CN109607735B

CN109607735B - A kind of method for degrading methylene blue with catalyst prepared from camphor leaves

Info

Publication number: CN109607735B
Application number: CN201910101682.8A
Authority: CN
Inventors: 陈进; 崔鹏鹤; 杨红星; 徐欣欣
Original assignee: Northeastern University China
Current assignee: Northeastern University China
Priority date: 2019-01-30
Filing date: 2019-01-30
Publication date: 2021-10-08
Anticipated expiration: 2039-01-30
Also published as: CN109607735A

Abstract

The invention relates to a method for degrading methylene blue with a catalyst prepared from camphor leaves, belonging to the technical field of organic pollutants and environmental restoration. The method is as follows: in the stirring process, the catalyst prepared from camphor leaves is added to a methylene blue solution with a concentration of 10-80 mg·L ^-1 , and a NaBH solution with a concentration of 0.02 mol·L _- ¹ is added to obtain a system solution. The catalyzer that Cinnamomum camphora makes, methylene blue and NaBH _The mass ratio is 40:1:30.4, and the reaction finishes when the color of the system solution is reduced to colorless; After mixing the dry powder of camphor leaves with the ammonium molybdate solution, a hydrothermal reaction is carried out, and the obtained product is dried and then carbonized at a high temperature. Compared with the existing degraded methylene blue, the degraded methylene blue concentration of the present invention is higher, the reaction is fast, the operation is simple, and has excellent degradation effect. When the degradation rate reaches 100%, the shortest time is 3.5min.

Description

Method for degrading methylene blue by using catalyst prepared from cinnamomum camphora leaves

Technical Field

The invention belongs to the technical field of organic pollutants and environmental remediation, and particularly relates to a method for degrading methylene blue by using a catalyst prepared from cinnamomum camphora leaves.

Background

Methylene Blue (MB) is an organic substance, is widely applied to the aspects of chemical indicators, dyes, biological coloring agents, medicines and the like, is stable in the air, is alkaline in aqueous solution, is toxic and has great harm to water, so that the research on the degradation method of the MB is of great significance.

The development of modern industry has promoted the development of various dyes, but the use of dyes in large quantities has a great impact on the environment. Because more than 20% of the dye will fade during use, water and soil pollution will result. The dye is easy to disperse in water, and the pollutants can enter human bodies along with food chains to cause diseases such as allergy, poisoning and even cancer. Meanwhile, dye pollution can cause eutrophication of water, and seriously threatens the balance of an ecological system. The most traditional modes for treating water pollution comprise precipitation, solidification, reduction, fusion, membrane separation, ion exchange, adsorption, photocatalysis and the like. Wherein, the reduction can be widely applied as a simple and efficient method. However, the reducing agent of the current research method has the defects of high cost, complex preparation, difficult recovery, low efficiency and the like, and cannot meet the concept of green treatment of dye wastewater. Therefore, it is very important to develop a reducing agent which is efficient, economical and recyclable.

The biomass is rich in source, and crop byproducts such as straws and rice husks or fallen leaves of ornamental trees have enough storage at home and abroad. These by-products are currently disposed of for incineration, landfill, feed and other uses. If a large amount of by-products are not treated in time or in an inappropriate manner, air pollution and the like can be caused. Patents CN108404947A and CN105498815A provide a heterogeneous Fenton-like catalyst of Fe respectively₃A degradation method of a C/C composite material and a rod-shaped bismuth phosphate loaded biomass carbon aerogel material degradation material. However, in these methods, the material preparation is complicated, the catalytic speed is slow, and the effect is not ideal.

Disclosure of Invention

The invention aims to provide a method for degrading methylene blue by using a catalyst prepared from cinnamomum camphora leaves, which can be used for efficiently degrading the methylene blue. In particular to a catalyst prepared by reaction after mixing by a hydrothermal method and high-temperature carbonization and application of the catalyst to the degradation of methylene blue.

The purpose of the invention can be realized by the following technical scheme:

a method for degrading methylene blue by using a catalyst prepared from cinnamomum camphora leaves comprises the following steps: adding the catalyst prepared from the cinnamomum camphora leaves into the catalyst with the concentration of 10-80 mg.L in the stirring process^-1Adding 0.02 mol.L methylene blue solution^-1NaBH of₄The solution is used for obtaining a system solution, and the catalyst, the methylene blue and the NaBH are prepared from the cinnamomum camphora leaves₄The mass ratio of the components is 40:1:30.4, and the reaction is finished when the color of the system solution is reduced to be colorless;

the catalyst prepared from the cinnamomum camphora leaves is prepared by the following method: mixing dry powder of cinnamomum camphora leaves with an ammonium molybdate solution, carrying out hydrothermal reaction, drying the obtained product, and carbonizing at high temperature.

Preferably, the dry powder of the cinnamomum camphora leaves is prepared by drying the cinnamomum camphora leaves in the sun and grinding the dried powder to micron level.

Preferably, the hydrothermal reaction is: mixing dry cinnamomum camphora leaves powder and an ammonium molybdate solution, wherein the mass ratio of the dry cinnamomum camphora leaves powder to the ammonium molybdate solution is 5:36, the concentration of the ammonium molybdate solution is 0.18g/ml, heating the mixture in a reaction kettle at 100 ℃ for 10-14 h, and centrifugally vacuum-drying the mixture for 10-14 h to obtain a hydrothermal reaction product.

Preferably, the high temperature carbonization is: grinding the hydrothermal reaction product to micron level, firing under the protection of nitrogen at 800 ℃ for 3h, cooling to room temperature, and grinding to obtain black powder, namely the catalyst prepared from the cinnamomum camphora leaves.

