1, 3, 5-tri (1 '-methylene-3'-vinyl imidazole) benzene functionalized hydrothermal bamboo charcoal adsorbent as well as preparation method and application thereof

Abstract

The invention discloses a 1, 3, 5-tri (1 '-methylene-3'-vinyl imidazole) benzene functionalized hydrothermal bamboo charcoal adsorption material and a preparation method and application thereof.The preparation method of the adsorption material comprises the steps that bamboo powder, 1, 3, 5-tri (1 '-methylene-3'-vinyl imidazole bromine) benzene, azodiisobutyronitrile and a solvent are evenly mixed and then subjected to a hydrothermal reaction, and the 1, 3, 5-tri (1 '-methylene-3'-vinyl imidazole bromine) benzene functionalized hydrothermal bamboo charcoal adsorption material is obtained. After the reaction is finished, the 1, 3, 5-tri (1 '-methylene-3'-vinyl imidazole) benzene functionalized hydrothermal bamboo charcoal adsorbent is obtained. The prepared adsorbent can effectively adsorb anion pollutants, the highest adsorption capacity of methyl orange at room temperature can reach 605mg / g, the highest adsorption capacity of 2, 4-D Na can reach 338mg / g, and the adsorbent can be recycled and has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the field of water pollution treatment, and in particular relates to a 1,3,5-tris(1'-methylene-3'-vinyl imidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent and a preparation method and application thereof. Background Art

[0002] With the rapid development of industrialization and agriculture, water pollution is becoming increasingly serious, especially the emission of dyes and pesticides has posed a great threat to the environment. Dyes are widely used in textile, leather, food and other industries, while pesticides are important chemicals in agricultural production. These two types of pollutants are often difficult to degrade after entering the water body, causing long-term ecological damage and water pollution. Although a large number of adsorbents such as MOFs, hydrogels, mesoporous materials, activated carbon, etc. have been used in wastewater treatment, they still have disadvantages such as low stability, high price, low adsorption capacity, and poor regeneration ability. Therefore, it is crucial to develop and utilize convenient, economical, and environmentally friendly materials to remove pollution sources in water environment systems. Hydrothermal carbonization is a green, environmentally friendly, and simple method for preparing carbon materials. It can convert agricultural and forestry wastes into carbon-rich materials under mild conditions. The prepared hydrothermal carbon has a small specific surface area and lacks specific binding sites on the surface, resulting in limited adsorption capacity for pollutants. In order to improve the adsorption capacity of hydrothermal carbon for pollutants, it is necessary to graft active sites onto the surface of hydrothermal carbon. Currently, the modification of active functional groups on the surface of hydrothermal carbon generally adopts post-modification synthesis, but this method has the disadvantages of complex steps, high cost, and great potential threat to environmental pollution. Compared with the post-modification synthesis method, the direct hydrothermal carbonization method for preparing hydrothermal carbon with rich functional groups is convenient, simple and low-cost.

[0003] As a renewable resource, bamboo has a short growth cycle and high yield, which can effectively alleviate the problem of wood resource reduction. Hydrothermal bamboo charcoal is a bamboo charcoal material prepared by hydrothermal carbonization technology. It has excellent adsorption properties and is widely used in air purification and wastewater treatment. In order to improve the adsorption performance of hydrothermal bamboo charcoal, various modification methods are commonly used, including acid-base, redox, metal oxide and organic modification, which can improve the surface properties and adsorption capacity of hydrothermal bamboo charcoal. However, these post-modification functionalized hydrothermal carbons require multiple steps to complete, which increases the preparation cost and other problems. Therefore, it is particularly important to find a way to directly hydrothermally carbonize biomass in one step to prepare hydrothermal carbon with high adsorption performance. Summary of the invention

[0004] Purpose of the invention: The present invention aims to provide a 1,3,5-tris(1′-methylene-3′-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent and a preparation method thereof. The preparation method adopts a one-step hydrothermal reaction combined with a free radical copolymerization method to synthesize a functionalized hydrothermal bamboo charcoal adsorbent material. Water is used as a solvent during the reaction process, which is simple and environmentally friendly. Another purpose of the present invention is to provide the application of the 1,3,5-tris(1′-methylene-3′-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent material in the adsorption of dyes and anionic pesticides. The adsorbent material has a stable structure and good cyclic adsorption performance.

[0005] Technical solution: The preparation method of the 1,3,5-tris(1′-methylene-3′-vinyl imidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent of the present invention comprises the following steps:

[0006] Bamboo powder, 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene, azobisisobutyronitrile and a solvent are uniformly mixed and then subjected to a hydrothermal reaction. After the reaction is completed, the 1,3,5-tris(1′-methylene-3′-vinyl imidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent is obtained.

[0007] The synthetic route of the above reaction is as follows:

[0008]

[0009] Furthermore, the mass ratio of the bamboo powder, 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene and azobisisobutyronitrile is (1-2):(1-2):(0.03-0.06); after being evenly mixed, they are added into a hydrothermal reactor and nitrogen is passed through for 15-30 minutes. The reaction conditions are thermochemical reaction; the reaction temperature is 200-240° C., and the reaction time is 8-12 hours.

[0010] Furthermore, after the hydrothermal reaction is completed, the reaction solution is cooled to room temperature, filtered, washed and dried, the drying temperature is 60-80° C., and the washing solvent is deionized water.

[0011] The 1,3,5-tris(1'-methylene-3'-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal adsorbent prepared by the preparation method can be used for adsorbing dyes and anionic pesticides, wherein the dye is methyl orange and the anionic pesticide is 2,4-D Na.

[0012] Principle of the invention: The present invention grafts 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene containing unsaturated double bonds onto the surface of hydrothermal bamboo charcoal rich in hydroxyl groups through a hydrothermal reaction combined with a free radical copolymerization method, introduces corresponding positively charged N functional groups and benzene ring functional groups, and makes the surface potential of the hydrothermal charcoal positive, thereby improving the adsorption capacity of the modified hydrothermal charcoal for anionic aromatic methyl orange and 2,4-D Na through electrostatic interactions and π-π interactions. 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal is positively charged under conditions below pH 11.2, which is conducive to the hydrothermal bamboo charcoal adsorbing anionic pollutants through electrostatic interactions in a wide pH range, and the adsorption capacity is relatively high.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The preparation method is simple and environmentally friendly. The adsorbent is prepared by a one-step hydrothermal carbonization method. The 1,3,5-tri(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal adsorption material is synthesized by a hydrothermal reaction combined with a free radical copolymerization method. Water is used as a solvent during the reaction process, which is green and environmentally friendly. (2) The adsorbent prepared by the preparation method can effectively adsorb anionic pollutants. The adsorption amount of methyl orange can reach up to 605 mg / g at room temperature, and the adsorption amount of 2,4-D Na can reach up to 338 mg / g. In addition, the adsorbent material can be recycled and has good application prospects in the field of water pollution control. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 a) is the adsorption capacity of 1,3,5-tri(1′-methylene-3′-vinyl imidazolyl bromide)benzene functionalized hydrothermal bamboo charcoal for methyl orange at different initial concentrations. Figure 1 b) is the adsorption capacity of 1,3,5-tri(1′-methylene-3′-vinyl imidazolium bromide)benzene functionalized hydrothermal bamboo charcoal for different initial concentrations of 2,4-D Na;

[0015] Figure 2 This is a test diagram for the reuse of 1,3,5-tris(1′-methylene-3′-vinylimidazole bromide)benzene functionalized hydrothermal bamboo charcoal for the adsorption of methyl orange and 2,4-D Na. DETAILED DESCRIPTION

[0016] Example 1

[0017] The preparation method of the 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal adsorbent is as follows:

[0018] 1 g of washed bamboo powder, 1 g of 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene, 0.03 g of azobisisobutyronitrile, and 3 mL of deionized water were weighed respectively, poured into a 100 mL polytetrafluoroethylene-lined high-pressure reactor, passed nitrogen for 15 min, heated at 200 °C for reaction for 8 h, and after cooling to room temperature, washed with deionized water until the filtrate was clear, and dried at 60 °C to obtain a free radical functionalized hydrothermal bamboo charcoal adsorbent, which was named VIm-3HC.

[0019] Example 2

[0020] The preparation method of the 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal adsorbent is as follows:

[0021] 1 g of washed bamboo powder, 2 g of 1,3,5-tris(1′-methylene-3′-vinylimidazole bromide)benzene, 0.03 g of azobisisobutyronitrile, and 6 mL of deionized water were weighed respectively, poured into a 100 mL polytetrafluoroethylene-lined high-pressure reactor, passed nitrogen for 15 min, heated at 220 °C for 10 h, and after cooling to room temperature, washed with deionized water until the filtrate was clear, and dried at 60 °C to obtain a free radical functionalized hydrothermal bamboo charcoal adsorbent, which was named VIm-3HC.

