JPS58131132A - Adsorbent for mercury vapor - Google Patents

Abstract

PURPOSE:To provide an adsorbent adsorbing mercury vapor in good efficiency and extremely high in adsorbing capacity of mercury, by supporting NH4SCN, (NH4)2S2O3, (NH4)2S, NH4OSO2NH2 by activated carbon. CONSTITUTION:A mercury vapor adsorbent is prepared by supporting one or more of NH4SCN, (NH4)2S2O3, (NH4)2S and NH4OSO2NH2 by activated carbon. By contacting this adsorbent with a gas containing mercury vapor, mercury vapor in the gas is adsorbed in good efficiency. This contact can be carried out, for example, by using a fixed layer, a moving layer or a fluidized layer.

Description

[Detailed description of the invention] The present invention relates to mercury vapor adsorbents in gases.

Mercury vapor is often contained in electrolyzed hydrogen gas, natural gas, incinerator exhaust gas, and exhaust gas from factories that handle mercury. In other words, electrolytic hydrogen is a medicine.

It is used in the process of manufacturing food and other products, and trace amounts of mercury vapor can cause problems as it can poison catalysts or mix into products. Mercury vapor in natural gas is
It corrodes aluminum heat exchangers in the gas liquefaction process, causing major accidents. Furthermore, mercury vapor in incinerator exhaust gas and exhaust gas from factories that handle mercury vapor poses problems in terms of air pollution and the working environment.

Therefore, mercury vapor in these gases cannot be removed unless some treatment is performed. Until now, known methods for removing mercury from gas include chemical cleaning methods and dry adsorption methods using adsorbents such as activated carbon and ion exchange resins. There are disadvantages such as insufficient removal efficiency and generation of waste liquid. The latter dry adsorption method has a small adsorption capacity for mercury vapor and is not fully satisfactory.

As a result of various studies in view of these points, the present inventors found that
The present invention was completed based on the discovery that activated carbon supporting anthenium thiocyanate, ammonium thiosulfate, ammonium sulfide, and ammonium sulfamate efficiently adsorbs mercury vapor in gas and has a significantly large adsorption capacity.

That is, the present invention is a mercury vapor adsorbent comprising activated carbon supporting at least one of ammonium thiocyanate, ammonium thiosulfate, ammonium sulfide, and ammonium sulfamate (referred to as [Fy ammonium salt).

Activated carbon used in the present invention includes charcoal, coke,
Manufactured by known methods using coconut guff, resin, etc. as raw materials, and has a specific surface area of 200 to 2000 m2/
/g can be used.

The amount of ammonium salt supported on activated carbon is 1g of activated carbon.
5 to 5 ooq, preferably 10 to 550 ooq.

In order to support the ammonium salt on the activated carbon, for example, a method of dissolving the ammonium salt in water, impregnating or spraying the ammonium salt on the activated carbon, and drying as necessary can be mentioned.

The mercury adsorbent of the present invention may carry a nonvolatile acid in addition to the ammonium salt, and by supporting the nonvolatile acid, the mercury adsorption ability of the adsorbent can be increased. The nonvolatile acid referred to herein refers to an acid having a vapor pressure of 50 mmHg or less at 100° C., such as sulfuric acid, phosphoric acid, oxalic acid, and citric acid. The amount of nonvolatile acid supported is 5 to 500, preferably 10 to 400, per gram of activated carbon. The method for supporting the non-volatile acid is carried out in the same manner as the method for supporting the ammonium salt on the activated carbon, and the order in which the ammonium salt and the non-volatile acid are supported on the activated carbon may be arbitrary.

For example, a method of impregnating or spraying activated carbon with an aqueous solution containing an ammonium salt and a non-volatile acid, a method of supporting an ammonium salt and then a non-volatile acid, or a method of supporting a non-volatile acid and then an ammonium salt. etc.

