JPS582211A - Reformed activated carbon - Google Patents

Abstract

PURPOSE:To obtain reformed activated carbon suitable for adsorbing org. solvent vapor by treating activated carbon so that the amount of oxygen is regulated to a specified value when the carbon is vacuum-degassed under specified conditions. CONSTITUTION:Activated carbon is subjected to oxidation treatment at room temp. up to about 400 deg.C for 1-15hr by an air oxidation method, an oxidation method using nitrogen oxide, sulfur oxide or halogen, or other method. The used carbon may be made of charcoal or coal, and the grain size, hardness, etc. are selected according to the purpose for which the carbon is used. By the treatment activated carbon contg. 20-50mg/g oxygen calculated from gaseous CO and CO2 generated by vacuum degassing at 950 deg.C for 30min is obtd. The resulting activated carbon adsorbs efficiently vapor of a mixture of a low molecular polar org. solvent with a nonpolar solvent, especially vapor of a mixture of gasoline with an alcohol such as methanol or ethanol.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel modified activated carbon. The details relate to modified activated carbon that is suitable for adsorbing organic solvent vapors that are difficult to adsorb with ordinary activated carbon.It has nine excellent properties, especially as activated carbon for car canisters that use a mixed fuel of gasoline and alcohol. It is made of activated charcoal, which is typical of preparation.

Activated carbon is a highly adsorbent material with fine pores developed and the log portion made of carbonaceous material), and can be used to adsorb gas or vapor to recover solvents, purify gases, or mix with liquids to purify solvents. , used for decolorization, etc. Furthermore, it is also used as a carrier for catalysts. The fields of use of these materials, for example, air pollution prevention, water pollution prevention, and resource reuse, are increasing more and more, and the properties required of activated carbon are also becoming more diverse and demanding.

For example, there is activated carbon for casters used to prevent fuel vapor dissipation in automobiles, but when alcohol is used in addition to conventional gasoline as a fuel, the activated carbon that has been commonly used in the past has a low adsorption capacity and must be filled with it. If so, the canister will not function satisfactorily.

We have conducted repeated research to obtain an activated carbon suitable for collecting the vapors of two types of mixtures, such as gasoline and alcohol mixtures, and moreover, polar solvents and non-polar solvents, and as a result, we have arrived at the present invention.

That is, the present invention is based on nine activated carbons having an oxygen amount (hereinafter referred to as surface oxygen amount) of 0~Sθ~/l calculated from carbon monoxide and carbon dioxide gas generated at the time of death by vacuum insufflation at 930°C for 30 minutes. Ru.

The present invention will be explained in detail below.

The modified activated carbon of the present invention is obtained by oxidizing various activated carbons obtained by conventional methods. As the oxidation treatment method, any method such as air oxidation method, oxidation method using nitrogen oxide, sulfur oxide or halogen, ozone oxidation method or nitric acid oxidation method is employed. The oxidation conditions can vary widely depending on the oxidizing agent used, but are usually arbitrarily selected within the range of 1 minute to 1 minute at a temperature of room temperature to WOO°C. Of course, the activated carbon used may be either charcoal-based or coal-based activated carbon produced by a conventional method, but its particle size, hardness, etc. are selected depending on the purpose of use. For example, when used as an automobile canister, it is preferable to have an average particle size of about 1/2 Sw and a JI8 hardness of 90 or more.

When powdered activated carbon is used as a raw material, it may be modified by oxidation treatment in its powder form, and the resulting powder may be granulated to an appropriate size. Prior to modification, it may be granulated and then subjected to modification treatment.

The obtained modified activated carbon of the present invention efficiently adsorbs a mixture of a low-molecular polar organic solvent and a non-polar solvent in a steam pipe. % of gasoline and an alcohol such as methanol or ethanol, it is suitable for use in a canister for an automobile that uses a mixture of gasoline and alcohol as fuel. It can be effectively used to separate, recover, and remove various other solvent vapors.

The present invention will be described in more detail with reference to Examples below, but it goes without saying that the present invention is not limited to the following Examples.

Example 1 Coal-based granular activated carbon Diahope 0 (registered trademark name>5on
While heating to 100°C in a rotary kiln, air was flowed for a predetermined period of time to prepare activated carbon with an oxygen content of 9.0 to 9.0/l. This activated carbon/
00 cc was packed into a column, the methanol/gasoline mixture ratio was set to t/t/Ik, the methanol mixed gasoline was heated and evaporated, and the mixed gas of the vapor and air was passed through the column, and the concentration at the outlet of the activated carbon layer was 0. / Immediately: adsorb until , then desorb by passing air through for 10 minutes,
After this desorption kJlil is repeated, the third adsorption starts at
t.

The total amount of alcohol and aspect ratio hydrogen (hereinafter referred to as initial leakage amount) tS leaking out of the activated carbon layer per minute was determined. As shown below, it can be seen that the initial leakage amount is significantly reduced in the product of the present invention.

Example: The amount of surface oxygen 'iJ? , methanol using TTP/IK and nine granular activated carbon? An initial leak test was conducted in the same manner as in Example 9 using a mixture of gasoline and gasoline. The results are shown in the table below.

It can be seen that even when the mixing ratio of methanol is increased, the effect is remarkable.

Example J Activated carbon of the same type as Example 1 44. 9. Fill in a tlYt Katsumu and perform oxidation treatment by flowing a mixed gas of ozone and air at room temperature for t6 hours.

The initial leakage amount t of this J611 activated carbon was measured in the same manner as in Example 1. The results are shown in the table below.

The activated carbon treated with this salt showed a remarkable effect on initial leakage.

Example part Surface oxygen amount f: 9.2 ail/1 Coconut husk activated carbon (commercial product) K used in a gasoline vapor diffusion prevention canister for a soul pillar automobile is oxidized by air:
30.0 Da/g Toshimaru.

The initial leakage amount of these activated carbons was measured by the same method as in Example/). The results are shown in the table below.

Sender: Mitsubishi Chemical Industries, Ltd. 1 person□　″

Claims (1)

[Claims] (1) The amount of oxygen calculated from the carbon monoxide and carbon dioxide gas generated during running in a vacuum at tSO℃ for 30 minutes is 10 -
j Activated carbon with OQ / I (2) vtO Calculated from carbon monoxide and charcoal gas generated when vacuumed for 30 minutes at O℃ -Activated carbon for vapor adsorption of alcohol mixed metals