CN115400738B - Tannic acid-carbon nano tube adsorbent and preparation method and application thereof - Google Patents
Tannic acid-carbon nano tube adsorbent and preparation method and application thereof Download PDFInfo
- Publication number
- CN115400738B CN115400738B CN202110584173.2A CN202110584173A CN115400738B CN 115400738 B CN115400738 B CN 115400738B CN 202110584173 A CN202110584173 A CN 202110584173A CN 115400738 B CN115400738 B CN 115400738B
- Authority
- CN
- China
- Prior art keywords
- tannic acid
- adsorbent
- carbon
- carbon nano
- adsorption
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- B01J20/205—Carbon nanostructures, e.g. nanotubes, nanohorns, nanocones, nanoballs
-
- 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
- B01J20/26—Synthetic macromolecular compounds
- B01J20/262—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon to carbon unsaturated bonds, e.g. obtained by polycondensation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/288—Treatment of water, waste water, or sewage by sorption using composite sorbents, e.g. coated, impregnated, multi-layered
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Nanotechnology (AREA)
- Crystallography & Structural Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention discloses a tannic acid-carbon nanotube adsorbent, a preparation method and application thereof. The tannic acid-carbon nano tube adsorbent provided by the invention has excellent chemical stability and broad-spectrum absorption performance, and the preparation process is simple and environment-friendly.
Description
Technical Field
The invention belongs to the technical field of adsorption materials, and particularly relates to a tannic acid-carbon nano tube adsorbent, and a preparation method and application thereof.
Background
With the continuous development of industry, water pollution and water environment treatment are gradually concerned worldwide. Dyes, pigments, related adjuvants, pharmaceutical intermediates, etc. that are reported to be useful in textile, paper, printing and pharmaceutical industries have become serious water pollutants. Unlike catalytic, oxidation, degradation and other treatment methods, the adsorption method has the advantages of low cost, high efficiency, no secondary pollution and the like in the aspect of dye removal, and has become a research and development hot spot for treating dye wastewater at present. Meanwhile, the dye can be recovered through a simple elution process after the adsorbent is saturated in adsorption, so that the recycling of resources is facilitated. However, the problems of complex textile wastewater components, poor water quality condition, high pollution concentration and the like are great challenges for developing efficient adsorption materials for removing dyes in wastewater. The defects of the adsorbent such as dissolution, few adsorption sites, low adsorption capacity and the like are bottleneck problems which restrict the wide application of the adsorption material. Carbon-based materials such as graphene and carbon nanotubes are applied to the development of novel dye adsorbents due to high specific surface area and unique structural properties, but the application of the materials in the adsorption field is limited by the problems of poor hydrophilicity, easiness in agglomeration, difficulty in recovery, low recycling rate and the like. Thus, modification of carbon-based adsorbent materials is an important aspect of the design and preparation of carbon-based adsorbents.
Tannic acid is a natural polyphenol which can be extracted from plant roots, stems and fruits in large quantity, and the polyphenol structure is easy to generate various adsorption forces with pollutants such as dye and the like, such as pi-pi interaction, coordination complexing, charge attraction, hydrogen bonding and the like. Therefore, tannic acid has been attracting attention in the development of novel adsorbent materials. However, the following disadvantages exist in the current use of tannic acid modified carbon-based adsorbents:
(1) The modified adsorbent is modified by adopting a non-covalent bond bonding or unstable covalent bond bonding mode, and the cross-linked structure of the adsorbent can be de-crosslinked in the adsorption process, so that tannic acid or other components are dissolved out, the adsorption performance is reduced, and secondary pollution is caused.
(2) Toxic substances including heavy metal ions, aldehyde compounds and the like are adopted as cross-linking agents, the preparation process is not environment-friendly, and the preparation process is complex.
Aiming at tannic acid modified carbon-based adsorption materials, particularly in adsorption application under a complex environment, an economic and environment-friendly preparation method with simple and convenient process, stability and high efficiency is urgently needed. Meanwhile, the dye wastewater is not a single component, so that the adsorbent is required to have high stability and high adsorption capacity and realize broad-spectrum adsorption of the dye.
Disclosure of Invention
Aiming at the problems in the prior art, the inventor researches a tannic acid-carbon nano tube adsorbent, and a preparation method and application thereof. The tannic acid-carbon nano tube adsorbent has excellent chemical stability and spectral absorption performance, and the preparation method has the advantages of mild preparation conditions, simple steps and green and safe raw materials, thereby completing the invention.
In order to achieve the above object, in a first aspect, the present invention provides a tannic acid-carbon nanotube adsorbent, which is prepared from tannic acid and carbon nanotubes, preferably oxidized carbon nanotubes.
In a second aspect, the present invention provides a method for preparing the tannic acid-carbon nanotube adsorbent of the first aspect, comprising:
step 1, dissolving tannic acid, carbon nano tubes and a catalyst to obtain a solution;
step 2, adding a cross-linking agent into the solution, and reacting at a certain temperature to obtain a precipitate;
and step 3, carrying out post-treatment on the precipitate to obtain the tannic acid-carbon nano tube adsorbent.
In a third aspect, the present invention provides the use of a tannic acid-carbon nanotube adsorbent prepared by the method of the first or second aspect.
