Sapling saline-alkali-resistant salt-isolating material based on modified activated carbon fibers as well as preparation method and application thereof

Abstract

The invention provides a sapling saline-alkali-resistant salt-isolating material based on modified activated carbon fibers and a preparation method and application of the sapling saline-alkali-resistant salt-isolating material. The preparation method comprises the following steps that firstly, an acid modified solution and an alkali modified solution are used for conducting stirring pretreatment reaction on the activated carbon fibers; washing the activated carbon fiber with deionized water until the pH value of the washing solution is neutral after the reaction is completed, performing vacuum drying for later use, adding a strong oxidant into the pretreated activated carbon fiber until the activated carbon fiber is completely immersed in the reaction solution, performing magnetic stirring reaction, washing the activated carbon fiber with deionized water until the pH value of the washing solution is neutral after the reaction is completed, and performing vacuum drying for later use; the salt-isolating material is applied to saline-alkali soil or a saline water irrigation environment, so that the salt tolerance of the saplings is improved. The salt-isolating material is simple in preparation process, mild in reaction condition, easy to control, stable in product quality, suitable for large-scale production and high in application feasibility.

Description

Technical Field

[0001] The invention belongs to the technical field of modified materials and their application in plant cultivation, and particularly relates to a seedling salt-alkali resistant and salt-isolating material based on modified activated carbon fiber, and a preparation method and application thereof. Background Art

[0002] Saline-alkali soils are widely distributed around the world, especially in arid and semi-arid areas, where the accumulation of salt poses a serious threat to the ecological environment and agricultural production. High salinity can inhibit plant growth and significantly reduce the survival rate of greening seedlings and crops. In addition, in the context of water scarcity, although brackish water has a certain reserve, due to its high salt content, direct use for irrigation often further aggravates soil salinization and threatens the survival of tree seedlings. Therefore, the rational use of brackish water resources and the reduction of salt damage to plants have become key issues that need to be addressed. In order to meet this challenge, it is urgent to develop an efficient salt isolation technology to reduce the impact of salt in soil or irrigation water on plant roots, thereby improving the survival rate and salt resistance of seedlings.

[0003] At present, commonly used salt-isolating materials include physical barrier materials such as geotextiles and polymer membranes, as well as some chemical modifiers. These materials can slow down the movement of salt to a certain extent, but they often have problems such as poor durability, high cost, and lack of environmental friendliness. In addition, the salt-isolating effect gradually weakens under high salt concentrations or long-term use. Therefore, in response to these problems, finding a new type of salt-isolating material with high efficiency and sustainability has become a key technical means to improve the survival rate of seedlings in saline-alkali land. Activated carbon fiber, due to its excellent adsorption performance, high specific surface area and structural adjustability, shows great potential as a salt-isolating material in saline-alkali land.

[0004] As a porous material, activated carbon fiber has good adsorption properties and can effectively adsorb salt in soil or irrigation water to prevent the migration of salt to plant roots. However, unmodified activated carbon fiber has certain disadvantages, such as the limited number of functional groups on its surface, the less than ideal adsorption capacity, and it is difficult to play the best salt isolation effect in harsh saline-alkali environments. Therefore, pretreatment and oxidation modification of activated carbon fiber to increase the oxygen-containing functional groups (such as carboxyl and hydroxyl) on its surface can significantly improve its adsorption capacity and hydrophilicity and enhance salt isolation performance. This modified activated carbon fiber material can not only effectively prevent the migration of salt, but also retain water, maintain a suitable moisture environment around the root system, and further improve the survival ability of plants in saline-alkali land.

[0005] Based on this, a salt-resistant and alkali-resistant salt-isolating material for seedlings based on modified activated carbon fiber was proposed. By acid-base pretreatment and oxidation modification of activated carbon fiber, the content of oxygen-containing functional groups on its surface was increased, effectively improving its performance as a salt-isolating material. Under saline-alkali soil and brackish water irrigation conditions, this material can prevent salt from penetrating into plant roots, reduce the damage of salt and alkali to seedlings, and significantly improve the survival rate of seedlings, providing an efficient and sustainable solution for ecological restoration and greening of saline-alkali land. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a salt-alkali resistant and salt-isolating material for seedlings based on modified activated carbon fiber and its application in view of the deficiencies of the above-mentioned prior art, so as to solve the problems raised in the above-mentioned background technology.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] In the first aspect, a method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber comprises the following steps:

[0009] S1, first stirring the activated carbon fiber with an acid-modified solution for pretreatment reaction, after the reaction is completed, washing the activated carbon fiber with deionized water until the pH of the washing solution is neutral, vacuum drying and then alkali stirring the activated carbon fiber with an acid-modified solution for pretreatment reaction, after the reaction is completed, washing the activated carbon fiber with deionized water until the pH of the washing solution is neutral, vacuum drying and standby;

[0010] S2. Add a strong oxidant to the pretreated activated carbon fiber in S1 until the activated carbon fiber is completely immersed in the reaction solution, and stir the reaction magnetically. After the reaction is completed, wash the activated carbon fiber with deionized water until the pH of the washing solution is neutral, and obtain the salt-isolating material after vacuum drying.

[0011] As a further illustration of the present invention, the acid-modified solution is hydrochloric acid with a mass fraction of 3.00-15.00%, and the alkali-modified solution is hydrochloric acid with a molar concentration of 0.20-1.00 mol·L -1 The volume ratio of the activated carbon fiber mass to the acid-modified solution or the alkali-modified solution is 50.00-100.00 g·L -1 .

[0012] As a further illustration of the present invention, the strong oxidant has a concentration of 2.00-6.00 mol·L -1 Nitric acid, concentration is 8.00-10.00 mol·L -1 Hydrogen peroxide or a concentration of 0.02-0.06 mol·L -1The volume ratio of the pretreated activated carbon fiber to the strong oxidant is 200.00-400.00 g·L -1 .

[0013] As a further illustration of the present invention, the stirring speed during treatment with the acid-modified solution or the alkaline-modified solution in S1 is 180-220 rpm, the stirring time is 1-3 h, the stirring temperature for the acid-modified solution treatment is 20-35 ° C, the stirring temperature for the alkaline-modified solution treatment is 50-65 ° C, the vacuum drying temperature is 60-100 ° C, and the vacuum drying time is 8-12 h.

[0014] As a further illustration of the present invention, the speed of magnetic stirring in S2 is 180-220 rpm, and the stirring time is 2-6 h; the temperature of magnetic stirring is 60-80° C., the vacuum drying temperature is 80-100° C., and the vacuum drying time is 12-18 h.

[0015] In a second aspect, a salt-alkali resistant and salt-isolating material for seedlings based on modified activated carbon fiber is prepared by the above-mentioned method for preparing the salt-isolating material.

[0016] In the third aspect, a salt-alkali resistant and salt-isolating material for seedlings based on modified activated carbon fiber is used to improve the salt tolerance of seedlings in saline-alkali soil or salt water irrigation environment.

[0017] As a further illustration of the present invention, the salt content of the saline-alkali soil is 0.10%-0.80%, the salt content of the salt water irrigation is 0.10%-1.50%, and the salt-isolating material wraps 2-5 mm around the roots of the seedlings.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The salt isolation material preparation process of the present invention is simple, the reaction conditions are mild, easy to control, and the product quality is stable, suitable for large-scale production, and has high application feasibility.

[0020] 2. The present invention significantly increases the content of oxygen-containing functional groups on the surface of activated carbon fiber, such as carboxyl and hydroxyl groups, by acid-base pretreatment and oxidation modification. According to the Boehm titration method, the content of oxygen-containing functional groups on the surface of the modified activated carbon fiber increases to 250% to 350% of that before modification. This modification enhances the material's ability to adsorb and block salt, effectively slowing down the damage of salt to the root system of seedlings, thereby significantly improving the survival rate of seedlings in saline-alkali soil.

[0021] 3. The salt-isolating material of the present invention has good environmental protection, low toxicity, and is economical and convenient to use. In saline-alkali soil or saltwater irrigation environment, it can not only block salt, but also reduce water resource consumption. It is suitable for greening and ecological restoration in water-scarce areas.

[0022] 4. The present invention constructs an efficient "physical barrier-chemical adsorption" double salt-isolating barrier by directly applying modified activated carbon fiber materials to the roots of seedlings, which greatly improves the salt-isolating effect, reduces the shortcomings of traditional salt-isolating technology, and provides an efficient and sustainable solution for the cultivation of seedlings in saline-alkali land.

