned background technology.

[0007] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0008] A preparation method of a bismuth sulfide inorganic / organic composite material comprises the following steps:

[0009] Step 1: dissolving a bismuth source and a sulfur source in an ethylene glycol solvent respectively, stirring and dispersing them uniformly after ultrasonication, adding the bismuth source to the sulfur source and stirring them uniformly to obtain a reaction precursor solution; wherein the bismuth source is bismuth nitrate pentahydrate, the sulfur source is L-cysteine ​​and ammonium sulfide, and the molar ratio of the bismuth source to the two sulfur sources is 1:1:1; the volume ratio of ethylene glycol to the bismuth source and the sulfur source in the solvent is 1:1, the ultrasonication time is 0.5h, and the stirring time is 0.5h;

[0010] Step 2: transferring the reaction precursor solution to a stainless steel reactor lined with polytetrafluoroethylene for constant temperature reaction. After the reaction is completed, washing and drying the obtained solid to obtain bismuth sulfide powder; wherein the temperature of the constant temperature reaction is 140-170°C, and the constant temperature reaction time is 12h; washing is 4-5 times with deionized water solution, 4-5 times with ethanol water solution by centrifugation, and drying is vacuum drying at 40-60°C for 6-12h;

[0011] Step 3: Disperse bismuth sulfide powder in Tris-HCl buffer solution, add dopamine and polyethyleneimine, stir at room temperature, wash and dry the obtained solid after the reaction is completed to obtain a modified bismuth sulfide composite material; wherein the washing is centrifugal washing with ethanol aqueous solution for 5-7 times, the drying is vacuum drying at 40-60°C for 6-12h; the reaction is a constant temperature reaction at 25°C for 12h.

[0012] A bismuth sulfide inorganic / organic composite material is prepared by any of the above-mentioned preparation methods.

[0013] The invention discloses an application of a bismuth sulfide inorganic / organic composite material in removing hexavalent chromium from industrial wastewater, and is applied to Cr(VI) removal.

[0014] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time:

[0015] 1. The present invention adopts a simple solvent heat and room temperature stirring method, with mild reaction conditions, simple operation process, low requirements for reaction equipment, good reproducibility, and is more suitable for large-scale production.

[0016] 2. The present invention realizes the synthesis of bismuth sulfide inorganic / organic composite materials by in-situ growth of dopamine on the surface of bismuth sulfide and chemical grafting of polyethyleneimine.

[0017] 3. The bismuth sulfide inorganic / organic composite material obtained by the present invention exhibits excellent performance in removing Cr(VI) from industrial wastewater.

[0018] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0020] Figure 1 The X-ray diffraction pattern of the bismuth sulfide inorganic / organic composite material obtained in Example 1 of the present invention;

[0021] Figure 2 This is an infrared spectrum of the bismuth sulfide inorganic / organic composite material obtained in Example 1 of the present invention;

[0022] Figure 3 This is a scanning electron microscope image of the bismuth sulfide inorganic / organic composite material obtained in Example 1 of the present invention;

[0023] Figure 4 This is a graph showing the adsorption and photocatalytic performance of Example 1 of the present invention in real waste electrolyte;

[0024] Figure 5 This is a graph showing the adsorption and photocatalytic performance of Example 1 of the present invention in a real electroplating cleaning solution.

[0025] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] See also Figure 1-5 As shown, in this embodiment, a preparation method of a bismuth sulfide inorganic / organic composite material is provided, comprising the following steps:

[0028] Step 1: dissolving a bismuth source and a sulfur source in an ethylene glycol solvent respectively, stirring and dispersing them uniformly after ultrasonication, adding the bismuth source to the sulfur source and stirring them uniformly to obtain a reaction precursor solution; wherein the bismuth source is bismuth nitrate pentahydrate, the sulfur source is L-cysteine ​​and ammonium sulfide, and the molar ratio of the bismuth source to the two sulfur sources is 1:1:1; the volume ratio of ethylene glycol to the bismuth source and the sulfur source in the solvent is 1:1, the ultrasonication time is 0.5h, and the stirring time is 0.5h;