The tannic acid-carbon nano tube adsorbent provided by the invention and the preparation method and application thereof can obtain the following beneficial effects:
(1) The invention adopts a chemical co-crosslinking-coating technology, so that the tannic acid-carbon nano tube adsorbent has good chemical stability, and no tannic acid molecules are dissolved out in the use process, and no secondary pollution is caused;
(2) The tannic acid-carbon nano tube adsorbent provided by the invention has various adsorption acting forces and can be used for absorbing pollutants in water in a broad spectrum;
(3) The preparation method disclosed by the invention is environment-friendly, simple to operate, easy to control and easy to realize industrial production.
Drawings
FIG. 1 shows a schematic reaction diagram of the tannic acid-carbon nanotube adsorbent of the present invention:
FIG. 2 shows FTIR diagrams of tannic acid-carbon nanotube adsorbent, tannic acid and oxidized carbon nanotubes prepared in experimental example 1 of the present invention;
FIG. 3 shows a Raman diagram of a tannic acid-carbon nanotube adsorbent and carbon oxide nanotubes prepared in example 2 of the present invention;
FIG. 4 shows TGA graphs of tannic acid-carbon nanotube adsorbent, comparative example 3 product and oxidized carbon nanotubes prepared in example 2 of the present invention;
FIG. 5 is a SEM image showing the tannic acid-carbon nanotube adsorbent prepared in example 1 of the present invention and the products obtained in comparative examples 1 to 2;
FIG. 6 is a UV-vis diagram showing the tannic acid-carbon nanotube adsorbent prepared in example 1 of the present invention and the resultant adsorption dye of comparative examples 1 to 2;
FIG. 7 is a graph showing the results of adsorption test of the tannic acid-carbon nanotube adsorbent prepared in example 1 of the present invention and the tetracycline drug adsorbed by the product obtained in comparative example 1.
Detailed Description
The invention is described in further detail below with reference to the drawings and the preferred embodiments. The features and advantages of the present invention will become more apparent from the description.
According to a first aspect of the present invention, there is provided a tannic acid-carbon nanotube adsorbent, which is prepared from tannic acid and carbon nanotubes, preferably oxidized carbon nanotubes.
The carbon nanotube adopted by the invention is preferably an oxidized carbon nanotube, and the surface of the oxidized carbon nanotube has a large number of reactive groups which are not possessed by the carbon nanotube on the basis of maintaining most of excellent physical properties of the carbon nanotube.
In a preferred embodiment of the present invention, the oxidized carbon nanotubes are epoxy-rich carbon nanotubes that have been subjected to a high temperature treatment.
The carbon oxide nanotubes used in the invention can be prepared by oxidizing carbon nanotubes, and can also be suitable for the carbon oxide nanotubes purchased in the market, for example, the carbon oxide nanotubes are purchased from Tuling artificial intelligence black technology Co.
The structure of the carbon oxide nano tube used in the invention contains epoxy groups, and the carbon oxide nano tube and phenolic hydroxyl of tannic acid undergo ring-opening reaction to realize chemical co-crosslinking, so that tannic acid is covalently grafted on the surface of the carbon nano tube.
According to the present invention, the mass ratio of tannic acid to carbon nanotube oxide should be in a proper range, and if the mass ratio is too large, it may result in more tannic acid remaining, thereby wasting raw materials, and if the mass ratio is too small, it may result in low tannic acid content on the carbon nanotubes, and a tannic acid functional coating layer cannot be formed. Thus, in the present invention, the mass ratio of tannic acid to carbon oxide nanotubes is 1: (0.01 to 0.8), preferably 1: (0.01 to 0.5), more preferably 1: (0.02-0.1).
According to the present invention, when the mass ratio of tannic acid to carbon oxide nanotubes is 1: (0.02-0.1), no oxidized carbon nanotubes are lost, and it can be judged that almost all the added oxidized carbon nanotubes participate in the crosslinking reaction, and the utilization rate is almost 100%, so that the maximization of the raw material utilization rate is realized.
In order to realize the co-crosslinking-coating of tannic acid on the surface of the carbon oxide nano tube, the invention also needs to add a crosslinking agent.
In a preferred embodiment of the invention, the crosslinking agent is a double-or multi-terminal epoxy compound;
preferably, the double or multiple terminal epoxy compound is selected from at least one of ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.
Wherein when polyethylene glycol diglycidyl ether and/or polypropylene glycol diglycidyl ether are selected as the crosslinking agent, the molecular weight thereof is controlled within a certain range. If the molecular weight is too large, the viscosity of the system reactants will be too great, which is detrimental to uniform mixing of the raw materials. Preferably, the molecular weight of the polyethylene glycol diglycidyl ether and/or the polypropylene glycol diglycidyl ether is 300 to 40000, more preferably 300 to 30000, still more preferably 350 to 10000.
According to the present invention, the amount of the crosslinking agent can directly affect the structural morphology and the degree of surface functional groups adsorbed by tannic acid-carbon nanotubes, but the amount of the crosslinking agent needs to be controlled within a certain suitable range. If the cross-linking agent is too little, a large amount of tannic acid and carbon oxide nanotubes are not crosslinked together, and a large amount of tannic acid and products with low cross-linking degree are dissolved in water after washing, so that the tannic acid content on the carbon nanotubes is low, and a tannic acid functional coating layer cannot be formed. If the crosslinking agent is too much, the polyphenol structure of tannic acid is consumed by the reaction of the crosslinking agent, resulting in damage of the adsorption sites of the adsorbent, resulting in a decrease in adsorption capacity. Therefore, in the present invention, the mass ratio of tannic acid to crosslinking agent is 1: (0.1 to 0.9), preferably 1: (0.2 to 0.7), more preferably 1: (0.2-0.5).
