Method for treating waste liquid produced during on-line chemical oxygen demand (COD) determination with potassium dichromate method

A potassium dichromate method and waste liquid treatment technology, applied in chemical instruments and methods, water/sewage multi-stage treatment, water/sludge/sewage treatment, etc., to achieve fast reaction speed, simple operation, and removal of toxic heavy metals Effect

Active Publication Date: 2012-07-18
马鞍山市桓泰环保设备有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the current environmental protection field adopting the national standard method (GB/T11914-1989) to measure the problem of the toxic heavy metal ion waste liquid treatment produced in the COD process, and the various defects of the waste liquid treatment in the prior art, the pres

Method used

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  • Method for treating waste liquid produced during on-line chemical oxygen demand (COD) determination with potassium dichromate method
  • Method for treating waste liquid produced during on-line chemical oxygen demand (COD) determination with potassium dichromate method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Add 1L of waste liquid into the reactor, the concentration of metal ions in the waste liquid is, Hg 2+ : 1g / L, Cr 3+ : 2.83g / L, Ag + : 0.1g / L; prepare interference-removing solvent: weigh potassium carbonate and sodium bicarbonate, prepare K + 、Na + 、HCO 3 - , CO 3 2- 5000g of ion solution, the concentration of each ion is: K + : 0.2g / L, Na + : 0.11g / L, HCO 3 - : 0.29g / L, CO 3 2- : 0.15g / L, the pH range of the solution is between 6.5 and 8.5; add 5000g of the prepared interference-removing solvent to the waste liquid, and then add 0g of reducing salt to it, at this time, the waste liquid does not contain Cr 6+ ions, containing only Cr 3+ Ion, stirring reaction, about 2 minutes to complete the reaction;

[0030] Add 10g alkali again in the reactor, the kind of alkali is NaOH or Na 2 CO 3 Any one of them, after stirring the reaction, the reaction ends in about 3 minutes;

[0031] Stand still, drain the supernatant, add 10% dilute hydrochloric acid to the ...

Embodiment 2

[0033] Add 1L of waste liquid into the reactor, the concentration of metal ions in the waste liquid is, Hg 2+ : 6.8g / L, Cr 6+ : 2.83g / L, Cr 3+ : 0g / L, Ag + : 2.22g / L; Preparation of interference-removing solvent: Weigh potassium carbonate and sodium bicarbonate, prepare K + 、Na + 、HCO 3 - , CO 3 2- Ionic solution 1000g, the concentration of each ion is: K + : 0.28g / L, Na + : 0.15g / L, HCO 3 - : 0.40g / L, CO 3 2- : 0.22g / L, the pH range of the solution is between 6.5 and 8.5; add 1000g of the prepared interference-removing solvent to the waste liquid, and then add 60g of reducing salt to it, and the reducing salt is Na 2 SO 3 30g, Na 2 S 2 o 3 ·5H 2 030g stirring reaction, about 2 minutes reaction finishes;

[0034] Add 480g alkali again in the reactor, the kind of alkali is NaOH or Na 2 CO 3 Any one of them, after stirring the reaction, the reaction ends in about 3 minutes;

[0035] Put it still, drain the supernatant, add hydrochloric acid with a concentra...

Embodiment 3

[0037] Add 1L of waste liquid into the reactor, the concentration of metal ions in the waste liquid is, Hg 2+ : 2.8g / L, Cr 6+ : 1.83g / L, Cr 3+ : 1.0g / L, Ag + : 1.22g / L; Preparation of interference-removing solvent: Weigh potassium carbonate and sodium bicarbonate, prepare K + 、Na + 、HCO 3 - , CO 3 2- 3000g of ion solution, the concentration of each ion is: K + : 0.33g / L, Na + : 0.19g / L, HCO 3 - : 0.50g / L, CO 3 2- : 0.25g / L, the pH range of the solution is between 6.5 and 8.5; add 3000g of the prepared interference-removing solvent to the waste liquid, and then add 100g of reducing salt, the reducing salt FeSO 4 ·7H 2 O is 20g, Fe 2 (SO 3 ) 3 20g, FeSO 4 30g, FeCl 2 For 30g stirring reaction, the reaction ends in about 2 minutes;

[0038] Add 480g alkali again in the reactor, the kind of alkali is NaOH or Na 2 CO 3 Any one of them, after stirring the reaction, the reaction ends in about 3 minutes;

[0039] Stand still, drain the supernatant, add hydrochlo...

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Abstract

The invention discloses a method for treating waste liquid produced during on-line chemical oxygen demand (COD) determination with a potassium dichromate method, and belongs to the field of waste liquid treatment. The method is characterized in that a certain proportion of reducing salt is adopted to react with the waste liquid into which an interference removing solvent is added; then alkali is added into the waste liquid and a precipitation reaction is conducted; and finally, the waste liquid stands still to precipitate, and a supernatant can be emitted up to standard after the pH (potential of hydrogen) value is regulated. The method has the advantages as follows: through using the interference removing solvent the utility model effectively solves the problems that high-concentration sulfuric acid in the waste liquid participates in the chemical reactions to produce SO2 to harm the physical health of an operator, and as SO42 minus ions in the waste liquid interferes following chemical reaction steps, the aim of toxic heavy metal removal,; through adding the reducing salt, high-toxic Cr6 plus ions are changed to low-toxic Cr3 plus ions; through adding the alkali, precipitates finally generated in the precipitation reaction only contain non-toxic or low-toxic compounds of the heavy metal; and the reaction speed is high, the whole reaction process can be completed within 5 minutes, and a reaction effect is easy to identify according to color.

Description

technical field [0001] The invention relates to a waste liquid treatment method, in particular to a waste liquid treatment method produced by online determination of COD by a potassium dichromate method. Background technique [0002] Potassium dichromate method for measuring COD is a standard method for measuring COD that is recognized both at home and abroad (Edited by National Environmental Protection Agency. Water and Wastewater Monitoring and Analysis Methods [M]. 4th Edition. Beijing: Environmental Science Press, 2002, 10-213 ). The principle of determination is: the mixture of water sample, potassium dichromate, silver sulfate and concentrated sulfuric acid is heated to 175°C in the digestion tank, and the chromium ion is used as an oxidant to change color from Ⅵ valence to Ⅲ valence. The degree of color change Corresponding to the content of organic compounds in the sample, COD max The analytical instrument directly displays the COD in the sample through colorimetri...

Claims

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Application Information

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IPC IPC(8): C02F9/04
Inventor 张娟储杰吕建奎储岳海聂中杰储岳喜
Owner 马鞍山市桓泰环保设备有限公司
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