Preferably, the firing is carried out in a tube furnace, the initial temperature of the tube furnace is set to be 0 ℃ by a program, the temperature rising speed is 2-8 ℃/min, and the tube furnace is cooled to the room temperature after the firing is finished, and the temperature reducing speed is 6-10 ℃/min.

Compared with the prior art, the invention has the advantages that: the catalyst prepared from the cinnamomum camphora leaves is simple in preparation process, and the raw materials are cheap and easy to obtain; compared with the methylene blue degraded by the prior art, the degraded methylene blue has high concentration, quick reaction, simple operation and excellent degradation effect. When the degradation rate reaches 100%, only 3.5min is needed at the shortest.

Drawings

Catalyst prepared from dry powder of cinnamomum camphora leaves, and Mo is abbreviated as follows₂C@CCL(NC)。

FIG. 1 shows Mo in example 1₂Transmission electron micrograph of C @ CCL (NC);

FIG. 2 shows Mo₂C @ CCL (NC) ultraviolet-visible spectrum of degraded methylene blue;

FIG. 3 shows Mo₂C @ ccl (nc) plot of MB concentration with time for methylene blue degradation.

Detailed Description

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.

The test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

Preparing dry cinnamomum camphora leaf powder:

sun-drying folium Cinnamomi Camphorae (The leaf of The cinammomum camphora, which can be abbreviated as CCL), pulverizing The sun-dried folium Cinnamomi Camphorae in a pulverizer to 500 + -50 μm, and storing The obtained powder in a clean wide-mouth bottle;

② preparing catalyst by using dry powder of cinnamomum camphora leaves, nitrogen-doping molybdenum carbide in cinnamomum camphora leaves, the following abbreviation Mo₂C@CCL(NC)：

a. Adding 0.5g of dry powder of cinnamomum camphora leaves into a beaker filled with 20mL of deionized water, adding 3.6g of ammonium molybdate crystals, and stirring for 1 h;

b. after the ammonium molybdate is completely dissolved, putting the solution obtained in the step a into a reaction kettle, and heating in an oven at 100 ℃ for 12 hours;

c. c, centrifuging the reaction product in the step b and drying in vacuum for 12 hours;

d. grinding the dried product in the step c to micron level, placing the product into a tubular furnace, firing the product under the protection of nitrogen, setting the initial temperature of the tubular furnace to be 0 ℃, the heating rate to be 5 ℃/min, heating the product to 800 ℃, keeping the temperature for 3h, cooling the product to room temperature at the cooling rate of 8 ℃/min, and finally grinding the product to obtain black powder Mo₂C@CCL(NC)。

Degrading methylene blue:

selecting the concentration of 50 mg.L^-1Methylene Blue (MB) is an organic dye of (1). Firstly, Mo is mixed in the stirring process₂C @ CCL (NC) (2mg) was added to 1.0mL of MB solution. Subsequently, freshly prepared NaBH was added₄(2.0mL，0.02mol·L^-1) And finishing the reaction when the color of the solution is reduced to be colorless.

FIG. 1 shows Mo₂Transmission electron micrograph of C @ CCL (NC), in which Mo is observed₂C @ ccl (nc) has a near spherical morphology. At the same time, it is apparent that Mo₂The size of the C crystal grains is within the size range of 7-12 nm and is almost uniformly distributed on the carbon substrate.

The results in FIGS. 2 and 3 show that Mo is contained₂C@The absorption peak of the CCL (NC) mixed solution disappeared completely only 3.5min, and Mo was observed₂C @ CCL (NC) has a high catalytic reduction effect on methylene blue.

Claims

1. a method for degrading methylene blue by a catalyzer prepared from Cinnamomum camphora, is characterized in that, described method is: in stirring process, the methylene blue of 10 ~ 80 mg L ^-1 is added to the catalyzer that Cinnamomum camphora makes is concentrated solution, adding the NaBH solution with a concentration of 0.02mol L _- ¹ to obtain a system solution, the mass ratio of the catalyst, methylene blue and NaBH made from the camphor leaf is ₄₀ :1:30.4, and the color of the system solution is returned to no When the color reaction ends;

The catalyzer prepared from the camphor leaf is prepared by the following method: the dry powder of the camphor leaf is mixed with the ammonium molybdate solution, and a hydrothermal reaction is carried out, and the obtained product is dried and subjected to high-temperature carbonization;

The hydrothermal reaction is as follows: the dry powder of camphor leaf and ammonium molybdate solution are mixed, the mass ratio of the dry powder of camphor leaf and ammonium molybdate is 5:36, and the concentration of the ammonium molybdate solution is 0.18g/ml , heated at 100 °C for 10-14 h in a reaction kettle, and centrifuged and vacuum-dried for 10-14 h to obtain a hydrothermal reaction product;

The high-temperature carbonization is as follows: grinding the hydrothermal reaction product to micron level, firing under nitrogen protection, firing temperature of 800° C., firing time of 3 hours, cooling to room temperature, and grinding to obtain black powder, that is, the product obtained from camphor leaves. catalyst.

2. method according to claim 1, is characterized in that, described camphor leaf dry powder is that camphor leaf is air-dried, pulverized to micron level to obtain.

3. The method according to claim 1, wherein the firing is carried out in a tube furnace, and the program setting initial temperature of the tube furnace is 0 °C, the heating rate is 2~8 °C/min, and the firing After the end, cool down to room temperature, and the cooling rate is 6~10℃/min.