According to the present invention, when the mass ratio of tannic acid to the crosslinking agent is 1: (0.2-0.5), the surface of the carbon oxide nano tube can form a micron-sized tannic acid functional coating layer, which is favorable for the synergistic effect of tannic acid and carbon oxide nano tube adsorption.
CH appears in the crosslinked tannic acid-carbon nanotube adsorbent 2 The absorption peaks of (a) indicate that tannic acid and carbon oxide nanotubes are covalently bonded and have a rough surface morphology, and a tannic acid layer grows on the tube wall in a cross-linking manner, that is, tannic acid can realize co-crosslinking-coating of the modified carbon oxide nanotubes.
The tannic acid-carbon nanotube adsorbent provided in the first aspect has various adsorption forces, such as hydrogen bond, electrostatic interaction, hydrophobic interaction, coordination, pi-pi interaction and the like, and provides basic conditions for adsorbing pollutants in water, such as dyes, aromatic pollutants, heavy metals and the like, in a broad spectrum. The prepared tannic acid-carbon nano tube adsorbent has a strong adsorption effect on methylene blue, the adsorption capacity can reach 182.5mg/g, the removal rate can reach 91%, and the removal rate on methyl green, rhodamine B and neutral red can reach more than 95%.
The tannic acid-carbon nanotube adsorbent provided in the first aspect has excellent stability, and tannic acid is not dissolved out in the adsorption process, so that secondary pollution is avoided.
In a second aspect, the present invention provides a method for preparing the tannic acid-carbon nanotube adsorbent, preferably the tannic acid-carbon nanotube adsorbent of the first aspect. The preparation method comprises the following steps:
and step 1, dissolving tannic acid, carbon nano tubes and a catalyst to obtain a solution.
According to the present invention, the carbon nanotubes are preferably oxidized carbon nanotubes. The oxidized carbon nanotubes are carbon nanotubes rich in epoxy groups which are subjected to high temperature treatment.
In a preferred embodiment of the present invention, step 1 may comprise the sub-steps of:
step 1-1, carrying out ultrasonic treatment on tannic acid, carbon nano tubes, a catalyst and a solvent to obtain a mixed solution;
in this step, the solvent used is selected from ester compounds, preferably at least one selected from methyl acetate, ethyl acetate, butyl acetate and isoamyl acetate.
Preferably selected from the group consisting of ethyl acetate and butyl acetate. The mixed solution of ethyl acetate and butyl acetate can well dissolve tannic acid and carbon oxide nano tubes, and is favorable for uniform reaction.
According to the invention, the amount of the solvent can affect the reaction yield, and if the amount of the solvent is too large, the concentration of the cross-linking agent is low, and the cross-linked product is mostly nano-scale or submicron-scale, and is difficult to recover by low-speed centrifugation. If the solvent amount is small, the dispersion of the system is uneven, the carbon oxide nano tube is seriously agglomerated, and the actual crosslinking efficiency is low. Therefore, the mass ratio of tannic acid to solvent of the present invention is 1: (12 to 33), preferably 1: (15 to 30), more preferably 1: (20-25).
According to the present invention, when the mass ratio of tannic acid to solvent is 1: (12-33) the yield of the reaction product can be maximized.
In this step, in order to enable the reaction to be carried out under mild conditions while ensuring a faster reaction rate, shortening the reaction time, a catalyst is also required to be added. Wherein the catalyst is selected from at least one of triphenylphosphine, triphenylphosphine oxide and tetrabutylammonium bromide.
According to the invention, the amount of catalyst used influences the reaction rate. When the catalyst is used in an excessive amount, the reaction rate is also increased more rapidly, and when the catalyst is used in an excessive amount, the reaction rate is not increased significantly, so that the catalyst is reduced as much as possible under the condition of ensuring the proper reaction rate in consideration of cost. Thus, in a preferred embodiment of the invention, the mass ratio of tannic acid to catalyst is 1: (0.01 to 0.08), preferably 1: (0.01 to 0.05), more preferably 1: (0.015-0.03).
According to the present invention, because of the special structure of tannic acid, it plays a promoting role in the dispersion of oxidized carbon nanotubes, so that only a short time of ultrasonic dissolution is required. In the present invention, the ultrasonic time is 0.3 to 5 hours, preferably 0.5 to 3 hours, more preferably 1 to 2 hours. Wherein the ultrasonic frequency and power are not easily too high, preferably the ultrasonic frequency is 40MHz and the power is 100W.
And step 1-2, heating, stirring and dissolving the mixed solution under the atmosphere of nitrogen or inert gas.
According to the invention, the heating and dissolving are carried out under the atmosphere of nitrogen or inert gas, so that the oxidation reaction of oxygen in the air and tannic acid is avoided.
According to the present invention, the higher the heating temperature is, the more advantageous the dissolution is, but the higher the temperature is, the more volatile the solvent is lost, and therefore, the heating temperature of the present invention is not preferably higher than 70 ℃. Preferably, the heating temperature is 30 to 70 ℃, preferably 40 to 65 ℃, more preferably 50 to 60 ℃.
