Preparation method of nano magnetite/diatomite composition for removing Cr6+ in water

A nano-magnet and diatomite technology, applied in water/sewage treatment, chemical instruments and methods, adsorption water/sewage treatment, etc., can solve the problems of inability to reduce hexavalent chromium to trivalent chromium, coarse particles, low treatment efficiency, etc. problems, to achieve the effect of reducing cost, reducing agglomeration, increasing effective surface area and utilization rate

Inactive Publication Date: 2008-07-09
GUANGZHOU INST OF GEOCHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the disadvantages of coarse mineral material particles used in the existing mineral adsorption method, low processing efficiency, and inability to reduce hexavalent chromium to trivalent chromium, and provide a composite mineral material for removing hexavalent chromium in wastewater The preparation method, the material is a nano-magnetite / diatomite composite, which has the advantages of high processing efficiency, can reduce hexavalent chromium to trivalent chromium, and is easy to recover and precipitate through an external magnetic field.

Method used

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  • Preparation method of nano magnetite/diatomite composition for removing Cr6+ in water
  • Preparation method of nano magnetite/diatomite composition for removing Cr6+ in water
  • Preparation method of nano magnetite/diatomite composition for removing Cr6+ in water

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Embodiment 1

[0017] 1) Weigh 170g FeCl 3 ·6H 2 O with 122gFeCl 2 4H 2 O, join in the reactor that is filled with 5L distilled water in advance, then add 200g diatomaceous earth, fully stir to form uniform suspension.

[0018] 2) Heat the suspension to 60°C and keep it warm, then slowly add the ammonium hydroxide solution with a concentration of 10% (mass percentage) into the suspension under continuous stirring until the pH of the suspension reaches 9 When the dropwise addition was stopped, the insulation was continued and stirred for 1 hour.

[0019] 3) Carry out solid-liquid separation of the suspension by centrifugation, wash with distilled water-centrifuge for several times, stop washing until the pH value of the supernatant is neutral.

[0020] 4) Vacuum-dry the obtained precipitate at 40° C. for 24 hours, and then grind and pulverize to obtain the nano-magnetite / diatomite composite of the present invention.

[0021] Using X-ray diffraction analysis, chemical analysis, infrared s...

Embodiment 2

[0023] 1) Weigh 8.5gFeCl 3 ·6H 2 O with 6.1gFeCl 2 4H 2 O, join in the beaker that is filled with 250ml distilled water in advance, then add 5g diatomaceous earth, fully stir to form uniform suspension.

[0024] 2) Heat the suspension to 60°C and keep it warm, then slowly add the ammonium hydroxide solution with a concentration of 10% (mass percentage) into the suspension under continuous stirring until the pH of the suspension reaches 9 When the dropwise addition was stopped, the insulation was continued and stirred for 2 hours.

[0025] 3) Centrifuge the suspension to separate the precipitate, wash with distilled water-centrifuge the precipitate for several times, stop washing when the pH value of the supernatant is neutral.

[0026] 4) Vacuum-dry the obtained precipitate at 40° C. for 24 hours, and then grind and pulverize to obtain the nano-magnetite / diatomite composite of the present invention.

[0027] Through X-ray diffraction analysis, chemical analysis, infrared ...

Embodiment 3

[0029] Potassium dichromate (K 2 Cr 2 o 7 ) for Cr 6+ source, formulated Cr 6+300ml of wastewater with a concentration of 200mg / L and a pH value of 3.0. Take by weighing the nano-magnetite / diatomaceous earth composite 38.5g that makes in the embodiment 1, add to the formulated Cr-containing 6+ In wastewater, stir for 5 minutes and let stand for 15 minutes. Then a common circular magnet with a diameter of 16 cm is used to realize the solid-liquid separation of the precipitate and the liquid. After testing, the pH of the treated water is neutral, where Cr 6+ The concentration is lower than 0.01mg / L, which meets the discharge standard.

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Abstract

The invention relates to a process for preparing compound of nano magnetite and diatomite capable of removing hexavalent chromium (Cr6+) from water, which comprise: proportionally mixing ferric salt and ferrous salt aqueous solutions with the same concentration of 0.02-0.5mol/L at room temperature, adding by diatomite powder and uniformly stirring, heating and stirring to slowly add ammonium hydroxide solution, then, stopping adding till the pH value of suspension reaching 8-9, solid-liquid separating and rinsing; vacuum grinding and disintegrating. The invention employed to treat hexavalent chromium in the waste water has the advantages of low cost, high efficiency, simple operation, easy recovery and the like, and can be widely used for waste water treatment in fields of plating, tanning, metallurgy, pigment, chromic salt chemical industry and the like.

Description

technical field [0001] The invention relates to a method for removing hexavalent chromium (Cr 6+ ) preparation method of nano magnetite / diatomaceous earth composite. Background technique [0002] Hexavalent chromium (Cr 6+ ) is a highly toxic heavy metal pollutant, which is extremely harmful to environmental safety and human health. It mainly comes from the wastewater discharged from industries such as electroplating, tanning, metallurgy, pharmaceuticals, pigments, ferrochrome smelting and chromium salt chemical industry. In order to prevent its harm, my country listed hexavalent chromium as the first type of pollutant in the comprehensive sewage discharge standard (GB8978-1996), and stipulated that its discharge concentration must be lower than 0.5mg / L. In the "Electroplating Industry Pollutant Discharge Standards" (draft for comments) compiled by the Standards Department of the State Environmental Protection Administration, it is stipulated that Cr 6+ The emission conc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/64C02F1/28C02F1/70
Inventor 袁鹏何宏平杨丹樊明德朱建喜颜文昌
Owner GUANGZHOU INST OF GEOCHEMISTRY - CHINESE ACAD OF SCI
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