[0029] Step 2: transferring the reaction precursor solution to a stainless steel reactor lined with polytetrafluoroethylene for constant temperature reaction. After the reaction is completed, washing and drying the obtained solid to obtain bismuth sulfide powder; wherein the temperature of the constant temperature reaction is 140-170°C, and the constant temperature reaction time is 12h; washing is 4-5 times with deionized water solution, 4-5 times with ethanol water solution by centrifugation, and drying is vacuum drying at 40-60°C for 6-12h;

[0030] Step 3: Disperse bismuth sulfide powder in Tris-HCl buffer solution, add dopamine and polyethyleneimine, stir at room temperature, wash and dry the obtained solid after the reaction is completed to obtain a modified bismuth sulfide composite material; wherein the washing is centrifugal washing with ethanol aqueous solution for 5-7 times, the drying is vacuum drying at 40-60°C for 6-12h; the reaction is a constant temperature reaction at 25°C for 12h.

[0031] A bismuth sulfide inorganic / organic composite material is prepared by any of the above-mentioned preparation methods.

[0032] The invention discloses an application of a bismuth sulfide inorganic / organic composite material in removing hexavalent chromium from industrial wastewater, and is applied to Cr(VI) removal.

[0033] The present invention adopts a simple solvent heat and room temperature stirring method, with mild reaction conditions, simple operation process, low requirements on reaction devices, good reproducibility, and is more suitable for large-scale production.

[0034] The invention realizes the synthesis of bismuth sulfide inorganic / organic composite material by in-situ growth of dopamine on the surface of bismuth sulfide and chemical grafting of polyethyleneimine.

[0035] The bismuth sulfide inorganic / organic composite material obtained by the invention exhibits excellent performance of removing Cr(VI) from industrial wastewater.

[0036] Example 1

[0037] This embodiment provides a bismuth sulfide inorganic / organic composite material, and the preparation method thereof comprises the following steps:

[0038] (1) accurately weighing 1.21 g of bismuth nitrate pentahydrate and dissolving it in 25 mL of ethylene glycol, weighing 0.303 g of L-cysteine ​​and 0.174 g of ammonium sulfide and dissolving them in 25 mL of ethylene glycol, and ultrasonically dispersing them uniformly to obtain bismuth source and sulfur source solutions respectively. Then, the bismuth source was added to the sulfur source and stirred uniformly to obtain a reaction precursor solution;

[0039] (2) transferring the reaction precursor solution to a stainless steel reactor lined with polytetrafluoroethylene, and reacting at a constant temperature of 160° C. for 12 hours. After the reaction, washing the obtained solid with deionized water for 4-5 times, and centrifuging the solid with an ethanol aqueous solution with a volume ratio of ethanol: water = 1:1 for 4-5 times at a centrifugal speed of 6000 r / min. The washed sample was vacuum dried at 60° C. for 12 hours to obtain bismuth sulfide powder;

[0040] (3) Dispersing bismuth sulfide powder in a Tris-HCl buffer solution, adding dopamine and polyethyleneimine successively, stirring at 25° C. for 18 h, and washing and drying the obtained solid after the reaction to obtain a bismuth sulfide inorganic / organic composite material.

[0041] Figure 1 The X-ray diffraction spectrum of the product obtained in Example 1 of the present invention is compared with the standard card, showing that the X-ray diffraction peak of the product synthesized under the conditions described in Example 1 corresponds well to bismuth sulfide, and no obvious impurity peak is observed. The bismuth sulfide composite material shows an obvious large package peak, indicating that the material is a composite of organic and inorganic, proving that the product obtained in Example 1 is a bismuth sulfide inorganic / organic composite material.

[0042] Figure 2 This is the infrared spectrum of the product obtained in Example 1 of the present invention, from which it can be found that the bismuth sulfide inorganic / organic composite material synthesized under the conditions described in Example 1.

[0043] Figure 3 This is a scanning electron microscope image of the product obtained in Example 1 of the present invention. It can be found that the morphology of the bismuth sulfide inorganic / organic composite material synthesized under the conditions described in Example 1 is coated, and the coated polydopamine particles are relatively regular in shape.

