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Method for removing hexavalent chromium in water

A hexavalent chromium and water removal technology, which is applied in chemical instruments and methods, water pollutants, adsorbed water/sewage treatment, etc., can solve problems such as limited adsorption capacity, and achieve the effect of low cost

Inactive Publication Date: 2013-04-24
CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Recently, waste biological materials have attracted attention in the treatment of heavy metal wastewater due to their wide sources, low cost and environmental friendliness. Agricultural by-products such as wood chips, bark, fruit peels, chaff and other non-living biological materials have been used for the adsorption of heavy metal ions. Removal research (Journal of Hazardous Materials, 2003, 100 (1-3): 53-63; Chemical Engineering Journal, 2008, 137: 529-541), but the adsorption capacity of such materials for Cr(VI) is limited and cannot for a wide range of applications

Method used

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  • Method for removing hexavalent chromium in water
  • Method for removing hexavalent chromium in water

Examples

Experimental program
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Effect test

Embodiment 1

[0039] 1.1 Wash the corn stalks, dry them in an oven at 105° C. for 24 hours, crush and sieve to obtain corn stalks with a particle size of 300 μm.

[0040] 1.2 Mix 10g of citric acid, 55ml of distilled water and 10g of the crushed corn stalks obtained in 1.1, stir magnetically in a 55°C water bath for 24h, then evaporate to dryness at 50°C, dry at 110°C for 24h, and then wash with sodium hydroxide Neutralize and wash, and dry at 45° C. for 14 hours to obtain modified corn stalks.

[0041] 1.3 The concentration of hexavalent chromium in water containing hexavalent chromium is 4.2mg / L, enter the acid adjustment pool, adjust the pH value to less than 3.0 with hydrochloric acid, and enter the mixing pool after 10 minutes of reaction, add 2g / L of the improved solution obtained in 1.2 Corn stalks and magnetite powder 1.0g / L, after stirring for 2 hours, enter the superconducting separator, and use the superconducting separator to separate the reacted modified corn stalk adsorbent an...

Embodiment 2

[0043] 2.1 Wash the corn stalks, place them in an oven to dry at 105° C. for 24 hours, then crush and sieve to obtain corn stalks with a particle size of 300 μm.

[0044] 2.2 Mix 10g of citric acid, 55ml of distilled water and 10g of the crushed corn stalks obtained in 2.1 thoroughly, stir magnetically in a water bath at 55°C for 24h, then evaporate to dryness at 50°C, dry at 110°C for 24h, then wash with sodium hydroxide Neutralize and wash, and dry at 45° C. for 14 hours to obtain modified corn stalks.

[0045] 2.3 The concentration of hexavalent chromium in water containing hexavalent chromium is 7.0mg / L, enter the acid adjustment pool, adjust the pH value to less than 3.0 with hydrochloric acid, and enter the mixing pool after 10 minutes of reaction, add 2g / L2. 1.0g / L of modified corn stalks and magnetite powder, stirred and reacted for 2 hours, then entered the superconducting separator, and the reacted modified corn stalk adsorbent and magnetite powder were separated fro...

Embodiment 3

[0047] 3.1 Wash the corn stalks, place them in an oven to dry at 105° C. for 24 hours, and then crush and sieve to obtain corn stalks with a particle size of 300 μm.

[0048] 3.2 Mix 10g of citric acid, 55ml of distilled water and 10g of the crushed corn stalks obtained in 3.1 thoroughly, stir magnetically in a water bath at 55°C for 24h, then evaporate to dryness at 50°C, dry at 110°C for 24h, then wash with sodium hydroxide Neutralize and wash, and dry at 45° C. for 14 hours to obtain modified corn stalks.

[0049] 3.3 The concentration of hexavalent chromium in the water containing hexavalent chromium is 14.7mg / L, enter the acid adjustment pool, adjust the pH value to less than 3.0 with hydrochloric acid, and after 10 minutes of reaction, enter the mixing pool, add 2g / L 3.2 of the improved 1.0g / L of modified corn stalks and magnetite powder, stirred and reacted for 2 hours, then entered the superconducting separator, and the reacted modified corn stalk adsorbent and magneti...

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Abstract

The invention provides a method for removing hexavalent chromium in water. The method comprises the following steps of: mixing ground maize straws, water and hydroxyl polybasic carboxylic acid, and carrying out heating reaction, thereby obtaining modified maize straws; mixing and stirring the modified maize straws and a water body containing the hexavalent chromium under an acidic condition, and then carrying out reaction. Compared with the prior art, the method has the following advantages: firstly, the cost of the maize straws is low, and no secondary pollution is generated due to the fact that the maize straws serve as a biological material; secondly, the modified maize straws contain a plurality of carboxyl groups and hydroxyl groups for absorbing heavy metal active sites, and the hexavalent chromium can be combined on the surfaces of modified maize straws through an ion exchange mechanism; thirdly, the modified maize straws mainly consist of celluloses, hemicelluloses, lignins and the like and contain a plurality of coordinating groups, and a chelate is prepared by the modified maize straws and hexavalent chromium ions; and finally, the hexavalent chromium mainly exists in a form of HcrO4<-> under the acidic condition, but the modified maize straw protons are positively charged, and the hexavalent chromium and the modified maize straw protons are statically adsorbed to remove the modified maize straw protons.

Description

technical field [0001] The invention belongs to the technical field of water treatment, in particular to a method for removing hexavalent chromium in water. Background technique [0002] Chromium mainly exists in two stable oxidation states of Cr(IV) and Cr(III) in nature. The toxicity of chromium is related to its valence state. Usually, the toxicity of Cr(IV) is 100 times higher than that of Cr(III), and it is easier to Carcinogenic accumulation in the body for human absorption, so the so-called chromium pollution mainly refers to hexavalent chromium pollution, hexavalent chromium is recognized as a teratogenic, carcinogenic, and mutagenic substance. Due to the strong toxicity of chromium, which cannot be decomposed by microorganisms and is easy to accumulate in organisms, water-soluble hexavalent chromium has been listed as one of the eight most harmful chemical substances to the human body, and is an internationally recognized three carcinogenic metal substances one. C...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/28C02F1/66B01J20/24C02F101/22
Inventor 刘志梅刘峰吴胜军王小晓雷阳明
Owner CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI
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