CN114395410A

CN114395410A - Preparation method of biochar with high adsorption capacity, biochar and application

Info

Publication number: CN114395410A
Application number: CN202210068955.5A
Authority: CN
Inventors: 陈荣志; 邹致远; 陈扬; 冯钦忠; 龙鑫鑫; 李肖平
Original assignee: University of Chinese Academy of Sciences
Current assignee: University of Chinese Academy of Sciences
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2022-04-26

Abstract

The invention provides a preparation method of biochar with high adsorption capacity, biochar and application, and relates to a new material technology, which comprises the following steps: drying corn straws, and then crushing the corn straws into corn straw powder; grinding and mixing the corn straw powder, the potassium bicarbonate and the urea according to a preset weight proportion to obtain mixed powder; heating the mixed powder to 300-900 ℃ in a nitrogen environment, keeping the temperature for 1-4 hours, and then cooling to room temperature; pouring the mixed powder into hydrochloric acid, stirring, and then washing with water until the effluent is neutral; drying and cooling to obtain the biochar. The invention adopts the mixed urea and the potassium bicarbonate to burn and form the corn straws in one time in an anaerobic mode, compared with the traditional method which comprises the steps of gradually burning, the burning efficiency is higher, and the performance of the material can be further improved, so that the material has very high adsorption capacity.

Description

Preparation method of biochar with high adsorption capacity, biochar and application

Technical Field

The invention relates to a new material technology, in particular to a preparation method of high-adsorption-capacity biochar, biochar and application.

Background

The problem of water pollution is a major environmental challenge facing China at present, wherein the discharge amount of industrial wastewater is increased year by year due to the rapid development of the chemical industry, and the industrial wastewater has more toxic and harmful substances and very serious damage to the water body environment. Among them, the waste water generated in the printing and dyeing industry is very typical. Data show that in recent years, the dye yield of China exceeds seventy-ten thousand tons, more than ten thousand tons of dyes are used in the textile printing and dyeing industry every year, and 5-10% of the dyes are directly discharged. The treatment method of the dye contamination generally includes an electrochemical method, a biodegradation method, an adsorption method and the like, and the adsorption method is most widely used. The adsorption method is most common in treating dye pollution, and has the advantages of simple and convenient operation, low energy consumption, wide treatment range, no secondary pollution and the like. The development of more easily available, efficient and cheap adsorbents has very important significance for treating dye pollution.

Biochar, namely a carbon material obtained by carbonizing/activating biomass in various ways, further increases the utilization rate of biomass due to the utilization of the residual biomass (such as straw and the like) in the production process, and is generally low in production cost, friendly to environment, simple and easy to obtain, so that attention is paid to the field of dye adsorption pollution. However, the conventional biochar usually has more micropores, so that the biochar only has strong adsorption capacity on small molecular pollutants, the performance of the biochar is obviously reduced due to the relatively large molecules of the adsorptive dye, the adsorption effect is poor, and the removal rate and the capacity are obviously reduced. The current research shows that the biological carbon can be modified by adopting a proper additive, so that the biological carbon material can be further regulated to be a mesoporous material in the activation process, and active sites are added on the surface of the material, thereby greatly improving the adsorption capacity of the biological carbon. However, many of the existing methods for preparing modified biochar have the problems of complex operation, more steps, poor performance of the final product and the like.

Therefore, there is an urgent need to find a simpler method for preparing modified biochar, and to obtain a biochar material with better performance.

Disclosure of Invention

The embodiment of the invention provides a preparation method of high-adsorption-capacity biochar, biochar and application, and the adsorption capacity and the preparation efficiency are improved.

In a first aspect of embodiments of the present invention, there is provided a method for preparing biochar with high adsorption capacity, including:

drying corn straws, and then crushing the corn straws into corn straw powder;

grinding and mixing the corn straw powder, the potassium bicarbonate and the urea according to a preset weight proportion to obtain mixed powder;

heating the mixed powder to 300-900 ℃ in a nitrogen environment, keeping the temperature for 1-4 hours, and then cooling to room temperature;

pouring the mixed powder into hydrochloric acid, stirring, and then washing with water until the effluent is neutral;

drying and cooling to obtain the biochar.

Optionally, in one possible implementation manner of the first aspect, the corn stalks are dried and then pulverized into corn stalk powder, including:

taking dried corn straws, and drying the dried corn straws in an oven at 60 ℃ for 24 hours;

grinding the corn straws into powder by using a ball mill, and sieving the powder by using a 150-mesh sieve to obtain corn straw powder;

and putting the obtained corn straw powder into the oven at 60 ℃ again for drying for 24 hours.

Optionally, in one possible implementation manner of the first aspect, the grinding and mixing the corn straw powder, the potassium bicarbonate and the urea according to a preset weight ratio includes:

weighing 2g of dried corn straw powder, 4g of potassium bicarbonate and 2g of urea, adding the dried corn straw powder, the potassium bicarbonate and the urea into an agate mortar, and grinding and mixing for 30 min;

wherein the mass ratio of the potassium bicarbonate to the urea is 1: 2-2: 1.

Optionally, in a possible implementation manner of the first aspect, the heating the mixed powder to 300-900 ℃ for 1-4 hours in a nitrogen environment, and then cooling to room temperature includes:

transferring the mixed powder into a corundum boat, and putting the corundum boat into a corundum tube furnace;

sealing and vacuumizing the tubular furnace, introducing nitrogen for 30min, placing the tail end of the gas outlet pipe in water to ensure that the furnace is in an anoxic atmosphere, and introducing nitrogen in the whole heating process;

the temperature is raised to 800 ℃ at the speed of 5 ℃/min, kept at the temperature for 2h, and then cooled to room temperature at the speed of 5 ℃/min.

Alternatively, in one possible implementation manner of the first aspect, pouring the mixed powder into hydrochloric acid to be stirred, and then washing with water until water is neutral, includes:

taking 50mL of 1mol/L hydrochloric acid, pouring the materials in the corundum boat into the hydrochloric acid, and stirring for 1h on a magnetic stirrer with the rpm of 400;

and (3) carrying out suction filtration on the material, repeatedly washing the material with ultrapure water, testing the pH of the eluate after washing with 1L of ultrapure water, and stopping washing when the pH is detected to be 6.80-7.20.

Optionally, in one possible implementation manner of the first aspect, drying and cooling to obtain the biochar comprises:

the material was dried in an oven at 60 ℃ for 24h and then removed to cool to obtain biochar.

In a second aspect of the embodiments of the present invention, there is provided a biochar obtained by the above-described method for producing biochar with a high adsorption capacity.

In a third aspect of the embodiments of the present invention, there is provided a use of the above biochar in removing organic pollutants from simulated wastewater, including:

taking 50mL of rhodamine B wastewater with the concentration of 400mg/L, 600mg/L, 800mg/L, 1000mg/L and 1200mg/L respectively, adjusting the pH of the solution to 5, and preparing a wastewater sample and marking;

adding biochar into a wastewater sample, wherein the addition amount is 10mg/50 mL;

putting the mixture into a shaking table, adsorbing the mixture at the rotating speed of 200rpm for 8 hours, and sampling;

and (3) measuring the concentration of rhodamine B in the sample in an ultraviolet-visible spectrophotometer at the wavelength of 554nm to obtain the adsorption quantity result.

In a fourth aspect of the embodiments of the present invention, there is provided a use of the above biochar in removing organic pollutants from simulated wastewater, including:

taking 5 parts of rhodamine B wastewater with the mass concentration of 1000mg/L, wherein the volume is 50mL, adjusting the pH values to be 3, 5, 7, 9 and 11 by using hydrochloric acid and sodium hydroxide solution, and preparing wastewater samples and marking;

In a fifth aspect of the embodiments of the present invention, there is provided a use of the above biochar in removing organic pollutants from simulated wastewater, including:

respectively taking 50mL of rhodamine B, methylene blue and azure A wastewater with the concentration of 1000mg/L, adjusting the pH of the solution to 5, and preparing a wastewater sample and marking;

the concentrations of rhodamine B, methylene blue and azure A in the sample are respectively measured in an ultraviolet-visible spectrophotometer under the wavelength of 554nm, 665nm and 602nm, and the adsorption quantity result is obtained.

According to the preparation method of the biochar with high adsorption capacity, the biochar and the application, the corn straws are subjected to one-time anaerobic burning forming by adopting the mixed urea and the potassium bicarbonate, compared with the traditional method of gradually burning in steps, the method has higher burning efficiency, and can further improve the performance of the material so as to achieve the very high adsorption capacity of the material.

Drawings

FIG. 1 is a schematic flow chart of a method for preparing biochar with high adsorption capacity according to an embodiment of the invention;

FIG. 2 is a schematic diagram of SEM scanning results of a biochar material prepared by an embodiment of the invention;

FIG. 3 is a graph showing the result of removing the pollutant adsorption amount in wastewater according to an embodiment of the present invention;

FIG. 4 is a graphical representation of the results of adsorption capacity over a wide pH range provided by the examples of the present invention;

FIG. 5 is a schematic illustration of the ability to remove different species from different wastewaters provided by an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein.

It should be understood that, in various embodiments of the present invention, the sequence numbers of the processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the internal logic of the processes, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

It should be understood that in the present application, "comprising" and "having" and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be understood that, in the present invention, "a plurality" means two or more. "and/or" is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "comprises A, B and C" and "comprises A, B, C" means that all three of A, B, C comprise, "comprises A, B or C" means that one of A, B, C comprises, "comprises A, B and/or C" means that any 1 or any 2 or 3 of A, B, C comprises.

It should be understood that in the present invention, "B corresponding to a", "a corresponds to B", or "B corresponds to a" means that B is associated with a, and B can be determined from a. Determining B from a does not mean determining B from a alone, but may be determined from a and/or other information. And the matching of A and B means that the similarity of A and B is greater than or equal to a preset threshold value.

As used herein, "if" may be interpreted as "at … …" or "when … …" or "in response to a determination" or "in response to a detection", depending on the context.

The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Examples

A method for preparing biochar with high adsorption capacity is disclosed, and referring to figure 1, the method comprises steps S101-S105, and comprises the following steps:

s101, drying the corn straws, and then crushing the corn straws into corn straw powder.

Specifically, the dried corn straw can be dried in an oven, then ground into powder by using a ball mill, sieved, and dried in the oven again.

As an example, the dried corn straw is dried in an oven at 60 ℃ for 24 hours, the corn straw is ground into powder by using a ball mill and is sieved by a 150-mesh sieve to obtain corn straw powder, and the corn straw powder is dried in the oven at 60 ℃ for 24 hours again.

S102, grinding and mixing the corn straw powder, the potassium bicarbonate and the urea according to a preset weight proportion to obtain mixed powder.

Specifically, the dried corn straw powder can be taken, the potassium bicarbonate and the urea are additionally and respectively taken, the mass ratio of the potassium bicarbonate to the urea can be 1: 2-2: 1, and the three are added into an agate mortar for grinding and mixing.

For example, 2g of dried corn straw powder, 4g of potassium bicarbonate and 2g of urea are weighed, added into an agate mortar, and ground and mixed for 30min to obtain mixed powder, wherein the mass ratio of the potassium bicarbonate to the urea is 1: 2-2: 1, and can be 2: 3, for example.

S103, heating the mixed powder to 300-900 ℃ in a nitrogen environment, keeping the temperature for 1-4 hours, and then cooling to room temperature.

Specifically, the mixed powder obtained in step S102 is transferred to a corundum boat, the corundum boat is placed in a corundum tube furnace, the tube furnace is sealed, the tube furnace is vacuumized, nitrogen is introduced, the tail end of an air outlet pipe is placed in water, the oxygen-deficient atmosphere in the furnace is ensured, and nitrogen is introduced in the whole heating process. And heating to 300-900 ℃ and keeping for 1-4 h, then cooling to room temperature, and then taking out the corundum boat, wherein the heating and cooling speed is 1-8 ℃/min.

Illustratively, the mixed powder is transferred into a corundum boat, the corundum boat is placed into a corundum tube furnace, the tube furnace is sealed and vacuumized, nitrogen is introduced for 30min, the tail end of an air outlet pipe is placed in water, the oxygen-deficient atmosphere in the furnace is ensured, the nitrogen is introduced in the whole heating process, the temperature is increased to 800 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and then the temperature is reduced to room temperature at the speed of 5 ℃/min.

