JPS6071081A - Removal of organic compound in water - Google Patents

Abstract

PURPOSE:To remove various kinds of org. compounds mixed in water with good efficiency, by passing water containing org. compounds through a filter bed, which is formed by packing activated carbons different in specific gravity in a laminar form, so as to traversely cross said filter bed. CONSTITUTION:Two kinds of activated carbons, of which the specific gravity is set to a range of 0.2-0.6g/ml by the baking or activating condition of a generally used petroleum pitch type activated carbon stock material are prepared from said stock material and these activated carbons different in the specific gravity are packed in a laminar form to form a filter bed. Water containing org. compounds is passed through this filter bed in an upward or downward stream. 1-80wt% of oxide or hydroxide of Na, K, Mg or Ca can be mixed in the aforementioned activated carbons. In addition, as the aforementioned activated carbons, ones receiving acid washing using an acid such as hydrochloric acid are suitably used. The height of the activated carbon packing layer in forming the filter bed is suitably selected in a range of 0.5-4m.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing organic compounds from water. More specifically, the present invention relates to a method for removing organic compounds from water. The present invention relates to a method for removing organic compounds in water, which is characterized by passing water containing the compounds through the water.

Activated carbon has been widely used and put to practical use as an adsorbent and remover for organic compounds in water.

Among these, it is said to be a versatile adsorbent for high-level water treatment. However, in recent years, as analysis technology has advanced and water treatment technology has become more sophisticated, it has become impossible to adsorb and remove all organic compounds in water simply by treating it with activated carbon as in the past. It's becoming clear. More specifically, when considered from a physical perspective such as differences in molecular weight and steric structure of organic compounds, and from a chemical perspective such as ionicity, hydrophilicity, hydrophobicity, or compatibility with metals,
It is not possible to completely and satisfactorily remove various compounds with different properties such as polyhydric alcohols, aromatic compounds such as benzene, alkyl halides, and aliphatic compounds by simply treating with activated carbon. It is no exaggeration to say that it is possible.

As a result of intensive research, the inventors of the present invention discovered that by forming a filter bed filled with layers of activated carbon with different specific gravity, it was possible to remove a wide range of organic compounds even if they were mixed in water. The present invention was achieved by discovering that this is possible.

According to the conventional adsorption method that uses a single activated carbon layer, when water containing organic compounds is passed through the activated carbon layer, the filter bed is clogged with coarse impurities, making it necessary to perform backwashing, etc.
If so, it was formed by adsorption of organic compounds. Whereas the so-called adsorption zone is destroyed, if the adsorbent layer is made of activated carbon with a difference in specific gravity as in the present invention, it is easy to restore the adsorption zone to almost the same state as before backwashing. Effective adsorption and removal properties can be maintained even during the subsequent water passage process, and the life of the adsorbent can be extended.

In addition, in adsorption using a single activated carbon layer, organic compounds that have been adsorbed on the activated carbon are replaced by other organic compounds and are often driven out. The layers adsorb different organic compounds.

Organic compounds can be removed efficiently. Another advantage of the present invention due to the formation of layers with different specific gravity is in the recycling of adsorbent that has passed through adsorption.

It is possible to separate and take out each type of activated carbon, and to carry out regeneration and activation suitable for each type of activated carbon.

Activated carbons with different specific gravities are used in the method of the present invention.

It is well known that scales can be produced by changing the activation conditions in conventional activated carbon production.

In the present invention, activated carbon having different specific gravity by mixing other components can also be used. In other words, the raw materials generally used for activated carbon are coconut kernel, coal, petroleum, and wood, but depending on the firing or activation conditions, the apparent specific gravity (indication of packing density) may range from 0.2 to 0.6 g/ lI+7! Can be set arbitrarily within the range. When mixing other components, the packing density should be 0.5 to 5.
g/mj! It can be adjusted arbitrarily within the range. Mixable components include Na + K + Mgl Ca, Ba, Sr,
TI+ Mn, Fe+ Zr+, 8l, S+, Sh+
Single or multiple oxidized compounds monohydroxide compounds such as pb.

