CN117416956A - Preparation process of bamboo-based activated carbon and high-adsorptivity bamboo-based activated carbon composite adsorbent - Google Patents
Preparation process of bamboo-based activated carbon and high-adsorptivity bamboo-based activated carbon composite adsorbent Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 239
- 235000017166 Bambusa arundinacea Nutrition 0.000 title claims abstract description 166
- 235000017491 Bambusa tulda Nutrition 0.000 title claims abstract description 166
- 241001330002 Bambuseae Species 0.000 title claims abstract description 166
- 235000015334 Phyllostachys viridis Nutrition 0.000 title claims abstract description 166
- 239000011425 bamboo Substances 0.000 title claims abstract description 166
- 239000003463 adsorbent Substances 0.000 title claims abstract description 31
- 239000002131 composite material Substances 0.000 title claims abstract description 30
- 238000002360 preparation method Methods 0.000 title claims abstract description 22
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical class O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000000126 substance Substances 0.000 claims abstract description 22
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 19
- 239000002994 raw material Substances 0.000 claims abstract description 11
- 239000000243 solution Substances 0.000 claims description 113
- 238000003756 stirring Methods 0.000 claims description 73
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 72
- 239000000463 material Substances 0.000 claims description 62
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 58
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 54
- 238000006243 chemical reaction Methods 0.000 claims description 52
- 238000002791 soaking Methods 0.000 claims description 47
- 239000000843 powder Substances 0.000 claims description 46
- 238000001035 drying Methods 0.000 claims description 45
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 42
- 238000001704 evaporation Methods 0.000 claims description 41
- 238000010438 heat treatment Methods 0.000 claims description 32
- 238000005406 washing Methods 0.000 claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- 238000001914 filtration Methods 0.000 claims description 28
- 229910052786 argon Inorganic materials 0.000 claims description 27
- 230000004913 activation Effects 0.000 claims description 24
- -1 sodium N, N-dimethylamino dithioformate Chemical compound 0.000 claims description 24
- 238000002425 crystallisation Methods 0.000 claims description 22
- 230000008025 crystallization Effects 0.000 claims description 22
- 239000000203 mixture Substances 0.000 claims description 22
- 238000002156 mixing Methods 0.000 claims description 21
- 239000011259 mixed solution Substances 0.000 claims description 20
- 239000005995 Aluminium silicate Substances 0.000 claims description 17
- 235000012211 aluminium silicate Nutrition 0.000 claims description 17
- 239000011777 magnesium Substances 0.000 claims description 17
- 239000000706 filtrate Substances 0.000 claims description 16
- 108010059892 Cellulase Proteins 0.000 claims description 15
- 101710112457 Exoglucanase Proteins 0.000 claims description 15
- BXQJYIXHTMSDRB-UHFFFAOYSA-N cyclohexane;hydrochloride Chemical compound Cl.C1CCCCC1 BXQJYIXHTMSDRB-UHFFFAOYSA-N 0.000 claims description 15
- XZTWHWHGBBCSMX-UHFFFAOYSA-J dimagnesium;phosphonato phosphate Chemical compound [Mg+2].[Mg+2].[O-]P([O-])(=O)OP([O-])([O-])=O XZTWHWHGBBCSMX-UHFFFAOYSA-J 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 15
- 235000019441 ethanol Nutrition 0.000 claims description 14
- 239000004115 Sodium Silicate Substances 0.000 claims description 13
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 13
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 13
- 238000001816 cooling Methods 0.000 claims description 12
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 12
- 239000000047 product Substances 0.000 claims description 12
- 238000007789 sealing Methods 0.000 claims description 12
- LADUENYEZHMRQH-UHFFFAOYSA-N 2-ethoxybenzohydrazide Chemical compound CCOC1=CC=CC=C1C(=O)NN LADUENYEZHMRQH-UHFFFAOYSA-N 0.000 claims description 11
- PUANAIYYEZIDDG-UHFFFAOYSA-N n-(hydroxymethyl)but-2-enamide Chemical compound CC=CC(=O)NCO PUANAIYYEZIDDG-UHFFFAOYSA-N 0.000 claims description 11
- 239000012295 chemical reaction liquid Substances 0.000 claims description 9
- 239000008367 deionised water Substances 0.000 claims description 8
- 229910021641 deionized water Inorganic materials 0.000 claims description 8
- 239000012153 distilled water Substances 0.000 claims description 8
- 230000007935 neutral effect Effects 0.000 claims description 8
- 238000002309 gasification Methods 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000000197 pyrolysis Methods 0.000 claims description 7
- 238000007873 sieving Methods 0.000 claims description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 238000010000 carbonizing Methods 0.000 claims description 6
- 235000011149 sulphuric acid Nutrition 0.000 claims description 2
- 238000001179 sorption measurement Methods 0.000 abstract description 28
- 239000011148 porous material Substances 0.000 abstract description 25
- 230000000694 effects Effects 0.000 abstract description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 3
- 239000001301 oxygen Substances 0.000 abstract description 3
- 229910052760 oxygen Inorganic materials 0.000 abstract description 3
- 230000003213 activating effect Effects 0.000 abstract description 2
- 239000003795 chemical substances by application Substances 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 54
- 238000000034 method Methods 0.000 description 35
- 238000009826 distribution Methods 0.000 description 15
- 230000035484 reaction time Effects 0.000 description 10
- 230000008569 process Effects 0.000 description 7
- 238000003763 carbonization Methods 0.000 description 6
- 229920000642 polymer Polymers 0.000 description 6
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 5
- 229910052740 iodine Inorganic materials 0.000 description 5
- 239000011630 iodine Substances 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 230000015556 catabolic process Effects 0.000 description 4
- 238000006731 degradation reaction Methods 0.000 description 4
- 125000000524 functional group Chemical group 0.000 description 4
