Method for removing complex-state heavy metals from magnetic iron-based material through reduction decomplexing

A technology for iron-based materials and heavy metals, which is applied in the field of magnetic iron-based materials to reduce complexes and remove complexed heavy metals. It can solve the problems of high cost, large demand for chemicals, flammability and explosion of sodium dithionite, etc., and achieve short reaction process. , simple process, good separation effect

Active Publication Date: 2017-07-07
TONGJI UNIV
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Problems solved by technology

Invention patent, "A treatment method for low-concentration complex copper-containing wastewater (201510496787.X)" uses sodium dithionite as a reducing agent, but sodium dithionite itself is flammable and explosive, and the reaction is easy to release H 2 S gas, the demand for medicine is large, and the cost is high

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  • Method for removing complex-state heavy metals from magnetic iron-based material through reduction decomplexing

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Embodiment 1

[0023] Take 200 mL of simulated wastewater. The water sample mainly contains complexed copper, the molar ratio of heavy metals to complexing agents is Cu:EDTA=1:1, the concentration of EDTA-Cu is 0.2 mmol / L, and pH=5.0.

[0024] (1) Weigh a certain amount of ferrous salt and dissolve it in water without dissolved oxygen, add 2 g / L Fe 3 o 4 nanoparticles, and gradually add oxygen-free NaOH solution to the above solution to control Fe(II) and OH - The molar ratio of the mixture was 1:2, and the reaction was stirred for 10 min while adding, and a black-green suspension was obtained.

[0025] (2) Control the oxidation-reduction potential ORP3 2- Add 1.0 mL of 2 mol / L Na 2 CO 3 solution so that CO in wastewater 3 2- The concentration is 600 mg / L. According to the type and concentration of heavy metal ions in the wastewater, the suspension prepared in step (1) was added to make the concentration 0.4 g / L, and the reaction was stirred slowly for 30 min.

[0026] (3) The waste ...

Embodiment 2

[0028] Take 200 mL of simulated wastewater. The water sample mainly contains complexed copper. The molar ratio of heavy metals to complexing agents is Cu:citric acid=1:1, the concentration of citric acid-Cu is 0.2 mmol / L, and pH=2.0.

[0029] (1) Weigh a certain amount of ferrous salt and dissolve it in water without dissolved oxygen, add 2 g / L Fe 3 o 4 nanoparticles, and gradually add oxygen-free NaOH solution to the above solution to control Fe(II) and OH - The molar ratio of the mixture was 1:5, and the reaction was stirred for 10 min while adding, and a black-green suspension was obtained.

[0030] (2) Adjust the pH of the wastewater containing heavy metals to above 5.0, and control the oxidation-reduction potential ORP of the wastewater by nitrogen exposure to 3 2- Add 1.0 mL of 2 mol / L Na 2 CO 3 solution so that CO in wastewater 3 2-The concentration is greater than 500 mg / L. According to the type and concentration of heavy metal ions in the wastewater, the suspen...

Embodiment 3

[0033] Take 200mL of simulated wastewater. The water sample mainly contains complexed copper, complexed cobalt, and complexed nickel. The molar ratios of heavy metals and complexing agents are Cd:Co:Ni:citric acid:NTA=1:1: 1:1:1, the concentration is 0.2 mmol / L, pH=8.0, CO in wastewater 3 2- The concentration is 745 mg / L.

[0034] (1) Weigh a certain amount of ferrous salt and dissolve it in water without dissolved oxygen, add 2 g / L Fe 3 o 4 nanoparticles, and gradually add oxygen-free NaOH solution to the above solution to control Fe(II) and OH - The molar ratio was 1:3, and the reaction was stirred for 10 min while adding, and a black-green suspension was obtained.

[0035] (2) Control the oxidation-reduction potential ORP<100 mV of wastewater by means of nitrogen aeration. According to the type and concentration of heavy metal ions in the wastewater, add the suspension prepared in step (1) to make the concentration 1.0 g / L, and stir slowly for 60 minutes.

[0036] (3)...

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Abstract

The invention relates to a method for removing complex-state heavy metals from a magnetic iron-based material through reduction decomplexing. The method comprises the following steps: weighing ferrite, dissolving ferrite into water which does not contain dissolved oxygen, adding Fe3O4 nano-particles, gradually adding an anaerobic NaOH solution into the solution, and simultaneously stirring to react for 10-30 minutes, so as to obtain black green turbid liquid; regulating the pH value of wastewater containing heavy metals to be more than 5.0, and controlling oxidation reduction potential ORP of the wastewater to be less than 100mV in an nitrogen aeration manner; adding a Na2CO3 solution according to the primary concentration of CO3<2-> in the wastewater so as to regulate the concentration CO3<2-> in the wastewater to be more than 500mg/L; adding the black green turbid liquid according to the type and concentration of heavy metal ions in the wastewater, and slowly stirring to react for 30-60 minutes; after the reaction is finished, introducing the wastewater into a magnetic separator, carrying out solid-liquid separation so as to finish the treatment of the wastewater, and separating magnetic seeds for later use. The method has the advantages that the preparation method is simple, conditions are mild, the cost is low, the effluent quality is good, and the reaction flow is short.

Description

technical field [0001] The invention relates to the field of industrial wastewater treatment, in particular to a method for removing complexed heavy metals by reducing and breaking complexes of magnetic iron-based materials. Background technique [0002] Complex heavy metals widely exist in industrial wastewater, mainly including metal smelting industry, printed circuit board industry, printing and dyeing industry, paper industry, electroplating industry and other industries. When heavy metal ions are combined with complexing agents such as EDTA, tartaric acid, citric acid, and NTA, the water solubility is high, and the traditional alkali precipitation method cannot remove them, which is a difficulty in wastewater treatment. [0003] The traditional methods for dealing with complex heavy metals mainly include redox method, chemical precipitation method, adsorption method, ion exchange method, membrane separation method and so on. Oxidation method using H 2 o 2 , Ozone, so...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/48C02F101/20
CPCC02F1/488C02F2101/20
Inventor 吴德礼田泽源张亚雷马鲁铭
Owner TONGJI UNIV
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