阅读说明：本技术 一种多孔氮化碳材料、其制备方法及应用 (Porous carbon nitride material, and preparation method and application thereof ) 是由 蔡可迎 周颖梅 徐蕾 何思敏 骆燕 莫满萍 于 2019-08-16 设计创作，主要内容包括：一种多孔氮化碳材料、其制备方法及应用。该制备方法为：首先将计量的石灰氮和去离子水加入烧杯中,将烧杯放入水浴锅中,开动磁力搅拌,控制物料温度为65～85℃,同时向去离子水中通入二氧化碳气体,控制烧杯内物料的pH为8～10,反应2～4h,冷却到室温、抽滤,将得到的物料研磨均匀后,在烘箱中干燥得到前驱体。将前驱体放入带盖坩埚中,并一同置于马弗炉中焙烧,马弗炉以4～8℃/min的速率升温至540～560℃,保温2～4h,自然冷却后,再用盐酸浸泡、洗涤,得到多孔氮化碳。本发明可简化制备过程、降低生产成本和对环境的污染、提高产品收率；制备的多孔氮化碳材料的比较面积大,能有效催化光降解亚甲基蓝。(A porous carbon nitride material, a preparation method and application thereof. The preparation method comprises the following steps: firstly, adding metered lime nitrogen and deionized water into a beaker, placing the beaker into a water bath kettle, starting magnetic stirring, controlling the temperature of materials to be 65-85 ℃, simultaneously introducing carbon dioxide gas into the deionized water, controlling the pH of the materials in the beaker to be 8-10, reacting for 2-4 h, cooling to room temperature, carrying out suction filtration, grinding the obtained materials uniformly, and drying in an oven to obtain a precursor. And putting the precursor into a crucible with a cover, putting the crucible and the precursor into a muffle furnace for roasting, heating the muffle furnace to 540-560 ℃ at the speed of 4-8 ℃/min, preserving the temperature for 2-4 h, naturally cooling, soaking in hydrochloric acid, and washing to obtain the porous carbon nitride. The invention can simplify the preparation process, reduce the production cost and the pollution to the environment and improve the product yield; the prepared porous carbon nitride material has large comparative area and can effectively catalyze and photodegrade methylene blue.)

1. A preparation method of a porous carbon nitride material is characterized by comprising the following steps:

(1) Adding the measured lime nitrogen and deionized water into a beaker, placing the beaker into a water bath kettle, starting magnetic stirring, controlling the water bath temperature to be 65-85 ℃, simultaneously introducing carbon dioxide gas into the deionized water, controlling the pH of materials in the beaker to be 8-10, reacting for 2-4 h, cooling to room temperature, carrying out suction filtration, grinding the obtained materials uniformly, and drying in an oven to obtain a precursor; the mass ratio of the lime nitrogen to the deionized water is 1: (3-6);

(2) And (2) putting the precursor obtained in the step (1) into a crucible with a cover, putting the crucible and the precursor into a muffle furnace for roasting, raising the temperature of the muffle furnace to 540-560 ℃ in a furnace cavity at a speed of 4-8 ℃/min, preserving the temperature for 2-4 h, naturally cooling, soaking in hydrochloric acid, and washing to remove calcium salt to obtain the porous carbon nitride.

2. the method for preparing the porous carbon nitride material according to claim 1, wherein the mass ratio of the lime nitrogen to the deionized water in the step (1) is 1: 4.

3. the method for preparing a porous carbon nitride material according to claim 1 or 2, wherein in the step (1), the reaction is carried out for 3 hours by controlling the temperature of the water bath to 75 ℃ and the pH of the material to 9.

4. the method for preparing a porous carbon nitride material according to claim 1 or 2, wherein the temperature in the muffle furnace is increased to 550 ℃ at a rate of 6 ℃/min in the step (2), and the temperature is maintained for 3 hours.

5. a porous carbon nitride material produced by the production method according to any one of claims 1 to 4.

6. Use of a porous carbon nitride material according to claim 5 in catalyzing the photodegradation of methylene blue.

Technical Field

the invention particularly relates to a porous carbon nitride material, and a preparation method and application thereof, and belongs to the field of material preparation and sewage treatment.

Background

With the rapid development of the industry, more and more industrial wastewater is generated, and the pollution to the environment is increasingly serious. Organic matters in the industrial wastewater, particularly widely used dyes, have the characteristics of high toxicity and difficulty in degradation, so that the difficulty in treating the industrial wastewater is increased, and the cost is increased. Therefore, it is desirable to provide a method for degrading dyes at low cost.

