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Method of adsorbing and method of recovering fluorine-containing compound

a fluorine-containing compound and adsorption method technology, applied in the field of adsorption of c2c6 fluorine-containing compound, can solve the problems of high adsorption of csub> and cost, and achieve the effect of avoiding heat decomposition of fluorine-containing compound

Active Publication Date: 2013-12-24
DAIKIN IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010]According to the present invention, it is capable to highly adsorb the C2-C6 fluorine-containing compound. In the desorbing process, it is capable to recycle the active carbon by heating the active carbon to a temperature of 150° C., which is suitable for desorption and avoids heat decomposition of the fluorine-containing compound. It is capable to recycle a C2-C6 fluorine-containing surfactant by collecting and concentrating the desorbed matters.

Problems solved by technology

It was difficult to highly adsorb the C2-C6 fluorine-containing compound, which has high solubility in water, with using the conventional active carbon having a specific surface area of 1,000 m2 / g or less.
Such adsorption method was associated with problems of cost.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0034]Into 500 cc glass bottle, each of active carbons (0.1 g) was charged and then 300 cc of aqueous solution containing 100 ppm of perfluorohexanoic acid (PFHA), which was adjusted to pH 2, was charged. The bottle was shaken at a temperature of 25° C. for 24 hours by a shaking apparatus, to adsorb perfluorohexanoic acid (PFHA) by the active carbon. Then, the equilibrium amount of adsorption was calculated. The concentrations of perfluorohexanoic acid (PFHA) in the raw water and the treated aqueous solution were compared, and the equilibrium adsorption amount of perfluorohexanoic acid (PFHA) per a unit weight of active carbon was determined. Adsorption rate of perfluorohexanoic acid (PFHA) to each active carbon is shown in Table 1.

[0035]The adsorption rate (%) is given by:

[[(Concentration of PFHA in initial raw water [ppm])−(Concentration of PFHA in treated water after adsorption [ppm])]×(Amount of raw water [g])] / [(Amount of used active carbon [g])×1,000,000]×100[%].

[0036]Accordin...

example 2

[0040]The same operation as in Example 1 was repeated except for using an ion-impregnated active carbon. The PFHA adsorption rates of the active carbons classified based on the impregnated ions are shown in Table 2.

[0041]

TABLE 2Impregnated IonAdsorption Rate [%]MgO I14.7MgO II14.6Amines16.0

example 3

[0042]An active carbon (0.1 g), to which PFHA was adsorbed until reaching the breakthrough point, was charged into an autoclave having an internal volume of 20 cc and backwashed with a steam having a temperature of 150° C. and a pressure of 0.5 MPa to 0.6 MPa for 10 minutes. The concentration of PFHA, which was adsorbed by the uptake tubes (two uptake tubes consisting of one uptake tube receiving 300 cc of water and another uptake tube receiving 300 cc of an aqueous solution of 0.1N sodium hydroxide), was determined. Then, the amount of desorption was calculated by multiplying the concentration of PFHA with the amount of the liquid. PFHA desorption effect by the steam from the active carbon is shown in Table 3.

[0043]

TABLE 3AdsorptionDesorptionTypes of ActiveAmountAmountDesorptionCarbon[g / AC-5 g][g / AC-5 g]Rate [%]Highly Activated1.321.2191.7Carbon 1Highly Activated1.171.1295.7Carbon 2Highly Activated1.030.9794.2Carbon 3Highly Activated0.930.9298.9Carbon 4General Carbon 10.390.3794.9G...

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Abstract

An adsorption process in which high adsorption of C2-C6 fluorine-containing compound can be attained without any morphological change thereof by the use of active carbon; and a desorption process in which active carbon and adsorbed substances can be recycled by desorption from active carbon. A liquid containing the C2-C6 fluorine-containing compound is brought into contact with active carbon to thereby cause the active carbon to adsorb the fluorine-containing compound and thus obtain a liquid of low fluorine-containing compound content. The active carbon having the adsorbed fluorine-containing compound is heated so as to desorb the fluorine-containing compound from the active carbon.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method of adsorbing a C2-C6 fluorine-containing compound, in which the C2-C6 fluorine-containing compound contained in a liquid phase is capable of highly adsorbed, and a method of recovering the C2-C6 fluorine-containing compound, in which the fluorine-containing compound is capable of highly recovered from an active carbon.[0002]According to the present invention, it is capable of efficiently and selectively recovering the C2-C6 fluorine-containing compound from a liquid phase, such as waste water from a plant, waste water from households and rivers. In addition, it is capable of recycling active carbon and recovering the adsorbed substances by desorbing the adsorbed substances from the active carbon which has adsorbed.BACKGROUND OF THE INVENTION[0003]A C2-C6 fluorine-containing compound, for example, perfluorohexanoic acid (PFHA) has a solubility in water of about 20% at normal temperature, which is about 100 times of...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C07C53/21
Inventor KURAMITSU, MASAKI
Owner DAIKIN IND LTD