阅读说明：本技术 一种亚铬酸锰粉末及其制备方法和应用 (Manganese chromite powder and preparation method and application thereof ) 是由 陶然 刘斌 谭青爽 范晓星 于 2021-11-15 设计创作，主要内容包括：本发明属于无机材料粉末制备技术领域,具体涉及一种亚铬酸锰粉末及其制备方法和应用。制备方法包括以下步骤：将铬盐与锰盐加入去离子水中,充分搅拌溶解；于所得混合溶液中加入适柠檬酸,继续搅拌,得溶胶体；将所得溶胶体置于烘箱中烘干,得前驱体；将所得前驱体研磨,在管式炉中空气环境下进行煅烧,得目标产物。本发明采用溶胶凝胶法制备亚铬酸锰,不但能够促进反应进行,缩短反应时间,而且能够显著降低反应产物的团聚现象。本发明工艺流程简单易行,且在光催化氧化环境污染控制方面具有独特的优势,成本低、操作简单、绿色环保、节能、有机污染物完全分解避免二次污染。(The invention belongs to the technical field of inorganic material powder preparation, and particularly relates to manganese chromite powder and a preparation method and application thereof. The preparation method comprises the following steps: adding chromium salt and manganese salt into deionized water, and fully stirring and dissolving; adding citric acid into the mixed solution, and continuously stirring to obtain a sol; drying the obtained sol in a drying oven to obtain a precursor; grinding the obtained precursor, and calcining in a tubular furnace under an air environment to obtain a target product. The method adopts a sol-gel method to prepare the manganese chromite, can promote the reaction, shorten the reaction time and obviously reduce the agglomeration phenomenon of reaction products. The method has the advantages of simple and easy process flow, unique advantages in the aspect of photocatalytic oxidation environmental pollution control, low cost, simple operation, environmental protection, energy conservation, complete decomposition of organic pollutants and avoidance of secondary pollution.)

1. The manganese chromite powder is characterized by comprising the following steps:

1) adding chromium salt and manganese salt into deionized water, and fully stirring and dissolving;

2) adding a proper amount of citric acid into the mixed solution obtained in the step 1), and continuously stirring to obtain a sol;

3) drying the sol obtained in the step 2) in a drying oven to obtain a precursor;

4) grinding the precursor obtained in the step 3), and calcining in a tubular furnace in an air environment to obtain a target product.

2. The manganese chromite powder of claim 1, wherein in step 1), said chromium salt is chromium nitrate nonahydrate.

3. A manganese chromite powder according to claim 2, wherein in step 1) said manganese salt is manganese nitrate hexahydrate.

4. The manganese chromite powder of claim 3, wherein in step 1), the molar ratio of chromium salt to manganese salt is 2: 1.

5. The manganese chromite powder of claim 4, wherein in step 2), said citric acid is citric acid monohydrate and is added in an amount of 1.2 times the total mole of the chromium salt and the manganese salt.

6. The manganese chromite powder of claim 5, wherein in step 2), the stirring time is 2 hours.

7. The manganese chromite powder of claim 6, wherein in step 3), said drying is carried out at a temperature of 100 ℃ and 120 ℃ for a time of 10-12 h.

8. The manganese chromite powder of claim 7, wherein in step 4), said calcining is carried out at a temperature of 600 ℃ for a time of 4 hours.

9. Use of a manganese chromite powder according to any one of claims 1 to 8 in the photocatalytic degradation of gaseous pollutants.

10. Use according to claim 9, characterized in that the method is as follows: adding the manganese chromite powder of any one of claims 1 to 8 into a photocatalytic reactor, adding a gas pollutant, and performing photocatalytic degradation under a xenon lamp.

Technical Field

The invention belongs to the technical field of inorganic material powder preparation, and particularly relates to manganese chromite powder and a preparation method and application thereof.

Background

With the progress of society and the rapid development of economy, the problems of energy crisis and environmental pollution are highlighted. The environmental pollution not only seriously affects the health of human beings, but also brings immeasurable economic loss to the society, and the control and treatment of the environmental pollution are major problems facing and waiting to be solved in the twenty-first century. The catalytic technology has wide development prospect in the field of environmental purification, and harmful substances are effectively degraded by the technologies such as photocatalysis, thermocatalysis, electrocatalysis and the like.

At present, the synthesis methods of manganese chromite at home and abroad include a solid-phase reaction method, a coprecipitation method and the like. Solid phase reaction, for example, manganese dioxide and chromium oxide in a molar ratio of 1:1, and calcining at high temperature to obtain manganese chromite. The coprecipitation method comprises the steps of adding a proper amount of deionized water into manganese nitrate and chromium nitrate according to the molar ratio of 1:2, stirring for 0.5h, adding a proper amount of ammonia water, drying and calcining to obtain the manganese chromite. However, the above-mentioned production method has problems that: the process is complex, the requirement on equipment is high, the large-scale production is difficult, and the product is impure. In addition, China is the country with the most abundant chromium resources, so that the development of chromate materials to replace toxic catalytic pigments has very superior conditions. Therefore, the development of a method which is simple and easy to operate, low in cost, green and environment-friendly and can produce manganese chromite powder in a large scale has important social significance and commercial value.

Disclosure of Invention

The invention aims to provide a preparation method of manganese chromite powder, which is simple, low in cost and easy to operate, and has outstanding effective effect on solving the problems of environmental pollution and organic matter degradation.

