Organic acid modified biochar, and preparation method and application thereof

Abstract

The present application relates to the technical field of biochar preparation, and discloses an organic acid modified biochar as well as a preparation method and application thereof.The preparation method of the organic acid modified biochar comprises the following steps: 1) performing calcination modification on biochar to obtain primary modified biochar; 2) placing the primary modified biochar prepared in step 1) in hydrochloric acid to perform impregnation modification on the primary modified biochar, and obtaining secondary modified biochar; and 3) mixing lauric acid, octadecylamine and the secondary modified biochar prepared in step 2), heating, and performing impregnation modification to obtain the organic acid modified biochar.The organic acid modified biochar provided by the present application has a permeability coefficient of 0.54*10 ‑8 m / s, has relatively optimal permeability resistance, and can be applied to building engineering permeability resistance.

Description

Technical Field

[0001] This invention relates to the field of biochar preparation technology, and more specifically, to an organic acid-modified biochar, its preparation method, and its application. Background Technology

[0002] Waterproofing and waterproofing of buildings have always been a major concern, as they have a significant impact on the safety and durability of buildings. From a durability perspective, long-term leakage will corrode the building structure, reducing its strength. This corrosion weakens the building's earthquake and compressive strength, thus severely damaging its durability. From a safety perspective, if a building structure suffers from long-term leakage, its internal moisture content will increase significantly. This will exacerbate the corrosion of the steel reinforcement and electrical wiring inside the walls. This corrosion will not only reduce the load-bearing capacity of the walls but may also cause short circuits or poor connections in the wiring, leading to serious safety risks and reducing the overall safety of the building.

[0003] Therefore, how to improve the impermeability of buildings has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide an organic acid-modified biochar, its preparation method, and its application, wherein the organic acid-modified biochar has superior impermeability.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] One of the technical solutions of this invention:

[0007] A method for preparing organic acid-modified biochar includes the following steps:

[0008] 1) Calcination modification of biochar yields primary modified biochar;

[0009] 2) Place the primary modified biochar prepared in step 1) in hydrochloric acid to impregnate and modify the primary modified biochar to obtain secondary modified biochar.

[0010] 3) Mix lauric acid, octadecylamine and the secondary modified biochar prepared in step 2), heat, and impregnate to obtain the organic acid modified biochar.

[0011] Further, in step 1), the calcination modification specifically involves: preheating the biochar at 200–300°C for 20 minutes under nitrogen gas protection, followed by calcination modification at 700–750°C for 10 minutes.

[0012] Further, in step 2), the concentration of the hydrochloric acid is 0.05–0.20 mol·L⁻¹.-1 .

[0013] Further, in step 2), the volume ratio of the primary modified biochar to hydrochloric acid is 1g:20mL.

[0014] Further, in step 2), the impregnation modification specifically involves impregnating at 70–90°C for 30 minutes.

[0015] Further, in step 3), the mass ratio of lauric acid, octadecylamine and secondary modified biochar is (5-10):(3-5):1.

[0016] Further, in step 3), the heating specifically involves heating to 55°C to completely melt lauric acid and octadecylamine.

[0017] Further, in step 3), the impregnation modification specifically involves impregnating at 55°C for 2–3 hours.

[0018] Furthermore, in step 3), the pH of the reaction system needs to be adjusted to 5 before impregnation modification.

[0019] The second technical solution of this invention:

[0020] The organic acid-modified biochar prepared by the above method is an organic acid-modified biochar.

[0021] The third technical solution of this invention:

[0022] The organic acid-modified biochar prepared by the above method is used in the impermeability of building engineering.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The organic acid-modified biochar provided by this invention has a permeability resistance coefficient of up to 0.54 × 10⁻⁶. -8 With a flow rate of m / s, it has excellent impermeability and can be applied to impermeability control in building engineering. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0026] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] In the following examples, all raw materials used were commercially available. The biochar was MF8 powdered activated carbon purchased from Shandong Yuyang Activated Carbon Co., Ltd.

[0031] The following embodiments illustrate a method for preparing organic acid-modified biochar, comprising the following steps:

[0032] 1) Under nitrogen protection, the biochar was preheated at 200-300℃ for 20 min, and then calcined at 700-750℃ for 10 min to obtain primary modified biochar.

[0033] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.05–0.20 mol·L⁻¹. -1 The modified biochar was impregnated in hydrochloric acid at 70-90℃ for 30 min, washed, and dried to obtain secondary modified biochar.

[0034] 3) The lauric acid, octadecylamine and the secondary modified biochar prepared in step 2) are mixed according to the mass ratio of lauric acid, octadecylamine and secondary modified biochar of (5-10): (3-5): 1. The mixture is heated to 55°C. After the lauric acid and octadecylamine are completely melted, the pH of the reaction system is adjusted to 5. The mixture is then impregnated and modified at 55°C for 2-3 hours. The mixture is filtered while hot, washed and dried to obtain the organic acid modified biochar.

[0035] Examples 1-6

[0036] Organic acid modified biochar

[0037] 1) Under nitrogen protection, the biochar was preheated at 250℃ for 20 min, and then calcined at 700℃, 710℃, 720℃, 730℃, 740℃ or 750℃ for 10 min to obtain primary modified biochar.

[0038] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.05 mol·L⁻¹. -1 The modified biochar was obtained by impregnation in hydrochloric acid at 70°C for 30 min, followed by washing and drying.

[0039] 3) The lauric acid, octadecylamine and the secondary modified biochar prepared in step 2) are mixed according to the mass ratio of lauric acid, octadecylamine and secondary modified biochar of 5:3:1. The mixture is heated to 55°C. After the lauric acid and octadecylamine are completely melted, the pH of the reaction system is adjusted to 5. The mixture is then impregnated and modified at 55°C for 2 hours. The mixture is filtered while hot, washed and dried to obtain the organic acid modified biochar.

[0040] The impermeability of the organic acid-modified biochar prepared in Examples 1-6 was tested, and the results are shown in Table 1.

[0041] Table 1. Results of impermeability test

[0042]

[0043] As shown in Table 1, changing the calcination temperature during the first modification will affect the impermeability of organic acid modified biochar to a certain extent. Within the calcination temperature range of 700-750℃, the impermeability of organic acid modified biochar first gradually increases and then gradually decreases with the increase of calcination temperature, and reaches the optimal impermeability at 720℃. Therefore, 720℃ is the optimal calcination temperature.

[0044] Examples 7-9

[0045] Organic acid modified biochar

[0046] 1) Under nitrogen protection, the biochar was preheated at 250℃ for 20 min and then calcined at 720℃ for 10 min to obtain primary modified biochar.

[0047] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.10 mol·L⁻¹. -1 0.15 mol·L -1 Or 0.2 mol·L -1 The modified biochar was obtained by impregnation in hydrochloric acid at 70°C for 30 min, followed by washing and drying.

[0048] 3) The lauric acid, octadecylamine and the secondary modified biochar prepared in step 2) are mixed according to the mass ratio of lauric acid, octadecylamine and secondary modified biochar of 5:3:1. The mixture is heated to 55°C. After the lauric acid and octadecylamine are completely melted, the pH of the reaction system is adjusted to 5. The mixture is then impregnated and modified at 55°C for 2 hours. The mixture is filtered while hot, washed and dried to obtain the organic acid modified biochar.

[0049] The impermeability of the organic acid-modified biochar prepared in Examples 7-9 was tested, and the results are shown in Table 2.

[0050] Table 2 Results of impermeability test

[0051]

[0052] As shown in Table 2, changing the hydrochloric acid concentration during secondary modification can affect the impermeability of organic acid-modified biochar to some extent, particularly within the range of 0.05–0.20 mol·L⁻¹. -1 Within the concentration range, as the concentration increases, the impermeability of organic acid-modified biochar first gradually increases and then gradually decreases, reaching a maximum at 0.10 mol·L⁻¹. -1 It achieved optimal impermeability at that time, therefore, 0.10 mol·L -1 The optimal hydrochloric acid concentration is [the concentration to be determined].

[0053] Examples 10-13

[0054] Organic acid modified biochar

[0055] 1) Under nitrogen protection, the biochar was preheated at 250℃ for 20 min and then calcined at 720℃ for 10 min to obtain primary modified biochar.

[0056] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.10 mol·L⁻¹. -1The modified biochar was obtained by impregnation in hydrochloric acid at 75℃, 80℃, 85℃ or 90℃ for 30 min, followed by washing and drying.

[0057] 3) The lauric acid, octadecylamine and the secondary modified biochar prepared in step 2) are mixed according to the mass ratio of lauric acid, octadecylamine and secondary modified biochar of 5:3:1. The mixture is heated to 55°C. After the lauric acid and octadecylamine are completely melted, the pH of the reaction system is adjusted to 5. The mixture is then impregnated and modified at 55°C for 2 hours. The mixture is filtered while hot, washed and dried to obtain the organic acid modified biochar.

[0058] The impermeability of the organic acid-modified biochar prepared in Examples 10-13 was tested, and the results are shown in Table 3.

[0059] Table 3. Results of impermeability test

[0060]

[0061] As shown in Table 3, changing the impregnation temperature during secondary modification will affect the impermeability of organic acid modified biochar to a certain extent. Within the impregnation temperature range of 70 to 90℃, the impermeability of organic acid modified biochar first gradually increases and then gradually decreases as the impregnation temperature increases, reaching the optimal impermeability at 80℃. Therefore, 80℃ is the optimal impregnation temperature.

[0062] Examples 14-18

[0063] Organic acid modified biochar

[0064] 1) Under nitrogen protection, the biochar was preheated at 250℃ for 20 min and then calcined at 720℃ for 10 min to obtain primary modified biochar.

[0065] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.10 mol·L⁻¹. -1 The modified biochar was impregnated in hydrochloric acid at 80°C for 30 min, washed, and dried to obtain secondary modified biochar.

[0066] 3) According to the mass ratio of lauric acid, octadecylamine and secondary modified biochar recorded in Table 4, mix lauric acid, octadecylamine and the secondary modified biochar prepared in step 2), heat to 55°C, wait for lauric acid and octadecylamine to completely melt, adjust the pH of the reaction system to 5, impregnate and modify at 55°C for 2 hours, filter while hot, wash, dry, and obtain the organic acid modified biochar.

[0067] Table 4. Mass ratio of lauric acid, octadecylamine, and secondary modified biochar

[0068]

[0069] The impermeability of the organic acid-modified biochar prepared in Examples 14-18 was tested, and the results are shown in Table 5.

[0070] Table 5. Results of impermeability test

[0071]

[0072] Examples 19-20

[0073] Organic acid modified biochar

[0074] 1) Under nitrogen protection, the biochar was preheated at 250℃ for 20 min and then calcined at 720℃ for 10 min to obtain primary modified biochar.

[0075] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.10 mol·L⁻¹. -1 The modified biochar was impregnated in hydrochloric acid at 80°C for 30 min, washed, and dried to obtain secondary modified biochar.

[0076] 3) According to the mass ratio of lauric acid, octadecylamine and secondary modified biochar recorded in Table 6, mix lauric acid, octadecylamine and the secondary modified biochar prepared in step 2), heat to 55°C, wait for lauric acid and octadecylamine to completely melt, adjust the pH of the reaction system to 5, impregnate and modify at 55°C for 2 hours, filter while hot, wash, dry, and obtain the organic acid modified biochar.

[0077] Table 6. Mass ratio of lauric acid, octadecylamine, and secondary modified biochar

[0078]

[0079] The impermeability of the organic acid-modified biochar prepared in Examples 19 and 20 was tested, and the results are shown in Table 7.

[0080] Table 7 Results of impermeability test

[0081]

[0082] As shown in Tables 5 and 7, changing the mass ratio of lauric acid, octadecylamine, and secondary modified biochar will affect the impermeability of organic acid modified biochar to a certain extent. The optimal mass ratio of lauric acid, octadecylamine, and secondary modified biochar was found to be 9:4:1.

[0083] Examples 21-22

[0084] Organic acid modified biochar

[0085] 1) Under nitrogen protection, the biochar was preheated at 250℃ for 20 min and then calcined at 720℃ for 10 min to obtain primary modified biochar.

[0086] 2) According to the volume ratio of primary modified biochar to hydrochloric acid of 1 g : 20 mL, place the primary modified biochar prepared in step 1) into a solution with a concentration of 0.10 mol·L⁻¹. -1 The modified biochar was impregnated in hydrochloric acid at 80°C for 30 min, washed, and dried to obtain secondary modified biochar.

[0087] 3) The lauric acid, octadecylamine and the secondary modified biochar prepared in step 2) are mixed in a mass ratio of 9:4:1. The mixture is heated to 55°C until the lauric acid and octadecylamine are completely melted. The pH of the reaction system is adjusted to 5. The mixture is then impregnated at 55°C for 2.5 h or 3 h. The mixture is filtered while hot, washed and dried to obtain the organic acid modified biochar.

[0088] The impermeability of the organic acid-modified biochar prepared in Examples 21-22 was tested, and the results are shown in Table 8.

[0089] Table 8 Results of impermeability test

[0090]

[0091] As shown in Table 8, changing the impregnation modification time during lauric acid and octadecylamine modification will affect the impermeability of organic acid modified biochar to a certain extent. Within the impregnation modification time range of 2 to 3 hours, the impermeability of organic acid modified biochar first gradually increases and then gradually decreases with the increase of impregnation modification time, and reaches the optimal impermeability at 2.5 hours. Therefore, 2.5 hours is the optimal impregnation modification time.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing organic acid-modified biochar, characterized in that, Includes the following steps: 1) Calcination modification of biochar yields primary modified biochar; 2) Place the primary modified biochar obtained in step 1) in hydrochloric acid to impregnate and modify the primary modified biochar to obtain secondary modified biochar. 3) Mix lauric acid, octadecylamine and the secondary modified biochar prepared in step 2), heat, and impregnate to obtain the organic acid modified biochar; In step 1), the calcination modification specifically involves: preheating the biochar at 200–300°C for 20 min under nitrogen protection, followed by calcination modification at 700–750°C for 10 min. In step 2), the concentration of the hydrochloric acid is 0.05–0.20 mol·L⁻¹. -1； In step 2), the volume ratio of the primary modified biochar to hydrochloric acid is 1g:20mL; In step 2), the impregnation modification specifically involves impregnating at 70–90°C for 30 minutes. In step 3), the mass ratio of lauric acid, octadecylamine and secondary modified biochar is (5-10):(3-5):1; The impregnation modification specifically involves impregnating the material at 55°C for 2–3 hours.

2. The method for preparing organic acid-modified biochar according to claim 1, characterized in that, In step 3), the heating specifically involves heating to 55°C to completely melt lauric acid and octadecylamine.

3. Organic acid modified biochar prepared by the method of any one of claims 1 to 2.

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