Piezoelectric optoelectronic material for degradation of organic pollutants and degradation method thereof

A technology of organic pollutants and optoelectronics, applied in the field of pollutant treatment, can solve the problem that the ability to degrade pollutants cannot meet the requirements, and achieve the effects of stable performance, strong adsorption capacity and efficient removal

Inactive Publication Date: 2018-09-04

SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA

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AI-Extracted Technical Summary

Problems solved by technology

At present, although some piezoelectric optoelectronic materials have been used to deg...

Method used

In above-mentioned degradation method, can make full use of two-dimensional KNbO The advantages such as large specific surface area, having more active exposed surfaces, strong adsorption capacity, easy deformation and higher piezoelectric constant of nano-sheets, combined with ultrasonic wave or light and ultrasonic wave Auxiliary, it can further improve the activity of KNbO3 nanosheets, which is beneficial to stimulate more electron-hole pairs, and react with water to generate more hydroxyl groups and superoxide radicals, thereby further improving the degradation performance of organic pollutants and realizing organic pollution Efficient removal of substances.

In concrete degradation method, can adopt described two-dimensional KNbO3 nano sheet of ultrasonic wave to carry out organic matter degradation, more can adopt illumination and ultrasonic wave to assist described two-dimensional KNbO3 nano sheet to carry out organic matter degradation, its degradation effect is better.

In sum, adopt two-dimensional KNbO3 nano sheet is better than powdery effect as the catalyzer of organic pollutant degradation, and further under the common assistance of ultrasonic wave and illumination condition, degradation rate can reach more than 90%, has Excellent degradation effect.

In this step, adopt ethylene glycol as solvent, have stronger solvency, and the viscosity of ethylene glycol is bigger with respect to water, in ethylene glycol solvent, the diffusion velocity of K and Nb ion is slower, The low nucleation rate when forming KNbO3 is favorab...

Abstract

The invention discloses a piezoelectric optoelectronic material for the degradation of organic pollutants. The piezoelectric optoelectronic material utilizes two-dimensional KNbO3 nanosheets. A preparation method of the two-dimensional KNbO3 nanosheet comprises orderly adding KOH and Nb2O5 into a container with ethylene glycol according to the ratio, carrying out full dispersion, transferring themixed solution into a high pressure reactor, carrying out heating for some time, carrying out cooling to the room temperature, carrying out cleaning and drying to obtain a white product, grinding thewhite product into powder, and carrying out calcination at a high temperature to obtain the two-dimensional KNbO3 nanosheet. The invention also provides an organic pollutant degradation method. The method utilizes the piezoelectric optoelectronic material as a catalyst, and ultrasonic wave or combination of illumination and ultrasonic waves to assist in the degradation of organic pollutants. The piezoelectric optoelectronic material fully utilizes the two-dimensional KNbO3 nanosheet advantages of a large ratio of the active exposed surface, a strong adsorption capacity, easy deformation and high piezoelectric constant, can be used as a photocatalyst to be excited by ultraviolet light, can excite more electron hole pairs under ultrasonic conditions through the piezoelectric effects and realizes the efficient removal of organic pollutants.

Application Domain

Water/sewage treatment by irradiationWater treatment compounds +4

Technology Topic

ChemistryOptoelectronic materials +13

Image

Examples

Experimental program(5)

Example Embodiment

[0041] Two-dimensional KNbO 3 Specific preparation examples of nanosheets:

[0042] (1) Weigh 1.403g KOH and 0.35g Nb 2 O 5 , Successively added to a 100mL beaker containing 25mL of ethylene glycol;

[0043] (2) Place the beaker containing the above mixed solution on a magnetic stirrer (stirring speed: 500rpm) and stir for 45 minutes to fully disperse;

[0044] (3) Put the above mixed liquid into a polytetrafluoroethylene liner and heat it at a temperature of 200°C for 12 hours.

[0045] (4) After cooling to room temperature, centrifugal washing with distilled water and ethanol for more than three times, drying to obtain a white product.

[0046] (5) Grind the above white product in an agate mortar for 5 minutes, place the obtained powder in a muffle furnace, and then calcinate at 900°C for 2 hours to obtain a two-dimensional KNbO with a thickness of 50nm and a length of 300nm. 3 Nanosheets.

[0047] See figure 1 , figure 2 , KNbO prepared by the invention 3 Nanosheets, under SEM observation, the nanosheets are assembled into a flower shape, and the prepared two-dimensional KNbO 3 The thickness of the nanosheet is 40-70nm, the length is 100-300nm, and the morphology is regular and neat.

[0048] Based on the above two-dimensional KNbO 3 For the preparation of nanosheets, the present invention also provides a method for degradation of organic pollutants, using the piezoelectric optoelectronic material described above-two-dimensional KNbO 3 Nanosheets act as a catalyst for the degradation of organic matter.

[0049] In the specific degradation method, ultrasound can be used to assist the two-dimensional KNbO 3 Nanosheets are used to degrade organic matter, and light and ultrasound can be used to assist the two-dimensional KNbO 3 Nanosheets degrade organic matter, and the degradation effect is better.

[0050] Specifically, the used ultrasonic power range: 150W-300W, frequency: 40kHz, light source power: 300W-400W.

[0051] In the above degradation methods, two-dimensional KNbO can be fully utilized 3 Nanosheets have the advantages of large specific surface area, more active exposed surfaces, strong adsorption capacity, easy deformation and higher piezoelectric constant. Combined with the assistance of ultrasound or light and ultrasound, it can further increase KNbO 3 The activity of the nanosheets is conducive to stimulating more electron-hole pairs, reacting with water to generate more hydroxyl groups and superoxide free radicals, thereby further improving the degradation performance of organic pollutants and realizing efficient removal of organic pollutants.

[0052] In the following, the above degradation method of the present invention and the achieved technical effects will be further detailed in combination with comparative experiments.

[0053] The organic pollutant selected for the following comparative experiment is rhodamine B.

Example

[0054] Comparative experiment example 1:

[0055] The photocatalytic activity test was performed under physical stirring conditions. Add 100mL of rhodamine B to a 200mL solution beaker (10mg/L), and then take 50mg of KNbO 3 Put the powder into a beaker containing rhodamine B solution, and stir for 1 hour in the dark to make the dye in the catalyst (KNbO 3 ) The surface reaches the adsorption/desorption equilibrium (dark reaction), and then the photocatalytic reaction is carried out under physical stirring conditions.

[0056] In the physical stirring process, the above beaker containing 100 mL of rhodamine B solution was placed on a magnetic stirrer (stirring speed: 500 rpm) to carry out the catalytic reaction. Samples were taken every 30 minutes, 3 mL of the reaction solution was taken each time, filtered, and then the supernatant was placed in a quartz glassware and tested with an ultraviolet-visible spectrophotometer.

[0057] According to the Lambert-Beer law, the change in the intensity of the characteristic absorption peak of organic matter can be quantitatively calculated. When the light-absorbing substance is the same and the thickness is the same, the change in absorbance can be used to directly indicate the change in solution concentration. Because Rhodamine B has a characteristic absorption peak at 540 nm, the change in absorbance can be used to measure the concentration change of Rhodamine B in the solution in this experimental example.

[0058] From image 3 (Abscissa: degradation time; ordinate: the ratio of the measured concentration of rhodamine B to the initial concentration of rhodamine B after a period of physical stirring) It can be seen that after 90 minutes of degradation time, under physical stirring conditions ( image 3 Dark line shown), Rhodamine B is only degraded by 6%. In other words, using KNbO 3 The powder acts as a photocatalyst and under the conditions of physical stirring, the degradation rate of the dye is very low.

Example

[0059] Comparative experiment example 2:

[0060] An ultrasonic cleaner (BRANSONIC, CPX2800H-C) (power: 250W, frequency: 40kHz) was used for the photocatalytic activity test.

[0061] Add 100mL of rhodamine B to a 200mL solution beaker (10mg/L), and then take 50mg of KNbO 3 Put the powder into a beaker containing rhodamine B solution, and stir for 1 hour in the dark to make the dye in the catalyst (KNbO 3 ) The surface reaches the adsorption/desorption equilibrium (dark reaction).

[0062] The beaker containing 100mL rhodamine B solution is placed in an ultrasonic cleaner (BRANSONIC, CPX2800H-C) (power: 250W, frequency: 40kHz) for ultrasonic degradation, and ice cubes are added to the ultrasonic cleaner, and the temperature is controlled at 30 °About. Samples were taken every 30 minutes, 3 mL of the reaction solution was taken each time, filtered, and then the supernatant was placed in a quartz glassware and tested with an ultraviolet-visible spectrophotometer.

[0063] From image 3 (Abscissa: degradation time; ordinate: the ratio of the concentration of rhodamine B measured after ultrasound to the initial concentration of rhodamine B) It can be seen that after 90 minutes of degradation, the ultrasound ( image 3 Under the condition of ultrasonic line shown), Rhodamine B was degraded by 28%. In other words, using KNbO 3 The powder acts as a photocatalyst and under ultrasonic conditions, the degradation rate of the dye is still very low.

PUM

Property	Measurement	Unit
Length	300.0	nm
Thickness	40.0 ~ 70.0	nm
Length	100.0 ~ 300.0	nm

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Strong adsorption capacity
Large specific surface area

Piezoelectric optoelectronic material for degradation of organic pollutants and degradation method thereof

A technology of organic pollutants and optoelectronics, applied in the field of pollutant treatment, can solve the problem that the ability to degrade pollutants cannot meet the requirements, and achieve the effects of stable performance, strong adsorption capacity and efficient removal

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

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Description & Claims & Application Information

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