CN110624501A - Adsorbent and adsorption purification device for strengthening radon gas removal - Google Patents

Abstract

The invention discloses a preparation method of activated carbon with radon gas selective adsorption capacity and gas purification equipment. The method includes the following steps: S1, activated carbon pretreatment; S2, activated carbon ultrasonic hole making; S3, _N2 or _H2 atmosphere under microwave irradiation. The present invention simply modifies commercially available activated carbon by means of ultrasonic pore making, microwave irradiation under _N2 or _H2 conditions, so that the specific surface area is about 850㎡/g, and the volume of micropores of 0.5-0.8nm increases. The surface oxygen content is reduced, which improves its selective adsorption capacity for radon gas, and the modification method is simple and the cost is low.

Description

Adsorbent and adsorption purification device for strengthening radon gas removal

technical field

The invention relates to the technical field of air purification, in particular to a preparation method of activated carbon with radon gas selective adsorption capacity and gas purification equipment.

Background technique

Radon is a decay product of radium, the only gaseous radioactive element that humans come into contact with, and one of the 19 major carcinogens announced by the World Health Organization (WHO). It is currently the second most common cause of human lung cancer after cigarettes. According to the data released by the World Health Organization, more than 100,000 people die from indoor Rn pollution every year in the world. For every 100Bq/m ³ increase in the average radon concentration over a long period of time, the risk of lung cancer increases by 16%. With the progress of social modernization and the improvement of living conditions, people are more likely to be exposed to high-concentration radon indoors than outdoors. Radon is widely found in building materials such as cinder blocks or cement blocks mixed with fly ash. In addition, fuels such as coal, natural gas, liquefied petroleum gas, and coal-bed methane also have relatively high concentrations of radon.

There are three radioactive isotopes of Rn widely existing in nature: ²²² Rn, ²²⁰ Rn and ²¹⁹ Rn. ²²² Rn is an intermediate product of ²³⁸ U decay, and its further decay can produce short-lived daughters such as ²¹⁸ Po, ²¹⁴ Pb, ²¹⁴ Bi and ²¹⁴ Po. The half-life of ²²² Rn is 3.82d, which can stay in the air for a long time, enough for it to enter the human body. The radiation and short-lived bodies produced by the decay of Rn are harmful to human health. The most harmful to the human body is mainly ²²² Rn and its Short-lived offspring.

At present, there are few effective protective measures against radon gas, mainly relying on technical means such as ventilation, shielding paint and adsorption.

CN206247489U discloses a kind of radon removal system used for fresh air system, comprising interconnected and continuous outlet pipes and porous pipes, the outlet pipes extend outwards to the outside of the building roof, and the porous pipes include porous pipes laid on the surface of the floor The main road, and the porous pipe auxiliary road extending downward to the foundation concrete layer, the main air inlet on the porous pipe main road faces the floor surface layer, and several auxiliary air inlets are arranged on the peripheral side of the porous pipe auxiliary road, the porous pipe There is also a porous pipe branch on the pipe auxiliary road, the other end of the porous pipe branch is closed, and several branch air inlets are provided on the peripheral side of the pipe, and filter screens are arranged in the outlet pipe along the direction of radon gas discharge. There is a sealed chamber of radon gas adsorption material, as well as a pipeline air pump, solid activated carbon sheets, and an exhaust port.

CN105983329A discloses a device and method for removing radon in the air, which uses chemical methods to convert radon into stable, non-radioactive substances, including three parts: a closed container, an air secondary treatment device and an air pump. Put the adsorption material in the airtight container, introduce the air into the adsorption material through the air pump for chemical reaction, export the reacted air to the secondary treatment device for filtration, disinfection, and deodorization treatment, and the treated air is discharged back to the atmosphere or environment.

CN204632348U discloses a kind of device by ZIF-8 adsorption radon. The device is equipped with an adsorption device, an air pump, a flow meter and a gas detector. The parts are connected by pipes. The adsorption device is equipped with powdery ZIF-8 adsorbent, and the gas detector is connected behind the flow meter, which can dynamically monitor the radon content in the gas flowing through it.

CN105289227A discloses a high-efficiency radon elimination agent. The formula includes 1-5 parts of ketazone, 60-80 parts of carrier, 0.5-1 part of synergist and 0.2-0.8 part of stabilizer. The carrier is a combination of zeolite powder, pottery clay powder and activated carbon, and the activated carbon is loaded with divalent copper ions, divalent iron ions and iodine.