- 230000008961 swelling Effects 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 229920002488 Hemicellulose Polymers 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 229920005610 lignin Polymers 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 244000302661 Phyllostachys pubescens Species 0.000 description 1
- 235000003570 Phyllostachys pubescens Nutrition 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001850 reproductive effect Effects 0.000 description 1
- VMSRVIHUFHQIAL-UHFFFAOYSA-M sodium;n,n-dimethylcarbamodithioate Chemical compound [Na+].CN(C)C([S-])=S VMSRVIHUFHQIAL-UHFFFAOYSA-M 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/30—Active carbon
- C01B32/312—Preparation
- C01B32/318—Preparation characterised by the starting materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/3085—Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/30—Active carbon
- C01B32/312—Preparation
- C01B32/336—Preparation characterised by gaseous activating agents
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/30—Active carbon
- C01B32/312—Preparation
- C01B32/342—Preparation characterised by non-gaseous activating agents
- C01B32/348—Metallic compounds
Abstract
The invention discloses a preparation process of a bamboo-based activated carbon and high-adsorptivity bamboo-based activated carbon composite adsorbent, and relates to the field of energy and chemical industry. According to the invention, the formed microporous structure is uniformly distributed in the carbon by treating the raw materials through the activating agent, the adsorption effect of the activated carbon on small molecular substances is improved, the problems of increased surface oxygen-containing complex and reduced surface adsorption performance caused by reducing ash content in the bamboo-based activated carbon are solved by post-treatment, and the problem that the pore channels formed by the bamboo-based activated carbon are easy to be blocked caused by adopting the modified kaolin is solved.
Description
Technical Field
The invention relates to the field of energy and chemical industry, in particular to a preparation process of a bamboo-based activated carbon and high-adsorptivity bamboo-based activated carbon composite adsorbent.
Background
Bamboo is a natural biomass raw material rich in cellulose, hemicellulose and lignin, and is widely distributed in China. The bamboo grows fast, the reproductive capacity is strong, if can be rationally utilized, higher economic benefit and social value can be produced.
At present, the active carbon is produced by smoldering and carbonizing raw materials and then activating by introducing water vapor. The bamboo with low cost and abundant resources is used as the raw material to prepare the activated carbon, so that the method has the advantages of low cost, wide raw material sources and improved industrial utilization rate, and can realize reasonable allocation of resources. Therefore, a method for preparing bamboo-based activated carbon from moso bamboo is becoming more popular. For example, chinese patent No. 107055529A discloses a method and a system for preparing activated carbon, wherein in the preparation method, when the activation temperature of high-temperature steam reaches 800-900 ℃, the efficiency of the activation treatment of the bamboo charcoal can be remarkably improved, and the quality of the prepared bamboo-based activated carbon is improved. However, in the actual process of the bamboo-based activated carbon, the water vapor can only reach 600-700 ℃ under the general condition, and the high-temperature steam activation temperature of 800-900 ℃ is required to be realized, so that the requirements on production equipment and experimental conditions are very severe, and the energy consumption is high. Meanwhile, in the prior art, ash in the bamboo-based activated carbon is generally removed through acid washing, but excessive acid washing cannot remove ash further, but increases oxidation complex on the surface of the bamboo-based activated carbon, reduces surface adsorption performance, and reduces the quality of the bamboo-based activated carbon.
In summary, how to solve the problems of insufficient carbonization and uneven distribution of microporous structures in the carbon, which result in reduced adsorption performance of the bamboo-based activated carbon, in the conventional process of the bamboo-based activated carbon, in the temperature range reached by water vapor in the conventional process of the bamboo-based activated carbon, thereby reducing the requirement of the process on the activation temperature of the water vapor, and improving the quality of the prepared bamboo-based activated carbon.
Disclosure of Invention
The invention aims at the problems and provides a preparation process of bamboo-based activated carbon with good adsorption performance and low ash content.
In order to achieve the above purpose, the invention provides a preparation process of bamboo-based activated carbon, which comprises the following steps:
(1) Pretreatment of raw materials: washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours;
(2) Chemical activation treatment:
a. mixing H2SO4 and absolute ethyl alcohol with the weight ratio of 1:80-100, adding bamboo powder, soaking for 1-2H, evaporating to dryness, then immersing the material in acetic acid solution, continuously introducing argon, controlling the argon speed to be 1000-1300 sccm, and soaking for 4-6H to obtain solution 1, wherein the volume fraction of the acetic acid solution is 6-10%;
b. taking 100 parts of solution 1, adding 3-6 parts of endoglucanase, reacting for 1-3 hours, adding 2-5 parts of exoglucanase, reacting for 5-8 hours, and evaporating to obtain a material 2;
c. mixing 6-8 parts of cyclohexane hydrochloride and 120-150 parts of ethanol, adding the material 2, uniformly stirring, adding 10-15 parts of Mg (OH) 2 and 3-5 parts of magnesium pyrophosphate, uniformly stirring, soaking for 16-24 hours, stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
(3) Carbonizing: and (3) slowly conveying the activated bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 400-700 ℃ at a heating rate of 10 ℃/min, introducing high-temperature superheated steam with the weight 3-5 times of the material weight for countercurrent contact, and preserving the heat for 0.5-2.5 h to obtain the bamboo-based activated carbon.