[0023] 5. The material of the present invention can flexibly adjust the wrapping thickness according to different salinity conditions, adapt to a variety of complex environments, further improve the survival ability of seedlings in high-salt environments, and provide new technical ideas for the restoration of saline-alkali land ecosystems and agricultural development. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a growth comparison chart of Ulmus pumila in Example 1 with and without the use of salt isolation material.

[0025] Figure 2 This is a comparison chart of the plant height of Ulmus pumila with and without the use of salt-isolating material in Example 1.

[0026] Figure 3 This is a growth comparison chart of water wax in Example 2 with and without the use of salt isolation material.

[0027] Figure 4 This is a comparison chart of the soil conductivity values ​​inside and outside the isolation layer of water wax using salt isolation material in Example 2.

[0028] Figure 5 This is a growth comparison chart of Forsythia suspensa in Example 3 with and without the use of salt isolation material.

[0029] Figure 6 This is a comparison chart of the salt content of the soil inside and outside the isolation layer of Forsythia suspensa when using salt isolation material in Example 3. DETAILED DESCRIPTION

[0030] 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.

[0031] The present invention provides a technical solution: a method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber, comprising the following steps:

[0032] S1, first stirring the activated carbon fiber with an acid-modified solution for pretreatment reaction, after the reaction is completed, washing the activated carbon fiber with deionized water until the pH of the washing solution is neutral, vacuum drying and then alkali stirring the activated carbon fiber with an acid-modified solution for pretreatment reaction, after the reaction is completed, washing the activated carbon fiber with deionized water until the pH of the washing solution is neutral, vacuum drying and standby;

[0033] The acid-modified solution is hydrochloric acid with a mass fraction of 3.00-15.00%, and the alkali-modified solution is hydrochloric acid with a molar concentration of 0.20-1.00 mol·L -1 The volume ratio of the activated carbon fiber mass to the acid-modified solution or the alkali-modified solution is 50.00-100.00 g·L -1 ;

[0034] The stirring speed is 180-220rpm for acid-modified solution or alkali-modified solution treatment, the stirring time is 1-3h, the stirring temperature is 20-35℃ for acid-modified solution treatment, the stirring temperature is 50-65℃ for alkali-modified solution treatment, the vacuum drying temperature is 60-100℃, and the vacuum drying time is 8-12h.

[0035] S2, adding a strong oxidant to the pretreated activated carbon fiber in S1, wherein the concentration of the strong oxidant is 2.00-6.00 mol·L -1 Nitric acid, concentration is 8.00-10.00 mol·L -1 Hydrogen peroxide or a concentration of 0.02-0.06 mol·L -1 The volume ratio of the pretreated activated carbon fiber to the strong oxidant is 200.00-400.00 g·L -1 , until the activated carbon fiber is completely immersed in the reaction solution, magnetic stirring reaction, the magnetic stirring speed is 180-220rpm, the stirring time is 2-6h; the magnetic stirring temperature is 60-80℃, after the reaction is completed, the activated carbon fiber is washed with deionized water until the pH of the washing solution is neutral, and the salt isolation material is obtained after vacuum drying, the vacuum drying temperature is 80-100℃, and the vacuum drying time is 12-18h.

[0036] Example 1: Using a 10% hydrochloric acid solution as the acid modification solution, the volume ratio of the activated carbon fiber mass to the hydrochloric acid solution is 75 g·L -1 , stirred at 200 rpm for 2 hours at 25 °C, and then washed with a large amount of deionized water until the pH of the washing solution was close to neutral;

[0037] The concentration of the re-use is 0.50 mol·L -1 The sodium hydroxide solution was used as the alkali modification solution, and the volume ratio of the activated carbon fiber mass to the sodium hydroxide solution was 75 g·L -1, stirred at 60 °C for 2 hours, then washed with deionized water until neutral, and vacuum dried at 80 °C for 10 hours;

[0038] The pretreated activated carbon fiber was added with 3 mol·L -1 In the nitric acid solution, the volume ratio of activated carbon fiber to nitric acid solution is 300g·L -1 , stirred at 200 rpm for 4 hours at 70 ° C. After the reaction was completed, it was washed with deionized water to neutrality and vacuum dried at 90 ° C for 15 hours to obtain a modified activated carbon fiber salt isolation material.

[0039] The carboxyl content on the surface of the modified activated carbon fiber increased to 350% of that before modification, as measured by the Boehm titration method.

[0040] Conduct application and comparative experiments:

[0041] like Figure 1 and Figure 2 As shown, the prepared modified activated carbon fiber material was wrapped around the root system of one-year-old yellow elm seedlings to form a salt isolation layer with a thickness of 3 mm, and 20 parallel groups were set up. In the saline-alkali soil environment, the salt concentration was 0.60%, and the transplanted yellow elm grew well during the 120-day planting period. During the experiment, the salt did not cause significant damage to its root system, the leaves of the seedlings maintained normal growth, the root system was healthy, and the survival rate reached 95%.

[0042] As a comparative experiment, a control group without salt-isolating materials was set up, which also consisted of 20 groups of yellow elm seedlings. Under the same saline-alkali soil conditions, the salt concentration was 0.60%;

[0043] The growth of the seedlings without salt-isolating materials was significantly affected by salt stress within 120 days. Salt gradually accumulated in the root system, causing root rot, leaf withering, and stunted growth. The final survival rate was only 35%.

[0044] Example 2: The activated carbon fiber was modified according to the following steps, using a 5% hydrochloric acid solution as the acid modification solution, and the volume ratio of the activated carbon fiber to the hydrochloric acid solution was 60 g·L -1 , stirred at 200 rpm for 1.50 hours at 30°C. After the reaction, washed with a large amount of deionized water until neutral;

[0045] The concentration used is 0.75 mol·L -1 The sodium hydroxide solution was used as the alkali modification solution, and the volume ratio of the activated carbon fiber mass to the sodium hydroxide solution was 60 g·L -1 , stirred at 55 °C for 3 h, subsequently washed with deionized water to neutrality, and dried in vacuo at 90 °C for 10 h.

[0046] The pretreated activated carbon fiber was added with 9 mol·L -1 In the hydrogen peroxide solution, the volume ratio of activated carbon fiber to hydrogen peroxide solution is 250 g·L -1 , stirred at 200 rpm for 5 hours at 65 ° C. After the reaction was completed, it was washed with deionized water to neutrality and vacuum dried at 80 ° C for 12 hours to obtain a modified activated carbon fiber salt isolation material.

[0047] The surface hydroxyl content of the modified activated carbon fiber increased to 280% of that before modification, as measured by Boehm titration.

[0048] Conduct application and comparative experiments:

[0049] like Figure 3 and Figure 4 As shown, the prepared modified activated carbon fiber material was wrapped around the roots of the annual water wax to form a salt isolation layer with a thickness of 4 mm, and 20 parallel groups were set up.

[0050] Under saline irrigation conditions, the salt concentration was 1.20%, and the water wax after transplanting showed high salt tolerance during the 120-day planting period. During the experiment, the salt did not have a significant impact on its root system, the leaves maintained normal growth, the root system was healthy, and the survival rate reached 85%.

[0051] In the comparative experiment, 20 groups of control groups were also set up for the waxwood seedlings that were not treated with salt-isolating materials. Under the same saline irrigation conditions, the salt concentration was 1.20%. During the 120-day planting period, the roots of the seedlings that were not treated with salt-isolating materials were significantly damaged by the gradual accumulation of salt. The leaves of the seedlings withered, their growth was stunted, and the final survival rate was only 25%.

[0052] Example 3: Modification of activated carbon fiber was carried out according to the following steps:

[0053] A 15% hydrochloric acid solution was used as the acid modification solution, and the volume ratio of the activated carbon fiber mass to the hydrochloric acid solution was 90 g·L -1 , stirred at 220 rpm for 3 hours at 20°C. After the reaction, the mixture was washed with a large amount of deionized water until it became neutral.

[0054] The concentration used is 1.00 mol·L -1 The sodium hydroxide solution was used as the alkali modification solution, and the volume ratio of the activated carbon fiber mass to the sodium hydroxide solution was 80 g·L -1 , stirred at 65 ° C for 3 hours. After the reaction was completed, it was washed with deionized water to neutrality and dried in vacuum at 100 ° C for 8 hours.

[0055] The pretreated activated carbon fiber was added with 0.04 mol·L -1The volume ratio of activated carbon fiber to potassium permanganate solution is 350 g·L -1 , stirred at 220 rpm for 3 hours at 75 ° C. After the reaction was completed, it was washed with deionized water to neutrality and vacuum dried at 85 ° C for 12 hours to obtain a modified activated carbon fiber salt isolation material.

[0056] The carboxyl content on the surface of the modified activated carbon fiber increased to 300% of that before modification, as measured by the Boehm titration method.

[0057] Conduct application and comparative experiments:

[0058] like Figure 5 and Figure 6 As shown, the prepared modified activated carbon fiber material was wrapped around the roots of the annual Forsythia suspensa to form a salt-isolating layer with a thickness of 5 mm, and 20 parallel groups were set up. In the saline-alkali soil environment with a salt concentration of 0.80%, the transplanted Forsythia suspensa showed good growth during the 120-day planting period. During the experiment, the salt tolerance of the seedlings was significantly enhanced, the roots were not damaged by salt, the seedlings grew well, and the survival rate reached 80%.

[0059] In the comparative experiment, 20 groups of control groups were also set up for the seedlings of Forsythia suspensa that were not treated with salt-isolating materials. Under the same saline-alkali soil conditions with a salt concentration of 0.80%, the root system of the seedlings that were not treated with salt-isolating materials was damaged by the gradual accumulation of salt during the 120-day planting period, and their growth was stunted. The leaves of the seedlings withered, and the final survival rate was only 10%.

[0060] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber, characterized in that: The following steps are involved: S1, first stirring the activated carbon fiber with an acid-modified solution for pretreatment reaction, after the reaction is completed, washing the activated carbon fiber with deionized water until the pH of the washing solution is neutral, vacuum drying and then alkali stirring the activated carbon fiber with an acid-modified solution for pretreatment reaction, after the reaction is completed, washing the activated carbon fiber with deionized water until the pH of the washing solution is neutral, vacuum drying and standby; S2. Add a strong oxidant to the pretreated activated carbon fiber in S1 until the activated carbon fiber is completely immersed in the reaction solution, and stir the reaction magnetically. After the reaction is completed, wash the activated carbon fiber with deionized water until the pH of the washing solution is neutral, and obtain the salt-isolating material after vacuum drying.

2. The method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber according to claim 1, characterized in that: The acid-modified solution is hydrochloric acid with a mass fraction of 3.00-15.00%, and the alkali-modified solution is hydrochloric acid with a molar concentration of 0.20-1.00 mol·L -1 The volume ratio of the activated carbon fiber mass to the acid-modified solution or the alkali-modified solution is 50.00-100.00 g·L -1 .

3. The method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber according to claim 1, characterized in that: The strong oxidant has a concentration of 2.00-6.00 mol·L -1 Nitric acid, concentration is 8.00-10.00 mol·L -1 Hydrogen peroxide or a concentration of 0.02-0.06 mol·L -1 The volume ratio of the pretreated activated carbon fiber to the strong oxidant is 200.00-400.00 g·L -1 .

4. The method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber according to claim 1, characterized in that: The stirring speed of the acid-modified solution or the alkali-modified solution in S1 is 180-220 rpm, the stirring time is 1-3 h, the stirring temperature of the acid-modified solution is 20-35 ° C, the stirring temperature of the alkali-modified solution is 50-65 ° C, the vacuum drying temperature is 60-100 ° C, and the vacuum drying time is 8-12 h.

5. The method for preparing a salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber according to claim 1, characterized in that: In S2, the speed of magnetic stirring is 180-220 rpm, and the stirring time is 2-6 h; the temperature of magnetic stirring is 60-80° C., the vacuum drying temperature is 80-100° C., and the vacuum drying time is 12-18 h.

6. A salt-alkali-resistant and salt-isolating material for seedlings based on modified activated carbon fiber, characterized in that: The salt-isolating material is prepared by the method for preparing the salt-isolating material according to any one of claims 1 to 5.

7. Use of the modified activated carbon fiber-based anti-salt-alkali and salt-isolating material for seedlings according to claim 6 in planting seedlings in saline-alkali soil or salt water irrigation environment.

8. The use according to claim 7, characterized in that: The salt content of the saline-alkali soil is 0.10%-0.80%, the salt content of the salt water irrigation is 0.10%-1.50%, and the salt-isolating material wraps the roots of the seedlings by 2-5 mm.

Images