CN104772117A - Activated carbon compound modification method - Google Patents

Abstract

The invention provides an activated carbon compound modification method. The activated carbon compound modification method comprises the following steps: (1) preparing potassium hydroxide (KOH) aqueous solution with the concentration of 2-9mol/L, adding activated carbon, stirring uniformly, performing water bath heating for 4-9h at 330-365K, and drying; and (2) adding tetraethylenepentamine with the volume ratio of tetraethylenepentamine to absolute ethyl alcohol of (1 to 10)-(1 to 50), carrying out water bath heating for 10-60min at 330-360K, and adding the activated carbon, treated by the step (1), while stirring, reacting for 4-9h, performing suction filtration, and drying to obtain a product. A produced product has high adsorbing capacity and high adsorptive selectivity, and can keep the stable adsorbing performance after multiple adsorption-desorption cycles.

Description

A kind of active carbon composite modifying method

Technical field

The present invention is specifically related to a kind of active carbon composite modifying method.

Background technology

In recent years, Global climate change causes international community to pay close attention to greatly the limit scheduling of greenhouse gases is raw, wherein CO ₂be main greenhouse gases, control and reduce the CO in industrial processes ₂discharge significant to preventing weather system to be subject to catastrophic failure.Since the industrial revolution, the transition of fossil fuel uses, CO ₂discharge capacity increasing year by year, it is predicted structural system according to now industry, 21 century Global emissions CO ₂total amount will reach 3480Gt-8050Gt, and from the middle of the 19th century to 20 end of the centurys, CO ₂discharge capacity only have 1110Gt, become striking contrast with it.But so far, CO in global atmosphere ₂concentration reached about 350ppm.Predict according to international general bureau, coal accounts for 63% of China's energy, and when the year two thousand thirty, the discharge capacity of China's carbon dioxide will reach 27% of the total release in the whole world.China is faced with huge carbon dioxide discharge-reduction pressure at present, therefore, reduces CO ₂discharge and CO ₂catch, be separated, need to possess simultaneously power consumption less, simple to operate, do not produce the features such as secondary pollution and become the focus of research.Based on above-mentioned situation, find an adsorption capacity large, absorption and desorption speed is fast, the novel C O that stability is high ₂adsorbent has become the emphasis of present research.

Publication number is the Chinese patent of 201410141106.3, the mode of later stage grafting modification is utilized by silane coupler diethylenetriamine base trimethoxy silane high for amine groups content to distinguish in grafting to the silica substrate of Four types with composite solid state sorbing material, and use it for the absorption of carbon dioxide, this material has good heat endurance, with the mass-transfer efficiency that it is higher, can more effectively carbon dioxide be caught.Publication number is the Chinese patent of 201410132974.5, design a kind of method improving active carbon carbon dioxide adsorption performance, it adopts impregnation technology improvement to molecular-sieve type activated carbon, maceration extract is made up of potassium sulfate solution and ammonium persulfate solution, dipping and active carbon are fully mixed to bubble-free, then heat, and are incubated to solution complete reaction to disappearing, again through washing and drying, the adsorption effect of this product is better.Publication number is the Chinese patent of 201210562808.X, by active carbon and pyrroles's ultrasonic disperse in deionized water, in uniform temperature, with ammonium persulfate as catalyst reaction, the porous carbon material of preparation, its process costs is low, has good separation absorption property.

Summary of the invention

The technical problem to be solved in the present invention, is to provide a kind of active carbon composite modifying method.

The present invention is achieved in that a kind of active carbon composite modifying method, comprises the following steps:

(1) potassium hydroxide is configured to the KOH aqueous solution of 2mol/L ~ 9mol/L, according to quality than active carbon: KOH solution=1:10 ~ 1:50 adds active carbon, stirs, at the Water Under bath 4 ~ 9h of temperature 330K ~ 365K, dry;

(2) according to volume ratio TEPA: absolute ethyl alcohol=1:10 ~ 1:50, TEPA 2.5 ~ 30g is added in the absolute ethyl alcohol of 10 ~ 200ml, heating water bath 10 ~ 60min under temperature is 330 ~ 360K, add the active carbon through (1) process gained while stirring, after reaction 1h ~ 6h, suction filtration, dry, obtained product; Wherein, quality is than active carbon: ethene five amine=1:1 ~ 1:10.