The invention also provides a preparation process of the high-adsorptivity bamboo-based activated carbon composite adsorbent, which comprises the following steps:
1. mixing the bamboo-based activated carbon and acetic acid with the volume fraction of 15% according to a solid-to-liquid ratio of 1: 17-20, heating the reaction kettle to 160-210 ℃, maintaining the reaction pressure at 3.0-5.0 MPa, and preserving the heat for 4-8 h;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. 2.5 to 5 parts of N- (hydroxymethyl) -2-butenamide, 1.5 to 4 parts of o-ethoxy benzoyl hydrazine and 11 to 17 parts of modified kaolin are dissolved in 120 to 145 parts of distilled water, stirred for 0.5h at a temperature of between 40 and 60 ℃ to ensure that the solutions are uniformly mixed, and then heated to a temperature of 100 ℃ to be boiled and stirred for 2h to obtain a modified mixed solution;
4. putting the filter residues in the step 2 into a muffle furnace, heating for 8 hours at 200-400 ℃, and according to a solid-liquid ratio of 1: 8-13, continuously stirring for 2.5 hours at 40-60 ℃, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a drying oven at 180 ℃ to obtain the high-adsorptivity activated carbon.
Further, in the step (4), the preparation method of the modified kaolin comprises the following steps:
1) Adding 18-30 parts of sodium N, N-dimethylamino dithioformate and 25-37 parts of potassium methyldithiomethylamine into 250-400 parts of sodium hydroxide solution, stirring until the mixture is clear, then adding 100-150 parts of kaolin and 45-55 parts of sodium silicate solution, and stirring uniformly to obtain a reaction solution 1, wherein the mass fraction of the sodium hydroxide solution is 20-30%, and the concentration of sodium silicate is 0.4-0.8 g/ml;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, placing the reaction solution in a constant-temperature drying oven, setting the temperature to be 80-120 ℃, and crystallizing the reaction solution for 12-36 h;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The invention has the beneficial effects that:
(1) The invention utilizes sulfuric acid and absolute ethyl alcohol to further dehydrate and primarily carbonize the bamboo powder, reduces the energy consumption of the subsequent procedures, softens the fibers, is beneficial to opening gaps, increases contact points in the fibers, is beneficial to carrying out an activation reaction, and improves the adsorption performance of the finally prepared bamboo-based activated carbon;
(2) The invention utilizes the interaction of solvent molecules through polymer solvents to weaken and replace the interaction between the original polymers, thereby realizing the swelling of cellulose, hemicellulose and lignin in the bamboo powder and reducing the length of polymer chains. In order to avoid excessive swelling and slight degradation to cause a large number of cracks in the polymer and even fragmentation of the polymer, the formed microporous structure is unevenly distributed in the carbon, the swelling rate is controlled through the process, and the degradation degree is controlled by endoglucanase and exoglucanase, so that the formed microporous structure is evenly distributed in the carbon, and the adsorption effect of the formed bamboo-based activated carbon on small molecular substances is improved.
(3) Combined with Mg (OH) 2 And the use of magnesium pyrophosphate increases the amount of interactive active sites exposed by the polymer, and a dehydration reaction occurs during thermal decomposition to produce metal oxide and water vapor. Further reaction of the metal oxide with carbon at high temperature causes localized burning off of the microcrystalline lamellae of the carbon. In the reaction process, substances with higher volatility are active among microcrystalline layers of the bamboo-based active carbon, so that pores are generated, the distribution of electron clouds of surrounding carbon atoms is influenced by the volatile substances, active points are formed, the reaction of water vapor and carbon is enhanced, and pore forming is easy. The invention uses cyclohexane hydrochloride to strengthen Mg (OH) 2 And the uniformity of the distribution of magnesium pyrophosphate in the space, thereby improving the uniformity of gaps formed in the subsequent reaction, reducing the temperature requirement of full carbonization on high-temperature superheated steam in actual production through preliminary carbonization and the like, reducing the energy consumption of the actual production, and avoiding the problem of the reduction of the adsorption performance of the bamboo-based activated carbon caused by insufficient carbonization.
(4) According to the invention, the ash content in the bamboo-based activated carbon can be reduced by acid pickling, but the acid pickling increases the amount of the oxygen-containing complex on the surface of the bamboo-based activated carbon, the oxygen-containing complex on the surface of the bamboo-based activated carbon can be effectively removed by a subsequent treatment method, and the surface of the bamboo-based activated carbon is further activated, so that the surface of the bamboo-based activated carbon is modified. The modification of the bamboo-based activated carbon aims at increasing the specific surface area of the bamboo-based activated carbon and adding specific functional groups, so that the adsorption of the bamboo-based activated carbon to certain compounds or certain elements is enhanced.
(5) The bamboo-based activated carbon prepared by the method is further modified by the N- (hydroxymethyl) -2-butenamide and the o-ethoxybenzoyl hydrazine, so that the types and the number of functional groups on the surface of the bamboo-based activated carbon are increased, the proportion of double bonds is increased, the specific surface area of the bamboo-based activated carbon is increased, the adsorption of the bamboo-based activated carbon to compounds or elements is enhanced due to the increased functional groups on the surface of the bamboo-based activated carbon, and the adsorption selectivity is increased. And the cohesive force among bamboo-based activated carbon molecules is improved, the surface adsorption force of the bamboo-based activated carbon is enhanced, and the adsorption performance of the composite adsorbent prepared by the bamboo-based activated carbon is further improved.
