Catalyst for high-efficiency photocatalytic degradation of rhodamine B at room temperature and preparation method thereof

Abstract

The invention discloses a catalyst for high-efficiency photocatalytic degradation of rhodamine B at room temperature and a preparation method of the catalyst. The catalyst is formed by compounding CeCO3OH and CdS. The invention discloses a preparation method of a CeCO3OH / CdS composite catalyst, which comprises the following steps: placing CeCO3OH in a solution, and reacting Cd < 2 + > with a carbon disulfide storage material (CS2SM, the application publication number: CN 109758901A) to prepare the CeCO3OH / CdS composite catalyst. The composite catalyst prepared by the invention can efficiently photocatalytically degrade rhodamine B at room temperature, and the preparation method is simple, low in cost and easy to popularize and apply.

Description

Technical Field

[0001] The invention belongs to the fields of catalyst materials, environmental catalysis and environmental protection, and particularly relates to a catalyst for efficiently photocatalytically degrading rhodamine B at room temperature and a preparation method thereof. Background Art

[0002] Rhodamine B (Rh B) is an important organic pollutant and belongs to azo dyes. It has the advantages of excellent color, strong dyeing, and wide applicability. It is widely used in dyeing and paper coloring and other printing and dyeing industries. After use, Rh B is often discharged into water bodies as waste, causing water bodies to exceed standards, polluting water resources, and endangering human health. Therefore, the treatment of Rh B in wastewater from the printing and dyeing industry has always been the focus of attention in the field of environmental protection.

[0003] At present, the commonly used methods for effectively removing Rh B include electrocoagulation, biodegradation and photocatalytic degradation. In contrast, photocatalytic degradation can absorb light energy under light to generate electron transitions, generate electron-hole pairs, redox the RhB on the catalyst surface, or generate hydroxyl radicals with strong oxidizing effect to oxidize RhB. The reaction conditions are mild, the catalyst is cheap and easy to obtain, and RhB can be converted into non-toxic and harmless H 2 O and CO 2 The commonly used photocatalysts for photocatalytic degradation are titanium dioxide (TiO 2 ), zinc oxide (ZnO) and cadmium sulfide (CdS), etc., especially CdS has become a research and development hotspot due to its excellent properties such as narrow band gap and high visible light response.

[0004] CdS particles are easy to agglomerate, have weak light-harvesting ability, and are prone to photocorrosion, which seriously affects the performance of visible light degradation of Rh B. In recent years, researchers have tried to improve the performance of CdS-based catalysts in visible light degradation of Rh B by dispersing CdS and doping with oxides (sulfides). The room temperature efficient photocatalytic degradation of Rhodamine B catalyst and its preparation method described in the present invention can successfully disperse CdS in needle-shaped CeCO 3 OH surface, which improves the visible light capture performance, inhibits the photocorrosion phenomenon of CdS-based catalysts, and realizes the efficient degradation of Rh B at room temperature, which has important practical significance for the purification of Rh B-containing wastewater. Summary of the invention

[0005] The present invention explores a room temperature efficient photocatalytic degradation catalyst for rhodamine B and a preparation method thereof. The catalyst is composed of CeCO 3 OH and CdS composite, and its microscopic morphology is a nanowire structure CeCO 3 A layer of CdS particles is wrapped around the OH; the CdS has a heterogeneous structure of hexagonal phase and cubic phase, and presents a microcrystalline mixed state at a microscopic level.

[0006] The present invention provides a catalyst for photocatalytic degradation of rhodamine B at room temperature and a preparation method thereof. 3 OH is placed in solution and Cd 2+ With CS 2 SM reaction to obtain CeCO 3 The OH / CdS composite catalyst comprises the following steps:

[0007] 1) Add 50mL (0.03~0.20)mol / L Ce 3+ Aqueous solution with (0.8~5.0)g CO 2 SM (patent number: ZL201410578343.6) mixed and stirred to form a mixed solution;

[0008] 2) Place 50 mL of the solution in step 1) in a 100 mL reactor, react at 120 °C for 2 h, filter, wash, and dry to obtain CeCO 3 OH is a nanowire-structured crystal;

[0009] 3) The CeCO 3 OH crystals dispersed in 50mL (10~50)g / L CS 2 SM (application publication number: CN109758901A) solution, drop (0.05-0.25) mol / L Cd 2+ The solution was stirred at a constant temperature of 60-90°C for (2-6) hours, centrifuged, washed and dried to obtain CeCO 3 OH / CdS composite catalyst. DETAILED DESCRIPTION

[0010] The present invention is described below in conjunction with a specific embodiment, namely a catalyst for efficient photocatalytic degradation of Rhodamine B at room temperature and a preparation method thereof. The specific implementation is as follows:

[0011] Embodiment 1:

[0012] 1) Weigh 7.5g CeCl 3 7H 2 O, add deionized water to 500 mL to obtain CeCl3 solution;

[0013] 2) Weigh 4.5g CO 2 SM was placed in a 100 mL reaction kettle, 50 mL of the solution obtained in step 1) was added, and stirred for 10 min;

[0014] 3) reacting the reactor in step 2) at 120° C. for 2 h to form a solution containing a white precipitate;

[0015] 4) filtering the solution in step 3) to obtain a white precipitate, and washing it with deionized water and anhydrous ethanol for 3 times;

[0016] 5) Dry the precipitate obtained in step 4) at 120°C for 2 hours to obtain CeCO with a nanowire structure. 3 OH crystals.