The above four schemes are mainly methods of ventilation, shielding coating and adsorption. Among them, ventilation takes a long time and the treatment effect is poor; shielding coatings are costly and difficult to install; the selective adsorption capacity of existing adsorption materials for radon is weak, and radon is an inert gas, which is almost incompatible with other Substance reaction, difficult to use other methods to deal with.

Contents of the invention

In view of the above technical problems, the technical problem to be solved by the present invention is to provide a preparation method of activated carbon with selective adsorption capacity of radon gas and gas purification equipment, so as to enhance the selective adsorption capacity of radon gas.

In order to realize above-mentioned technical purpose, the present invention adopts following technical scheme:

A preparation method of active carbon with radon selective adsorption capacity, comprising the following steps:

S1, activated carbon pretreatment;

S1.1, the activated carbon was placed in hydrofluoric acid and hydrochloric acid for static treatment for 3 hours; the concentrations of the hydrofluoric acid and hydrochloric acid were both 0.1mol/L, and the hydrofluoric acid and hydrochloric acid had not passed the activated carbon during the static treatment;

S1.2. Wash the activated carbon after static treatment with deionized water, filter with filter paper, and stop washing with water when the pH value of the filtrate is 7.0;

S1.3. Place the above-mentioned activated carbon after washing in an oven for drying treatment. The temperature of the oven is set at 110°C, and the drying time is 24 hours;

S2. Ultrasonic pore making with activated carbon;

S2.1. Place the above-mentioned pretreated activated carbon in an ultrasonic generator, and perform ultrasonic treatment for 2 hours; during the above-mentioned ultrasonic treatment, the power of the ultrasonic generator is 100-200W, the ultrasonic frequency is 53Hz, and the temperature is controlled at 45°C;

Microwave irradiation under S3, N ₂ or H ₂ atmosphere;

The activated carbon after the above ultrasonic treatment is placed in a multi-mode resonant microwave cavity for processing, and the processing methods are different under different atmospheres, specifically:

When the above-mentioned activated carbon after ultrasonic treatment is irradiated with microwave under _N2 atmosphere, place the above-mentioned activated carbon after ultrasonic treatment in a quartz reactor, and in _N2 atmosphere, heat in a multi-mode resonant microwave cavity for 5-10min;

When the above ultrasonically treated activated carbon is irradiated with microwaves under _H2 atmosphere, the above ultrasonically treated activated carbon is placed in a quartz reactor, and heated in a multimode resonant microwave cavity for 30-60min under _H2 atmosphere.

In step S3, the ultrasonically treated activated carbon is irradiated with microwaves under _N2 atmosphere, and the input power of the multimode resonant microwave cavity is 550-650W;

The activated carbon after the ultrasonic treatment is irradiated with microwaves under H ₂ atmosphere, and the input power of the multi-mode resonant microwave cavity is 550-600W.

The invention further discloses a gas purification device, which adopts the activated carbon with selective adsorption capacity of radon gas.

The gas purification equipment includes a casing, an air inlet arranged at the bottom of the casing, an air outlet arranged at the upper part of the casing, a filter unit arranged inside the casing, and a filter unit for transporting air to be filtered through the filter unit The ventilation device, the filter unit includes at least one primary effect filter layer arranged in sequence along the air circulation direction, and the activated carbon layer with radon selective adsorption capacity arranged behind the primary effect filter layer.

The casing is also provided with at least one VOCs adsorption layer for adsorbing VOCs gas.

Beneficial effect:

The present invention simply modifies commercially available activated carbon by means of ultrasonic pore making, microwave irradiation under _N2 or _H2 conditions, so that the specific surface area is about 850㎡/g, and the volume of micropores of 0.5-0.8nm increases. The surface oxygen content is reduced, which improves its selective adsorption capacity for radon gas, and the modification method is simple and the cost is low. The invention provides an air purification device for strengthening the removal of radon gas, which has a reasonable layout, can strengthen the removal of radon gas in the air, and can realize the joint removal of various gaseous pollutants.