And step 2, adding a cross-linking agent into the solution, and reacting at a certain temperature to obtain a precipitate.
According to the present invention, the reaction temperature in this step is 60 to 120 ℃, preferably 70 to 100 ℃, more preferably 80 to 90 ℃ in view of the balance between the physical properties (boiling point) of the solvent and the reaction time, that is, the reaction temperature is not too high and the reaction time is not too long.
According to the present invention, if the reaction time is too short, crosslinking between tannic acid and carbon oxide nanotubes is insufficient, a large amount of products with low crosslinking degree are produced, and the yield of the washed products is low. The reaction time in this step is therefore from 9 to 52 hours, preferably from 12 to 48 hours, more preferably from 18 to 24 hours.
In a preferred embodiment of the invention, the tannic acid-carbon nanotube adsorbent is prepared from the following raw materials in parts by weight:
1 part of tannic acid;
0.01 to 0.8 part, preferably 0.01 to 0.5 part, more preferably 0.02 to 0.1 part of carbon nanotubes;
0.1 to 0.9 part, preferably 0.2 to 0.7 part, more preferably 0.2 to 0.5 part of cross-linking agent;
0.01 to 0.08 part of catalyst, preferably 0.01 to 0.05 part, more preferably 0.015 to 0.03 part;
12 to 33 parts, preferably 15 to 30 parts, more preferably 20 to 25 parts of solvent.
And step 3, carrying out post-treatment on the precipitate to obtain the tannic acid-carbon nano tube adsorbent.
Preferably, the precipitate obtained in step 2 is washed and dried. The washing reagent is absolute ethyl alcohol and/or deionized water, preferably absolute ethyl alcohol is adopted to repeatedly wash for a plurality of times, preferably more than 3 times, the solid-phase product is collected through centrifugation, the solid-phase product is washed for a plurality of times, preferably more than 3 times through deionized water, the solid-phase product is collected through centrifugation, and finally the final product tannic acid-carbon nano tube adsorbent is obtained through drying.
Preferably, the reaction solvent and the washed absolute ethyl alcohol are collected and recycled in a rectification mode.
According to the invention, the solvent, the catalyst and the cross-linking agent are all organic matters, and the solvent, the catalyst and the unreacted cross-linking agent which are involved in the product can be removed by washing with inorganic ethanol. Since tannic acid is a water-soluble molecule, the uncrosslinked or low crosslinked product is soluble in water, and washing with deionized water can remove unreacted tannic acid and low crosslinked product. Until the washing is clean, that is, no ultraviolet absorption peak of tannic acid exists in the final washing reagent.
According to the present invention, since the microstructure of the tannic acid-carbon nanotube adsorbent is uncontrollably changed by high temperature, freeze-drying or low-temperature reduced-pressure drying is preferably employed, wherein the drying time is 20 to 40 hours, and the drying time is preferably 24 to 36 hours for sufficient drying.
The tannic acid-carbon nano tube adsorbent provided in the second aspect is simple in preparation process, free of generating strong toxicity and cancerogenic substances, environment-friendly, mild in condition and high in efficiency.
In a third aspect, the present invention provides the use of a tannic acid-carbon nanotube adsorbent prepared by the method of the first or second aspect. Mainly applied to the fields of sewage treatment, medicine separation or precious metal extraction and recovery.
In order to further understand the present invention, the tannic acid-carbon nanotube adsorbent provided by the present invention is described below with reference to examples, and the scope of the present invention is not limited by the following examples.
Examples
Example 1
Adding 1.7g of tannic acid, 25.5mg of triphenylphosphine and 50mg of carbon oxide nanotubes into 40mL of a mixed solvent of ethyl acetate and butyl acetate (volume ratio is 3:2), performing ultrasonic treatment at room temperature for 1h, placing the reaction materials into a reactor, heating and stirring, and heating to 60 ℃ under the protection of nitrogen for 1h;
adding 0.6g of ethylene glycol diglycidyl ether, raising the temperature to 85 ℃, and carrying out reflux condensation reaction for 12 hours;
after the reaction is finished, centrifuging (3000 rpm) to separate and collect solid phase matters and solvent, washing the solid phase matters with 25mL of absolute ethyl alcohol, ultrasonically centrifuging to collect the solid phase matters, recovering the ethyl alcohol, repeating the steps for three times, repeatedly washing the solid phase matters with deionized water for three times, and freeze-drying the solid phase matters for 24 hours to obtain the gray powdery tannic acid-carbon nano tube adsorbent.
Example 2
Adding 4g of tannic acid, 60mg of triphenylphosphine and 300mg of carbon oxide nanotubes into 90mL of a mixed solvent of ethyl acetate and butyl acetate (volume ratio is 3:2), performing ultrasonic treatment at room temperature for 1h, transferring the materials into a reactor, heating and stirring, and heating at 60 ℃ for 1h under the protection of nitrogen;
1g of diethylene glycol diglycidyl ether is added, the temperature is increased to 90 ℃, and reflux reaction is carried out for 12 hours;
after the reaction is finished, separating and collecting a solid phase and a solvent by centrifugation (3000 r/min), washing the solid phase with 50mL of absolute ethyl alcohol, collecting the solid phase by ultrasonic and centrifugal treatment, recovering the ethyl alcohol, repeating the washing for three times by using 50mL of deionized water, and drying the solid phase and the solvent under reduced pressure at 40 ℃ for 36 hours to obtain the gray powdery tannic acid-carbon nano tube adsorbent.