The technical scheme adopted by the invention is as follows: a method for preparing manganese chromite powder, comprising the steps of:

1) adding chromium salt and manganese salt into deionized water, and fully stirring and dissolving;

2) adding a proper amount of citric acid into the mixed solution obtained in the step 1), and continuously stirring to obtain a sol;

3) drying the sol obtained in the step 2) in a drying oven to obtain a precursor;

4) grinding the precursor obtained in the step 3), and calcining in a tubular furnace in an air environment to obtain a target product.

Further, in the above method for preparing manganese chromite powder, the chromium salt is chromium nitrate nonahydrate.

Further, in the above method for preparing manganese chromite powder, the manganese salt is manganese nitrate hexahydrate.

Further, the above method for preparing manganese chromite powder comprises the steps of mixing chromium salt and manganese salt in a molar ratio of 1: 2.

Further, in the above method for preparing manganese chromite powder, the citric acid is citric acid monohydrate, and the amount of the citric acid added is 1.2 times of the total mole of the chromium salt and the manganese salt.

Further, in the above method for preparing manganese chromite powder, in step 2), the stirring time is 2 hours.

Further, in the above preparation method of manganese chromite powder, in the step 3), the drying temperature is 100-.

Further, in the above preparation method of manganese chromite powder, in step 4), the calcination is performed at a calcination temperature of 600 ℃ for 4 hours.

The manganese chromite powder provided by the invention is applied to photocatalytic degradation of gas pollutants.

Further, the method is as follows: adding manganese chromite powder into a photocatalytic reactor, adding gas pollutants, and performing photocatalytic degradation under a xenon lamp.

The invention has the beneficial effects that:

1. the preparation method of the invention has the advantages of low cost of required materials, stable structure of manganese chromite powder synthesized by chromium salt and manganese salt, and high photocatalytic activity.

2. The preparation method has the advantages of low production cost, easily obtained materials, simple method and convenience for large-scale production.

3. The preparation method of the invention has no industrial waste gas and waste water in the whole production process, is environment-friendly and has high yield.

4. The method adopts a sol-gel method to prepare the manganese chromite, can promote the reaction, shorten the reaction time and obviously reduce the agglomeration phenomenon of reaction products. The method has the advantages of simple and easy process flow, unique advantages in the aspect of photocatalytic oxidation environmental pollution control, low cost, simple operation, environmental protection, energy conservation, complete decomposition of organic pollutants and avoidance of secondary pollution.

Drawings

FIG. 1 is a flow chart of manganese chromite prepared by the present invention.

FIG. 2 is an XRD pattern of manganese chromite prepared according to the present invention.

FIG. 3 is a graph showing the amount of acetone produced by the degradation of isopropanol by manganese chromite prepared according to the present invention.

Detailed Description

Example 1

Manganese (II) chromite (MnCr)₂O₄) The preparation method of the powder comprises the following steps:

1) 0.4g (2mmol) of chromium nitrate nonahydrate and 0.287g (1mmol) of manganese nitrate hexahydrate are respectively dissolved in 50ml of deionized water, stirred for 0.5h and mixed uniformly.

2) Adding 0.757g of citric acid monohydrate into the mixed solution obtained in the step 1), stirring for 2 hours at room temperature, and stirring uniformly to obtain the sol.

3) And (3) placing the sol obtained in the step 2) in a blast drying oven at 120 ℃, and drying for 10-12h to obtain a precursor.

4) Grinding the precursor obtained in the step 3), placing the ground precursor in a tubular furnace, and roasting the ground precursor for 4 hours at the temperature of 600 ℃ to obtain the manganese chromite.

(II) detection

FIG. 1 is a flow chart of manganese chromite prepared by the present invention.

FIG. 2 is an XRD pattern of manganese chromite prepared in accordance with the present invention, compared to a standard card of JADE of manganese chromite, demonstrating the successful synthesis of manganese chromite nanomaterials.

Example 2 application of manganese chromite powder to photocatalytic degradation of gaseous pollutants

The method comprises the following steps: 0.1g of manganese chromite prepared in example 1 was weighed and placed in a photocatalytic reactor, 5. mu.L of isopropyl alcohol was extracted and introduced into the photocatalytic reactor, and after reacting for 2 hours in the dark, it was irradiated with a xenon lamp for two hours and analyzed with a gas chromatography apparatus.

FIG. 3 is a graph showing the amount of acetone produced by the degradation of isopropanol by manganese chromite prepared according to the present invention. From the analysis of macroscopic results, the amount of acetone generated at 20min was 2.94ppm/min, and the amount of acetone generated at 120min was 14.43ppm/min, and the effect of degrading isopropanol was better, and 4.91 times of the degradation rate at 20 min. The result shows that under the irradiation of light, the manganese chromite has obvious effects on improving the environment and degrading pollutants. From microscopic results, the manganese chromite is used as a photocatalyst with high efficiency, high yield and low cost, and under the irradiation of light, the surface of the manganese chromite can generate photocatalytic reaction similar to photosynthesis to generate free hydroxyl and active oxygen with strong oxidation capacity, has strong photooxidation-reduction capacity, can oxidize and decompose various organic compounds and partial inorganic matters, and decomposes organic pollutants into pollution-free water and carbon dioxide.