(6) The preparation method of the bamboo-based activated carbon composite adsorbent comprises the steps of combining a molecular main body containing an aromatic ring structure with a bamboo-based activated carbon surface activation site by means of an irreversible covalent bond formed by N- (hydroxymethyl) -2-butenamide and o-ethoxybenzoyl hydrazine, removing an oxidation complex on the bamboo-based activated carbon surface, simultaneously skillfully introducing an adsorption functional group, making up the defect of weak adsorption force on the bamboo-based activated carbon surface, and improving the stability of the bamboo-based activated carbon in the composite adsorbent.
(7) The bamboo-based activated carbon prepared by the method is superior in chemical adsorption performance, and the prepared composite adsorbent is strong in chemical adsorption performance, but the physical adsorption effect of the bamboo-based activated carbon prepared by the method is reduced in the adsorbent preparation process. According to the preparation process of the bamboo-based activated carbon composite adsorbent, the kaolin is modified, and the crystallinity of the kaolin after the reaction is improved through the sodium N, N-dimethylamino dithioformate and the potassium methyl dithioformate, so that the kaolin not only has the capability of being combined with the activated sites on the surface of the bamboo-based activated carbon to chemically modify the surface of the bamboo-based activated carbon, but also has a cubic lattice structure which can be preferentially combined with N- (hydroxymethyl) -2-butenamide and o-ethoxybenzoyl hydrazine molecules, and the problem that the physical adsorption effect of the bamboo-based activated carbon is reduced due to the fact that the N- (hydroxymethyl) -2-butenamide and the o-ethoxybenzoyl hydrazine molecules are adsorbed in the pore canal formed by the bamboo-based activated carbon in the preparation process of the bamboo-based activated carbon is avoided.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
Example 1
(1) Pretreatment of raw materials: washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours;
(2) Chemical activation treatment:
a. will H 2 SO 4 Mixing with anhydrous ethanol and according to a weight ratio of 1:80, adding bamboo powder, soaking for 1h, evaporating to dryness, then immersing the material in acetic acid solution with a volume fraction of 6%, continuously introducing argon, controlling the argon speed at 1300sccm, and soaking for 4h to obtain solution 1;
b. taking 100 parts of solution 1, adding 6 parts of endoglucanase, reacting for 1 hour, adding 2 parts of exoglucanase, reacting for 5 hours, and evaporating to obtain a material 2;
c. 8 parts of cyclohexane hydrochloride and 120 parts of ethanol are mixed, then material 2 is added, and 15 parts of Mg (OH) is added after uniform stirring 2 And 5 parts of magnesium pyrophosphate, uniformly stirring, soaking for 16 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
(3) Carbonizing: and (3) slowly conveying the activated bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 400 ℃ at a heating rate of 10 ℃/min, introducing high-temperature superheated steam with the weight of 3 times of the material, carrying out countercurrent contact, and preserving the heat for 0.5h to obtain the bamboo-based activated carbon.
Example 2
(1) Pretreatment of raw materials: washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours;
(2) Chemical activation treatment:
a. will H 2 SO 4 Mixing with anhydrous ethanol at a weight ratio of 1:100, adding bamboo powder, soaking for 2h, evaporating to dryness, soaking the material in acetic acid solution with volume fraction of 10%, continuously introducing argon gas with a rate of 1000sccm, and soaking for 6h to obtain solution 1;
b. taking 100 parts of solution 1, adding 3 parts of endoglucanase, reacting for 3 hours, adding 5 parts of exoglucanase, reacting for 8 hours, and evaporating to obtain a material 2;
c. 6 parts of cyclohexane hydrochloride and 150 parts of ethanol are mixed, then material 2 is added, and 10 parts of Mg (OH) is added after uniform stirring 2 And 3 parts of magnesium pyrophosphate, uniformly stirring, soaking for 24 hours, and carrying out soakingStirring and evaporating the materials at 100 ℃ to dryness to obtain activated bamboo powder;
(3) Carbonizing: and (3) slowly conveying the activated bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 700 ℃ at a heating rate of 10 ℃/min, introducing high-temperature superheated steam with the weight of 5 times of the material, carrying out countercurrent contact, and preserving the heat for 2.5 hours to obtain the bamboo-based activated carbon.
Example 3
(1) Pretreatment of raw materials: washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours;
(2) Chemical activation treatment:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
(3) Carbonizing: and (3) slowly conveying the activated bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 550 ℃ at a heating rate of 10 ℃/min, introducing high-temperature superheated steam with the weight of 4 times of the material, carrying out countercurrent contact, and preserving the heat for 1.5 hours to obtain the bamboo-based activated carbon.
Comparative example 1
Washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours; and (3) slowly conveying the dried bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 550 ℃ at a heating rate of 10 ℃/min for carbonization, introducing high-temperature superheated steam with the weight of 4 times of the material to perform countercurrent contact for activation, and preserving the activation temperature at 850 ℃ for 1.5 hours to obtain the bamboo-based activated carbon.
