Treatment method of arsenic-containing wastewater

A treatment method and wastewater technology, which is applied in the treatment of industrial arsenic-containing waste liquid and arsenic-containing wastewater, can solve the problems of arsenic treatment meeting discharge standards, etc., and achieve the effects of prolonging the service life of equipment, less corrosion of equipment, and simple equipment

Inactive Publication Date: 2017-09-15
CHENZHOU YANGTAO CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, the chemical precipitation method mainly includes neutralization precipitation method, flocculation precipitation method and sulfide method, etc., which are suitable for the initial treatment ...

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0031] Measure 500mL of arsenic-containing wastewater discharged from the sulfuric acid production process and pour it into a beaker, add dilute sulfuric acid to adjust the pH of the wastewater to 5, and then add FeSO with a mass fraction of 90% to the beaker 4 ·7H 2 O 13.2g, after mixing, add H with a mass concentration of 30% 2 O 2 3.3g, mechanically stirred for 0.5h; after stopping stirring, the solution changed from colorless and transparent to yellow-brown turbidity, and pH=5 was measured. Add Ca(OH) to the solution 2 Adjust pH=8, a large amount of brown precipitation appears, continue stirring for 0.5h, when the precipitation is complete, the solution is allowed to stand, suction filtration to obtain filter residue and filtrate; the filter residue is a mixture of ferric hydroxide and ferric arsenate, which is recovered; the filtrate is detected Medium arsenic content, up to standard efflux.

[0032] sample name

Embodiment 2

[0034] Measure 500mL of arsenic-containing wastewater discharged from the sulfuric acid production process and pour it into a beaker, add dilute sulfuric acid to adjust the pH of the wastewater to 5, and then add FeSO with a mass fraction of 90% to the beaker. 4 ·7H 2 O 19.8g, after mixing, add H with a mass concentration of 30% 2 O 2 3.3g. The glass rod was stirred for 0.5 h. After the stirring was stopped, the solution changed from colorless and transparent to yellow-brown turbidity, and pH=5 was measured. Add Ca(OH) to the solution 2 Adjust pH=8, a large amount of brown precipitation appears, continue stirring for 0.5h, when the precipitation is complete, the solution is allowed to stand, suction filtration to obtain filter residue and filtrate; the filter residue is a mixture of ferric hydroxide and ferric arsenate, which is recovered; the filtrate is detected Medium arsenic content, up to standard efflux.

[0035] sample name

Embodiment 3

[0037] Measure 500mL of arsenic-containing wastewater discharged from the sulfuric acid production process and pour it into a beaker, add dilute nitric acid to adjust the pH of the wastewater to 5, and then add FeSO with a mass fraction of 90% to the beaker. 4 ·7H 2 O 16.5g, after mixing, add H with a mass concentration of 30% 2 O 2 4.4g. The glass rod was stirred for 0.5 h. After the stirring was stopped, the solution changed from colorless and transparent to yellow-brown turbidity, and pH=5 was measured. Add Ca(OH) to the solution 2 Adjust pH=8, a large amount of brown precipitation appears, continue stirring for 0.5h, when the precipitation is complete, the solution is allowed to stand, suction filtration to obtain filter residue and filtrate; the filter residue is a mixture of ferric hydroxide and ferric arsenate, which is recovered; the filtrate is detected Medium arsenic content, up to standard efflux.

[0038] sample name

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Abstract

The invention discloses a treatment method of arsenic-containing wastewater. The method comprises the following steps: adding ferrous sulfate heptahydrate to the arsenic-containing wastewater at a pH value of 5-6 according to a mass ratio of iron to arsenic of 14-25, adding hydrogen peroxide as an assistant according to a mass ratio of hydrogen peroxide to arsenic of 10-30 in order to oxidize the arsenic in the wastewater into to pentavalent arsenic and oxidize ferrous iron in ferrous sulfate into ferric iron, and reacting the ferric iron with the arsenic to produce a high-stability ferric arsenate precipitate; and adding an alkali to adjust the pH value to 7-9, reacting the remaining ferric iron with calcium hydroxide to produce iron hydroxide, allowing the iron hydroxide and the iron arsenate to undergo adsorption co-precipitation in order to achieve arsenic solidification, carrying out solid-liquid separation, and discharging standard meeting wastewater. Compared with traditional pretreatment and deep arsenic removal two-stage treatment technologies, the method which realizes standard meeting discharge through one-shot arsenic-containing wastewater treatment has the advantages of short flow, proceeding under normal conditions, cheap and easily available reagents, low cost, small investment, and convenience in promotion and application.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and relates to a method for treating arsenic-containing wastewater, which is suitable for the treatment of industrial arsenic-containing wastewater. Background technique [0002] Arsenic is widely present in nature, distributed in a variety of minerals, usually coexisting with sulfur and metal elements, and is leached during metal smelting. Arsenic is a highly toxic substance and belongs to the first category of pollutants. At present, the maximum allowable discharge concentration of arsenic in wastewater in my country is 0.5mg / L. Arsenic-containing wastewater must be treated before it can be discharged into the environment. [0003] At present, the treatment methods of arsenic-containing wastewater mainly include chemical precipitation method, physical adsorption method and microbial method. Among them, chemical precipitation methods mainly include neutralization precipitation meth...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F101/10
CPCC02F9/00C02F1/001C02F1/5281C02F1/66C02F1/722C02F2101/103C02F2301/08
Inventor 刘伟涛蔡德龙谢龙臣李诗琪
Owner CHENZHOU YANGTAO CHEM
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