A method for preparing a composite catalyst for degrading rhodamine B in organic dyes

Abstract

A method for preparing a composite catalyst for degrading rhodamine B in organic dyes, relating to a method for preparing a composite catalyst for degrading pollutants in organic dyes, the invention discloses a Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 Composite catalyst and preparation method, and the catalyst for ultrasonic catalytic degradation of organic dye Rhodamine B (Rh B). 2 ·2H 2 O, CaCl 2 and Na 2 MoO 4 ·2H 2 O as raw material and deionized water as solvent. Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The optimal experimental conditions were obtained through experiments, 30mg Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite catalyst combined with sonocatalysis has an initial concentration of 4 mg / L organic dye Rh B, and the removal rate can reach 97.10%±2.10%. The composite catalyst prepared by the present invention has good degradation effect of organic pollution, is non-toxic, highly safe, and can be reused, effectively solves the water pollution of Rhodamine B in organic dyes, and has good application prospects.

Description

Technical Field

[0001] The invention relates to a method for preparing a composite catalyst for degrading organic dye pollutants, in particular to a method for preparing a composite catalyst for degrading rhodamine B in organic dyes. Background Art

[0002] The research and use of organic dyes bring convenience to human life, but are also accompanied by a lot of environmental pollution and damage to the ecological balance. Most organic dyes, such as rhodamine B, have the characteristics of high concentration, high chromaticity, high chemical oxygen demand, high toxicity, and high carcinogenicity, which seriously threaten environmental safety and human health. Therefore, the problem of dye wastewater treatment is urgent. As a member of advanced oxidation technology, sonocatalysis technology is simple and inexpensive to use, and can achieve complex reactions. Through cavitation, it can degrade difficult-to-degrade organic macromolecules into low-toxic or non-toxic small molecules, and can even be close to complete mineralization.

[0003] According to the literature, calcium molybdate (CaMoO 4 ) is an n-type semiconductor with high chemical stability and wide charge transfer band and other structural characteristics, and can effectively remove organic pollutants in water through sonocatalytic reaction. 3 (MoO 4 ) 2 (OH) 2 It is a molybdenum-copper mineral salt with a lamellar morphology that is rarely found in nature. It has certain adsorption, catalytic, magnetic and other potentials, so it has attracted much attention in the field of inorganic materials.

[0004] In order to further strengthen the CaMoO 4 The sonocatalytic performance of the catalyst is improved by using a semiconductor composite method. Among the previously reported technical methods, the use of a semiconductor composite method can increase the specific surface area, electrical and thermal conductivity, and the number of active sites of the catalyst, maximize the use of the energy brought by the sonoluminescence and thermal effects in sonocatalysis, and optimize some of the shortcomings of single-component catalysts. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a composite catalyst for degrading rhodamine B in organic dyes. 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite catalyst is prepared by a hydrothermal synthesis method specially used in the process of the invention, and the prepared catalyst can effectively and quickly remove organic dyes in water.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a composite catalyst for degrading Rhodamine B in an organic dye, the method comprising the following preparation process:

[0008] First, CuCl2·2H2O and CaCl2 were dissolved in deionized water and stirred for 30 minutes, and then the two were mixed and stirred evenly after being fully dissolved; then Na2MoO4·2H2O was slowly poured in and magnetically stirred for 30 minutes; after the stirring was completed, the mixed solution was placed in a polytetrafluoroethylene reactor and reacted in an oven at 180°C for 24 hours; when the reaction was complete, it was cooled to room temperature, the precipitate was collected by centrifugation, washed with deionized water and ethanol several times, dried at 80°C, and ground to obtain a Cu3(MoO4)2(OH)2 / CaMoO4 complex;

[0009] The molar ratio of the reaction products CuCl2·2H2O:CaCl2:Na2MoO4·2H2O is 0.2:1:1;

[0010] The Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst was added to the wastewater containing the organic dye Rhodamine B. Under the condition of ultrasonic power of 500W, the ultrasound was carried out for 2 hours, and the initial concentration of Rhodamine B was 4 mg / L; the addition amount of Cu3(MoO4)2(OH)2 / CaMoO4 composite nanomaterial catalyst was 1.5 mg / mL.

[0011] The advantages and effects of the present invention are:

[0012] The process of the invention is simple and energy-saving. The prepared composite catalyst has unique morphological characteristics and can effectively and quickly remove organic dyes in water. The sonocatalytic degradation rate of Rhodamine B organic solution reaches 97.10%±2.10%, showing excellent wastewater treatment efficiency. The catalyst has high chemical stability and is reusable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 XRD patterns of Cu3(MoO4)2(OH)2 / CaMoO4 prepared for different MOLs (Cu2+:Ca2+);

[0014] Figure 2 This is the SEM image of 20%Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst;

[0015] Figure 3 This is a diagram showing the sonocatalytic degradation effect of Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst on Rhodamine B solution. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the embodiments.

[0017] The present invention is a Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The preparation method of the composite catalyst comprises the following steps:

[0018] CuCl 2 ·2H 2 O and CaCl 2 Dissolve them in deionized water and stir for 30 minutes. After they are fully dissolved, mix them and stir evenly. 2 MoO 4 •2H 2 O was slowly poured in and magnetically stirred for 30 minutes. After stirring, the mixed solution was placed in a 100 ml polytetrafluoroethylene reactor and reacted in an oven at 180°C for 24 hours. When the reaction was complete, it was cooled to room temperature, and the precipitate was collected by centrifugation, washed with deionized water and ethanol several times, dried at 80°C, and ground to obtain Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 Complex.