[0022] Example 3

[0023] The preparation method of the 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal adsorbent is as follows:

[0024] 2 g of washed bamboo powder, 2 g of 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene, 0.06 g of azobisisobutyronitrile, and 6 mL of deionized water were weighed respectively, poured into a 100 mL polytetrafluoroethylene-lined high-pressure reactor, passed nitrogen for 30 min, heated at 240 °C for 12 h, and after cooling to room temperature, washed with deionized water until the filtrate was clear, and dried at 80 °C to obtain a free radical functionalized hydrothermal bamboo charcoal adsorbent, which was named VIm-3HC.

[0025] Application Examples

[0026] 50 mg of the dried adsorbent VIm-3HC prepared in Example 1 was added to the solution at initial concentrations of 300, 400, 500, 600, 700, 800, 900, 1000, and 1100 mg·L -1 of methyl orange solution and 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 mg·L -1The adsorption capacity at different initial concentrations was determined and calculated.

[0027] like Figure 1 a) shows the adsorption capacity of 1,3,5-tri(1′-methylene-3′-vinyl imidazolium bromide)benzene functionalized hydrothermal bamboo charcoal for different initial concentrations of methyl orange. Figure 1 b) shows the adsorption capacity of 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal for different initial concentrations of 2,4-D Na. It can be seen from the figure that at room temperature, the 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal has an adsorption capacity of up to 605 mg / g for methyl orange and a maximum adsorption capacity of 338 mg / g for 2,4-D Na, both showing excellent adsorption performance.

[0028] Reuse Test

[0029] 0.50 g of the adsorbent was mixed with 500 mL of methyl orange solution with a concentration of 500 mg / L, and oscillated at room temperature until adsorption equilibrium was reached. Subsequently, a mixture of 250 mL of ethanol and 0.2 mol / L sodium hydroxide solution (volume ratio 1:1) was added as a desorbent for desorption, and the regenerated adsorbent was acidified with 100 mL of 0.2 mol / L hydrochloric acid, filtered and dried, and its adsorption performance was repeatedly tested.

[0030] 0.50 g of the adsorbent was mixed with 500 mL of 500 mg / L 2,4-D Na solution, and oscillated at room temperature until adsorption reached equilibrium. Subsequently, 500 mL of 0.2 mol / L sodium chloride solution was used as a desorbent for desorption. After filtering and drying, the adsorption performance was repeatedly tested.

[0031] The experimental results show that (see Figure 2 ), the adsorption amount of methyl orange by the adsorbent still remained at 83% after 5 cycles, and the adsorption amount of 2,4-D Na hardly changed. It showed excellent cycle stability and recycling performance. This shows that the 1,3,5-tris(1′-methylene-3′-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal is an adsorption material with stable structure and excellent performance, and has good application prospects in the field of water pollution control.

Claims

1. A method for preparing a 1,3,5-tris(1'-methylene-3'-vinyl imidazole bromide)benzene functionalized hydrothermal bamboo charcoal adsorbent, characterized in that: The steps include: Bamboo powder, 1,3,5-tris(1'-methylene-3'-vinyl imidazole bromide)benzene, azobisisobutyronitrile and solvent are uniformly mixed and then subjected to hydrothermal reaction. After the reaction is completed, the 1,3,5-tris(1'-methylene-3'-vinyl imidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent is obtained.

2. The method for preparing the 1,3,5-tris(1'-methylene-3'-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent according to claim 1, characterized in that: The reaction temperature of the hydrothermal reaction is 200-240° C., and the reaction time is 8-12 hours.

3. The method for preparing the 1,3,5-tris(1'-methylene-3'-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent according to claim 1, characterized in that: The mass ratio of the bamboo powder, 1,3,5-tris(1'-methylene-3'-vinyl imidazole bromide)benzene and azobisisobutyronitrile is (1-2):(1-2):(0.03-0.06).

4. The method for preparing the 1,3,5-tris(1'-methylene-3'-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent according to claim 1, characterized in that: The hydrothermal reaction is carried out in a nitrogen environment, and the nitrogen is introduced for 15-30 minutes.

5. The method for preparing the 1,3,5-tris(1'-methylene-3'-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent according to claim 1, characterized in that: After the hydrothermal reaction is completed, the reaction solution is cooled to room temperature, filtered, washed and dried. The drying temperature is 60-80° C. and the washing reagent is deionized water.

6. A 1,3,5-tris(1'-methylene-3'-vinyl imidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the 1,3,5-tris(1'-methylene-3'-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent according to claim 6 in the adsorption of dyes and anionic pesticides.

8. The use of 1,3,5-tris(1'-methylene-3'-vinylimidazole)benzene functionalized hydrothermal bamboo charcoal adsorbent in adsorbing dyes and anionic pesticides according to claim 7, characterized in that: The dye is methyl orange, and the anionic pesticide is 2,4-D sodium.

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