Method for treating trivalent arsenic in water by photooxidation of small molecule diketone

A technology for oxidation treatment and trivalent arsenic, applied in the direction of oxidation water/sewage treatment, chemical instruments and methods, water/sludge/sewage treatment, etc., can solve the problem of destroying chromophore, slow oxygen oxidation rate, and toxic by-products of chlorine gas and other problems, to achieve the effect of wide pH range and fast speed

Active Publication Date: 2017-06-16
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the oxidation methods for As(III) mainly include air oxidation, chlorine oxidation, iron manganese oxide oxidation and Fenton reagent oxidation, etc. These methods have different problems: the oxidation rate of oxygen is slow, and chlorine gas has toxic by-products The risk of iron-manganese oxide oxidation and Fenton reagent oxidation need to adjust the solution to a suitable acidity and alkalinity, which requires harsh reaction conditions
[0008] The decolorization of dyes by small molecule diketones (AA, BD, HD) mainly absorbs photons, forms dye-diketone photoexcited complexes, and carries out electron and energy transfer, thereby destroying the chromophore in the dye; and arsenous acid is An inorganic acid whose structure and chemical properties are completely different from those of organic dyes. Its light absorption efficiency is very low. It is not yet known whether it can form a photo-stimulated complex with a small molecule diketone
At present, there is no report on the oxidation treatment of As(III) in water by UV / small molecule diketone method

Method used

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  • Method for treating trivalent arsenic in water by photooxidation of small molecule diketone
  • Method for treating trivalent arsenic in water by photooxidation of small molecule diketone
  • Method for treating trivalent arsenic in water by photooxidation of small molecule diketone

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] (1) UV / AA oxidation effect

[0033] Add Na to a 25mL colorimetric tube 3 AsO 3 Stock solution and AA solution, add the As(III) stock solution of 1g / L (unit is with Na 3 AsO 3 In terms of As(III), 3.468 g Na 3 AsO 3Dissolved in 1 L of water, the concentrations mentioned below are calculated as As(III)) and diluted step by step to As(III) concentration of 2 mg / L and AA concentration of 0.05 mM; then poured into 25 mL reaction In the tube, the photochemical oxidation reaction was carried out for 10 minutes, and the As(III) concentration was detected by sampling every 2 minutes; at the same time, a control experiment (control) was set up without AA (As(III) concentration was 2 mg / L);

[0034] figure 1 It is a schematic diagram of the concentration change of As(III) in the reaction solution in 10 minutes. In the figure, the abscissa is the time (min), and the ordinate is the real-time As(III) concentration (C) and the initial As(III) concentration (C 0 ) ratio, by fi...

Embodiment 2

[0056] Utilize Na 3 AsO 3 The stock solution and AA solution were diluted step by step in a 25 mL colorimetric tube. After dilution, the concentration of As(III) was 5 mg / L, and the concentration of AA was 0.1 mM, and then the solution was poured into the photoreaction tube for photochemical oxidation reaction For 20 min, samples were taken every 10 min to detect the concentration of As(III), and at the same time, Na 3 AsO 3 Solution (As(III) concentration is 5 mg / L) was used as control.

[0057] According to the final result, such as Figure 6 shown by Figure 6It can be seen that compared with the control group, after adding AA, the oxidation rate of As(III) is very fast, basically within 10 min, the oxidation reaction of As(III) has completely occurred to form As(V).

Embodiment 3

[0059] Utilize Na 3 AsO 3 The stock solution and AA solution were diluted step by step in a 25mL colorimetric tube. After dilution, the concentration of As(III) was 20 mg / L, and the concentration of AA was 0.5 mM. Then the solution was poured into the photoreaction tube for photochemical oxidation reaction 60 min, samples were taken every 10 min to detect As(III) concentration, and Na 3 AsO 3 Solution (As(III) concentration of 20 mg / L) was used as control.

[0060] Test results such as Figure 7 As shown, compared with the control group, after the addition of AA, 20 mg / L of As(III) could be completely oxidized within 60 min.

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Abstract

The invention discloses a method of photo-oxidizing treatment on trivalent arsenic in water through small-molecular diketones, wherein the method includes the steps of adding the small-molecular diketone to water containing trivalent arsenic, wherein the concentration of the small-molecular diketone is 0.05-1 mM, regulating the pH to 3-9 and irradiating the water under an ultraviolet light source for 10-60 min to oxidize the trivalent arsenic in water into pentavalent arsenic. By means of the UV / small-molecular diketone system established in the method, the trivalent arsenic in the water is rapidly oxidized to form the pentavalent arsenic which is easier to remove through physical methods under irradiation by the ultraviolet light source, wherein the first-order kinetic constant of the reaction can reach 0.15 / min. When As(III) is 0-10 mg / l in concentration, the oxidizing reaction time is basically controlled to be within 10 min. The method is simple in operation. Compared with conventional methods of UV / H2O2, UV / TiO2 and the like, the method is wider in available solution pH range being 3-9. The method can be widely used in oxidizing treatment of the As(III) in underground water containing the As(III) and waste water being high in concentration of the As(III).

Description

technical field [0001] The invention relates to the field of water treatment, in particular to a method for photooxidizing trivalent arsenic in water by using small molecular diketone. Background technique [0002] Arsenic (As) is a widespread element in groundwater. Drinking water with excessive arsenic content for a long time may lead to skin pigmentation, skin keratinization, skin cancer, bladder cancer, high blood pressure, cardiovascular and cerebrovascular diseases, neuropathy, and diabetes A series of health problems, such as human health, have great harm. Arsenic pollution caused by natural geological reasons (dissolution of arsenic-containing ores caused by geological activities) and human activities (discharge of arsenic-containing wastewater from industry) has become a worldwide environmental problem. [0003] The World Health Organization stipulates that the maximum allowable content of arsenic in drinking water is 10 µg / L, and the United States Environmental Pr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/72C02F101/20
Inventor 张淑娟陈志豪吴兵党宋孝杰王晓萌张国洋
Owner NANJING UNIV
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