[0017] 6) Weigh 8g CS 2 SM, add deionized water to 500 mL to obtain CS2SM solution;

[0018] 7) Weigh 3.5 g CdCl 2 2.5H 2 O, add deionized water to dissolve to 50 mL to obtain CdCl 2 Solution;

[0019] 8) Weigh 1.0 g CeCO 3 OH was placed in a round-bottom flask, 50 mL of the solution obtained in step 6) was added, and ultrasonic dispersion was performed for 20 min;

[0020] 9) stirring the solution in step 8) at 90° C., slowly adding 10 mL of the solution obtained in step 7) and reacting for 6 h to form a solution containing a yellow precipitate;

[0021] 10) The solution in step 9) was centrifuged at a speed of 8000 rpm for 5 min, the precipitate was collected after centrifugation, and deionized water was added for washing, and the mixture was centrifuged again, and the centrifugation washing was repeated 5 times; anhydrous ethanol was added for washing, and the mixture was centrifuged again, and the centrifugation washing was repeated 2 times;

[0022] 11) The precipitate obtained in step 10) was dried under vacuum at 80°C for 12 h to obtain CeCO 3 OH / CdS composite catalyst.

[0023] In addition, as a comparison, the inventor used CS 2 SM and CdCl 2 The solution is stirred to obtain CdS, and the titration stirring and drying processes are similar to those of CeCO 3 The preparation process of the OH / CdS composite catalyst (ie, steps 6-7, 9-11 in this embodiment) is the same.

[0024] The CeCO prepared in Example 1 3 OH, CdS and CeCO 3 OH / CdS composite catalysts were tested by SEM. Figure 1 CeCO prepared in Example 1 3 SEM image of OH, CeCO can be seen 3 OH presents a linear structure. Figure 2 This is a SEM image of the CdS prepared in Example 1. It can be seen that the CdS sample appears as nanoparticles and exhibits agglomeration. Figure 3 The XRD spectrum of CdS prepared in Example 1 shows that the CdS sample exhibits a heterogeneous structure of hexagonal phase and cubic phase. Figure 4 CeCO prepared in Example 1 3 SEM image of OH / CdS, showing that CdS is successfully dispersed in the linear CeCO 3 OH surface.

[0025] Embodiment 2:

[0026] 1) Weigh 6g (CH 3 CO 2 ) 3 ·xH 2 O, add deionized water to 500 mL, and obtain (CH 3 CO 2 ) 3 Ce solution;

[0027] 2) Weigh 4g CO 2 SM was placed in a 100 mL reaction kettle, 50 mL of the solution obtained in step 1) was added, and stirred for 10 min;

[0028] 3) reacting the reactor in step 2) at 120° C. for 2 h to form a solution containing a white precipitate;

[0029] 4) filtering the solution in step 3) to obtain a white precipitate, and washing it with deionized water and anhydrous ethanol for 3 times;

[0030] 5) Dry the precipitate obtained in step 4) at 120°C for 2 hours to obtain CeCO with a nanowire structure. 3 OH crystals.

[0031] 6) Weigh 5g CS 2 SM, add deionized water to 500 mL to obtain CS2SM solution;

[0032] 7) Weigh 3.0 g Cd(CH 3 COO 2 ·2H 2 O, add deionized water to dissolve to 50 mL to obtain Cd(CH 3 COO 2 Solution;

[0033] 8) Weigh 0.5 g CeCO 3 OH was placed in a round-bottom flask, 50 mL of the solution obtained in step 6) was added, and ultrasonic dispersion was performed for 20 min;

[0034] 9) stirring the solution in step 8) at 90° C., slowly adding 10 mL of the solution obtained in step 7) and reacting for 6 h to form a solution containing a yellow precipitate;

[0035] 10) The solution in step 9) was centrifuged at a speed of 8000 rpm for 5 min, the precipitate was collected after centrifugation, and deionized water was added for washing, and the mixture was centrifuged again, and the centrifugation washing was repeated 5 times; anhydrous ethanol was added for washing, and the mixture was centrifuged again, and the centrifugation washing was repeated 2 times;

[0036] 11) The precipitate obtained in step 10) was dried under vacuum at 80°C for 12 h to obtain CeCO 3 OH / CdS composite catalyst.