Example 3
Adding 8.5g of tannic acid, 0.25g of triphenylphosphine oxide and 0.5g of carbon nano tube into 300mL of mixed solvent of methyl acetate and butyl acetate (volume ratio is 4:2), performing ultrasonic treatment at room temperature for 2 hours, placing the materials into a reactor, heating and stirring, and heating for 2 hours at 55 ℃ under the protection of nitrogen;
3.5g of polyethylene glycol diglycidyl ether is added, the temperature is increased to 80 ℃, and reflux reaction is carried out for 16 hours;
after the reaction is finished, centrifuging (3000 r/min) to separate and collect solid phase matters and solvent, washing the solid phase matters with 100mL of absolute ethyl alcohol, carrying out ultrasonic treatment and centrifuging to collect the solid phase matters and the solvent, recovering the ethyl alcohol, repeating the steps for three times, washing with 100mL of deionized water for three times, and freeze-drying to obtain the gray powdery tannic acid-carbon nano tube adsorbent.
Example 4
17g of tannic acid, 0.4g of tetrabutylammonium bromide and 1g of carbon oxide nano tube are added into 500mL of mixed solvent of ethyl acetate and butyl acetate (volume ratio is 3:2), ultrasonic treatment is carried out at room temperature for 2 hours, the transfer material is heated and stirred in a reactor, and the transfer material is heated for 2 hours at 70 ℃ under the protection of nitrogen;
5g of 1, 6-hexanediol diglycidyl ether is added, the temperature is increased to 85 ℃, and the reflux reaction is carried out for 24 hours;
after the reaction is finished, centrifuging (3000 r/min), separating and collecting solid phase matters and solvent, washing the solid phase matters with 200mL of absolute ethyl alcohol, ultrasonically and centrifugally collecting the solid phase matters, recovering the ethyl alcohol, repeating the steps for three times, repeatedly washing with 200mL of deionized water for three times, and freeze-drying to obtain the gray powdery tannic acid-carbon nano tube adsorbent.
Comparative example
Comparative example 1
The procedure was similar to that of example 1, except that no carbon nanotubes were added, resulting in a brown-yellow powdery adsorbent.
Comparative example 2
The procedure was similar to that of example 1, except that no crosslinking agent was added, giving a black powdery adsorbent.
Comparative example 3
The procedure was similar to that of example 2, except that no carbon nanotubes were added, resulting in a brown-yellow powdery adsorbent.
Experimental example
Experimental example 1 Infrared Spectroscopy (FTIR) analysis
The tannic acid-carbon nanotube adsorbent, tannic acid and carbon oxide nanotubes prepared in example 1 were respectively subjected to infrared spectroscopy (FTIR) analysis, and the test results are shown in fig. 2.
As can be seen from FIG. 2, 1040cm -1 、3200cm -1 ～3600cm -1 The characteristic peak of epoxy group and the peak of hydroxyl group of the carbon oxide nano tube respectively show that the carbon oxide nano tube has epoxy ring opening activity. CH appears in the crosslinked tannic acid-carbon nanotube adsorbent compared with tannic acid 2 The structure is derived from the epoxy compound as a crosslinking agent, indicating that the product has a structure formed during the epoxy ring-opening crosslinking reaction.
Experimental example 2 Raman (Raman) Spectroscopy
The tannic acid-carbon nanotube adsorbent and the oxidized carbon nanotube prepared in example 2 were subjected to Raman (Raman) test, respectively, and the test results are shown in fig. 3.
As can be seen from FIG. 3, the oxidized carbon nanotube and the tannic acid-carbon nanotube adsorbent were each at 1330cm -1 And 1575cm -1 Two characteristic peaks, namely a D peak and a G peak. Wherein the intensity ratio of the D peak and the G peak (I D /I G ) The degree of carbon functionalization can be measured, and the method is a measure of carbon structural defects. With the original oxidized carbon nanotube (I) D /I G =1.65), tannic acid-carbon nanotube adsorbent exhibits slightly higher I D /I G The ratio (1.78) shows that the tannic acid increases the degree of carbon atom defect on the surface after covalent crosslinking with the oxidized carbon nanotubes. This suggests that tannic acid and carbon oxide nanotubes are covalently bound, that is, tannic acid is capable of achieving co-crosslinking-coating of modified carbon oxide nanotubes.
Experimental example 3 Thermogravimetric (TGA) analysis
Thermogravimetric (TGA) analysis was performed on the tannic acid-carbon nanotube adsorbent prepared in example 2, the product obtained in comparative example 3, and the oxidized carbon nanotube, respectively.
The specific process is as follows: 10mg of each of the above three products was heated from room temperature to 800℃under a nitrogen atmosphere at a heating rate of 10℃per minute, and thermogravimetric test was performed. The content of the oxidized carbon nanotubes in example 2 was calculated from the weight loss of the sample, and the conversion rate of the oxidized carbon nanotubes to participate in the crosslinking reaction was calculated, and the test results are shown in fig. 4.
