High-performance malachite green adsorbent as well as preparation method and application thereof

Abstract

The invention discloses a high-performance malachite green adsorbent as well as a preparation method and application thereof, and belongs to the technical field of preparation of malachite green adsorbents. The method comprises the following steps: with a carbon-based adsorbent as a raw material and an ethanol aqueous solution and a sodium hydroxide solution as modifiers, heating and stirring on a magnetic stirrer to form a turbid liquid; and further carrying out solid-liquid separation on the turbid liquid, washing a solid product with deionized water until the solid product is neutral, and drying. The prepared high-performance malachite green adsorbent is used for treating malachite green printing and dyeing wastewater, and compared with a carbon-based adsorbent raw material, the adsorption performance is effectively improved. The preparation method of the high-performance malachite green adsorbent is simple, rapid, low in energy consumption and good in environmental protection property.

Description

Technical Field

[0001] The invention relates to the technical field of malachite green adsorbent preparation, in particular to a high-performance malachite green adsorbent and a preparation method and application thereof. Background Art

[0002] Carbon-based materials have attracted much attention as potential adsorbents for wastewater treatment. Carbon-based adsorbents used for wastewater treatment usually have high specific surface area and good pore structure, and exhibit the advantages of fast adsorption / desorption kinetics and high adsorption capacity. The pore development of carbon-based adsorbents is an important factor in physical adsorption. Carbonization and activation are the two most common and effective methods for preparing porous adsorbents. Carbon-containing organic matter is usually used as a precursor to prepare carbon-based adsorbents by pyrolysis in a high-temperature inert atmosphere for a certain period of time directly or after adding an activator. In the process of preparing carbon-based adsorbents, high temperature increases the carbonization degree and specific surface area of ​​carbon-containing organic matter, but it also brings a serious negative impact, that is, the functional groups on the surface of the carbon-based adsorbent are significantly reduced, especially when the pore structure of the adsorbent is increased by adding an activator.

[0003] The type and number of surface functional groups of carbon-based adsorbents are also important factors affecting their adsorption performance. Therefore, loading more functional groups that are beneficial to pollutant adsorption on the surface of carbon-based adsorbents after carbonization or activation is one of the main challenges in improving the application potential of carbon-based adsorbents in the field of wastewater treatment. Correspondingly, how to successfully load surface functional groups that are beneficial to adsorption on the surface of carbon-based adsorbents after carbonization or activation is a cutting-edge direction for improving the adsorption performance of carbon-based adsorbents. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a high-performance malachite green adsorbent and a preparation method and application thereof, which can achieve more effective and faster adsorption of malachite green in sewage. The method prepares a high-performance malachite green adsorbent by modifying with sodium hydroxide and ethanol, thereby increasing the content of hydroxyl functional groups on the surface of the carbon-based adsorbent. In addition, during the modification process, sodium hydroxide provides an alkaline environment, so that the hydroxyl functional groups on the surface of the carbon-based adsorbent are in a deprotonated state and negatively charged, thereby facilitating the adsorption of the cationic dye malachite green in sewage.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for preparing a high-performance malachite green adsorbent comprises the following steps: Step 1, adding a certain amount of carbon-based adsorbent as a raw material into an ethanol aqueous solution, and then adding a certain amount of sodium hydroxide solution, heating and stirring on a magnetic stirrer to form a suspension; Step 2: The suspension obtained in step 1 is subjected to solid-liquid separation, and the solid product is washed with deionized water until it is neutral and dried.

[0006] Furthermore, the step 1 is specifically as follows: the sampling amount of the carbon-based adsorbent raw material is 1~10 g, added to 1 L of ethanol aqueous solution, the volume ratio of ethanol to water is 10:1~15:1, and then 20~30 mL of 0.1 mol / L sodium hydroxide solution is added, and heated and stirred on a magnetic stirrer for 1~3 h to form a suspension, the stirring speed of the magnetic stirrer is 300~800r / min, and the heating temperature is 65~100°C.

[0007] Furthermore, in step 2, the suspension is separated from the solid by vacuum filtration or centrifugation, and the collected solid is washed with deionized water until the pH of the washing liquid is neutral, and then dried in a vacuum drying oven or a forced air drying oven until the solid is constant weight, thereby obtaining a high-performance malachite green adsorbent.

[0008] The present invention also relates to a high-performance malachite green adsorbent prepared by the method.

[0009] The present invention also relates to the application of the high-performance malachite green adsorbent prepared by the method in wastewater containing malachite green.

[0010] Furthermore, the malachite green adsorbent is adsorbed for 0.5 to 24 h.

[0011] Furthermore, the added amount of the malachite green adsorbent is 0.1~1.6 g / L.

[0012] Furthermore, the pH of the malachite green wastewater is 2-10.

[0013] Furthermore, the concentration of the malachite green wastewater is 0.1~1 g / L.

[0014] Furthermore, the temperature of the malachite green adsorbent adsorption environment is 15-45 °C.

[0015] Furthermore, the concentration of the impure ion KCl added to the malachite green wastewater is 0~1 mol / L.

[0016] The beneficial effects of the present invention are: (1) the preparation method of high-performance malachite green adsorbent is universal; (2) The prepared high-performance malachite green adsorbent has higher malachite green adsorption performance; (3) The preparation method of high-performance malachite green adsorbent is simple to operate and the reaction conditions are mild; (4) The modified reagents can be recycled multiple times during the preparation of high-performance malachite green adsorbents, which has significant environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a flow chart of a method for preparing a high-performance malachite green adsorbent according to the present invention; Figure 2 It is a comparison chart of the adsorption performance of the carbon-based adsorbent raw material and the modified carbon-based adsorbent of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0020] The carbon-based adsorbent in this embodiment uses potassium hydroxide to activate pine wood activated carbon. The preparation method of modified potassium hydroxide activated pine wood activated carbon is as follows: First, the potassium hydroxide activated pine wood activated carbon prepared in the laboratory was crushed and passed through 100 and 200 mesh sieves, and placed in a 105 ± 5 ℃ air drying oven to constant weight. Then, 10 g of potassium hydroxide activated pine wood activated carbon was weighed, placed in a 2 L beaker, and 1 L of ethanol aqueous solution was added, the volume ratio of ethanol to water was 5:1, and then 25 mL of 0.1 mol / L sodium hydroxide solution was added, and heated and stirred on a magnetic stirrer for 1 h to form a suspension. The stirring speed of the magnetic stirrer was 300~800 r / min, and the heating temperature was 65 ℃. Subsequently, the suspension as described above was separated from the solid by vacuum filtration, and the solid was washed with deionized water until the pH of the washing solution was neutral. The washed solid product was placed in a blast drying oven and dried at a temperature of 105 ± 5 ℃ until the solid was constant weight, and the modified potassium hydroxide activated pine wood activated carbon was obtained.

[0021] The adsorption effect experimental steps of modified potassium hydroxide activated pine wood activated carbon prepared in this example are as follows: ① Prepare a 0.5 g / L malachite green stock solution by dissolving a certain amount of malachite green (≥99%) solid powder in deionized water; ② Adjust the pH of the malachite green stock solution to neutral with 0.1 mol / L HCl or 0.1 mol / L NaOH; ③ Use an analytical balance to weigh 10 mg of the prepared high-performance malachite green adsorbent modified potassium hydroxide activated pine wood activated carbon and potassium hydroxide activated pine wood activated carbon, respectively, and add them to a total volume of 50 mL of 0.5 g / L malachite green solution; ④ Place in a constant temperature water bath oscillator and oscillate at 150 rpm, and keep the water bath temperature at 25 °C for 24 h; ⑤ Use a 0.45 µm organic needle filter to separate the malachite green solution and the adsorbent; ⑥ Use an ultraviolet-visible spectrophotometer (UV-1800PC) to measure at a maximum wavelength of 618 nm to detect the concentration of the residual malachite green solution to determine the adsorption amount.

[0022] The adsorption effect of this embodiment Figure 2 The adsorption performance of pine wood activated carbon activated by potassium hydroxide and pine wood activated carbon activated by modified potassium hydroxide was compared. By comparing the adsorption with potassium hydroxide activated pine wood activated carbon, the adsorption capacity of modified potassium hydroxide activated pine wood activated carbon for malachite green printing and dyeing wastewater increased from 2189.9 mg / g to 2453.5 mg / g, and the removal rate increased from 87.6% to 98.1%. This group of experimental results shows that the adsorption capacity of potassium hydroxide activated pine wood activated carbon for malachite green is significantly improved after modification, achieving a good printing and dyeing wastewater treatment effect, and the pollutant malachite green is almost completely removed. In addition, the results also prove the effectiveness of the modified potassium hydroxide activated pine wood activated carbon adsorbent method. Embodiment 2

