CN110743604B - Preparation method of organic sewage efficient photodegradation catalyst - Google Patents

Abstract

The invention discloses a preparation method of an organic sewage high-efficiency photodegradation catalyst, which comprises the steps of grinding fibrous light calcium carbonate to obtain a micron-sized calcium carbonate sheet template, then adding zinc sulfate, carbon nitride and a catalyst, carrying out hydrothermal reaction, drying, grinding to obtain precursor powder, and carrying out high-temperature calcination and natural cooling to obtain the organic sewage high-efficiency photodegradation catalyst. The catalyst is formed by loading nano-scale zinc oxide and carbon nitride on calcium carbonate in a mixed manner, has the characteristics of high efficiency and high speed, and can reach a removal rate of more than 98% for 30min for nitrobenzene under the condition that the use concentration is 0.05-0.2 mg/L.

Description

A kind of preparation method of organic sewage efficient photodegradation catalyst

technical field

The invention relates to the technical field of photodegradation catalysts, in particular to a preparation method of a high-efficiency photodegradation catalyst for organic sewage.

Background technique

Photocatalytic degradation is the use of highly active free radicals generated by radiation and photocatalysts in the reaction system, and then through the addition, substitution, and electron transfer between free radicals and organic pollutants. All pollutants are degraded into inorganic substances. the process of.

The redox mechanism of photocatalysts is mainly that the catalyst is irradiated by light, absorbs light energy, undergoes electron transition, generates electron-hole pairs, directly redoxes the pollutants adsorbed on the surface, or oxidizes the hydroxide (OH-) adsorbed on the surface. , generating strong oxidizing hydroxyl radicals ( OH), oxidizing pollutants.

The mechanism of photocatalytic degradation of halogenated organic pollutants (HOPs) is generally characterized by electron transfer, that is, the active species generated by photo-excited catalysts, such as eaq, eCB or OH, hVB, etc., reduce HOPs to anionic radicals or oxidize them to cations, respectively. free radicals, and degradation is achieved through C-X bond cleavage.

In 2009, a new metal-free carbon nitride photocatalyst with a graphitic phase was developed, which exhibits low oxidation efficiency. On this basis, a lot of related research has been done at home and abroad. Among them, Chinese invention patent CN105536846A discloses a titanium dioxide/carbon nitride composite photocatalyst, which effectively improves the separation ability of photogenerated electrons and positive charges, and the photocatalytic oxidation efficiency is significantly improved. In order to further improve the photocatalytic oxidation efficiency of the catalyst, the present invention provides a preparation method of a high-efficiency photodegradation catalyst for organic sewage.

SUMMARY OF THE INVENTION

Based on the technical problems existing in the background art, the present invention proposes a preparation method of a high-efficiency photodegradation catalyst for organic sewage.

The technical scheme of the present invention is as follows:

A preparation method of an organic sewage high-efficiency photodegradation catalyst, comprising the following steps:

A, adding fibrous light calcium carbonate to ethanol;

B, add grinding aid to ethanol, and obtain slurry after dispersing uniformly;

C. Grind the slurry repeatedly, pass through an 800-mesh sieve, and get the slurry;

D. Add zinc sulfate, carbon nitride and catalyst to the slurry, mix them evenly, and place them in a polytetrafluoroethylene-lined hydrothermal reactor. The solution is evaporated, dried, and ground to obtain precursor powder;

E. High-efficiency photodegradation catalyst for organic sewage can be obtained after high temperature calcination and natural cooling.

Preferably, in the step A, the fibrous light calcium carbonate has an aspect ratio of (60-120):1.

Preferably, in the step B, the grinding aid is glycerol.

Preferably, in the step C, in the slurry, the mass concentration of light calcium carbonate is 1-3%.

Preferably, in the step D, the catalyst is hydrogen fluoride.

Preferably, in the step D, the added amount of the catalyst is 10-20% of the added amount of zinc sulfate.