Comparative example 2
Chemical activation treatment in this comparative example:
a. adding bamboo powder into absolute ethyl alcohol, soaking for 1.5 hours, evaporating to dryness, then soaking the material into acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the speed of the argon to 1150sccm, and soaking for 5 hours to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 3
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with anhydrous ethanol at a weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, continuously introducing argon in the soaking process, controlling the argon speed at 1150sccm, and obtaining solution 1 after the soaking is finished;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 4
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 And absolute ethanol and in a 1:9 ratioMixing with a weight ratio of 0, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then soaking the material in acetic acid solution with a volume fraction of 5%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 5
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 11%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 6
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 7
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 And 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, and stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 8
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. material 2 was mixed with 136 parts ethanol and after stirring well 12.5 parts Mg (OH) was added 2 4 parts of magnesium pyrophosphateStirring uniformly, soaking for 20h, stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 9
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. mixing 7 parts of cyclohexane hydrochloride and 135 parts of ethanol, adding the material 2, uniformly stirring, adding 4 parts of magnesium pyrophosphate, uniformly stirring, soaking for 20 hours, stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 10
Chemical activation treatment in this comparative example:
a. will H 2 SO 4 Mixing with absolute ethyl alcohol and according to the weight ratio of 1:90, adding bamboo powder, soaking for 1.5h, evaporating to dryness, then immersing the material in acetic acid solution with the volume fraction of 8%, continuously introducing argon, controlling the argon speed at 1150sccm, and soaking for 5h to obtain solution 1;
b. taking 100 parts of solution 1, adding 4.5 parts of endoglucanase, reacting for 2 hours, adding 3.5 parts of exoglucanase, reacting for 6.5 hours, and evaporating to obtain a material 2;
c. 7 parts of cyclohexane hydrochloride and 135 parts of ethanol are mixed, then material 2 is added, and after being stirred uniformly, 12.5 parts of Mg (OH) is added 2 Stirring uniformly, soaking for 20h, stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
the procedure is as in example 3.
Comparative example 11
Washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours; and (3) slowly conveying the dried bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 550 ℃ at a heating rate of 10 ℃/min for carbonization, introducing high-temperature superheated steam with the weight of 4 times of the material to perform countercurrent contact for activation, and preserving the heat for 1.5 hours at the activation temperature of 550 ℃ to obtain the bamboo-based activated carbon.
The testing method comprises the following steps:
iodine adsorption value is measured according to GB/T12496.8-2015 determination of iodine adsorption value of wooden activated carbon test method
Ash content determination according to GB/T12496.3-1999 method for determining ash content of woody activated carbon test method
The specific surface area, pore volume and pore diameter values of the activated carbon were tested using an SSA-4200BET analytical tester, and the fractal dimension D of pore diameter distribution was calculated.
Calculating the fractal dimension of the pore size distribution:
Inv(x)＝(3-D)In(x/xmax)
wherein x is the pore diameter value of the activated carbon, and v (x) is the pore volume within a certain pore diameter range.
The fractal dimension D of the distribution is a measure of the degree of complexity (non-uniformity) of the fractal pore size distribution. When d=0, it is indicated that the activated carbon has the same pore size, and there is no pore size distribution; when D >0, it is shown that there is a self-similar pore size distribution over a range of pore sizes (no scale area). In the middle pore and large pore ranges, the larger the value of the fractal dimension of the pore diameter distribution is, the more the pore diameter content is relatively small; conversely, the smaller the fractal dimension value of the pore size distribution, the more the relatively large pore size content.
The technical indexes of examples 1 to 3 of the present invention and comparative examples 1 to 11 were compared as shown in Table 1.
TABLE 1
| Iodine value (mg/g) | Average pore size/nm | Aperture distribution fractal dimension D | |
| Example 1 | 864.35 | 2.18 | 0.4635 |
| Example 2 | 870.05 | 2.16 | 0.4852 |
| Example 3 | 889.22 | 2.15 | 0.4501 |
| Comparative example 1 | 784.35 | 2.27 | 0.5732 |
| Comparative example 2 | 580.45 | 3.25 | 0.4302 |
| Comparative example 3 | 702.36 | 4.12 | 4.3651 |
| Comparative example 4 | 782.02 | 3.15 | 3.1026 |
| Comparative example 5 | 851.35 | 3.19 | 3.3945 |
| Comparative example 6 | 612.36 | 2.04 | 1.4852 |
| Comparative example 7 | 682.77 | 2.13 | 1.4632 |
| Comparative example 8 | 485.32 | 3.95 | 5.9655 |
| Comparative example 9 | 502.32 | 2.58 | 1.4832 |
| Comparative example 10 | 589.95 | 2.36 | 1.5384 |
| Comparative example 11 | 354.35 | 4.37 | 5.3945 |
As can be seen from the data of examples 1 to 3 and comparative examples 1 to 11 in Table 1, the present invention further dehydrates and primarily carbonizes bamboo powder using sulfuric acid and absolute ethyl alcohol, improves the adsorption performance of the prepared bamboo-based activated carbon, and enhances Mg (OH) using cyclohexane hydrochloride by controlling concentration of acetic acid, avoiding excessive swelling and slight degradation, controlling degradation degree by combining endoglucanase and exoglucanase 2 And the distribution uniformity of magnesium pyrophosphate in space, and the adsorption performance and the spatial distribution uniformity of the finally prepared bamboo-based activated carbon are improved.