[0019] MOL (Cu 2+ ：Ca 2+ ) 0%~40%; MOL (Cu 2+ ：Ca 2+ ) 20%; MOL (CuCl2·2H2O：CaCl2：Na2MoO4•2H2O) It is 0.2:1:1.

[0020] Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 Application of composite catalyst in treatment of organic dye wastewater with organic pollutant as Rhodamine B;

[0021] Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite catalyst was added into the wastewater containing organic dyes, and ultrasonicated for 2 h under the condition of ultrasonic power of 500 W.

[0022] The initial concentration of organic pollutants in wastewater is 4 mg / L; Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The added amount of the composite nanomaterial catalyst was 1.5 mg / mL.

[0023] Example 1 Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 Composite Catalyst

[0024] 1. Preparation method

[0025] Take 0.003 mol CuCl 2 ·2H 2 O and 0.015 mol CaCl 2 , respectively dissolved in deionized water and stirred for 30 minutes. After fully dissolved, the two were mixed and stirred evenly. Then 0.015 mol Na 2 MoO 4 ·2H 2 O was slowly poured in and stirred magnetically for 30 min.

[0026] After stirring, the mixed solution was placed in a 100 ml polytetrafluoroethylene reactor and reacted in an oven at 180° C. for 24 h.

[0027] When the reaction is complete, cool it to room temperature, collect the precipitate by centrifugation, wash it several times with deionized water and ethanol, dry it at 80 ° C, and grind it to obtain 20% Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 Complex.

[0028] 2. Testing

[0029] Figure 1 For different MOL (Cu 2+ ：Ca 2+ ) Preparation of Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 XRD pattern of the composite catalyst. Figure 1 It can be seen that Cu 3 (MoO 4 )2 (OH) 2 / CaMoO 4 Composite catalyst and CaMoO 4 Standard card, Cu 3 (MoO 4 ) 2 (OH) 2 Compared with the standard card, it can be seen that the characteristic peak is basically consistent with the peaks of the other two standard cards, indicating that Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite catalyst was successfully prepared. At the same time, the peak of the composite catalyst was sharp and basically free of impurity peaks, indicating that Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite catalyst has high phase purity and high crystallinity.

[0030] Figure 2 20%Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 SEM image of the composite catalyst. Figure 2 It can be seen that 20%Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite has a certain lamellar structure and spherical particles with rough surfaces attached to the upper layer.

[0031] Example 2 Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 Sonocatalytic degradation of rhodamine B using composite catalyst

[0032] Method 1: Stirring adsorption in dark: 30 mg Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4The composite catalyst was added to 20 ml of 4 mg / L rhodamine B solution, adsorbed in the dark for 30 min under magnetic stirring, and after reaching adsorption-desorption equilibrium, 5 ml of the sample was centrifuged and the absorbance at a wavelength of 554 nm was measured using a UV-visible spectrophotometer.

[0033] Method 2 - Sonocatalytic degradation: Weigh 30 mg (MOL (Cu 2+ ：Ca 2+ ) 0%, 5%, 10%, 20%, 30%, 40%) of Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The composite catalyst was measured and 20 ml of 4 mg / L Rhodamine B solution was placed in a conical flask and subjected to ultrasonic degradation experiment under light-proof conditions. The ultrasonic power was 500 W and the ultrasonic time was 2 h. After the reaction was completed, 3 ml of the sample was centrifuged and the absorbance at a wavelength of 554 nm was measured using a UV-visible spectrophotometer.

[0034] Process the data. Calculate the Cu prepared at different molar ratios 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The adsorption and degradation efficiency of Rhodamine B by the composite catalyst. Figure 3 It can be seen that the ultrasonic catalytic degradation effect is significantly better than that of stirring adsorption, among which 20% Cu 3 (MoO 4 ) 2 (OH) 2 / CaMoO 4 The degradation efficiency of the composite catalyst is the best.

Claims

1. An application method of a Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst for degrading an organic dye Rhodamine B, characterized in that: The application method is as follows: first, dissolve CuCl2·2H2O and CaCl2 in deionized water respectively and stir for 30 minutes, and after fully dissolved, mix and stir the two evenly; then slowly pour Na2MoO4·2H2O and stir magnetically for 30 minutes; after stirring, place the mixed solution in a polytetrafluoroethylene reactor and react in an oven at 180°C for 24 hours; when the reaction is complete, cool to room temperature, collect the precipitate by centrifugation, wash with deionized water and ethanol several times, dry at 80°C, and grind to obtain a Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst; The molar ratio of the reactants CuCl2·2H2O:CaCl2:Na2MoO4·2H2O is 0.2:1:1; The Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst was added to the wastewater containing the organic dye Rhodamine B. Under the condition of ultrasonic power of 500W, the ultrasound was carried out for 2 hours, and the initial concentration of Rhodamine B was 4 mg / L; the addition amount of the Cu3(MoO4)2(OH)2 / CaMoO4 composite catalyst was 1.5 mg / mL.

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