Description of drawings

Fig. 1 is the structural representation of gas purification equipment of the present invention;

Among them: 1—shell; 2—air inlet; 3—air outlet; 4—fan; 5—perforated plate; 11—primary filter layer; 21—activated carbon with radon selective adsorption capacity; 31—the first Level adsorption layer; 32—the second level adsorption layer.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

A preparation method of active carbon with radon selective adsorption capacity:

A kind of preparation method of activated carbon with radon gas selective adsorption capacity The preparation steps are as follows:

(1) Activated carbon pretreatment

(2) Activated carbon ultrasonic hole making

(3) Microwave irradiation under N2 or H2 atmosphere

Specifically, for the activated carbon pretreatment described in (1) above; the pretreated activated carbon is commercially available activated carbon, and the activated carbon is placed in hydrofluoric acid and hydrochloric acid for standing treatment for 3 hours;

Further, the concentrations of the hydrofluoric acid and hydrochloric acid are both 0.1mol/L, and the hydrofluoric acid and hydrochloric acid can be submerged in activated carbon during standing treatment;

Further, the gac after standing treatment was cleaned with deionized water, filtered with filter paper, and when the pH value of the filtrate was 7.0, the water washing was stopped.

Further, the above water-washed activated carbon was placed in an oven for drying treatment, the temperature of the oven was set at 110° C., and the drying time was 24 hours.

Specifically, for the above-mentioned activated carbon described in (2) ultrasonic pore making: the above-mentioned activated carbon after pretreatment is placed in an ultrasonic generator, and ultrasonically treated for 2 hours;

Further, in the above ultrasonic treatment, the power of the ultrasonic generator is 150W, and the ultrasonic frequency is 53Hz. In the ultrasonic step, the temperature is controlled at 45°C.

Specifically, for the above (3) microwave irradiation under N2 or H2 atmosphere, the above-mentioned activated carbon after ultrasonic treatment is placed in a multi-mode resonant microwave cavity for treatment, and the treatment methods are different under different atmospheres;

Further, the above-mentioned activated carbon after ultrasonic treatment was irradiated with microwaves under N2 atmosphere, and the above-mentioned activated carbon after ultrasonic treatment was placed in a quartz reactor, and heated in a multi-mode resonant microwave cavity for 5 minutes in N2 atmosphere;

Further, the ultrasonically treated activated carbon is irradiated with microwaves under N2 atmosphere, and the input power of the multimode resonant microwave cavity is 600W.

Further, the above-mentioned activated carbon after ultrasonic treatment was irradiated with microwave under H2 atmosphere, the above-mentioned activated carbon after ultrasonic treatment was placed in a quartz reactor, and heated in a multi-mode resonant microwave cavity for 30min under H2 atmosphere

Further, the ultrasonically treated activated carbon is irradiated with microwaves in H2 atmosphere, and the input power of the multimode resonant microwave cavity is 600W.

Example 1

Select commercially available coconut shell-based activated carbon, pretreat the commercially available coconut shell-based activated carbon according to the above-mentioned activated carbon pretreatment method, and only perform ultrasonic pore-making on the pretreated activated carbon. The ultrasonic conditions are as follows: the power of the ultrasonic generator is 100W, and the ultrasonic frequency The temperature is 53Hz, the temperature is controlled at 45°C during the ultrasonic process, and the ultrasonic time is 2h.

For the coconut shell-based activated carbon prepared above, the radon gas adsorption experiment was carried out in a ^13.5m3 radon chamber, and the radon gas activity concentration was ~2000Bq/m3.

The dynamic adsorption coefficient (DAC) is used as a parameter to measure the adsorption capacity of the adsorbent:

DAC=F t/ω

In the formula, F is the flow rate of the sampling pump, L/min; t is the moment when the radioactivity concentration in the radon chamber is half of the initial value; ω is the mass of the adsorbent.

Example 2

The same commercially available coconut shell-based activated carbon as in Example 1 was selected, and the activated carbon pretreatment method was the same as in Example 1. The pretreated activated carbon was only subjected to ultrasonic pore making, and the power of the ultrasonic generator was changed to 150W, while other conditions remained unchanged.

The radon dynamic adsorption coefficient of activated carbon after the treatment is detected by the method of Example 1.

Example 3

The same commercially available coconut shell-based activated carbon as in Example 1 was selected, and the activated carbon pretreatment method was the same as in Example 1. Only ultrasonic pore-forming was performed on the pretreated activated carbon, and the power of the ultrasonic generator was changed to 200W, while other conditions remained unchanged.

The radon adsorption kinetic coefficient of the activated carbon after the treatment was detected by the method of Example 1.

Example 4

Select the same commercially available coconut shell-based activated carbon as in Example 1, the activated carbon pretreatment method is the same as in Example 1, and the pretreated activated carbon is subjected to ultrasonic pore-forming, and the ultrasonic pore-forming method is the same as in Example ₂ , under N Atmosphere Microwave irradiation is carried out, and the treatment process is as follows: the activated carbon after ultrasonic pore-making treatment is evenly placed in a quartz reactor, the above-mentioned quartz reactor is placed in a multi-mode resonant microwave cavity, and N2 is passed into it to adjust the multi-mode resonance. The input power of the microwave cavity is 600W, and it is heated for 5 minutes.

The radon dynamic adsorption coefficient of activated carbon after the treatment is detected by the method of Example 1.

Example 5

Select the same commercially available coconut shell-based activated carbon as in Example 1, the activated carbon pretreatment method and the ultrasonic pore-making method are the same as in Example ₄ , and microwave irradiation is carried out under the H atmosphere, and the process is as follows: The activated carbon is evenly placed in a quartz reactor, the above-mentioned quartz reactor is placed in a multimode resonant microwave cavity, H2 is passed into it, the input power of the multimode resonant microwave cavity is adjusted to be 600W the same as in Example 4, and the heating is carried out for 30min.

The radon dynamic adsorption coefficient of activated carbon after the treatment is detected by the method of Example 1.

The specific surface area, the volume of 0.5～0.8nm micropores and the dynamic adsorption coefficient of radon are detected by the specific surface area, the volume of 0.5～0.8nm micropores and the dynamic adsorption coefficient of radon through the activated carbon of embodiment 1～5; The specific surface area, the volume of 0.5 ~ 0.8nm micropores and the dynamic adsorption coefficient of radon gas were detected and counted, and the conclusions of the above samples were compared. The results are shown in Table 1:

From the data in Table 1, it can be known that Examples 1 to 3 only carry out ultrasonic treatment on commercially available activated carbon. Compared with Example 3, the micropore volume and surface oxygen content of 0.5 to 0.8nm in Example 1 are not much different, but Example 3 The larger the specific surface area of activated carbon, the smaller the dynamic adsorption coefficient of radon gas, which shows that there is an optimal specific surface area for radon gas adsorption. The larger the specific surface area, the better the performance of adsorbing radon gas. Compared with Example 1 and Example 3, the dynamic adsorption coefficient of radon gas in Example 2 is significantly increased. The main reason is the increase of its 0.5-0.8nm micropore volume, which fully shows that when the specific surface area of activated carbon is about 850m ² /g , and when the 0.5-0.8nm micropore volume is larger, the selective adsorption capacity for radon gas is stronger. Comparative example 3, embodiment 4 and embodiment 5, the main difference of gac in three embodiments is the content of surface oxygen, data shows, when gac surface oxygen content reduces, radon dynamic adsorption coefficient significantly increases, and in N2 atmosphere Microwave irradiation under the atmosphere and H2 atmosphere can effectively reduce the oxygen content on the surface of activated carbon.

To sum up, the specific surface area of activated carbon is about 850㎡/g, the volume of 0.5-0.8nm micropores increases, and the selective adsorption capacity of radon gas is significantly enhanced when the surface oxygen content decreases.

As shown in Figure 1, the present invention further discloses a kind of air purification device that strengthens radon gas removal:

Example 6

A device for strengthening radon gas removal is divided into two parts: a radon gas adsorption part and a gaseous pollutant treatment part.

The above-mentioned radon gas adsorption part is composed of primary filter layer net 11 and radon adsorption layer 21; the above-mentioned other gaseous pollutant treatment part is composed of first-stage adsorption layer 31 and second-stage adsorption layer 32.