As can be seen from fig. 4, the oxidized carbon nanotubes showed a slow weight loss process after 300 c, which is mainly due to thermal decomposition of oxygen-containing groups, and the weight loss rate was approximately 30%. In the formulation of example 2, about 6% of the carbon nanotubes were used, and if the crosslinking was completely involved, the estimated theoretical thermal weight loss remained at about 4.3%. The product of example 2 had a carbon remaining amount of 4.6% more at 800 c, which is close to the theoretical calculated value (4.3%) compared to comparative example 3, indicating that the added oxidized carbon nanotubes formed a tannic acid-carbon nanotube composite adsorbent through the co-crosslinking-coating process. In addition, in view of the fact that the liquid phase is a clear solvent after the reaction products are separated, no oxidized carbon nanotubes are lost, and the added oxidized carbon nanotubes can be judged to be almost completely involved in the crosslinking reaction by combining a thermogravimetric analysis structure, and the utilization rate of the added oxidized carbon nanotubes is nearly 100%.
Experimental example 4 Scanning Electron Microscope (SEM) test
The tannic acid-carbon nanotube adsorbent prepared in example 1 and the products obtained in comparative examples 1 to 2 were subjected to Scanning Electron Microscope (SEM) tests, respectively, and the test results are shown in fig. 5.
As can be seen from fig. 5, in the tannic acid-carbon nanotube adsorbent prepared in example 1, oxidized carbon nanotubes were used as a skeleton, a tannic acid functional layer formed a micron-sized coating layer around a tube wall, the surface morphology was rough, and the tannic acid layer grew on the tube wall by crosslinking, demonstrating a co-crosslinking-coating morphology. The product of comparative example 1 was smooth in surface and large in size. The product obtained in comparative example 2, because of the limited oxygen-containing groups on the surface of the oxidized carbon nanotubes, has a low content of tannic acid grafted on the surface, and cannot form a tannic acid functional coating layer.
Experimental example 5 methylene blue adsorption test
The tannic acid-carbon nanotube adsorbent prepared in example 1 and the products obtained in comparative examples 1 to 2 were subjected to methylene blue (available from source leaf biotechnology Co., ltd.) adsorption test, respectively.
The specific process is as follows: three equal parts of 20mL methylene blue aqueous solution with the mass concentration of 200mg/L are respectively taken, 20mg of the three products of the example 1 and the comparative examples 1-2 are respectively added under the conditions of 25 ℃ and pH=10, the three products are stirred and adsorbed on a constant temperature magnetic stirrer at the rotating speed of 600 revolutions per minute, after 300 minutes of adsorption, the absorbance of the adsorbed clear solution is analyzed and calculated by using ultraviolet-visible light (UV-vis) photometry, and the residual concentration of the dye in the adsorbed solution is analyzed and calculated.
Wherein the dye removal rate R% and the adsorption quantity q per unit mass of the dye e The calculation formula of (2) is as follows:
wherein C is 0 、C e The initial concentration of dye, the concentration at adsorption equilibrium (mg/L), m is the mass of tannic acid-based dye adsorbent, and V is the volume of dye solution.
The specific test results are shown in table 1:
TABLE 1
| Sample of | Adsorption per unit mass mg/g | Removal rate% |
| Example 1 | 182.5 | 91.2 |
| Comparative example 1 | 121.4 | 60.7 |
| Comparative example 2 | 68.2 | 34.1 |
As can be seen from Table 1, the tannin-carbon nanotube adsorbent has strong adsorption effect on methylene blue, the adsorption capacity can reach 182.5mg/g, and the removal rate reaches 91%. The products obtained in comparative examples 1 and 2 were low in adsorption and removal rate. It is apparent that the synergistic effect of tannic acid and carbon oxide nanotubes enhances the adsorption effect.
Experimental example 6 broad-Spectrum adsorption test of dyes
The tannic acid-carbon nanotube adsorbent prepared in example 2 and the product obtained in comparative example 3 were examined for their adsorption ability for other dyes, respectively, using a static adsorption experiment.
The specific process is as follows: two equal parts of methyl green (purchased from atanan Hong Wang chemical company, inc.), rhodamine B (purchased from atanan Hui jin chemical company, inc.) and neutral red aqueous solution (purchased from Shanghai purple one reagent factory) with a mass concentration of 50mg/L are respectively measured for 20mL, then 20mg of the products of the example 2 and the comparative example 3 are respectively added into each dye solution under the conditions of 25 ℃ and pH=7, the mixture is stirred and adsorbed on a constant temperature magnetic stirrer at a rotating speed of 600 revolutions per minute for 300 minutes, and after the adsorption, the absorbance of the clear solution after the adsorption is analyzed by using an ultraviolet-visible light photometer to analyze and calculate the residual concentration of the dye in the solution after the adsorption, and the dye removal rate R% is respectively calculated.
The specific test results are shown in table 2:
TABLE 2
As can be seen from Table 2, the removal rates for the three dyes methyl green, rhodamine B and neutral Red of comparative example 3 were 21.3%, 68.4% and 93.3%, respectively. However, it is apparent that the tannin-carbon nanotube adsorbent prepared in example 2 has excellent adsorption effect (removal rate of more than 95%) on different dyes, showing broad-spectrum adsorption capacity, with the removal rates of methyl green, rhodamine B and neutral red being improved to 95.9%, 98.2% and 99.6%, respectively, by the example 2 incorporating carbon nanotubes oxide.
Experimental example 7 Mixed dye dynamic adsorption test
Dynamic adsorption experiments were performed using an adsorption column to investigate the ability of example 4 to mix adsorption of multiple dyes.
The specific process is as follows: 200mL of a dye mixed solution with the mass concentration of 100mg/L is prepared, wherein the concentration of methylene blue, methyl orange, methyl green, rhodamine B and neutral red water solution is 20mg/L, and the pH is adjusted to 7 by hydrochloric acid and sodium hydroxide solution. 0.2g of the tannic acid-carbon nanotube adsorbent prepared in example 4 was filled in a 25mL pipette, and the filling height of the bottom adsorption layer was 2cm. Adding mixed dye aqueous solution, controlling the flow rate to be 0.5mL/min so as to keep the height of a liquid column on an adsorption layer to be 30cm, and collecting effluent below a glass adsorption column; samples were taken once every 10mL of the effluent, the absorbance of the effluent was measured with an ultraviolet-visible photometer, the residual condition of each component dye in the liquid phase was calculated, and a total of 100mL of the dye mixture was introduced. The ultraviolet visible (UV-vis) spectrum of the effluent is shown in FIG. 6.
As can be seen from FIG. 6, after passing through 100mL of the mixed solution, only the ultraviolet absorption peak of the anionic dye methyl orange was detected, and other dyes such as methylene blue, methyl green, rhodamine B, neutral red, etc. were not detected, indicating that only the anionic dye methyl orange could pass through the adsorption column, while other cationic dyes were almost completely adsorbed. Therefore, the tannic acid-carbon nano tube adsorbent has strong mixed dye resolution capability, and the characteristic shows that the tannic acid-carbon nano tube adsorbent can be applied to separation and recovery of dyes.
Experimental example 8 adsorption test of drug pollutants
The tannic acid-carbon nanotube adsorbent prepared in example 1 and comparative example 1 were examined for their adsorption ability to tetracycline (purchased from ideas biosciences (beijing)) using a static adsorption experiment.
The specific process is as follows: 20mL of the aqueous tetracycline solution (10 mg/L, 20mg/L, 40mg/L, 60mg/L, 80mg/L, 120 mg/L) was measured, 20mg of the products of example 1 and comparative example 1 was added at 25℃and pH=5, and the mixture was stirred and adsorbed at 600 rpm on a constant temperature magnetic stirrer, and the mixture was centrifuged and sampled after 300 minutes, and the absorbance of the supernatant obtained by ultraviolet-visible light photometry was analyzed to calculate the residual tetracycline concentration of the adsorbed solution, and the adsorption result was shown in FIG. 7.
As can be seen from FIG. 7, the adsorption capacity for tetracycline in comparative example 1 was 9.5mg/g, whereas the adsorption capacity for tetracycline in example 1 reached 55mg/g, and the adsorption capacity was improved by nearly 6 times by the introduction of the carbon oxide nanotubes. Through analysis, the product of comparative example 1 lacks the hydrophobic interaction provided by the oxidized carbon nanotube, and it is difficult to adsorb tetracycline having a hydrophobic group. The tannic acid-carbon nanotube adsorbent prepared in example 1 has both a hydrophilic region providing an aqueous solution permeation diffusion channel and a hydrophobic region providing adsorption sites, so that its adsorption capacity for tetracycline is greatly improved.
The invention has been described in detail with reference to preferred embodiments and illustrative examples. It should be noted, however, that these embodiments are merely illustrative of the present invention and do not limit the scope of the present invention in any way. Various improvements, equivalent substitutions or modifications can be made to the technical content of the present invention and its embodiments without departing from the spirit and scope of the present invention, which all fall within the scope of the present invention. The scope of the invention is defined by the appended claims.
Claims (10)
1. The tannic acid-carbon nano tube adsorbent is characterized in that raw materials for preparing the adsorbent comprise tannic acid, carbon nano tubes, a cross-linking agent and a catalyst, wherein the mass ratio of the tannic acid to the carbon nano tubes to the cross-linking agent is 1: (0.01 to 0.8): (0.1 to 0.9),
the cross-linking agent is a double-or multi-terminal epoxy compound, and the double-or multi-terminal epoxy compound is at least one selected from ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether;
the carbon nanotubes are oxidized carbon nanotubes and contain epoxy groups.
2. A method for preparing the tannic acid-carbon nanotube adsorbent of claim 1, comprising:
step 1, dissolving tannic acid, carbon nano tubes and a catalyst to obtain a solution;
step 2, adding a cross-linking agent into the solution, and reacting at a certain temperature to obtain a precipitate;
and step 3, carrying out post-treatment on the precipitate to obtain the tannic acid-carbon nano tube adsorbent.
3. The method according to claim 2, wherein in step 1, the solvent used is selected from the group consisting of esters, and is at least one selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate and isoamyl acetate; and/or
The catalyst is selected from at least one of triphenylphosphine, triphenylphosphine oxide and tetrabutylammonium bromide.
4. A method of preparation according to claim 2 or 3, wherein step 1 comprises:
step 1-1, carrying out ultrasonic treatment on tannic acid, carbon nano tubes, a catalyst and a solvent to obtain a mixed solution;
and step 1-2, heating, stirring and dissolving the mixed solution under the atmosphere of nitrogen or inert gas.