The bamboo-based activated carbon prepared in example 3 of the invention is used as a raw material to prepare a high-adsorptivity bamboo-based activated carbon composite adsorbent, examples 4 to 6 and comparative examples 12 to 22 are as follows:
example 4
Preparation of modified kaolin:
1) Adding 18 parts of sodium N, N-dimethylamino dithioformate and 37 parts of potassium methyldithiomethylamine into 250 parts of 30% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 100 parts of kaolin and 45 parts of 0.4g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to 120 ℃, and the crystallization reaction time is 12 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
Preparing a high-adsorptivity bamboo-based active carbon composite adsorbent:
1. the bamboo-based activated carbon prepared in example 3 and acetic acid with 15% of volume percentage are mixed according to a solid-to-liquid ratio of 1:17, mixing and adding the mixture into a reaction kettle, heating the reaction kettle to 160 ℃, maintaining the reaction pressure to 3.0MPa, and preserving the heat for 8 hours;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. 2.5 parts of N- (hydroxymethyl) -2-butenamide, 1.5 parts of o-ethoxybenzoyl hydrazine and 17 parts of modified kaolin are dissolved in 145 parts of distilled water, stirred for 0.5h at 40 ℃ to uniformly mix the solutions, and then heated to 100 ℃ to boil and stir for 2h to obtain a modified mixed solution;
4. and (2) placing the filter residues in the step (2) into a muffle furnace, heating for 8 hours at 200 ℃, adding the modified mixed solution, and according to a solid-liquid ratio of 1:13 adding the modified mixed solution, continuously stirring for 2.5 hours at 40 ℃, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a drying oven at 180 ℃ to obtain the high-adsorptivity bamboo-based activated carbon composite adsorbent.
Example 5
Preparation of modified kaolin:
1) Adding 30 parts of sodium N, N-dimethylamino dithioformate and 25 parts of potassium methyldithiomethylamine into 400 parts of 20% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 150 parts of kaolin and 55 parts of 0.8g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to 80 ℃, and the crystallization reaction time is 36 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
Preparing a high-adsorptivity bamboo-based active carbon composite adsorbent:
1. the bamboo-based activated carbon prepared in example 3 and acetic acid with 15% of volume percentage are mixed according to a solid-to-liquid ratio of 1:20, mixing and adding the mixture into a reaction kettle, heating the reaction kettle to 210 ℃, maintaining the reaction pressure to 5.0MPa, and preserving the heat for 4 hours;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. dissolving 5 parts of N- (hydroxymethyl) -2-butenamide, 4 parts of o-ethoxybenzoyl hydrazine and 11 parts of modified kaolin in 120 parts of distilled water, stirring for 0.5h at 60 ℃ to uniformly mix the solutions, and then heating to 100 ℃ to boil and stir for 2h to obtain a modified mixed solution;
4. and (2) placing the filter residues in the step (2) into a muffle furnace, heating at 400 ℃ for 8 hours, adding the modified mixed solution, and according to a solid-liquid ratio of 1:8 adding the modified mixed solution, continuously stirring at 60 ℃ for 2.5 hours, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a 180 ℃ oven to obtain the high-adsorptivity bamboo-based activated carbon composite adsorbent.
Example 6
Preparation of modified kaolin:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate and 31 parts of potassium methyldithiomethylamine into 325 parts of 25% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 125 parts of kaolin and 50 parts of 0.6g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
Preparing a high-adsorptivity bamboo-based active carbon composite adsorbent:
1. the bamboo-based activated carbon prepared in example 3 and acetic acid with 15% of volume percentage are mixed according to a solid-to-liquid ratio of 1:18, mixing and adding the mixture into a reaction kettle, heating the reaction kettle to 185 ℃, maintaining the reaction pressure to 4.0MPa, and preserving the heat for 6 hours;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. 3.8 parts of N- (hydroxymethyl) -2-butenamide, 2.8 parts of o-ethoxybenzoyl hydrazine and 14 parts of modified kaolin are dissolved in 132 parts of distilled water, stirred for 0.5h at 50 ℃ to uniformly mix the solutions, and then heated to 100 ℃ to boil and stir for 2h to obtain a modified mixed solution;
4. and (3) putting the filter residues in the step (2) into a muffle furnace, heating for 8 hours at 300 ℃, adding the modified mixed solution, and according to a solid-liquid ratio of 1:10 adding the modified mixed solution, continuously stirring for 2.5 hours at 50 ℃, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a drying oven at 180 ℃ to obtain the high-adsorptivity bamboo-based activated carbon composite adsorbent.
Comparative example 12
Preparing a high-adsorptivity bamboo-based active carbon composite adsorbent:
1. taking out the bamboo-based activated carbon prepared in the embodiment 3, stirring for 0.5h at 90 ℃ with 3mol/LHCl, filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
2. dissolving 14 parts of kaolin in 132 parts of distilled water, stirring for 0.5h at 50 ℃ to uniformly mix the solutions, and then heating to 100 ℃ to boil and stir for 2h to obtain a mixed solution;
3. putting the filter residues in the step 1 into a muffle furnace, heating for 8 hours at 300 ℃, adding mixed solution, and according to a solid-liquid ratio of 1:10 adding the mixed solution, continuously stirring at 50 ℃ for 2.5 hours, filtering the solution mixed with the bamboo-based active carbon, and drying filter residues in a drying oven at 180 ℃ to obtain the high-adsorptivity bamboo-based active carbon.
