Photoreduction/liquid-liquid-liquid three-phase extraction coupled method for removing and recycling chromium

A coupling liquid, three-phase technology, applied in chemical instruments and methods, extraction water/sewage treatment, process efficiency improvement, etc., to achieve the effect of promoting reduction rate and broad application prospects

Inactive Publication Date: 2012-06-20
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method can also solve the problem of how to achieve regeneration and reuse of polymers and organic solvents

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add 1.5 g of polyethylene glycol with a weight average molecular weight of 4000 and 5 g of ammonium sulfate to 20 mL of a solution containing 100 mg / L of Cr(VI) to dissolve, adjust pH=6 with sulfuric acid and sodium hydroxide, then add 3.3 mL of 30% ( v / v) Di(2-ethylhexyl) phosphate / n-hexane mixed organic solvent, after shaking for 5 minutes, centrifuged at 3000 rpm for 10 minutes, at this time a liquid-liquid-liquid three-phase system was formed. The extraction rate of Cr(VI) in the polyethylene glycol middle phase reached 90.5%. After 30 minutes of irradiation under sunlight, the Cr(VI) in the middle phase was completely reduced to Cr(III) and all transferred to the upper phase. The phase-loaded Cr(III) is recovered by stripping with dilute sulfuric acid solution with pH=2.5.

Embodiment 2

[0028] To 100mL containing Cr (VI) is 150mg / L solution, add 27.5g weight-average molecular weight and be 1000 ethylene oxide-propylene oxide copolymers and 10g sodium sulfate, adjust pH=3 with sulfuric acid and ammoniacal liquor, then add 100mL30% ( v / v) bis(2-ethylhexyl) phosphate / kerosene mixed organic solvent, after shaking for 30 minutes, centrifuge at 3000 rpm for 20 minutes, at this time a liquid-liquid-liquid three-phase system is formed. The extraction rate of Cr(VI) in the middle phase reached 99.3%. After 80 minutes of irradiation under sunlight, the Cr(VI) in the middle phase was completely reduced to Cr(III) and all transferred to the upper phase. The Cr loaded on the upper phase (III) Recovery by stripping with dilute sulfuric acid solution with pH=1.

Embodiment 3

[0030] Add 3.5 g of ethylene oxide-propylene oxide copolymer and 3 g of sodium phosphate (or potassium phosphate) with a weight average molecular weight of 10,000 to 20 mL of 50 mg / L solution containing Cr(VI), adjust pH=3 with sulfuric acid and ammonia water, Then add 10 mL of 60% (v / v) bis(2-ethylhexyl) phosphate / n-dodecane mixed organic solvent, shake for 30 minutes, and then centrifuge at a speed of 3000 rpm for 10 minutes. At this time, a liquid-liquid-liquid three phase system. The extraction rate of Cr(VI) in the middle phase reached 98.5%. After irradiating for 50 minutes under a 300W xenon lamp, the Cr(VI) in the middle phase was completely reduced to Cr(III) and all transferred to the upper phase, and the Cr(VI) loaded on the upper phase (III) Recovery by stripping with dilute hydrochloric acid solution with pH=2.

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PUM

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Abstract

The invention relates to a photoreduction / liquid-liquid-liquid three-phase extraction coupled method for removing and recycling chromium, belonging to field of heavy metal ion treatment in waste water. The method comprises the following steps: adding inorganic strong electrolyte salts and water-soluble high polymers into a water solution containing Cr (VI) to regulate the pH value of the water phase; adding an organic solvent, thoroughly mixing, and standing or carrying out centrifugal phase splitting to obtain the liquid-liquid-liquid three-phase system; putting the solution under illumination so that the Cr (VI) is reduced to Cr (III) and completely transferred to the upper phase; and finally, carrying out back extraction to recycle the Cr (III) loaded on the upper phase. The invention not only can remove hexavalent chromium in the chrome-containing waste water, but also can reduce the hexavalent chromium into trivalent chromium to be extracted and recycled, thereby achieving the goal of clean discharge of chrome-containing waste water and bringing about economic benefits to the enterprise. No sludge is generated in the whole process, so the invention has wide application prospects in environmental sewage treatment and resource comprehensive utilization.

Description

technical field [0001] The invention relates to the field of wastewater heavy metal ion treatment, in particular to a method for photoreduction coupling liquid-liquid-liquid three-phase extraction removal and recovery of chromium. Background technique [0002] Metallic chromium is a common industrial pollutant, which is mostly found in the wastewater of electroplating, tanning, smelting, printing and dyeing, pigment and textile industries, and often exists in the form of hexavalent and trivalent. Cr(VI) has strong toxicity. Its intake can affect the redox of cells, can combine with nucleic acid, stimulate the digestive tract and respiratory tract, have carcinogenic and mutagenic effects, and cause serious harm to human health. In August 2011, chromium pollution from a chemical plant in Qujing, Yunnan caused tens of thousands of cubic meters of water quality to deteriorate in the Nanpan River at the source of the Pearl River. The news that villagers near the chemical plant su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/08C22B3/26C02F1/30C02F1/26C02F101/22C22B34/32
CPCY02P10/20Y02W10/37
Inventor 刘会洲谢铿黄焜
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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