Preferably, in the step D, the added amount of zinc sulfate and carbon nitride and the mass ratio of light calcium carbonate in the slurry are (8-15):100 and (1-2.5):100, respectively.

Preferably, in the step E, the temperature of the high-temperature calcination is 500-550° C., and the time is 1.5-2 h.

The advantages of the present invention are: in the preparation method of the organic sewage efficient photodegradation catalyst of the present invention, the fibrous light calcium carbonate is ground to obtain a micron-scale calcium carbonate sheet template, and then zinc sulfate, carbon nitride and a catalyst are added. , hydrothermal reaction, drying and grinding to obtain precursor powder, and then high-temperature calcination and natural cooling to obtain a high-efficiency photodegradation catalyst for organic sewage. The catalyst is a composite photodegradation catalyst composed of nano-scale zinc oxide and carbon nitride mixed on calcium carbonate to form a zinc oxide/carbon nitride/calcium carbonate composite photodegradation catalyst. The catalyst has the characteristics of high efficiency and rapidity. Under the condition of mg/L, the removal rate of 2mg/L nitrobenzene can reach more than 98% in 30min.

Detailed ways

Example 1

A preparation method of an organic sewage high-efficiency photodegradation catalyst, comprising the following steps:

A, adding fibrous light calcium carbonate to ethanol;

B. Add 1.5% glycerol by volume to ethanol, and disperse uniformly to obtain slurry;

C. Grind the slurry repeatedly, pass through an 800-mesh sieve, and get the slurry;

D. Add zinc sulfate, carbon nitride and catalyst to the slurry, mix them evenly, and place them in a polytetrafluoroethylene lined hydrothermal reactor. , dried, and ground to obtain precursor powder;

E. High-efficiency photodegradation catalyst for organic sewage can be obtained after high temperature calcination and natural cooling.

In the step A, the fibrous light calcium carbonate has an aspect ratio of (60-120):1.

In the step C, in the slurry, the mass concentration of light calcium carbonate is 1.8%.

In the step D, the catalyst is hydrogen fluoride, and the added amount is 15% of the added amount of zinc sulfate.

The mass ratios of zinc sulfate and carbon nitride to light calcium carbonate in the slurry were 12:100 and 1.8:100, respectively.

In the step E, the temperature of the high-temperature calcination is 530°C, and the time is 1.8h.

Example 2

A preparation method of an organic sewage high-efficiency photodegradation catalyst, comprising the following steps:

A, adding fibrous light calcium carbonate to ethanol;

B. Add 3.2% glycerin by volume to ethanol, and disperse uniformly to obtain slurry;

C. Grind the slurry repeatedly, pass through an 800-mesh sieve, and get the slurry;

D. Add zinc sulfate, carbon nitride and catalyst to the slurry, mix them evenly, and place them in a polytetrafluoroethylene-lined hydrothermal reactor. Under the condition of 240-250 °C, the hydrothermal reaction is carried out for 18 hours, and the solution is evaporated. , dried, and ground to obtain precursor powder;

E. High-efficiency photodegradation catalyst for organic sewage can be obtained after high temperature calcination and natural cooling.

In the step A, the fibrous light calcium carbonate has an aspect ratio of (60-120):1.

In the step C, in the slurry, the mass concentration of light calcium carbonate is 3%.

In the step D, the catalyst is hydrogen fluoride, and the added amount is 10% of the added amount of zinc sulfate.

The mass ratios of zinc sulfate and carbon nitride to light calcium carbonate in the slurry were 15:100 and 1:100, respectively.

In the step E, the temperature of the high-temperature calcination is 550°C, and the time is 1.5h.