Preferably, described active carbon is one or more arbitrary proportions combination in coal mass active carbon, timber active carbon, active fruit shell carbon, cocoanut active charcoal, apricot shell active carbon, jujube shell active carbon.

Preferably, in described step (1), baking temperature is 350 ~ 373K, and drying time is 1.0 ~ 4h.

Preferably, in described step (3), baking temperature is 360 ~ 383K, and drying time is 1 ~ 5h.

The invention has the advantages that: obtained product not only has higher adsorbance and adsorptive selectivity, and can also keep stable absorption property after multiple adsorb de-adsorption cycle.

Accompanying drawing explanation

The present invention is further illustrated in conjunction with the embodiments with reference to the accompanying drawings.

Fig. 1 is the schematic diagram of modified activated carbon to carbon dioxide adsorption testing arrangement.

Fig. 2 is the nitrogen adsorption of modified activated carbon under 77.3K, desorption schematic diagram in the present invention.

Fig. 3 is the aperture structure distribution schematic diagram of modified activated carbon in the present invention.

Fig. 4 is the CO of the composite modified front and back of active carbon in the present invention ₂adsorbance curve synoptic diagram.

Fig. 5 is the CO of modified activated carbon in the present invention ₂breakthrough curve.

Fig. 6 is CO2 adsorption isotherm and the heat of adsorption of modified activated carbon in the present invention.

Detailed description of the invention

A kind of active carbon composite modifying method, comprises the following steps:

(1) potassium hydroxide is configured to the KOH solution of 2mol/L ~ 9mol/L, according to quality than active carbon: KOH solution=1:10 ~ 1:50 adds active carbon, stir, at the Water Under bath 4 ~ 9h of temperature 330K ~ 365K, dry, baking temperature is 350 ~ 373K, and drying time is 1 ~ 4h.Described active carbon is one or more arbitrary proportions combination in coal mass active carbon, timber active carbon, active fruit shell carbon, cocoanut active charcoal, apricot shell active carbon, jujube shell active carbon.

(2) according to volume ratio TEPA: TEPA adds in absolute ethyl alcohol by absolute ethyl alcohol=1:10 ~ 1:50, heating water bath 10 ~ 60min under temperature is 330 ~ 360K, add the active carbon through (1) process gained while stirring, wherein, quality is than active carbon: TEPA (TEPA)=1:1 ~ 1:10, after reaction 1h ~ 6h, and suction filtration, drying, obtained product; Wherein, baking temperature is 360 ~ 383K, and drying time is 1 ~ 5h.

For more clearly describing the present invention, especially exemplified by following embodiment:

The raw material of each embodiment of table 1 and parameter situation

For above-mentioned respectively execute example preparation method as follows:

(1) potassium hydroxide is added to the water is made into the aqueous solution, then add active carbon, stir, heating water bath at the temperature in Table 1, dry;

(2) TEPA (TEPA) is added be equipped with in the conical flask of absolute ethyl alcohol, heating water bath at temperature in Table 1, add the active carbon through step (1) process gained while stirring, and quality is than active carbon: (wherein, embodiment 1-7 is respectively active carbon to TEPA (TEPA)=1:1 ~ 1:10: TEPA=1:1,1:2,1:3,1:10,1:5,1:6,1:8.)；

(3), after stoichiometric number hour, suction filtration, dry, the composite modified active carbon of obtained KOH+TEPA namely.

To the pore character of the modified activated carbon that embodiment 1 obtains and to CO in simulated flue gas ₂absorption property is studied, adopt specific area (BET method) and the parameter of pore structure (DFT method) of ASAP-2020 type specific area and Porosimetry working sample, STA409PG type normal pressure synthesis analyzer measures static adsorbance, ADSORPTION IN A FIXED BED post-chromatograph joint used measurement device dynamic adsorbance as shown in Figure 1, in Fig. 1,1-N ₂; 2-simulated flue gas; 3-ADSORPTION IN A FIXED BED post; 4-flowmeter; 5-chromatogram; ADSORPTION IN A FIXED BED column internal diameter 10mm, long 500mm, external application high temperature cotton and high temperature cloth are evenly wrapped up, and use temperature controller control temperature.Specific operation process is:

(1) carry out at ambient pressure, before absorption, heating adsorption post is to 363K, constant temperature 1h, stops heating, is cooled to target temperature;

(2) gaseous mixture (i.e. N is passed into ₂and simulated flue gas) (50cm ³/ min), the CO of outlet is measured with GC ₂concentration.

