Application and method of transient electromagnetic pulse combined Fe modified charcoal

Abstract

The invention relates to the technical field of modified biochar, in particular to application and method of transient electromagnetic pulse and Fe modified biochar, and the method comprises the following steps: S1, biochar is put into a transient electromagnetic pulse field for treatment for 0.5-3.5 h, the voltage is 5-25 kV, and the frequency is 10-80 Hz; s2, adding the biochar obtained in the step S1 into a FeCl3 solution, adjusting the pH value of the solution to 9-11 by using 1mol / L NaOH, and controlling the reaction temperature on a shaking table at 25 DEG C for 24 hours; and S3, after the reaction in the step S2 is finished, filtering, washing with distilled water until the pH value of the filtrate is neutral, and then drying in a drying oven at 70 DEG C for 24 hours to obtain the transient electromagnetic pulse combined Fe modified charcoal. The surface structure and the pore structure of the biochar are improved through treatment of a transient electromagnetic pulse technology, and the specific surface area and the porosity of the biochar are remarkably increased, so that more favorable conditions are provided for Fe loading, and phosphate in water is effectively adsorbed.

Description

Technical Field

[0001] The present invention relates to the technical field of modified biochar, and in particular to an application of transient electromagnetic pulse combined with Fe modified biochar and a method thereof. Background Art

[0002] Biochar is a general term for carbon-containing polymers produced by incomplete combustion of biomass (such as straw, weeds, wood and other agricultural and forestry wastes) under anaerobic conditions. Biochar has a highly aromatic structure, a porous surface and rich oxygen-containing functional groups, and has the characteristics of surface adsorption and stable chemical properties. Biochar itself is difficult to react with the surrounding environmental substances and disappear. Even through geological cycle processes such as sedimentation, burial, and weathering, it can still exist in large quantities in the atmosphere, soil, sediments, rocks, water bodies and ice bodies.

[0003] Unmodified biochar and modified biochar have excellent adsorption capacity and can adsorb and remove organic matter, heavy metal ions and other pollutants in water. The high specific surface area and rich pore structure of unmodified biochar provide a good adsorption platform, while modified biochar further improves the adsorption capacity and selectivity by introducing functional groups or changing the surface properties. This makes unmodified biochar and modified biochar have broad application prospects in water treatment, wastewater treatment, soil remediation and air pollution control.

[0004] There are many methods for modifying biochar, including physical modification (ball milling, gas activation, ultraviolet irradiation, etc.), chemical modification (acid, alkali, metal salts or other oxidants, etc.) and biological modification (addition of microorganisms, etc.). However, the improvement effect of modified biochar prepared under different conditions on the soil after being added to the soil needs to be improved.

[0005] As an emerging physical external field treatment process, electromagnetic pulse treatment introduces electromagnetic pulse energy into materials or parts in the form of pulse current or pulse magnetic field, so as to achieve the purpose of changing their microstructure, shape, mechanical properties, etc. No chemical substances are added during the electromagnetic pulse treatment process, so there will be no pollution problem. In addition, the electromagnetic pulse treatment time is short and the efficiency is high. In recent years, the response behavior of electromagnetic pulse in the organization and mechanical properties of metal materials to electric pulse treatment has attracted extensive attention from scholars at home and abroad. Since the 1960s, scholars have conducted extensive research on electromagnetic pulse treatment technology, but this technology is mostly applied to metal materials. There are currently few studies on the modification technology of biogenic materials such as biochar, and there are no related research reports on the use of transient electromagnetic pulses to modify biochar. In the previous research, it was found that compared with unmodified biochar, the transient electromagnetic pulse modification of the present invention can increase the specific surface area and pore size of biochar, increase the richness of functional groups, and increase more adsorption sites for Fe loading. The transient electromagnetic pulse combined with Fe modified biochar has improved the adsorption capacity of phosphorus in water, and also does not produce secondary pollution in the process of improving soil.

[0006] Solving these problems and defects is of great significance to promote the application of modified biochar, which can play a greater role in environmental pollution control, soil improvement, agricultural production and other fields. Therefore, it is necessary to further study the preparation method of modified biochar, optimize the selection and use of modifiers, and improve the stability and performance of modified biochar to meet the growing application needs. Summary of the invention

[0007] The purpose of the present invention is to provide an application and method of transient electromagnetic pulse combined with Fe modified biochar. Transient electromagnetic pulse modification can increase the specific surface area and pore size of biochar, increase the richness of functional groups, add more adsorption sites for Fe loading, and provide combined Fe modified biochar. The transient electromagnetic pulse combined with Fe modified biochar improves the adsorption capacity of phosphorus in water.

[0008] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0009] Application of transient electromagnetic pulse combined with Fe-modified biochar in the adsorption of phosphate in water.

[0010] On the other hand, the present invention proposes the above-mentioned method of transient electromagnetic pulse combined with Fe modification of biochar, comprising: placing the biochar in a transient electromagnetic pulse field for treatment, and then adding it to a FeCl3 solution for joint modification to obtain transient electromagnetic pulse and iron jointly modified biochar EFBC.

[0011] Further, the method specifically includes the following steps:

[0012] S1: placing the biochar in a transient electromagnetic pulse field for treatment for 0.5 to 3.5 hours, with a voltage of 5 to 25 kV and a frequency of 10 to 80 Hz;

[0013] S2: Add the biochar obtained in step S1 to the FeCl3 solution, adjust the pH of the solution to 9-11 with 1 mol / L NaOH, and control the reaction temperature at 25°C on a shaker for 24 hours;

[0014] S3: After the reaction in step S2 is completed, filter and wash with distilled water until the pH of the filtrate is neutral, and then dry in an oven at 70°C for 24h to obtain transient electromagnetic pulse combined with Fe modified biochar.

[0015] Beneficial effects of the present invention:

[0016] The transient electromagnetic pulse combined with Fe modification method proposed in the present invention can significantly improve the phosphorus adsorption performance of biochar. Through transient electromagnetic pulse treatment, the transient electric field of high frequency and high voltage is used to increase the number of cracks and pores on the surface of biochar, make the texture looser, and increase the specific surface area and pore size. At the same time, the electric field changes caused by transient electromagnetic pulses may prompt the formation of more active functional groups (such as carboxyl, phenolic hydroxyl, etc.) on the surface of biochar. These functional groups provide more binding sites for Fe loading, so that Fe substances can be more evenly loaded on the surface of biochar, thereby improving the adsorption effect.

[0017] Traditional chemical modification processes usually require the use of acids, alkalis or other chemical reagents. These chemicals may remain in the biochar during the modification process and then be released in actual applications, causing secondary pollution. The transient electromagnetic pulse technology used in the present invention is a non-chemical physical treatment method that destroys the original structure of biochar through electromagnetic pulses to form new pores and active surfaces without introducing any external chemicals. At the same time, the modification process does not produce harmful waste, ensuring the safety of modified biochar in environmental applications.

[0018] During the Fe modification process, the Fe(III) ions in the Fe salt solution are hydrolyzed in an alkaline environment regulated by NaOH to form iron hydroxides, which are evenly loaded on the pores and active sites of the biochar, forming a large number of active sites that can bind to phosphates. In water bodies, phosphates quickly bind to these active sites to form iron phosphate precipitates, thereby achieving efficient removal. Transient electromagnetic pulse treatment not only increases the specific surface area and the number of pores, but also increases the richness of active functional groups, which can provide more adsorption sites for Fe loading, making the Fe loading more stable, thereby improving the stability of the overall adsorption performance.

[0019] The present invention can effectively control the pore characteristics of the biochar surface and the generation of active functional groups by adjusting the processing time, voltage and frequency of the transient electromagnetic pulse. If the processing time is appropriately extended or the voltage is increased, the specific surface area of ​​the biochar and the formation of active sites can be further enhanced. In the Fe modification process, by adjusting the solution pH and reaction temperature, the hydrolysis reaction rate of Fe (III) ions and the formation of ferric hydroxide can be effectively controlled, thereby optimizing the loading of Fe on the biochar surface. Such parameter controllability not only enables the modified biochar to adapt to a wider range of applications, but also optimizes performance according to specific needs.

[0020] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the technical route of the present invention;

[0023] Figure 2 This is a schematic diagram of modified biochar of the present invention;

[0024] Figure 3 This is a schematic diagram of the transient electromagnetic pulse combined with iron-modified biochar experiment of the present invention;

[0025] Figure 4 Schematic diagram of phosphorus adsorption experiment on modified biochar

[0026] Figure 5 Schematic diagram of the surface structure of biochar before and after modification of the present invention; a is unmodified biochar, b is transient electromagnetic pulse modified biochar. DETAILED DESCRIPTION

[0027] 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.

[0028] Example 1

[0029] This embodiment describes the application of a transient electromagnetic pulse combined with Fe-modified biochar in the adsorption of phosphate in water.

[0030] Example 2

[0031] The method for modifying biochar by transient electromagnetic pulse combined with Fe in this embodiment specifically comprises the following steps:

[0032] S1: The biochar was placed in a transient electromagnetic pulse field for treatment for 0.5 h, with a voltage of 5 kV and a frequency of 10 Hz;

[0033] S2: Add the biochar obtained in step S1 to the FeCl3 solution, adjust the pH of the solution to 9 with 1 mol / L NaOH, and control the reaction temperature at 25°C on a shaker for 24 hours;

[0034] S3: After the reaction in step S2 is completed, filter and wash with distilled water until the pH of the filtrate is neutral, and then dry in an oven at 70°C for 24h to obtain transient electromagnetic pulse combined with Fe modified biochar.

[0035] Example 3

[0036] The method for modifying biochar by transient electromagnetic pulse combined with Fe in this embodiment specifically comprises the following steps:

[0037] S1: The biochar was placed in a transient electromagnetic pulse field for treatment for 2 h, with a voltage of 20 kV and a frequency of 20 Hz;

[0038] S2: Add the biochar obtained in step S1 to the FeCl3 solution, adjust the pH of the solution to 10 with 1 mol / L NaOH, and control the reaction temperature at 25°C on a shaker for 24 hours;

[0039] S3: After the reaction in step S2 is completed, filter and wash with distilled water until the pH of the filtrate is neutral, and then dry in an oven at 70°C for 24h to obtain transient electromagnetic pulse combined with Fe modified biochar.

[0040] Example 4

[0041] The method for modifying biochar by transient electromagnetic pulse combined with Fe in this embodiment specifically comprises the following steps:

[0042] S1: The biochar was placed in a transient electromagnetic pulse field for treatment for 2 h, with a voltage of 25 kV and a frequency of 80 Hz;

[0043] S2: Add the biochar obtained in step S1 to the FeCl3 solution, adjust the pH of the solution to 11 with 1 mol / L NaOH, and control the reaction temperature at 25°C on a shaker for 24 hours;

[0044] S3: After the reaction in step S2 is completed, filter and wash with distilled water until the pH of the filtrate is neutral, and then dry in an oven at 70°C for 24h to obtain transient electromagnetic pulse combined with Fe modified biochar.

[0045] Example 5

[0046] Study on the adsorption properties of phosphate

[0047] Accurately weigh 0.1000 modified corn straw biochar into a 50 mL reagent bottle, and add 30 mL of 20 mg / L phosphate solution. Place the reagent bottle in a constant temperature oscillator and oscillate at a constant temperature of 25 ° C and 150 rpm for 24 hours, then take it out and filter it through a 0.45 μm filter membrane. Measure the phosphate content in the filtrate according to the ammonium molybdate spectrophotometry method (GB 11893-89). Calculate the removal rate η and adsorption amount Qe according to formula (1) and formula (2), respectively.

[0048] η=(C0-Ce) / C0×100% (1)

[0049] Wherein, η is the phosphate removal rate, %;

[0050] C0 and C e are the initial and equilibrium phosphate concentrations of the solution, mg / L, respectively.

[0051] Q e =((C0-C e )V) / m (2)

[0052] In the formula, Q e is the adsorption amount at equilibrium, mg / m is the mass of biochar

[0053] BC: Unmodified Biochar

[0054] FBC: Iron modified biochar

[0055] EBC: Transient Electromagnetic Pulse Modified Biochar

[0056] EFBC: Transient Electromagnetic Pulse and Iron Combined Modification of Biochar

[0057] Subscript 0.5-1: Biochar with a particle size of 0.5-1 mm

[0058] Subscript 1-2: Biochar with a particle size of 1-2 mm

[0059] Subscript 2-4: Biochar with a particle size of 2-4 mm

[0060] Such as BC 0.5-1 Represents unmodified biochar in the particle size range of 0.5-1 mm

[0061] like Figure 4The surface of corn straw biochar before modification is relatively smooth and has a neat structure. After transient electromagnetic pulse modification, the pore structure is irregular and the surface is smooth and irregular. It can be seen that the porosity of biochar after transient electromagnetic modification increases, the adsorption sites increase, and the specific surface area increases. The results of corn straw biochar with smaller particle size are more significant.

[0062] Experimental Results

[0063] (1) Effect of different pulse treatment times on adsorption rate and adsorption amount

[0064] At a frequency of 50 Hz and a voltage of 15 kV, the effects of different treatment times on the adsorption rate and adsorption amount are shown in Table 1. Unmodified biochars all released phosphorus, with an average release rate of 14%-30%. Compared with unmodified biochar, EBC has different adsorption properties for phosphorus at different treatment times, partially releasing phosphorus, and with a higher average release rate. When the treatment time is 0.5h-2h, the adsorption rate is higher, and it shows a trend of first increasing and then decreasing with time. EBC 0.5-1 Under the above conditions, the adsorption rate at 1.5h was the highest, which was 19.03%.

[0065] Compared with unmodified biochar, EFBC has different adsorption performance for phosphorus. Under some conditions, EFBC releases phosphorus, and the best adsorption rate occurs when the treatment time is 0.5-2h, and it shows a trend of first increasing and then decreasing with the increase of time. 1-2 The adsorption rate was the highest when the pulse treatment time was 1h, which was 17.60%.

[0066] Table 1 Effect of pulse treatment time on adsorption rate and adsorption amount

[0067]

[0068]

[0069] (2) Effect of different voltages on adsorption rate and adsorption amount

[0070] When the modification frequency is 50 Hz, the effects of different voltages on the adsorption rate and adsorption amount are shown in Table 2. Compared with the unmodified biochar, the EBC treatment group showed phosphorus release, and the average release rate was greater. The higher release rate occurred under the 10 kV condition, and the overall release showed a trend of first increasing and then decreasing with the increase of voltage. Under the 10 kV condition, EBC 0.5-1 The phosphorus release rate was 40.54%.

[0071] Compared with unmodified biochar, EFBC showed adsorption under 5kV and 10kV conditions, and 7 groups released phosphorus under 15kV conditions. The higher adsorption rate appeared under 10kV conditions, and the overall trend of adsorption first increased and then decreased with the increase of voltage. 1-2 The highest adsorption rate is 48.80%.

[0072] Table 2 Effect of modified voltage on adsorption rate and adsorption amount

[0073]

[0074] (3) Effect of modification frequency on adsorption rate and adsorption amount

[0075] The effects of different frequency treatments on the adsorption rate and amount of biochar at a voltage of 5 kV and a treatment time of 1 h are shown in Table 3. Compared with unmodified biochar, EBC treated with different frequencies released phosphorus, and the average release rate was greater. The overall trend was that the release first increased and then decreased with the increase of frequency. When the frequency was 50 Hz, EBC 0.5-1 The adsorption rate was 48.8%. Compared with the unmodified organisms, 2 of the EFBC treatment groups released phosphorus, and the rest absorbed phosphorus. 0.5-1 Particle size and EFBC 1-2 The adsorption rate of EFBC increases with the frequency. 2-4 As the frequency increases, the adsorption rate gradually decreases. When the frequency is 10Hz, EFBC 2-4 The highest adsorption rate was 31.36%.

[0076] Table 3 Effect of modification frequency on adsorption rate and adsorption amount

[0077]

[0078] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Application of transient electromagnetic pulse combined with Fe-modified biochar in the adsorption of phosphate in water.

2. The method for modifying biochar by transient electromagnetic pulse combined with Fe modification as claimed in claim 1, Features: include: The biochar was placed in a transient electromagnetic pulse field for treatment and then added to the FeCl 3 The combined modification is carried out in the solution to obtain transient electromagnetic pulse and iron combined modified biochar EFBC.

3. The modification method according to claim 2, Features: The specific steps include: S1: placing the biochar in a transient electromagnetic pulse field for treatment for 0.5 to 3.5 hours, with a voltage of 5 to 25 kV and a frequency of 10 to 80 Hz; S2: Add the biochar obtained in step S1 to FeCl 3 In the solution, the pH of the solution was adjusted to 9-11 with 1 mol / L NaOH, and the reaction temperature was controlled at 25°C on a shaker for 24 h; S3: After the reaction in step S2 is completed, filter and wash with distilled water until the pH of the filtrate is neutral, and then dry in an oven at 70°C for 24h to obtain transient electromagnetic pulse combined with Fe modified biochar.

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