Method and device for removing heavy metal ions in wastewater by virtue of photoelectrocatalysis

A heavy metal ion, photoelectric catalysis technology, applied in chemical instruments and methods, light water/sewage treatment, water/sewage treatment, etc., can solve the problems of high energy consumption, high cost, low voltage efficiency, etc., achieve low energy consumption, Simple method and high voltage efficiency

Active Publication Date: 2015-09-30
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the existence of overvoltage and the voltage loss of the transmission conductor, the cell voltage required for electrocatalysis is much higher than the theoretical electrolysis voltage, and the electrolysis reaction needs to be carried out at a higher voltage, so its voltage efficiency is low and energy consumption is high.
At the same time, electrocatalytic technology requires the use of complex technical means to modify the electrode, and generally requires the use of complex electrochemical technology, which makes its cost high and is greatly limited in industrial applications.

Method used

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  • Method and device for removing heavy metal ions in wastewater by virtue of photoelectrocatalysis
  • Method and device for removing heavy metal ions in wastewater by virtue of photoelectrocatalysis
  • Method and device for removing heavy metal ions in wastewater by virtue of photoelectrocatalysis

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Embodiment 1

[0033] In this embodiment, a titanium mesh is used as a photoanode, and a Pt electrode is used as a counter electrode to remove Cr(VI) ions in wastewater.

[0034] The preparation method of the photoanode: cut the titanium mesh purchased in the market into a certain size rectangle, and then ultrasonically clean it in acetone, ethanol, and deionized water, and then wash it in HF:HNO 3 :H 2 Polish in O=1:3:16 mixed solution for 30s, rinse with deionized water, and dry.

[0035] The preparation method of the counter electrode: After polishing the Pt electrode purchased in the market with sandpaper, immerse it in dilute nitric acid for a period of time, rinse it with deionized water after taking it out, and dry it in the air.

[0036] In this example, a 76mm×26mm titanium mesh (thickness 0.2mm, purity 99.9%, wire diameter 0.12mm, mesh number 60 mesh) was used as the photoanode, the Pt electrode was used as the counter electrode, and the cathode-to-anode area ratio was 1:50. The ...

Embodiment 2

[0039] Using the method and device of the present invention, the initial concentration of Cr(VI) in the reaction system is 0.34mmol / L, reaction conditions: pH3.4, citric acid 0.5mmol / L, Na 2 SO 4 0.5mol / L, voltage 1.5V. Reproducible experiments for photocatalytic reduction of Cr(VI) using Ti mesh photoanode and Pt electrode photocathode. image 3 It means that the same clean titanium mesh was used to repeat 5 experiments, and the relative standard deviation of the 5 experiments was 2.4%, and the repeatability was very good, indicating that the titanium mesh can be used repeatedly for a long time.

Embodiment 3

[0041] Using the method and device of the present invention, the initial concentration of Cr(VI) in the reaction system is 0.34mmol / L, reaction conditions: pH3.4, citric acid 0.5mmol / L, Na 2 SO 4 0.5mol / L, voltage 1.5V. Using the Ti mesh photoanode and Ti mesh photocathode to carry out the photocatalytic reduction experiment of Cr(VI), 76% of Cr(VI) with an initial concentration of 0.34mmol / L can be degraded within 60 minutes.

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Abstract

The invention relates to a method and a device for removing heavy metal ions in wastewater by virtue of photoelectrocatalysis. According to the method, a metal material is used as a photo-anode, an organic substance contained in a reaction solution is used as a reducing agent, the organic substance is excited by virtue of ultraviolet illumination to generate free electrons and active free radicals, the active free radicals move to the photo-anode and are oxidized under the action of an external electric field, and the free electrons reduce the heavy metal ions in the solution. The device comprises a metal photo-anode, a counter electrode, a direct-current power supply, an ultraviolet source and a reaction vessel. Under an experimental condition, the rate of reducing Cr (VI) in the wastewater by virtue of titanium mesh photo-anode photoelectrocatalysis is 5.5 times that of typical TiO2 film semiconductor catalyst under the same reaction condition, and the repeatability is very good. The method and the device provided by the invention overcome certain defects of a photoelectrocatalysis technology and an electrocatalysis technology, and a new method capable of efficiently degrading the heavy metal ions in the wastewater is put forward, and the method is very high in practical value and application prospect, and is easy to popularize and use.

Description

technical field [0001] The invention relates to a method and a device for removing heavy metal ions in wastewater by photoelectric catalysis, and belongs to the technical field of environmental chemical industry. Background technique [0002] With the acceleration of urbanization and the rapid development of industry, the pollution of water environment caused by heavy metal discharge is becoming more and more serious. Heavy metals in water are difficult to decompose, easy to migrate, and can be enriched in organisms through the food chain, thereby polluting the environment, endangering the ecology, and threatening human health. In recent years, heavy metal pollution incidents such as mercury, chromium, and cadmium have aroused human attention to heavy metal environmental pollution. At present, the major rivers, lakes and reservoirs in our country are generally polluted by heavy metal ions in different degrees. The discharge of chemical industry (such as mining, smelting, le...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/32C02F1/467C02F1/62
Inventor 尚静冯想
Owner PEKING UNIV
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