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Treatment and resource reclaiming method for chromium-containing wastewater containing high concentration sodium sulfate

A technology of resource recovery and sodium sulfate, applied in chemical instruments and methods, multi-stage water/sewage treatment, water/sludge/sewage treatment, etc., can solve problems such as resin blockage, resin poisoning, and complex wastewater components, and avoid The effect of clogging

Inactive Publication Date: 2008-08-06
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the actual wastewater composition is complex, in addition to hexavalent chromium, it also contains salts and some metal cations
If the waste water is directly passed through the anion exchange column, some sodium sulfate will crystallize out in the ion exchange column, which will cause a "poison" effect on the resin, and the sodium sulfate cannot be recovered, resulting in a waste of resources
Secondly, if the cation exchange column is not passed first, the resin will be blocked by the formation of hydroxide insolubles
Existing reports failed to combine "removal of salt", "removal of cation" and "removal of chromium"

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Take 10mL of cation exchange resin and anion exchange resin respectively and put them in two glass columns (Φ10×200mm), and connect the two columns in series.

[0021] Take 100mL of waste water, first remove the insoluble matter by filtration, then add 0.5 g of sodium sulfate as a seed crystal, cool and crystallize to remove the sodium sulfate in the water, and a total of 8 grams of sodium sulfate can be recovered.

[0022] The filtrate passes through the ion exchange system at a flow rate of 2BV / h, and the removal rate of chromium in the wastewater reaches 95%.

[0023] Use 80mL of sodium hydroxide aqueous solution with a mass concentration of 5% as a desorbent, regenerate and recover hexavalent chromium at a flow rate of 1BV / h at 25°C, and the recovery rate reaches 96%. The first 20mL of high-concentration recovery solution can be reused In the upstream section, the last 60mL can be used to configure the next batch of desorption liquid.

Embodiment 2

[0025] Take 10mL of cation exchange resin and anion exchange resin respectively and put them in two glass columns (Φ10×200mm), and connect the two columns in series.

[0026] Take 200mL of waste water, remove insoluble matter by filtration first, then add 0.8 g of sodium sulfate as a seed crystal, cool and crystallize to remove sodium sulfate in the water, and a total of 16 grams of sodium sulfate can be recovered.

[0027] The filtrate passes through the ion exchange system at a flow rate of 1BV / h, and the removal rate of chromium in the wastewater reaches 98%.

[0028] Use 100mL of sodium hydroxide aqueous solution with a mass concentration of 5% as a desorbent, regenerate and recover hexavalent chromium at a flow rate of 1BV / h at 25°C, and the recovery rate reaches 95%. The first 30mL of high-concentration recovery solution can be reused In the upstream section, the last 70mL can be used to configure the next batch of desorption liquid.

Embodiment 3

[0030] Take 10mL of cation exchange resin and anion exchange resin respectively and put them in two glass columns (Φ10×200mm), and connect the two columns in series.

[0031] Take 150mL of waste water, first remove the insoluble matter by filtration, then add 0.6 g of sodium sulfate as a seed crystal, cool and crystallize to remove the sodium sulfate in the water, and a total of 12 grams of sodium sulfate can be recovered.

[0032] The filtrate passes through the ion exchange system at a flow rate of 3BV / h, and the removal rate of chromium in the wastewater reaches 94%.

[0033] Use 80mL of sodium hydroxide aqueous solution with a mass concentration of 5% as a desorbent, regenerate and recover hexavalent chromium at a flow rate of 1BV / h at 25°C, and the recovery rate reaches 98%. The first 20mL of high-concentration recovery solution can be reused In the upstream section, the last 60mL can be used to configure the next batch of desorption liquid.

[0034] Use 50mL of dilute h...

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Abstract

The invention discloses a method for treating wastewater containing sodium sulfate with high concentration and chromium and a method for reclaiming resource, wherein the steps are: A) the wastewater containing chromium in industrial production is filtered to remove undissolved substance in the wastewater; B) filtrate is crystallized in a crystallizing pond to separate the sodium sulfate in the water; C) the filtrate respectively orderly passes through a positive ion exchange column and a negative ion exchange column to adsorb the useful components; D) after a saturated adsorption, the ion exchange columns are regenerated by desorbing agent; E) the desorbed liquid with high concentration can be used in an upper stream section of production, and the desorbed liquid with low concentration is used for preparing desorbing agent in the next batch for circulation and utilization. The chromium concentration in the wastewater containing the chromium treated by the method can be decreased to 0.5mg / L, and meets the national discharging standard; besides, the reclaiming rate of useful components is over 90 percent, thus realizing the treatment of wastewater and reclaiming of resources.

Description

technical field [0001] The invention relates to a treatment and resource recovery method of chromium-containing wastewater, which belongs to the wastewater treatment technology. Background technique [0002] With the development of industry, the harm of heavy metals to human health and ecological environment is becoming more and more serious, among which the harm of heavy metal chromium is the most prominent. Chromium has two valence states of trivalent and hexavalent, Cr(III) exists as a cation, and Cr(VI) exists as a chromate anion. Water-soluble Cr(VI) is a strong carcinogenic metal substance, listed as one of the eight most harmful chemical substances to the human body, and also one of the 129 key pollutants recognized by the US Environmental Protection Agency. Cr(III) is an essential trace element for the human body, but excessive accumulation of Cr(III) has carcinogenic effects on the human body, and Cr(III) is easily converted into more toxic Cr(VI) under certain env...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F1/42C01D5/00B01J49/00B01J47/028
Inventor 刘晓宁魏荣卿李响
Owner NANJING UNIV OF TECH
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