[0037] Embodiment 3:

[0038] 1) Weigh 8g Ce(NO 3 ) 3 6H 2 O, add deionized water to 500 mL to obtain Ce(NO 3 ) 3 Solution;

[0039] 2) Weigh 6g CO 2 SM was placed in a 100 mL reaction kettle, 50 mL of the solution obtained in step 1) was added, and stirred for 10 min;

[0040] 3) reacting the reactor in step 2) at 120° C. for 2 h to form a solution containing a white precipitate;

[0041] 4) filtering the solution in step 3) to obtain a white precipitate, and washing it with deionized water and anhydrous ethanol for 3 times;

[0042] 5) Dry the precipitate obtained in step 4) at 120°C for 2 hours to obtain CeCO with a nanowire structure. 3 OH crystals.

[0043] 6) Weigh 8.5g CS 2 SM, add deionized water to 500mL to obtain CS 2 SM solution;

[0044] 7) Weigh 4 g Cd(NO 3 ) 2 ·4H 2 O, add deionized water to dissolve to 50 mL to obtain Cd(NO 3 ) 2 Solution;

[0045] 8) Weigh 1.5 g CeCO3 OH was placed in a round-bottom flask, 50 mL of the solution obtained in step 6) was added, and ultrasonic dispersion was performed for 20 min;

[0046] 9) stirring the solution in step 8) at 90° C., slowly adding 10 mL of the solution obtained in step 7) and reacting for 6 h to form a solution containing a yellow precipitate;

[0047] 10) The solution in step 9) was centrifuged at a speed of 8000 rpm for 5 min, the precipitate was collected after centrifugation, and deionized water was added for washing, and the mixture was centrifuged again, and the centrifugation washing was repeated 5 times; anhydrous ethanol was added for washing, and the mixture was centrifuged again, and the centrifugation washing was repeated 2 times;

[0048] 11) The precipitate obtained in step 10) was dried under vacuum at 80°C for 12 h to obtain CeCO 3 OH / CdS composite catalyst.

[0049] Under visible light, the CeCO 3 The process and performance of photocatalytic degradation of 2g / L Rh B by OH / CdS composite catalyst are as follows: 30mL of 2g / L Rh B aqueous solution was placed in a 50mL quartz reaction bottle, and 0.0500g of photocatalyst was added. Before photocatalytic degradation, the mixture was stirred at room temperature for 30min, reacted at 300rpm and under visible light for 1h, and the absorbance of the diluted solution was monitored at 554nm by UV-visible spectrophotometer. The concentration of Rh B was reduced by 87%, and the cyclic degradation performance was good, indicating that CeCO 3 The OH / CdS composite catalyst has the ability to efficiently photocatalytically degrade Rh B at room temperature.

Claims

1. A catalyst for efficient photocatalytic degradation of Rhodamine B at room temperature and a preparation method thereof, characterized in that: The catalyst is a CeCO3OH / CdS composite catalyst, which is composed of CeCO3OH and CdS. Its microscopic morphology is a nanowire structure of CeCO3OH wrapped with a layer of obvious CdS particles. The CdS is a heterogeneous structure of hexagonal phase and cubic phase, and presents a microcrystalline mixed state at the microscopic level.

2. A catalyst for efficient photocatalytic degradation of Rhodamine B at room temperature and a preparation method thereof according to claim 1, characterized in that: 1) Add 50mL (0.03~0.20)mol / L Ce 3+ The aqueous solution is mixed with (0.8-5.0) g of carbon dioxide storage material (CO2SM) and stirred to form a mixed solution; 2) placing 50 mL of the solution in step 1) in a 100 mL reactor, reacting at 120° C. for 2 h, filtering, washing, and drying to obtain CeCO3OH as nanowire-structured crystals; 3) Disperse the CeCO3OH crystals described in step 2) in 50 mL (10-50) g / L carbon disulfide storage material (CS2SM) solution, and drop (0.05-0.25) mol / L Cd 2+ The solution is stirred at a constant temperature of 60 to 90° C. for reaction for (2 to 6) hours, centrifuged, washed and dried to obtain a CeCO3OH / CdS composite catalyst.

3. A catalyst for efficient photocatalytic degradation of Rhodamine B at room temperature and a preparation method thereof according to claim 2, characterized in that: 1) In the step, the Ce 3+ It is cerium chloride, cerium nitrate or cerium acetate; the CO2SM preparation method is derived from ZL201410578343.

6.

4. A catalyst for efficient photocatalytic degradation of Rhodamine B at room temperature and a preparation method thereof according to claim 2, characterized in that: 3) In the step, the Cd 2+ It is cadmium chloride, cadmium nitrate or cadmium acetate; the CS2SM preparation method is derived from CN109758901A.

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