And S104, pouring the mixed powder into hydrochloric acid, stirring, and then washing with water until the effluent is neutral.

Specifically, a proper amount of hydrochloric acid is taken, the materials in the corundum boat are poured into the hydrochloric acid, the mixture is stirred on a magnetic stirrer, then the materials are filtered, and the material is repeatedly washed with ultrapure water until the effluent water is neutral, so that the washing can be stopped.

Illustratively, 50mL of 1mol/L hydrochloric acid is taken, materials in a corundum boat are poured into the hydrochloric acid, the mixture is stirred for 1h on a magnetic stirrer with the speed of 400rpm, the materials are filtered, the material is repeatedly washed with ultrapure water, the pH of an eluate is tested after every 1L of ultrapure water is used, and the washing is stopped when the pH is detected to be between 6.80 and 7.20.

And S105, drying and cooling to obtain the biochar.

Specifically, the material is dried in an oven, then taken out and cooled, and the material obtained after cooling is the required high adsorption capacity biological carbon material.

Illustratively, the material may be oven dried at 60 ℃ for 24 hours, and then removed for cooling to yield a biochar.

The scheme adopts the mixed urea and the potassium bicarbonate to burn and form the corn straw in one-time anaerobic mode, has higher burning efficiency compared with the traditional step-by-step burning mode, and can further improve the performance of the material so as to achieve the very high adsorption capacity of the material.

The embodiment also provides a biological carbon, which is obtained by the preparation method of the biological carbon with high adsorption capacity.

Referring to fig. 2, which is a schematic diagram of SEM scanning results of the biochar material prepared in the embodiment of the present invention, the prepared biochar material exhibits fluffy black uneven particles, and a large number of pore-size structures can be observed under a scanning electron microscope, which is advantageous for adsorption.

In order to prove the performance of the material, the application of removing the organic pollutants in the simulated wastewater by the biochar is also provided, and the application comprises the following steps:

The result of the adsorption amount is shown in fig. 3, and it can be known from the data in fig. 3 that the removal rate of the organic pollutants in the simulated wastewater removed by the biochar prepared by the embodiment of the invention is high and the adsorption amount is large.

In addition, in order to prove that the material has good effect in a wide pH range, the application of removing organic pollutants in simulated wastewater by the biochar is also provided, and the application comprises the following steps:

As can be seen from the data in fig. 4, the adsorption amount of the organic pollutants in the simulated wastewater removed by the biochar prepared by the embodiment of the invention is relatively large, and the biochar has a good effect in a wide pH range.

Besides, in order to prove that the material has good effect on various pollutants, the application of removing the organic pollutants in the simulated wastewater by the biochar is also provided, and the application comprises the following steps:

The results of the adsorption amount are shown in fig. 5, and it can be known from the data in fig. 5 that the adsorption amount of the organic pollutants in the simulated wastewater removed by the biochar prepared by the embodiment of the invention is large, and the biochar has a good effect on various pollutants.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing biochar with high adsorption capacity is characterized by comprising the following steps:

drying corn straws, and then crushing the corn straws into corn straw powder;

drying and cooling to obtain the biochar.

2. The method of claim 1, wherein the corn stover is dried and thereafter comminuted into a corn straw meal, comprising:

3. The method of claim 1, wherein the grinding and mixing of the corn straw powder, the potassium bicarbonate and the urea in a predetermined weight ratio comprises:

wherein the mass ratio of the potassium bicarbonate to the urea is 1: 2-2: 1.

4. The method of claim 1, wherein the step of heating the mixed powder to 300-900 ℃ for 1-4 hours in a nitrogen environment and then cooling to room temperature comprises:

5. The method of claim 4, wherein the mixing the powder mixture with hydrochloric acid and then washing the powder mixture with water until the water is neutral comprises:

6. The method of claim 1, wherein drying and cooling to obtain biochar comprises:

7. A biochar obtained by the method for producing biochar with high adsorption capacity according to any one of claims 1 to 6.

8. Use of biochar to remove organic pollutants from simulated wastewater according to claim 7,

9. Use of biochar to remove organic pollutants from simulated wastewater according to claim 7,

10. Use of biochar to remove organic pollutants from simulated wastewater according to claim 7,