[0023] The carbon-based adsorbent in this embodiment uses pyrolytic carbon of blue algae, and the preparation method of modified pyrolytic carbon of blue algae is as follows: First, the pyrolytic carbon of blue algae prepared in the laboratory was crushed and passed through 100 and 200 mesh sieves, and placed in a 105 ± 5 ℃ air drying oven until constant weight. Then 10 g of pyrolytic carbon of blue algae was weighed, placed in a 2 L beaker, and 1 L of ethanol aqueous solution was added, the volume ratio of ethanol to water was 5:1, and then 25 mL of 0.1 mol / L sodium hydroxide solution was added, and heated and stirred on a magnetic stirrer for 1 h to form a suspension. The stirring speed of the magnetic stirrer was 300~800 r / min, and the heating temperature was 65 ℃. Subsequently, the suspension as described above was separated from the solid by vacuum filtration, and the solid was washed with deionized water until the pH of the washing solution was neutral. The washed solid product was placed in a blast drying oven and dried at a temperature of 105 ± 5 ℃ until the solid was constant weight to obtain modified pyrolytic carbon of blue algae.

[0024] The adsorption effect experimental steps of the modified cyanobacteria pyrolysis carbon prepared in this example are as follows: ① Prepare a 0.5 g / L malachite green stock solution by dissolving a certain amount of malachite green (≥99%) solid powder in deionized water; ② Adjust the pH of the malachite green stock solution to neutral with 0.1 mol / L HCl or 0.1 mol / L NaOH; ③ Use an analytical balance to weigh 10 mg of the modified cyanobacteria pyrolytic carbon and cyanobacteria pyrolytic carbon prepared above and add them to a total volume of 50 mL of 0.5 g / L malachite green solution; ④ Place in a constant temperature water bath oscillator and oscillate at a speed of 150 rpm, and keep the water bath temperature at 25 °C for 24 h; ⑤ Use a 0.45 µm organic needle filter to separate the malachite green solution and the adsorbent; ⑥ Use an ultraviolet-visible spectrophotometer (UV-1800PC) to measure at a maximum wavelength of 618 nm to detect the concentration of the residual malachite green solution to determine the adsorption amount.

[0025] The adsorption effect of this embodiment Figure 2 The adsorption performance of pyrolytic carbon of cyanobacteria and modified pyrolytic carbon of cyanobacteria was compared. By comparing the adsorption with pyrolytic carbon of cyanobacteria, the adsorption capacity of modified pyrolytic carbon of cyanobacteria for malachite green printing and dyeing wastewater increased from 2063.5 mg / g to 2229.3 mg / g, and the removal rate increased from 82.1% to 89.2%.

[0026] The experimental results show that the adsorption capacity of cyanobacteria pyrolytic carbon for malachite green is significantly improved after modification, and the method of preparing cyanobacteria pyrolytic carbon adsorbent by modification is effective. Embodiment 3

[0027] The carbon-based adsorbent in this embodiment uses potassium hydroxide to activate Zhundong coal activated carbon. The preparation method of modified potassium hydroxide activated Zhundong coal activated carbon is as follows: First, the potassium hydroxide activated Zhundong coal activated carbon prepared in the laboratory was crushed and passed through 100 and 200 mesh sieves, and placed in a blast drying oven at 105 ± 5 °C until constant weight. Then, 10 g of potassium hydroxide activated Zhundong coal activated carbon was weighed, placed in a 2 L beaker, 1 L of ethanol aqueous solution was added, the volume ratio of ethanol to water was 5:1, and then 25 mL of 0.1 mol / L sodium hydroxide solution was added, and heated and stirred on a magnetic stirrer for 1 h to form a suspension. The stirring speed of the magnetic stirrer was 300~800 r / min, and the heating temperature was 65 °C. Subsequently, the suspension as described above was separated from the solid by vacuum filtration, and the solid was washed with deionized water until the pH of the washing solution was neutral. The washed solid product was placed in a blast drying oven and dried at a temperature of 105 ± 5 °C until the solid was constant weight to obtain the modified potassium hydroxide activated Zhundong coal activated carbon.

[0028] The experimental steps for the adsorption effect of modified potassium hydroxide activated Zhundong coal activated carbon prepared in this example are as follows: ① Prepare a 0.5 g / L malachite green stock solution by dissolving a certain amount of malachite green (≥99%) solid powder in deionized water; ② Adjust the pH of the malachite green stock solution to neutral with 0.1 mol / L HCl or 0.1 mol / L NaOH; ③ Use an analytical balance to weigh 10 mg of the modified potassium hydroxide activated Zhundong coal activated carbon and potassium hydroxide activated Zhundong coal activated carbon prepared above and add them to a total volume of 50 mL of 0.5 g / L malachite green solution; ④ Place in a constant temperature water bath oscillator and oscillate at a speed of 150 rpm, and keep the water bath temperature at 25 °C for 24 h; ⑤ Use a 0.45 µm organic needle filter to separate the malachite green solution and the adsorbent; ⑥ Use an ultraviolet-visible spectrophotometer (UV-1800PC) to measure at a maximum wavelength of 618 nm to detect the concentration of the residual malachite green solution to determine the adsorption amount.