[0044] Performance Testing

[0045] Taking two real industrial electroplating wastewaters as targets, the Cr(VI) adsorption and photocatalytic reaction activity evaluation of the materials obtained in the examples of the present invention were carried out, and the specific steps are as follows:

[0046] The Cr(VI) adsorption activity experiment was carried out under a constant temperature shaker, and the photocatalytic activity experiment was carried out under 300 W xenon lamp illumination. The activity of the bismuth sulfide inorganic / organic composite material was evaluated by measuring the Cr(VI) concentration using the diphenylcarbazide spectrophotometric method (GB 7467-87).

[0047] from Figure 4 It can be seen that the bismuth sulfide inorganic / organic composite material has a good Cr(VI) adsorption capacity in real waste electrolyte, and can remove 85.48% of Cr(VI) in the waste electrolyte. At the same time, it also has excellent photocatalytic performance, which can remove the remaining 14.52% in the waste electrolyte. Through adsorption and photocatalysis, the complete removal of Cr(VI) in real waste electrolyte can be achieved.

[0048] from Figure 5 It can be seen that the bismuth sulfide inorganic / organic composite material has a good Cr(VI) adsorption capacity in the real electroplating cleaning solution, and can remove 84.49% of Cr(VI) in the electroplating cleaning solution. At the same time, it also has excellent photocatalytic performance, which can remove the remaining 15.51% in the electroplating cleaning solution. Through adsorption and photocatalysis, the complete removal of Cr(VI) in the real electroplating cleaning solution can be achieved.

[0049] In summary, if Figure 4-Figure 5 As shown, the bismuth sulfide inorganic / organic composite material has both high adsorption performance and good photocatalytic activity, and has good Cr(VI) removal activity in two real industrial electroplating wastewaters. After adsorption and photocatalysis, it can completely remove Cr(VI) in the two real wastewaters, indicating that the bismuth sulfide inorganic / organic composite material obtained by the present invention has superiority in treating Cr(VI) in electroplating wastewater.

[0050] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A preparation method of a bismuth sulfide inorganic / organic composite material, characterized in that: The steps include: Step 1: dissolving a bismuth source and a sulfur source in an ethylene glycol solvent respectively, stirring and dispersing them uniformly after ultrasonication, adding the bismuth source to the sulfur source and stirring them uniformly to obtain a reaction precursor solution; Step 2: transferring the reaction precursor solution to a stainless steel reactor lined with polytetrafluoroethylene for constant temperature reaction. After the reaction is completed, washing and drying the obtained solid to obtain bismuth sulfide powder; Step 3: Disperse bismuth sulfide powder in a Tris-HCl buffer solution, add dopamine and polyethyleneimine, stir at room temperature, and wash and dry the obtained solid after the reaction to obtain a modified bismuth sulfide composite material.

2. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step 1, the bismuth source is bismuth nitrate pentahydrate, the sulfur sources are L-cysteine ​​and ammonium sulfide, and the molar ratio of the bismuth source to the two sulfur sources is 1:1:

1.

3. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step 1, the volume ratio of ethylene glycol of the bismuth source and the sulfur source in the solvent is 1:

1.

4. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step 1, the ultrasonic time is 0.5 h and the stirring time is 0.5 h.

5. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step 2, the temperature of the isothermal reaction is 140-170° C., and the duration of the isothermal reaction is 12 hours.

6. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step 2, washing is performed by washing with deionized water for 4-5 times, washing with ethanol water by centrifugation for 4-5 times, and drying is performed by vacuum drying at 40-60° C. for 6-12 hours.

7. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step three, washing is performed by centrifugation washing with ethanol aqueous solution for 5-7 times, and drying is performed by vacuum drying at 40-60° C. for 6-12 hours.

8. The preparation of a bismuth sulfide inorganic / organic composite material according to claim 1, characterized in that: In step three, the reaction is carried out at a constant temperature of 25° C. for 12 hours.

9. A bismuth sulfide inorganic / organic composite material, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 8.

10. Application of a bismuth sulfide inorganic / organic composite material in removing hexavalent chromium from industrial wastewater, characterized in that: Applied for Cr(VI) removal.

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