the cost can be obviously reduced by degrading organic matters by utilizing visible light. The carbon nitride is a novel photocatalyst, can absorb more visible light, has the advantages of high stability, low price, environmental protection and the like, and has wide application prospect. The most common method is to prepare carbon nitride by using melamine or dicyandiamide as a raw material and adopting a thermal polymerization method, but the carbon nitride prepared by the method has smaller specific surface area and low catalytic activity. The thermal polymerization of urea or thiourea as raw material can prepare carbon nitride with large specific surface area, but its yield is very low. The specific surface area of the carbon nitride can also be increased by using a template method. The patent with publication number CN105879829A discloses a method for preparing ordered mesoporous carbon nitride, which comprises using mesoporous molecular sieve SBA-15 as hard template to prepare carbon nitride, and removing the template by hydrofluoric acid etching at later stage. The molecular sieve and the silicon dioxide are used as templates, and the molecular sieve and the silicon dioxide can be removed only by using highly corrosive hydrofluoric acid, which is not beneficial to environmental protection. Shenchaxiao, Zhang Ling, etc. use polystyrene emulsion as soft template, and dicyandiamide as raw material to synthesize porous carbon nitride (Shenchaxiao, Zhang Ling, Jianglong, light, chemical research and application, 2017, 9 (6): 873-877.). However, the soft template method is relatively expensive and not suitable for industrial production. Therefore, the development of a method for preparing porous carbon nitride, which has low cost, environmental friendliness and simple process, has very important practical significance.

Disclosure of Invention

The invention provides a porous carbon nitride material, a preparation method and application thereof, and the method can simplify the preparation process, reduce the production cost and the pollution to the environment and improve the product yield; the prepared porous carbon nitride material has large comparative area and can effectively catalyze and photodegrade methylene blue.

a preparation method of a porous carbon nitride material comprises the following steps:

(1) Adding the measured lime nitrogen and deionized water into a beaker, placing the beaker into a water bath kettle, starting magnetic stirring, controlling the water bath temperature to be 65-85 ℃, simultaneously introducing carbon dioxide gas into the deionized water, controlling the pH of materials in the beaker to be 8-10, reacting for 2-4 h, cooling to room temperature, carrying out suction filtration, grinding the obtained materials uniformly, and drying in an oven to obtain a precursor; the mass ratio of the lime nitrogen to the deionized water is 1: (3-6);

(2) And (2) putting the precursor obtained in the step (1) into a crucible with a cover, putting the crucible and the precursor into a muffle furnace for roasting, raising the temperature of the muffle furnace to 540-560 ℃ in a furnace cavity at a speed of 4-8 ℃/min, preserving the temperature for 2-4 h, naturally cooling, soaking in hydrochloric acid, and washing to remove calcium salt to obtain the porous carbon nitride.

Preferably, the mass ratio of the lime nitrogen to the deionized water in the step (1) is 1: 4.

Preferably, the temperature of the water bath in the step (1) is 75 ℃, the pH of the reaction material is controlled to be 9, and the reaction is carried out for 3 hours.

Preferably, in the step (2), the temperature of the muffle furnace is increased to 550 ℃ at the speed of 6 ℃/min, and the temperature is kept for 3 h.

A porous carbon nitride material is prepared by the preparation method.

The porous carbon nitride material prepared by the preparation method is applied to catalytic photodegradation of methylene blue.

the invention takes cheap lime nitrogen as raw material, the lime nitrogen is firstly hydrolyzed to generate cyanamide and calcium hydroxide, the cyanamide is polymerized to obtain dicyandiamide, and the calcium hydroxide reacts with the introduced carbon dioxide to generate calcium carbonate. In the calcining process, dicyandiamide is thermally polymerized to generate carbon nitride, calcium carbonate is used as a pore-foaming agent to obtain a mixture of the carbon nitride and the calcium carbonate, and the calcium carbonate is removed by acid washing to obtain the porous carbon nitride.

Compared with the prior art, the method takes cheap and easily available lime nitrogen as a raw material and cheap and nontoxic carbon dioxide as an auxiliary material, and obtains the carbon nitride material through hydrolysis, polymerization and calcination; the whole preparation process does not need any special treatment, one part of the hydrolysis product of the lime nitrogen is used as a precursor, the other part of the hydrolysis product of the lime nitrogen is used as a template agent, and no template agent or pore-forming agent is needed to be added in the preparation process, so that the production process can be simplified, and the production cost can be reduced; the carbon dioxide escaping in the acid washing process is easy to treat and has little influence on the environment; in addition, the yield of the porous carbon nitride material prepared by the method reaches 24.4 percent (calculated by calcium cyanamide), and the product yield is improved. The porous carbon nitride material prepared by the preparation method has large specific surface area, is used as a catalyst for photodegradation of methylene blue, has high catalytic activity and good repeatability, and has potential utilization value in the aspect of sewage treatment.

drawings

FIG. 1 is an X-ray diffraction pattern of a porous carbon nitride material prepared in accordance with a first example of the present invention;

FIG. 2 is an infrared spectrum of a porous carbon nitride material prepared in the first example of the present invention;

FIG. 3 is an isothermal adsorption-desorption curve of the porous carbon nitride material prepared in the first embodiment of the present invention;

FIG. 4 is a transmission electron microscope image of the porous carbon nitride material prepared in the first example of the present invention;

FIG. 5 is an activity diagram of the porous carbon nitride material prepared in the first embodiment of the present invention catalyzing photodegradation of methylene blue solution;

FIG. 6 is a repeated diagram of the solution of methylene blue photo-degraded by the catalysis of porous carbon nitride prepared in the first embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples.