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Method for recovering perfluorinated compounds from sewage

A perfluorinated compound and sewage technology, applied in the field of electrochemical technology and environmental protection, can solve the problems of difficult continuous operation, secondary pollution, unfavorable environmental protection, etc., and achieves the effect of adapting to a wide range of concentrations, less sludge production, and convenient operation.

Inactive Publication Date: 2016-05-04
BEIJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the steps of the precipitation method are simple, metal salts must be added, which easily causes secondary pollution and is not conducive to environmental protection
The ion exchange process needs to consume a large amount of ammonia water for elution, and also needs to introduce a large amount of concentrated sulfuric acid during the acidification process, which easily causes secondary pollution
The process design of the combination of foam separation method and nanofiltration method is complex and difficult to operate continuously

Method used

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  • Method for recovering perfluorinated compounds from sewage
  • Method for recovering perfluorinated compounds from sewage

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Electrocoagulation treatment of solutions containing high concentrations of perfluorooctanoic acid.

[0036] Measure 500mL of perfluorooctanoic acid solution with a concentration of 200mg / L and place it in the electrolytic cell. The anode zinc plate and the cathode are titanium plates. At a current density of 10mA / cm 2 1. Under the condition that the distance between the plates is 15mm, the DC power supply is used for electrolysis at room temperature, and the sampling and analysis are carried out regularly. After 30 minutes of electrolysis reaction, the recovery rate of PFOA in the solution is above 99%.

Embodiment 2

[0038] Electrocoagulation treatment of solutions containing low concentrations of perfluorooctanoic acid.

[0039] Measure 500mL of perfluorooctanoic acid solution with a concentration of 500μg / L and place it in the electrolytic cell. The anode is made of zinc plate and the cathode is made of titanium plate. 2 1. Under the condition that the distance between the plates is 15mm, the DC power supply is used for electrolysis at room temperature, and the sampling and analysis are carried out regularly. After the electrolysis reaction for 10 minutes, the recovery rate of PFOA in the solution is over 90%.

Embodiment 3

[0041] Electrocoagulation treatment of solutions containing high concentrations of perfluorooctane sulfonic acid.

[0042] Measure 500mL of perfluorooctane sulfonic acid solution with a concentration of 200mg / L and place it in an electrolytic cell. The anode is a zinc plate and the cathode is a titanium plate. At a current density of 15mA / cm 2 1. Under the condition that the distance between the plates is 15mm, the DC power supply is used for electrolysis at room temperature, and the sampling and analysis are carried out regularly. After 30 minutes of electrolysis reaction, the recovery rate of PFOS in the solution is above 99.0%.

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Abstract

A method for recovering perfluorinated compound from sewage, which comprises the following steps: an electric flocculation step, using an electric flocculation method to adsorb the perfluorinated compound in an aqueous solution or a water-organic solvent mixed solution onto the surface of flocs produced by electric flocculation to form sludge; an elution step, carrying out an organic solvent elution treatment on the above-mentioned sludge containing perfluorinated compound to separate the perfluorinated compound from the sludge and form a concentrated perfluorinated compound solution; and a distillation step, distilling the produced concentrated perfluorinated compound solution to obtain perfluorinated compound solids and a distillate, the distillate being used as an elution liquid of the above-mentioned elution step. Zn(OH)2 flocs produced in situ by electric flocculation have a very high adsorption capacity and a fast adsorption rate for the perfluorinated compound and can recover high-concentration and low-concentration perfluorinated compounds from sewage and purify the sewage simultaneously. Since the electric flocculation treatment has low costs and low sludge production amount, the large-scale application of the method is economically feasible.

Description

technical field [0001] The invention relates to a method for recovering perfluorinated compounds from sewage, belonging to the fields of electrochemical technology and environmental protection. Background technique [0002] Perfluorinated compounds (PFCs), as a kind of synthetic compounds, have been produced and used for more than 50 years. Due to its unique physical and chemical properties such as hydrophobicity, oleophobicity and high stability, it is widely used in fire extinguishing agents, surface treatment agents for photosensitive materials, antifouling coatings on paper surfaces, photoresists in the semiconductor industry, and electroplating antifogging agents. , leather finishing agent, etc., and can be used as an ingredient of pesticides, herbicides, lubricants, adhesives and cosmetics, etc. Among them, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are the two most frequently detected PFCs in environmental media, and have been detected in ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10C02F1/463
CPCC02F1/463
Inventor 牛军峰林辉
Owner BEIJING NORMAL UNIVERSITY
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