[0029] The adsorption effect of this embodiment Figure 2The adsorption performance of Zhundong coal activated carbon activated by potassium hydroxide and activated carbon activated by modified potassium hydroxide was compared. By comparing the adsorption with pyrolytic carbon of cyanobacteria, the adsorption capacity of modified pyrolytic carbon of cyanobacteria for malachite green printing and dyeing wastewater increased from 1894.4 mg / g to 2079.3 mg / g, and the removal rate increased from 75.8% to 83.2%. This group of experimental results shows that the adsorption capacity of malachite green by activated carbon activated by potassium hydroxide is significantly improved after modification, and the modified activated carbon activated by potassium hydroxide prepared by this method is effective. Embodiment 4

[0030] The carbon-based adsorbent in this embodiment uses zinc chloride activated Zhundong coal activated carbon, and the preparation method of modified zinc chloride activated Zhundong coal activated carbon is as follows: First, the zinc chloride activated Zhundong coal activated carbon prepared in the laboratory was crushed and passed through 100 and 200 mesh sieves, and placed in a blast drying oven at 105 ± 5 °C until constant weight. Then, 10 g of zinc chloride activated Zhundong coal activated carbon was weighed, placed in a 2L beaker, 1 L of ethanol aqueous solution was added, the volume ratio of ethanol to water was 5:1, and then 25 mL of 0.1 mol / L sodium hydroxide solution was added, and heated and stirred on a magnetic stirrer for 1 h to form a suspension. The stirring speed of the magnetic stirrer was 300~800 r / min, and the heating temperature was 65 °C. Subsequently, the suspension as described above was separated from the solid by vacuum filtration, and the solid was washed with deionized water until the pH of the washing solution was neutral. The washed solid product was placed in a blast drying oven and dried at a temperature of 105 ± 5 °C until the solid was constant weight to obtain modified zinc chloride activated Zhundong coal activated carbon.

[0031] The experimental steps for the adsorption effect of modified zinc chloride activated Zhundong coal activated carbon prepared in this example are as follows: ① Prepare a 0.5 g / L malachite green stock solution by dissolving a certain amount of malachite green (≥99%) solid powder in deionized water; ② Adjust the pH of the malachite green stock solution to neutral with 0.1 mol / L HCl or 0.1 mol / L NaOH; ③ Use an analytical balance to weigh 10 mg of the hydrogen-modified zinc chloride-activated Zhundong coal activated carbon and zinc chloride-activated Zhundong coal activated carbon respectively and add them to a total volume of 50 mL of 0.5 g / L malachite green solution; ④ Place in a constant temperature water bath oscillator and oscillate at a speed of 150 rpm, and keep the water bath temperature at 25 °C for 24 h; ⑤ Use a 0.45 µm organic needle filter to separate the malachite green solution and the adsorbent; ⑥ Use an ultraviolet-visible spectrophotometer (UV-1800PC) to measure at a maximum wavelength of 618 nm to detect the concentration of the residual malachite green solution to determine the adsorption amount.

[0032] The adsorption effect of this embodiment Figure 2 The adsorption performance of zinc chloride activated Zhundong coal activated carbon and modified zinc chloride activated Zhundong coal activated carbon was compared. By comparing the adsorption with zinc chloride activated Zhundong coal activated carbon, the adsorption capacity of modified zinc chloride activated Zhundong coal activated carbon for malachite green printing and dyeing wastewater increased from 2163 mg / g to 2383 mg / g, and the removal rate increased from 86.5% to 95.3%. This group of experimental results shows that the adsorption capacity of zinc chloride activated Zhundong coal activated carbon for malachite green is significantly improved after modification, and the modification method is effective in preparing zinc chloride activated Zhundong coal activated carbon adsorbent. Embodiment 5

[0033] The carbon-based adsorbent in this embodiment uses Zhundong coal, and the preparation method of modified Zhundong coal is as follows: First, the Zhundong coal was crushed and passed through 100 and 200 mesh sieves, and placed in a blast drying oven at 105 ± 5 °C until constant weight. Then 10 g of Zhundong coal was weighed, placed in a 2 L beaker, 1 L of ethanol aqueous solution was added, the volume ratio of ethanol to water was 5:1, and then 25 mL of 0.1 mol / L sodium hydroxide solution was added, and heated and stirred on a magnetic stirrer for 1 h to form a suspension. The stirring speed of the magnetic stirrer was 300~800 r / min, and the heating temperature was 65 °C. Subsequently, the suspension as described above was separated from the solid by vacuum filtration, and the solid was washed with water to remove the modified Zhundong coal until the pH of the washing solution was neutral. The washed solid product was placed in a blast drying oven and dried at a temperature of 105 ± 5 °C until the solid was constant weight to obtain modified Zhundong coal.