5. The method according to claim 4, wherein,
in step 1-1: the ultrasonic time is 0.3-5 h; and/or
In step 1-2: the heating temperature is 30-70 ℃.
6. The method according to claim 4, wherein,
the ultrasonic time is 0.5-3 h; and/or
In step 1-2: the heating temperature is 40-65 ℃.
7. The preparation method according to claim 2, wherein in step 2, the reaction temperature is 60-120 ℃; and/or
The reaction time is 9-52 h.
8. The preparation method according to claim 2, wherein in step 2, the reaction temperature is 70 to 100 ℃; and/or
The reaction time is 12-48 h.
9. The method according to claim 2, wherein in step 3, the post-treatment comprises washing, drying,
the washing reagent is selected from absolute ethanol and/or deionized water.
10. Use of the tannic acid-carbon nanotube adsorbent of claim 1 or the tannic acid-carbon nanotube adsorbent prepared according to the method of one of claims 2 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110584173.2A CN115400738B (en) | 2021-05-27 | 2021-05-27 | Tannic acid-carbon nano tube adsorbent and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110584173.2A CN115400738B (en) | 2021-05-27 | 2021-05-27 | Tannic acid-carbon nano tube adsorbent and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115400738A CN115400738A (en) | 2022-11-29 |
| CN115400738B true CN115400738B (en) | 2023-08-08 |
Family
ID=84155524
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110584173.2A Active CN115400738B (en) | 2021-05-27 | 2021-05-27 | Tannic acid-carbon nano tube adsorbent and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115400738B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102553532A (en) * | 2012-01-17 | 2012-07-11 | 同济大学 | Method for preparing magnetic carbon nano-tube adsorbent having high adsorption capacity and used for removing dye from aqueous phase |
-
2021
- 2021-05-27 CN CN202110584173.2A patent/CN115400738B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102553532A (en) * | 2012-01-17 | 2012-07-11 | 同济大学 | Method for preparing magnetic carbon nano-tube adsorbent having high adsorption capacity and used for removing dye from aqueous phase |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115400738A (en) | 2022-11-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Torrejos et al. | Synthesis and characterization of multi-walled carbon nanotubes-supported dibenzo-14-crown-4 ether with proton ionizable carboxyl sidearm as Li+ adsorbents | |
| CN109772178B (en) | Preparation method and application of pyrimethamine molecularly imprinted composite membrane based on click chemistry double-sided loading | |
| CN113351248B (en) | Selective photodegradable acid orange molecularly imprinted polymer, and preparation method and application thereof | |
| CN112316741B (en) | Mixed matrix membrane of beaded MOF filled silicone rubber | |
| CN112516112B (en) | Rapid aqueous phase synthesis method of multifunctional cyclodextrin polymeric microspheres | |
| CN113698579B (en) | Porphyrin conjugated microporous polymer and its synthesis method and application | |
| CN112979985A (en) | Composite metal organic framework material and preparation method thereof | |
| CN112427021A (en) | Magnetic nanoparticle-cyclodextrin composite adsorbent, preparation method and application | |
| CN115970656A (en) | Amino acid covalent grafting cyclodextrin-metal organic framework material and application thereof | |
| CN115400738B (en) | Tannic acid-carbon nano tube adsorbent and preparation method and application thereof | |
| CN113372525B (en) | Covalent organic framework material with molecular imprinting type and preparation method and application thereof | |
| CN106866900B (en) | A kind of photoresponse molecularly imprinted material on surface and its preparation method and application | |
| CN111644160A (en) | Green preparation method of super-hydrophobic microporous polymer adsorption material | |
| CN111440354A (en) | Preparation method and application of bisphenol A molecularly imprinted composite membrane with through hierarchical pore structure | |
| Liu et al. | Separating 2-phenylethanol from aqueous solution by mixed matrix composite membranes based on beta-cyclodextrin metal organic frameworks | |
| Lu et al. | Surface molecularly imprinted polymers prepared by two‐step precipitation polymerization for the selective extraction of oleanolic acid from grape pomace extract | |
| CN113600150B (en) | Method for preparing magnetic super-crosslinked polymer from vacuum residue | |
| CN105921113A (en) | Adsorbent used for removing phthalic acid in water and preparation method thereof | |
| CN113797899B (en) | Preparation method of P (Allyl-beta-CD)/PSA microspheres and application of P (Allyl-beta-CD)/PSA microspheres in adsorption of cinchonine | |
| CN112619708B (en) | Molecularly imprinted polymer based on porphyrin functionalized carbon nanotube and preparation method and application thereof | |
| CN114887597A (en) | Aflatoxin surface molecularly imprinted nanofiber membrane adsorbent and preparation method and application thereof | |
| CN107915788B (en) | Cyclodextrin-based micromolecular pollutant adsorption material and preparation method thereof | |
| CN112316919A (en) | Preparation method and application of novel polyvinylamine/(graphene oxide-carbon nanotube) composite aerogel | |
| CN110669172A (en) | Preparation method and application of molecularly imprinted polymer | |
| CN114653344B (en) | Triazole gel material, preparation method thereof and application thereof in adsorbing organic pollutants |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |