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Photochemical reduction method for treating chromium-containing waste water without additional reducing agent and sacrificial agent

A sacrificial agent and reducing agent technology, used in chemical instruments and methods, reduced water/sewage treatment, physical/chemical process catalysts, etc. Broad application prospects and the effect of improving utilization

Active Publication Date: 2008-09-17
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The addition of sacrificial agent will also lead to the generation of secondary pollution and the increase of treatment cost

Method used

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  • Photochemical reduction method for treating chromium-containing waste water without additional reducing agent and sacrificial agent
  • Photochemical reduction method for treating chromium-containing waste water without additional reducing agent and sacrificial agent
  • Photochemical reduction method for treating chromium-containing waste water without additional reducing agent and sacrificial agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add 50 ml of simulated hexavalent chromium-containing wastewater containing potassium dichromate at a concentration of 20, 80, and 200 mg / liter (calculated as chromium mass) into three glass reactors, and add nitrogen-fluorine co-doped titanium dioxide nanometer visible light Catalyst 50 milligrams (consumption amount 1 gram / liter contains hexavalent chromium wastewater), adjusts the pH value of simulated hexavalent chromium-containing wastewater with sulfuric acid to be 1.5, magnetically stirs and disperses the catalyst, the artificial light source used is a 500W xenon lamp, and a cut-off filter of 450nm is configured. Light sheet, turn on the light source and irradiate with visible light for 240 minutes, so that the nitrogen-fluorine co-doped titanium dioxide nano-visible light photocatalyst is excited by visible light to undergo charge separation, and the generated conduction band electrons are used to reduce the highly toxic hexavalent chromium in the water body to lo...

Embodiment 2

[0026] In three glass reactors, add respectively 50 milliliters of simulated waste water containing hexavalent chromium containing potassium dichromate concentration of 40 mg / liter (calculated in terms of chromium mass), and add respectively nitrogen-fluorine co-doped Titanium dioxide nano-visible light photocatalyst, the dosage is 0.2 g / L waste water containing hexavalent chromium, 1 g / L waste water containing hexavalent chromium, 5 g / L waste water containing hexavalent chromium, and sulfuric acid is used to adjust the pH of the simulated waste water containing hexavalent chromium The value is 2.0, and magnetic stirring is used to disperse the catalyst. The artificial light source used is a 500W xenon lamp, equipped with a 450nm cut-off filter, and the light source is turned on to irradiate with visible light for 60 minutes, so that the titanium dioxide nano-visible light photocatalyst co-doped with nitrogen and fluorine is excited by visible light and undergoes charge separati...

Embodiment 3

[0028] In a glass reactor, add 50 milligrams of simulated waste water containing hexavalent chromium containing potassium dichromate concentration of 20 mg / liter (calculated in terms of chromium quality), and add 50 milligrams of titanium dioxide nanometer visible light photocatalysts mixed with nitrogen and fluorine (amount of 1 g / L waste water containing hexavalent chromium), use hydrochloric acid to adjust the pH value of the simulated waste water containing hexavalent chromium to 1.0, and magnetically stir to disperse the catalyst. The light source is irradiated with visible light for 100 minutes, so that the nitrogen-fluorine co-doped titanium dioxide nano-visible light photocatalyst is excited by visible light to undergo charge separation, and the generated conduction band electrons are used to reduce the highly toxic hexavalent chromium in the water body to low-toxic trivalent chromium, while the valence band is empty. The holes were trapped by the hole scavenger water, ...

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Abstract

The invention relates to the technology field of industrial wastewater treatment, particularly to a photochemical reduction method for treating wastewater containing hexavalent chromium without using external reducing agent and sacrificial agent. The method comprises the steps of exciting a nitrogen-fluorine codoped titanium oxide nanometer visible light photocatalyst with photoresponse under the irradiation of visible light to allow charge separation, and reducing highly toxic hexavalent chromium to trivalent chromium with low toxicity and solubility by using conducting electrons, so as to clean chromium-containing wastewater without using external reducing agent and sacrificial agent. The inventive method has the advantages of room temperature implementation, wide application range, no need of pretreatment of wastewater, reusability of catalyst during reaction, remarkably improved utilization rate of solar energy, no secondary pollution, and wide application range.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater treatment, in particular to a sewage treatment technology that uses visible light to excite a photocatalyst to reduce highly toxic hexavalent chromium in chromium-containing wastewater without adding any reducing agent or sacrificial agent. Background technique [0002] In the industrial production process of metallurgy, electroplating, metal surface treatment, leather processing, etc., wastewater containing hexavalent chromium exists widely, which seriously pollutes the environment. The hexavalent chromium in the wastewater is mainly composed of Cr 2 o 7 2- and CrO 4 2- Exist in form, very strong oxidation, harmful to human respiratory and digestive system, skin, etc., in severe cases, it will cause teratogenic, mutagenic and carcinogenic effects, and has strong toxicity. As an important indicator, all countries have formulated chromium-containing wastewater discharge standards....

Claims

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Application Information

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IPC IPC(8): C02F1/30C02F1/70B01J21/06C02F101/22
CPCY02W10/37
Inventor 赵进才塔里克王齐籍宏伟陈春城马万红
Owner INST OF CHEM CHINESE ACAD OF SCI
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