Comparative example 13
Preparing a high-adsorptivity bamboo-based active carbon composite adsorbent:
1. the bamboo-based activated carbon prepared in example 3 and acetic acid with 15% of volume percentage are mixed according to a solid-to-liquid ratio of 1:18, mixing and adding the mixture into a reaction kettle, heating the reaction kettle to 185 ℃, maintaining the reaction pressure to 4.0MPa, and preserving the heat for 6 hours;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. 2.8 parts of o-ethoxybenzoyl hydrazine and 14 parts of modified kaolin are dissolved in 132 parts of distilled water, stirred for 0.5h at 50 ℃ to uniformly mix the solutions, and then heated to 100 ℃ to boil and stir for 2h to obtain a modified mixed solution;
4. and (3) putting the filter residues in the step (2) into a muffle furnace, heating for 8 hours at 300 ℃, adding the modified mixed solution, and according to a solid-liquid ratio of 1:10 adding the modified mixed solution, continuously stirring at 50 ℃ for 2.5 hours, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a drying oven at 180 ℃ to obtain the high-adsorptivity bamboo-based activated carbon.
The procedure is as in example 6.
Comparative example 14
Preparing a high-adsorptivity bamboo-based active carbon composite adsorbent:
1. the bamboo-based activated carbon prepared in example 3 and acetic acid with 15% of volume percentage are mixed according to a solid-to-liquid ratio of 1:18, mixing and adding the mixture into a reaction kettle, heating the reaction kettle to 185 ℃, maintaining the reaction pressure to 4.0MPa, and preserving the heat for 6 hours;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. dissolving 3.8 parts of N- (hydroxymethyl) -2-butenamide and 14 parts of modified kaolin in 132 parts of distilled water, stirring for 0.5h at 50 ℃ to uniformly mix the solutions, and then heating to 100 ℃ to boil and stir for 2h to obtain a modified mixed solution;
4. and (3) putting the filter residues in the step (2) into a muffle furnace, heating for 8 hours at 300 ℃, adding the modified mixed solution, and according to a solid-liquid ratio of 1:10 adding the modified mixed solution, continuously stirring at 50 ℃ for 2.5 hours, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a drying oven at 180 ℃ to obtain the high-adsorptivity bamboo-based activated carbon.
The procedure is as in example 6.
Comparative example 15
Modified kaolin was prepared in this comparative example:
1) 31 parts of potassium methyldithiomethylate is added into 325 parts of sodium hydroxide solution with mass fraction of 25% and stirred until the solution is clear, then 125 parts of kaolin and 50 parts of sodium silicate solution with mass fraction of 0.6g/ml are added, and reaction liquid 1 is obtained after uniform stirring;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
Comparative example 16
Modified kaolin was prepared in this comparative example:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate into 325 parts of sodium hydroxide solution with mass fraction of 25% and stirring until the solution is clear, then adding 125 parts of kaolin and 50 parts of sodium silicate solution with mass fraction of 0.6g/ml, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
Comparative example 17
Modified kaolin was prepared in this comparative example:
preparation of modified kaolin:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate and 31 parts of potassium methyldithiomethylamine into 325 parts of 25% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 125 parts of kaolin, and stirring the mixture uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
Comparative example 18
Modified kaolin was prepared in this comparative example:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate and 31 parts of potassium methyldithiomethylamine into 325 parts of 15% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 125 parts of kaolin and 50 parts of 0.6g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
Comparative example 19
Modified kaolin was prepared in this comparative example:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate and 31 parts of potassium methyldithiomethylamine into 325 parts of 35% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 125 parts of kaolin and 50 parts of 0.6g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
Comparative example 20
Modified kaolin was prepared in this comparative example:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate and 31 parts of potassium methyldithiomethylamine into 325 parts of 25% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 125 parts of kaolin and 50 parts of 0.3g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
Comparative example 21
Modified kaolin was prepared in this comparative example:
1) Adding 24 parts of sodium N, N-dimethylamino dithioformate and 31 parts of potassium methyldithiomethylamine into 325 parts of 25% sodium hydroxide solution by mass fraction, stirring until the mixture is clear, then adding 125 parts of kaolin and 50 parts of 0.9g/ml sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, and then placing the kettle in a constant-temperature drying oven, wherein the temperature is set to be 100 ℃, and the crystallization reaction time is 24 hours;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
The procedure is as in example 6.
The testing method comprises the following steps:
iodine adsorption value is measured according to GB/T12496.8-2015 determination of iodine adsorption value of wooden activated carbon test method
Ash content determination according to GB/T12496.3-1999 method for determining ash content of woody activated carbon test method
The specific surface area of the activated carbon was tested using an SSA-4200BET analytical tester.
The technical indexes of examples 4 to 6 according to the present invention and comparative examples 12 to 21 are compared as shown in Table 1.
TABLE 2
As can be seen from the data of examples 4 to 6 and comparative examples 12 to 15 in table 2, the present invention adopts acetic acid washing to remove ash, reduces the ash content in the bamboo-based activated carbon, increases the specific surface area of the bamboo-based activated carbon in the composite adsorbent by using N- (hydroxymethyl) -2-butenamide and o-ethoxybenzoyl hydrazine, enhances the surface adsorption force of the bamboo-based activated carbon, and remarkably improves the adsorption of the composite adsorbent; as can be seen from the data of examples 4 to 6 and comparative examples 15 to 21 in Table 2, the kaolin added with sodium N, N-dimethylaminodithioformate and potassium methyldithioformate has uniform pore size distribution, solves the problem of blocking the pore canal of the bamboo-based activated carbon generated in the process of preparing the composite adsorbent, and obviously enhances the adsorption performance of the bamboo-based activated carbon composite adsorbent.
