A method for photocatalytic degradation of perfluorinated compounds

A technology of perfluorinated compounds and photocatalysis, applied in chemical instruments and methods, water treatment of special compounds, water pollutants, etc., can solve problems such as high operating costs, high energy consumption, and inability to defluorinate

Active Publication Date: 2020-10-27
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Conventional biological methods and physicochemical methods cannot effectively defluorinate them. Electrochemical and ultrasonic degradation have good degradation effects on PFCs, but they consume a lot of energy, high operating costs, and are not widely used.
The reaction conditions of the photocatalytic system are relatively mild and controllable, and the C-C bond is broken by taking electrons from the C atoms in the PFCs structure, but the defluorination cycle is relatively long

Method used

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  • A method for photocatalytic degradation of perfluorinated compounds
  • A method for photocatalytic degradation of perfluorinated compounds
  • A method for photocatalytic degradation of perfluorinated compounds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Dissolve 5.22g of CTAB in 208mL of deionized water, stir at a medium speed until CTAB is completely dissolved, slowly add 16mLTEOS, then quickly add 4.8mL of 25% ammonia water, continue stirring until the solution turns into a white gel, filter and dry. The base material BMMs were obtained by heating from room temperature to 550°C for 6 hours at a heating rate of 5°C / min.

[0036] Dissolve 0.10g~0.50g (0.10g, 0.20g, 0.40g, 0.50g) of phosphotungstic acid in 10mL of deionized water respectively, add 1.00g of BMMs after the dissolution is complete, adjust the pH to 0.90 with nitric acid, stir for 12 hours, 80 The solvent was evaporated to dryness at 110°C for 12 hours, and the grinding was complete. Under a nitrogen atmosphere, the temperature was raised from room temperature to 200°C at a rate of 5°C / min and calcined for 2 hours to obtain the catalyst BMMs / HPW.

[0037] In this embodiment, the catalyst BMMs / HPW with a loading rate of phosphotungstic acid of 10% to 50% (10...

Embodiment 2

[0039] Put 500mL of perfluorooctanoic acid (PFOA) solution containing 10mg / L in a cylindrical reactor, without adjusting the pH, set up 3 groups of comparative experiments, the first group did not add catalyst, the second group added 0.10g phosphotungstic acid, and the third group Add 0.10g catalyst BMMs / HPW with a loading rate of 40% to the group, cover a low-pressure mercury lamp with an emission wavelength of 185nm with a glass sleeve, place it vertically in the reactor, and place the reactor on a constant temperature magnetic stirrer. When the ultraviolet lamp is in use, the compartment outside the reactor is closed to start defluorination, and a sample is taken every 40 minutes. After 4 hours, the reaction was completed, and the fluoride ion concentration in the water was measured by ion chromatography, and the defluorination effect was shown in image 3 .

[0040] F in initial solution of perfluorooctanoic acid (PFOA) - The concentration is about 0 (not detected), no p...

Embodiment 3

[0044] Put 500mL of perfluorooctanoic acid (PFOA) solution containing 10mg / L in a cylindrical reactor, do not adjust the pH, and add 0.10g each with a loading rate of 10% to 50% (10%, 20%, 40%, 50%) For BMMs / HPW, a low-pressure mercury lamp with an emission wavelength of 185nm is covered with a glass sleeve, placed vertically in the reactor, and the reactor is placed on a constant temperature magnetic stirrer. When the ultraviolet lamp is in use, the compartment outside the reactor is closed to start defluorination, and a sample is taken every 40 minutes. After 4 hours, the reaction was completed, and the fluoride ion concentration in the water was measured by ion chromatography, and the defluorination effect was shown in Figure 4 .

[0045] F in initial solution of perfluorooctanoic acid (PFOA) - The concentration is about 0 (not detected), no pretreatment is required, and it can be directly degraded.

[0046] In this example, the BMMs / HPW synthesized in Example 1 was add...

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Abstract

The invention belongs to the field of degradation of persistent pollutants and discloses a method of photocatalytically degrading perfluoro-compounds. The method includes the steps of: a) preparing a double-model mesoporous SiO2 material BMMs, and with phosphotungstic acid as an active component, preparing a HPW / BMMs catalyst through impregnation; b) adding the HPW / BMMs catalyst to a perfluoro-compound solution, and at normal temperature and under normal pressure, irradiating the solution under an ultraviolet lamp to achieve degradation and defluorination to the perfluoro-compounds. The method is simple and has gentle conditions, increases the defluorination rate on the perfluoro-compounds, and achieves effective degradation of the perfluoro-compounds.

Description

technical field [0001] The invention belongs to the field of persistent organic pollutant degradation, in particular to a method for defluorinating and degrading perfluorinated compounds in water bodies. Background technique [0002] Perfluorinated compounds (PFCs) have good surface activity, chemical stability, and hydrophobic and oleophobic properties, and are widely used in civil and light industrial fields such as textiles, printing and dyeing, packaging, pesticides, electronics, and fire-fighting foams. The large-scale production and use of PFCs have caused very serious environmental accumulation and persistent pollution. PFCs can be detected in papermaking wastewater, electroplating wastewater, and printing and dyeing wastewater. Among them, perfluorooctanoic acid and perfluorooctane sulfonate are currently the most widely used perfluorinated organic compounds. [0003] The C-F bond of perfluorinated compounds has a high polarity. The C-F bond is the strongest bond am...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/32C02F1/72C02F1/74C02F101/14
CPCC02F1/32C02F1/725C02F1/74C02F2101/14C02F2305/10
Inventor 程建华游霞杨草
Owner SOUTH CHINA UNIV OF TECH
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