Example 3

A preparation method of an organic sewage high-efficiency photodegradation catalyst, comprising the following steps:

A, adding fibrous light calcium carbonate to ethanol;

B. Add 1.1% glycerol by volume to ethanol, and disperse uniformly to obtain slurry;

C. Grind the slurry repeatedly, pass through an 800-mesh sieve, and get the slurry;

D. Add zinc sulfate, carbon nitride and catalyst to the slurry, mix them evenly, and place them in a polytetrafluoroethylene-lined hydrothermal reactor. Under the condition of 220-225 °C, hydrothermally react for 24 hours, and evaporate the solution , dried, and ground to obtain precursor powder;

E. High-efficiency photodegradation catalyst for organic sewage can be obtained after high temperature calcination and natural cooling.

In the step A, the fibrous light calcium carbonate has an aspect ratio of (60-120):1.

In the step C, in the slurry, the mass concentration of light calcium carbonate is 1%.

In the step D, the catalyst is hydrogen fluoride, and the added amount is 20% of the added amount of zinc sulfate.

The mass ratios of zinc sulfate and carbon nitride to light calcium carbonate in the slurry were 8:100 and 2.5:100, respectively.

In the step E, the temperature of the high-temperature calcination is 500°C, and the time is 2h.

0.5 g of the catalyst powder of the above Examples 1-3 was ball-milled and dispersed in 10 L of water to prepare a dispersion liquid, and the dispersion liquid was added to 1 L of organic sewage whose pollutant was nitrobenzene. At this time, the concentration of catalyst in the water body was 0.1mg/L, and the concentration of nitrobenzene was 2mg/mL. The sewage was placed in a Q-SUN aging box with a light intensity of 0.51W/m ² @340nm for 30min and 60min respectively. , 120min test, test the residual amount of nitrobenzene, and carry out comparative test with comparative example (the catalyzer of Chinese invention patent CN105536846A embodiment 1 preparation), obtain following test data:

It can be known from the above test data that the high-efficiency photodegradation catalyst for organic sewage of the present invention has a very good photodegradation effect on nitrobenzene, and the degradation speed is very fast.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (7)

1. A preparation method of an organic sewage high-efficiency photodegradation catalyst is characterized by comprising the following steps:

A. adding fibrous light calcium carbonate into ethanol;

B. adding a grinding aid into ethanol, and uniformly dispersing to obtain slurry;

C. repeatedly grinding the slurry, sieving with a 800-mesh sieve, and taking the slurry;

D. adding zinc sulfate, carbon nitride and a catalyst into the slurry, uniformly mixing, placing the mixture into a hydrothermal reactor with a polytetrafluoroethylene lining, carrying out hydrothermal reaction for 18-24h at the temperature of 220-250 ℃, evaporating and drying the solution, and grinding to obtain precursor powder;

E. the organic sewage high-efficiency photodegradation catalyst can be obtained after high-temperature calcination and natural cooling;

in the step E, the temperature of the high-temperature calcination is 500-550 ℃, and the time is 1.5-2 h.

2. The method for preparing the catalyst for high efficiency photodegradation of organic wastewater according to claim 1, wherein in the step A, the fibrous light calcium carbonate has an aspect ratio of (60-120): 1.

3. the method for preparing the catalyst for efficiently photodegradation of organic wastewater according to claim 1, wherein in the step B, the grinding aid is glycerol.

4. The method for preparing the catalyst for high efficiency photodegradation of organic wastewater according to claim 1, wherein in the step C, the slurry contains light calcium carbonate with a mass concentration of 1-3%.

5. The method according to claim 1, wherein in step D, the catalyst is hydrogen fluoride.

6. The method for preparing the catalyst for high efficiency photodegradation of organic wastewater according to claim 1, wherein in the step D, the addition amount of the catalyst is 10-20% of the addition amount of zinc sulfate.

7. The method for preparing the catalyst for high efficiency photodegradation of organic wastewater according to claim 1, wherein in the step D, the mass ratio of the zinc sulfate and the carbon nitride to the light calcium carbonate in the slurry is (8-15): 100 and (1-2.5): 100.