Claims (6)
1. A preparation process of bamboo-based activated carbon is characterized in that: the preparation process of the bamboo-based activated carbon comprises the following steps:
(1) Pretreatment of raw materials: washing fresh bamboo with water to remove surface impurities, crushing by using a crusher, sieving with a 100-mesh sieve, and drying the crushed and sieved bamboo powder in an oven at 100 ℃ for 4 hours;
(2) Carrying out chemical activation treatment on the bamboo powder:
a. mixing H2SO4 and absolute ethyl alcohol according to the weight ratio of 1:80-100, adding bamboo powder, soaking for 1-2H, evaporating to dryness, then soaking the materials into acetic acid solution, continuously introducing argon, controlling the argon speed to be 1000-1300 sccm, and soaking for 4-6H to obtain solution 1;
b. taking 100 parts of solution 1, adding 3-6 parts of endoglucanase, reacting for 1-3 hours, adding 2-5 parts of exoglucanase, reacting for 5-8 hours, and evaporating to obtain a material 2;
c. mixing 6-8 parts of cyclohexane hydrochloride and 120-150 parts of ethanol, adding the material 2, uniformly stirring, adding 10-15 parts of Mg (OH) 2 and 3-5 parts of magnesium pyrophosphate, uniformly stirring, soaking for 16-24 hours, stirring and evaporating the soaked material at 100 ℃ to obtain activated bamboo powder;
(3) Carbonizing: and (3) slowly conveying the activated bamboo powder into a feeding screw of a pyrolysis gasification furnace, heating the inside of the furnace to 400-700 ℃ at a heating rate of 10 ℃/min, introducing high-temperature superheated steam with the weight 3-5 times of the material weight for countercurrent contact, and preserving the heat for 0.5-2.5 h to obtain the bamboo-based activated carbon.
2. The process for preparing bamboo-based activated carbon as claimed in claim 1, wherein: in the step a, the volume fraction of the acetic acid solution is 6-10%.
3. A preparation process of a high-adsorptivity bamboo-based active carbon composite adsorbent is characterized by comprising the following steps of: the preparation process of the high-adsorptivity bamboo-based active carbon composite adsorbent comprises the following steps:
1. the bamboo-based activated carbon and acetic acid with the volume fraction of 15% are mixed according to the solid-to-liquid ratio of 1: 17-20, heating the reaction kettle to 160-210 ℃, maintaining the reaction pressure at 3.0-5.0 MPa, and preserving the heat for 4-8 h;
2. filtering and separating the reaction liquid to obtain filtrate and filter residue, and washing the filter residue with deionized water until the filtrate is neutral;
3. 2.5 to 5 parts of N- (hydroxymethyl) -2-butenamide, 1.5 to 4 parts of o-ethoxy benzoyl hydrazine and 11 to 17 parts of modified kaolin are dissolved in 120 to 145 parts of distilled water, stirred for 0.5h at a temperature of between 40 and 60 ℃ to ensure that the solutions are uniformly mixed, and then heated to a temperature of 100 ℃ to be boiled and stirred for 2h to obtain a modified mixed solution;
4. putting the filter residues in the step 2 into a muffle furnace, heating for 8 hours at 200-400 ℃, and according to a solid-liquid ratio of 1: 8-13, continuously stirring for 2.5 hours at 40-60 ℃, filtering the solution mixed with the bamboo-based activated carbon, and drying filter residues in a 180 ℃ oven to obtain the high-adsorptivity bamboo-based activated carbon composite adsorbent.
4. The process for preparing the high-adsorptivity bamboo-based activated carbon composite adsorbent as claimed in claim 3, wherein: the preparation method of the modified kaolin comprises the following steps:
1) Adding 18-30 parts of sodium N, N-dimethylamino dithioformate and 25-37 parts of potassium methyldithioformate into 250-400 parts of sodium hydroxide solution, stirring until the mixture is clear, then adding 100-150 parts of kaolin and 45-55 parts of sodium silicate solution, and stirring uniformly to obtain a reaction solution 1;
2) Transferring the reaction solution 1 into a hydrothermal reaction kettle, sealing, placing the reaction solution in a constant-temperature drying oven, setting the temperature to be 80-120 ℃, and crystallizing the reaction solution for 12-36 h;
3) And cooling the product after the crystallization time is finished to room temperature, and filtering, washing and drying to obtain the modified kaolin.
5. The process for preparing the high-adsorptivity bamboo-based activated carbon composite adsorbent as claimed in claim 4, which is characterized in that: in the step 1), the mass fraction of the sodium hydroxide solution is 20-30%.
6. The process for preparing the high-adsorptivity bamboo-based activated carbon composite adsorbent as claimed in claim 4, which is characterized in that: in the step 1), the concentration of the sodium silicate is 0.4-0.8 g/ml.
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| CN117839633A (en) * | 2024-03-07 | 2024-04-09 | 广东韩研活性炭科技股份有限公司 | Preparation process and application of shell activated carbon with adsorption and degradation functions |
| CN117839633B (en) * | 2024-03-07 | 2024-05-10 | 广东韩研活性炭科技股份有限公司 | Preparation process and application of shell activated carbon with adsorption and degradation functions |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117839633A (en) * | 2024-03-07 | 2024-04-09 | 广东韩研活性炭科技股份有限公司 | Preparation process and application of shell activated carbon with adsorption and degradation functions |
| CN117839633B (en) * | 2024-03-07 | 2024-05-10 | 广东韩研活性炭科技股份有限公司 | Preparation process and application of shell activated carbon with adsorption and degradation functions |
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