Examples include carbonate compounds alone or in mixtures. A preferred specific example is + MgO+ CaO+ 7'+O*
+Fea 03 + Fe3O4+ 8I2 03 +
SiO21MgCO31CaCOa + Nag O
・Alx 03 5t0211x O-based compound + Mg
Examples include 6.Ah (Oll) 16.Co, .41h O-based compounds, and the like. The type of mixture and its mixing ratio vary depending on the type of organic compound to be adsorbed and the required specific gravity, but the amount of the mixture is usually 1 to 80% based on activated carbon.
Weight % is sufficient. In addition to the above mixtures, polyvinyl alcohol, molasses,
In addition to adding tar pitch or the like to give strength, it can also be made into an adsorbent with many pores.

The activated carbon used in the present invention is fired or activated during production as described above, but by performing these processes in a reduced state, it improves the adsorption performance of organic compounds and also removes organic compounds that are difficult to remove with conventional activated carbon. It can be made so that it can also be removed. An example of the reducing atmosphere gas is a gas containing hydrogen and/or carbon monoxide.

Furthermore, similar effects can be obtained by reducing activated carbon. For example, using activated carbon in a 0.1 wt% aqueous solution at 20°C.
It may be treated for 6 hours.

The activated carbon used in the present invention is also preferably acid-washed. The acid is hydrochloric acid.

Hydrofluoric acid is preferably used. In the case of hydrochloric acid, the cleaning method may be, for example, immersion in a 5 wt % aqueous solution at 20° C. for 3 hours. Even better adsorption properties can be obtained by repeating similar washing as necessary. In the case of fluoro5-acid, for example, at 2°C in a 20 wt% aqueous solution.
It is sufficient to immerse the material in water for 3 hours, and if the same immersion is performed after washing with hydrochloric acid, the adsorption performance will be significantly improved. In either case, it is preferable to thoroughly wash with water after immersion.

The present invention uses a filter bed formed by filling a column or a filter basin with activated carbon having different specific gravity.

It is preferable that the height of the packed bed is arbitrarily selected within the range of 0.5 to 4 m in consideration of the target water quality of the treated water, head loss, etc. Two to four types of activated carbon having different specific gravities are sufficient, but more than that may be used if necessary. Note that the height of each activated carbon layer may be the same or different depending on the purpose.

Water may be passed through the filter bed either upwardly or downwardly, but preferably downwardly. In the case of upward flow, it is also possible to pass water through only the upper layer, which has a lower specific gravity, as a fluidized bed. If head loss increases due to water flow, backwashing can be performed. Due to long-term use.

When the adsorption performance of activated carbon has deteriorated, it is most preferable to take out the activated carbon by fractionation based on the difference in specific gravity and regenerate it under regeneration conditions suitable for each, but depending on the case, it may be carried out in a mixed state.

The method of the present invention reduces organic compounds (including odors) in drinking water.
Removal, purification of water for fermentation 1 Purification of water for food use, electrical parts!
It can be used in many fields such as V-shaped agglomeration, washing water purification, etc.

Hereinafter, the present invention will be explained in more detail by giving specific examples.

Example I Coal-based activated 1jL charcoal (Tararecol G1, C; manufactured by Kuraray Chemical Co., Ltd., 8 to 32 meshes, packing density o, 25 g, /m
7rito coconut shell activated carbon (Shirasagi Wlh C: Takeda Pharmaceutical Co., Ltd., 8 to 32 meshes, packing density 0.45 g/mj!
).

40 each in a glass tube with a tube diameter of 50 mm and a length of 1 m.
Two layers of 0 mm each were filled to a total height of 800 mm. 100μg of chloroform from the top of this glass tube filled with activated carbon.
An aqueous solution containing 2 mg/R of humic acid and 2 mg/R of humic acid was passed through the tube at a linear velocity (1, ν) of 15 m/llr. Both chloroform and humic acid are almost completely removed at the initial stage of water flow.

The removal rate was maintained at over 90% after one month and over 70% after two months.

On the other hand, when the above activated carbon is used alone, Tararecol GLC
In the case of Shirasagi WNZC, the removal rate of chloroform decreased to less than 50% after 2 months, and in Shirasagi WNZC, the removal rate of humic acid was 50%.
It decreased to below.

Patent applicant: Uni-Tei Riki Co., Ltd.

Claims (1)

[Claims] A method for removing organic compounds in water, comprising: forming a filter bed by filling layers of activated carbon with different specific gravities, and passing water containing organic compounds vertically through the filter bed.