Above-mentioned radon adsorption part, under the effect of blower fan 4, polluted gas enters device shell 1 from air inlet 2, and described air inlet 2 is arranged on the bottom both sides of removing device, because radon is heavier than air, air inlet 2 It is set at the bottom to facilitate the maximum inhalation of radon in the ambient air. The polluted air passes through the primary effect filter screen 11 to intercept larger particles and enters the radon adsorption layer 21. The radon adsorption layer 21 is filled with the activated carbon with radon selective adsorption capacity prepared above, and the radon adsorption layer 21 is placed in the primary effect. After the filter screen 11, the processing capacity of the active carbon with radon gas selective adsorption capacity has been brought into full play to the greatest extent, and the effect of radon gas removal has been strengthened. Tested in a 35m ³ room, the initial radon concentration was 523Bq/m ³ , and the concentration of radon and its daughters could drop by about 50% within 10 minutes. After 2 hours, the indoor radon concentration dropped to 138Bq/m ³ . It meets the standards of Class I civil construction engineering in GB50325-2010.

In the above-mentioned gaseous pollutant treatment part, the gas passing through the radon gas adsorption part passes through the perforated plate 5 and enters the other gaseous pollutant treatment part under the action of the fan 4 . The gas passes through the first-level adsorption layer 31 and the second-level adsorption layer 32 respectively, and has a better adsorption treatment effect on gaseous pollutants such as VOCs. An air purification device for enhanced radon gas removal is provided. The above-mentioned activated carbon with selective adsorption capacity for radon gas is used as the main component for radon gas removal to strengthen the ability to remove radon gas, rationally arrange various functional modules, and realize the joint removal of various gaseous pollutants.

Claims (5)

1. a preparation method with radon selective adsorption capacity gac, is characterized in that, comprises the following steps: S1, activated carbon pretreatment; S1.1, the activated carbon was placed in hydrofluoric acid and hydrochloric acid for static treatment for 3 hours; the concentrations of the hydrofluoric acid and hydrochloric acid were both 0.1mol/L, and the hydrofluoric acid and hydrochloric acid had not passed the activated carbon during the static treatment; S1.2. Wash the activated carbon after static treatment with deionized water, filter with filter paper, and stop washing with water when the pH value of the filtrate is 7.0; S1.3. Place the above-mentioned activated carbon after water washing in an oven for drying treatment. The temperature of the oven is set at 110° C., and the drying time is 24 hours; S2. Ultrasonic pore making with activated carbon; S2.1. Place the above-mentioned pretreated activated carbon in an ultrasonic generator, and perform ultrasonic treatment for 2 hours; during the above-mentioned ultrasonic treatment, the power of the ultrasonic generator is 100-200W, the ultrasonic frequency is 53Hz, and the temperature is controlled at 45°C; Microwave irradiation under S3, N ₂ or H ₂ atmosphere; The activated carbon after the above ultrasonic treatment is placed in a multi-mode resonant microwave cavity for processing, and the processing methods are different under different atmospheres, specifically: When the above-mentioned activated carbon after ultrasonic treatment is irradiated with microwave under _N2 atmosphere, place the above-mentioned activated carbon after ultrasonic treatment in a quartz reactor, and in _N2 atmosphere, heat in a multi-mode resonant microwave cavity for 5-10min; When the above ultrasonically treated activated carbon is irradiated with microwaves under _H2 atmosphere, the above ultrasonically treated activated carbon is placed in a quartz reactor, and heated in a multimode resonant microwave cavity for 30-60min under _H2 atmosphere. _2. according to claim 1, there is the preparation method of radon selective adsorption capacity active carbon, it is characterized in that, in step S3, the active carbon after described ultrasonic treatment is N under atmosphere Microwave irradiation, described multimode resonant microwave Cavity input power is 550~650W; The activated carbon after the ultrasonic treatment is irradiated with microwaves under H ₂ atmosphere, and the input power of the multi-mode resonant microwave cavity is 500-650W. 3. A gas purification device, characterized in that the activated carbon with radon selective adsorption capacity as claimed in claim 1 or 2 is used. 4. The gas purification device according to claim 3, comprising a housing, an air inlet arranged at the bottom of the housing, an air outlet arranged at the upper part of the housing, a filter unit arranged inside the housing, and a filter unit for transporting to-be-filtered Air passes through the ventilation device of the filter unit, characterized in that the filter unit includes at least one primary effect filter layer arranged in sequence along the air circulation direction, and the filter layer according to claim 1 or 2 arranged behind the primary effect filter layer The activated carbon layer with radon gas selective adsorption capacity. 5. The gas purification device according to claim 4, characterized in that, at least one VOCs adsorption layer for adsorbing VOCs gas is provided in the housing.