[0034] The adsorption effect experimental steps of the modified Zhundong coal prepared in this example are as follows: ① Prepare a 0.5 g / L malachite green stock solution by dissolving a certain amount of malachite green (≥99%) solid powder in deionized water; ② Adjust the pH of the malachite green stock solution to neutral with 0.1 mol / L HCl or 0.1 mol / L NaOH; ③ Use an analytical balance to weigh 10 mg of the modified Zhundong coal and Zhundong coal prepared above and add them to a total volume of 50 mL of 0.5 g / L malachite green solution; ④ Place in a constant temperature water bath oscillator and oscillate at a speed of 150 rpm, and keep the water bath temperature at 25 °C for 24 h; ⑤ Use a 0.45 µm organic needle filter to separate the malachite green solution and the adsorbent; ⑥ Use an ultraviolet-visible spectrophotometer (UV-1800PC) to measure at a maximum wavelength of 618 nm to detect the concentration of the residual malachite green solution to determine the adsorption amount.

[0035] The adsorption effect of this embodiment Figure 2 The adsorption performance of Zhundong coal and modified Zhundong coal was compared. By comparing the adsorption with Zhundong coal, the adsorption capacity of modified Zhundong coal for malachite green printing and dyeing wastewater increased from 852.0 mg / g to 1764.1 mg / g, and the removal rate increased from 34.1% to 70.6%. This group of experimental results shows that the adsorption capacity of Zhundong coal for malachite green is significantly improved after modification, and the preparation of Zhundong coal adsorbent by modification is effective.

[0036] See also Figure 2 The graphs are comparative diagrams of the adsorption effects of the carbon-based adsorbent and the modified carbon-based adsorbent of the present invention. The experimental results show that the preparation method of the high-performance malachite green adsorbent improves the adsorption capacity of the carbon-based adsorbent for malachite green. It can be seen that the preparation method of the high-performance malachite green adsorbent provided by the present invention is universal and can achieve a good adsorption effect on malachite green pollutants.

[0037] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a high-performance malachite green adsorbent, characterized in that: The steps include: Step 1, adding a certain amount of carbon-based adsorbent as a raw material into an ethanol aqueous solution, and then adding a certain amount of sodium hydroxide solution, heating and stirring on a magnetic stirrer to form a suspension; Step 2: The suspension obtained in step 1 is subjected to solid-liquid separation, and the solid product is washed with deionized water until it is neutral and dried.

2. The method for preparing a high-performance malachite green adsorbent according to claim 1, characterized in that: The step 1 is specifically as follows: a sample amount of 1-10 g of the carbon-based adsorbent raw material is added to 1 L of ethanol aqueous solution, the volume ratio of ethanol to water is 10:1-15:1, and then 20-30 mL of 0.1 mol / L sodium hydroxide solution is added, and the suspension is heated and stirred on a magnetic stirrer for 1-3 h to form a suspension, the stirring speed of the magnetic stirrer is 300-800 r / min, and the heating temperature is 65-100°C.

3. The method for preparing a high-performance malachite green adsorbent according to claim 1 or 2, characterized in that: In the step 2, the suspension is separated into solid and liquid by vacuum filtration or centrifugation, and the collected solid is washed with deionized water until the pH of the washing liquid is neutral, and then dried in a vacuum drying oven or a forced air drying oven until the solid is constant weight, thereby obtaining a high-performance malachite green adsorbent.

4. A high-performance malachite green adsorbent prepared by the method described in any one of claims 1 to 3.

5. Use of the malachite green adsorbent according to claim 4 in wastewater containing malachite green.

6. The use according to claim 5, characterized in that: The malachite green adsorbent is adsorbed for 0.5 to 24 h.

7. The use according to claim 5, characterized in that: The added amount of the malachite green adsorbent is 0.1~1.6g / L.

8. The use according to claim 5, characterized in that: The pH of the malachite green wastewater is 2-10.

9. The use according to claim 5, characterized in that: The concentration of the malachite green wastewater is 0.1-1 g / L; the temperature of the adsorption environment of the malachite green adsorbent is 15-45°C.

10. The use according to claim 5, characterized in that: The concentration of the impure ion KCl added to the malachite green wastewater is 0-1 mol / L.

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