In order to remove mercury vapor from a gas using the mercury vapor adsorbent of the present invention, it is sufficient to bring the gas containing mercury vapor into contact with the adsorbent of the present invention. The contact temperature is 150°C or less, preferably -10 to 120°C, and the contact pressure is 50 kg/
cm2 or less, preferably 0.1 to 35 kg/cm
2, the contact time is 1 at 25℃l kg/c+++2.
It is 710 to 30 seconds, preferably 115 to 20 seconds. Further, the contact between the present adsorbent and the mercury vapor-containing gas can be carried out using, for example, a fixed bed, a moving bed, a fluidized bed, or the like.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Example/4 to 6 mesh with BET specific surface area of 1150 m/g
Granular activated carbon was crushed and sized into 16 to 24 mesh.

In this activated carbon A, NH4SCN, (NH4)2s2o
An aqueous solution containing 3゜(NH4)23 and NH40S02NH2 was uniformly sprayed, and NH45, CN, (?
[4) 28203° (NH4)28 and NH40S0
100w1/g of 2NH2 was supported on each and dried at 110°C (adsorbents P to E).

As a control, 100111g of each sodium salt was supported in place of these ammonium salts in the same manner as above.
Dry at 110°C (adsorbent b-e).

A solution of carbon disulfide in which sulfur was dissolved was sprayed on a single active patient and dried at 120°C to prepare activated carbon (adsorbent f) containing 100'f of sulfur.

6d each of adsorbents A to E and b to f obtained as above were packed into a glass column of 1.6C [llφ,
Gas at 30°C containing 9 Q/m3 of mercury vapor (N284.
8”1%+0214=5v01%, [1200,
A breakthrough adsorption test for mercury vapor was conducted by flowing 7vO1%) at a linear flow rate of 40 cm/secC. The results are shown in Table 1.

Example U The adsorbents B-E and b-e of Example/ were further loaded with 10011 f/g of sulfuric acid and dried at 110°C (adsorbents B-E1 and b1-e).

Adsorbents A to E, B1 to E obtained in this way
1, b''-6, and each of b1 to j1 611 as 1.
Fill a 6cmφ glass column with 9wF of mercury vapor.
Nitrogen gas containing I/m3 at 30°C at a linear flow rate of 40 cm/
sec, and a mercury vapor breakthrough adsorption test was conducted.

The results are shown in Table 2.

Example 3 Activated carbon A (16-24 mesh) of Example 1 was added with N.
H4SCN 5.10, 50, 100, 200, 400
．． 500 and 550 q/g were loaded and dried at 110°C.

Each 61 pieces of the adsorbent thus obtained was divided into 1°5 cmφ
mercury vapor 9q/m303
0℃ gas (N2-84.8v01%, o2-14, 5
v01%, H2O-0, 'tvo1%) Line flow rate 4
After flowing at 0 cm/see for 300 hours, the amount of mercury adsorbed on each adsorbent was measured and the results are shown in Table 3.

Table 2 Table 3 Example
CN was supported at 125q/g and dried at 110°C. In addition to this, sulfuric acid, phosphoric acid, and oxalic acid.

50 W/g of citric acid was loaded on each sample and dried at 110'l:.

Each 6d of adsorbent thus prepared is 1.6cm
A breakthrough adsorption test for mercury vapor was carried out by filling a φ glass column and passing nitrogen gas at 30° C. containing 9 q/m of mercury vapor at a linear flow rate of 40 cm/sec. The result is the 4th
As shown in the table.

Table 4 Example j 6 ml each of adsorbents B-E and B1 to El of Example Y
was packed into a 1.6 cmφ glass column, and hydrogen gas at 30°C containing 1qim3 of mercury vapor was introduced at a linear flow rate of 40 cm/
It was circulated at sθC and a breakthrough adsorption test for mercury vapor was conducted. The results are shown in Table 5.

Table 5 -11-

Claims (2)

[Claims] (1) A mercury vapor adsorbent which supports at least one of ammonium thiocyanate, ammonium thiosulfate, ammonium sulfide, and ammonium sulfamate at an active level. (2) The mercury vapor adsorbent according to claim 1, which carries a nonvolatile acid together with at least one of ammonium thiocyanate, ammonium thiosulfate, ammonium sulfide, and ammonium sulfamate.