$q_a=\frac{1}{m}\underset{0}{\overset{t}{\∫}}(Q_{\mathrm{in}}\×C_0-C_{\mathrm{out}}\×C)\mathrm{dt}$

According to modified activated carbon described in above formulae discovery to CO ₂adsorbance (q _a,mmol/g), wherein:

M-modified activated carbon quality, g;

Q _in, Q _out-import and export gas flow, cm ³/ min, and Q _out=Q _in× (1-C ₀)/(1-C);

C ₀, C-import and export CO ₂concentration, vol.%.

According to modified activated carbon described in following formulae discovery to CO in flue gas ₂equivalent absorption

$\left(\frac{\∂\left(\mathrm{in\; p}\right)}{\∂(1/T)}\right)=\frac{Q_{\mathrm{st}}}{R}$

In formula: p is CO ₂dividing potential drop (Pa); T is temperature (K); Q _stfor heat of adsorption (KJ/mol).

Experimental result as shown in figures 2-6, wherein, in Fig. 4 identify 1 refer to composite modified after active carbon and modified activated carbon to CO ₂static adsorbance, mark 1 refers to that active carbon is before modified to CO ₂static adsorbance.The specific area of the active carbon that KOH+TEPA is composite modified and modified activated carbon is at 500m ²/ g, aperture is mainly distributed in 1.6nm and 2.0nm, and average pore volume is at 0.28cm ³about/g (see Fig. 3).Under 303K condition, to simulated flue gas (10vol.%CO ₂, 90vol.%N ₂) middle CO ₂static adsorbance bring up to 1.182mmol/g (shown in the mark 1 in Fig. 4) from 0.518mmol/g (mark 2 shown in) Fig. 4 before modified, after 10 absorption/de-adsorption cycle tests, dynamic adsorbance all remains on (see Fig. 5) between 0.97 ~ 1.152mmol/g, demonstrates good absorption stability.Dynamic analysis shows, the modified activated carbon that the present invention obtains is to CO in simulated flue gas ₂average adsorption calorific value be-52.0KJ/mol, ensure that the economy of industrial practical application.

The present invention has the following advantages:

1, technique is simple, and simple operation is with low cost, is suitable for commercial introduction application.

2, on the basis that activated carbon pore size structure has been shaped, adopt KOH and TEPA composite modified, can significantly change activated carbon surface character;

3, improve the carbon dioxide adsorption performance of active carbon further by changing activated carbon surface character, product is used for the CO of flue gas in industry ₂absorb, the absorptivity of carbon dioxide can be improved further, increase work efficiency significantly, and there is very high economic benefit.

4, the modified activated carbon that the present invention obtains not only has higher adsorbance, and can also keep stable absorption property after multiple adsorb de-adsorption cycle.

Claims (4)

1. an active carbon composite modifying method, is characterized in that: comprise the following steps:

(1) potassium hydroxide is configured to the KOH aqueous solution of 2mol/L ~ 9mol/L, according to quality than active carbon: KOH solution=1:10 ~ 1:50 adds active carbon, stirs, at the Water Under bath 4 ~ 9h of temperature 330K ~ 365K, dry;

(2) according to volume ratio TEPA: absolute ethyl alcohol=1:10 ~ 1:50, TEPA 2.5 ~ 30g is added in the absolute ethyl alcohol of 10 ~ 200ml, heating water bath 10 ~ 60min under temperature is 330 ~ 360K, add the active carbon through (1) process gained while stirring, after reaction 1h ~ 6h, suction filtration, dry, obtained product; Wherein, quality is than active carbon: ethene five amine=1:1 ~ 1:10.

2. a kind of active carbon composite modifying method as claimed in claim 1, is characterized in that: described active carbon is one or more arbitrary proportions combination in coal mass active carbon, timber active carbon, active fruit shell carbon, cocoanut active charcoal, apricot shell active carbon, jujube shell active carbon.

3. a kind of active carbon composite modifying method as claimed in claim 1, it is characterized in that: in described step (1), baking temperature is 350 ~ 373K, and drying time is 1.0 ~ 4h.

4. a kind of active carbon composite modifying method as claimed in claim 1, it is characterized in that: in described step (3), baking temperature is 360 ~ 383K, and drying time is 1 ~ 5h.