Method for removing trace chromium in aqueous solution

An aqueous solution and removal technology, which is applied in chemical instruments and methods, water/sewage treatment, water/sewage multi-stage treatment, etc., can solve the problems of unsatisfactory removal effect, large amount of reagents, and a large amount of waste residue, etc. Small amount, short processing time, and less waste residue generation

Inactive Publication Date: 2011-08-17
TIANJIN UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The traditional method of removing chromium by iron salt and aluminum salt is suitable for treating waste liquid with high chromium content, but the removal effect is not ideal for waste liquid treatment with low chromium content, and the amount of reagent used in the treatment is large, so Produces a large amount of waste residue, and may also introduce unwanted ions such as excess iron and aluminum ions into the water body

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Embodiment 1: Measure Cr (Ⅲ) content and be 1L of aqueous solution of 16mg / L, add 0.1g Ca (NO 3 ) 2 4H 2 O (calcium nitrate tetrahydrate), then adjust its pH to 7 with NaOH solution, and control the temperature of the aqueous solution to 40°C. Under the conditions of vigorous stirring and controlling the pH of the system to 7-7.2, add 50 mL of an aqueous solution containing 50 mg of sodium bicarbonate dropwise. After the dropwise addition was complete, stirring was continued for 1 hour. Thereafter, it was cooled to room temperature, allowed to stand, settled and filtered to remove chromium-containing precipitates. The chromium content of the filtrate was analyzed by ICP (inductively coupled plasma emission spectrometry, the same below) to be less than 0.01mg / L.

Embodiment 2

[0016] Example 2: Measure 1 L of an aqueous solution with a Cr(III) content of 16 mg / L, add 0.4 g of calcium chloride, and control the temperature of the aqueous solution to 10° C. Under the conditions of vigorous stirring and controlling the pH of the system to 7.2-7.5, add 6 mL of an aqueous solution containing 20 mg of sodium carbonate dropwise. After the dropwise addition was complete, stirring was continued for 1 hour. Afterwards, cool to room temperature, let stand, settle and centrifuge to remove chromium-containing precipitates. The chromium content of the filtrate analyzed by ICP is less than 0.01mg / L.

Embodiment 3

[0017] Example 3: Measure 1 L of an aqueous solution with a Cr(III) content of 16 mg / L, and adjust the pH of the solution to 7. Under vigorous stirring at 20°C, 5 mg of calcium sulfate and 0.3 g of calcium carbonate were simultaneously added. Stirring was continued for 1 hour. Afterwards, let stand, settle and centrifuge to remove the chromium-containing precipitate. The chromium content of the filtrate analyzed by ICP is less than 0.01mg / L.

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PUM

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Abstract

The invention discloses a method for removing trace chromium in aqueous solution. The method comprises the following steps of: culturing and analyzing a plant grown under a chromium environment, regulating the pH value of chromium-containing aqueous solution by using acid or alkali, adding calcium-containing reagent and carbonate simultaneously or respectively, standing, precipitating, and separating out water containing chromium slag, wherein the chromium content of the water is less than 0.01 mg / L by detection. The method has the characteristics that: the trace chromium compound in the aqueous solution can be removed by controlling the adding quantity of the calcium-containing reagent and the carbonate and controlling the pH value of the solution; and the water treatment time is short, the raw materials are economic and easily obtained, and any harmful element is not added into the system, so the method is an environmentally-friendly and economic treatment process. The process can be widely applied to the treatment of the discharged chromium-containing waste water in the fields of metal processing industry, electroplating industry, leather making industry, textile industry and the like.

Description

【Technical field】 [0001] The invention relates to the field of waste water treatment in environmental technology, in particular to a method for removing trace chromium in aqueous solution. 【Background technique】 [0002] With the rapid increase of industrial waste, the pollution of heavy metal chromium in water is becoming more and more serious. Chromium is often found in industrial wastewater, with the largest sources of chromium contamination coming from the metalworking, electroplating, tanning and textile industries. These industrial effluents often contain a considerable amount of toxic chromium compounds. [0003] The traditional method of removing chromium by iron salt and aluminum salt is suitable for treating waste liquid with high chromium content, but the removal effect is not ideal for waste liquid treatment with low chromium content, and the amount of reagent used in the treatment is large, so A large amount of waste residue is produced, and unwanted ions such...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/62C02F9/04C02F1/66
Inventor 孙波牛力华安钢吴新世
Owner TIANJIN UNIVERSITY OF TECHNOLOGY
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