Method for improving hydrophobic property of biomass and application thereof
By pulverizing and pretreating the biomass, and reacting with alcohol solution and long-chain silane coupling agent, a stable three-dimensional network structure is established, which solves the problem of poor hydrophobicity of biomass and achieves significant hydrophobic performance improvement and widespread biomass Application reduces costs.
Patent Information
- Application Number
- CN202411372803.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2024-12-24
AI Technical Summary
In the prior art, the hydrophobicity of biomass is poor, which limits its application value in the fields of composite materials, packaging materials, building materials, etc., and a high feed ratio is required during the use of short-chain silane coupling agent and there are side reactions. The long-chain coupling agent has low solubility and poor reactivity, which fails to effectively improve the hydrophobic properties of biomass.
By pulverizing, pretreating, reacting with alcohol solution and long-chain silane coupling agent, a stable three-dimensional network structure is established to improve the hydrophobic performance of the biomass. A simple, safe and pollution-free method is adopted to reduce silane coupling The dosage of the coupling agent is used to adjust the reaction system to improve the solubility and reaction activity of the long-chain coupling agent.
It significantly improves the hydrophobic properties of biomass, reduces costs, and realizes the wide application of biomass in various application fields. It has simple methods, safe and pollution-free, and has important scientific significance and application prospects.
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Figure CN119176952A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of high-quality conversion of farmland waste biomass and material synthesis, and in particular to a method for improving the hydrophobicity of biomass and an application thereof. Background Art
[0002] As my country's agriculture continues to grow and develop, the amount of straw waste produced each year is also on the rise. However, the current utilization rate and added value of straw are low, and straw burning will also have a great impact on the environment. Bamboo is a renewable resource. Bamboo grows quickly and has a short harvesting cycle. It usually reaches maturity within a few years, much faster than most trees. This rapid natural regeneration ability allows bamboo forests to continuously supply raw materials. Improving the comprehensive utilization rate of waste straw and bamboo and reusing straw and bamboo are effective ways to open up new energy channels. In recent years, natural fibers have attracted widespread attention due to their environmental friendliness, good biocompatibility and high strength. At present, global forest protection policies are pushing up the cost of all-natural fiber products.
[0003] Wood plastic composite (WPC) is a functional material produced by mixing waste plant fibers (including wood and other lignocellulose) with thermosetting materials or thermoplastics. It has attracted more and more attention due to its dual characteristics. Its characteristics include sustainability, renewability, low cost and low energy consumption. In addition, natural fibers can effectively alleviate or even replace the dependence on non-renewable energy and material sources, and are a new type of environmentally friendly material. The antibacterial, corrosion-resistant, low-cost and high-strength characteristics of wood plastic composites not only solve the environmental pollution of straw waste, but also provide new ideas for new environmentally friendly materials. The hydrophobicity of plant fibers themselves is weak, which limits their application in many aspects. Therefore, plant fibers can be modified to improve their hydrophobic properties, thereby unlocking their potential application value in composite materials, packaging materials, building materials and more fields.
[0004] Silane coupling agents can effectively improve the hydrophobicity of straw and bamboo, but current research mainly focuses on short-chain silane coupling agents, including methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane and butyltriethoxysilane. Due to their good water solubility and reactivity, this type of silane coupling agent can effectively improve the hydrophobicity of straw. However, short-chain coupling agents require a very high feed ratio during use, generally higher than 10:1, and a large amount of short-chain coupling agents can react with water. Long-chain coupling agents have extremely low solubility in water and poor reactivity, so they have not been reported in the hydrophobic modification of biomass. Summary of the invention
[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for improving the hydrophobicity of biomass and its application. The method is simple, safe and pollution-free, and the obtained modified biomass has significant hydrophobic effect, which effectively solves the problem of poor hydrophobicity of biomass.
[0006] To achieve the above object, the technical solution adopted by the present invention to solve the technical problem is: to provide a method for improving the hydrophobicity of biomass, comprising the following steps:
[0007] S1, crushing and sieving the biomass, then pre-treating it, stirring, washing and drying it to obtain the pre-treated biomass;
[0008] S2, adding an alcohol solution to the pretreated biomass obtained in step S1, then adding a silane coupling agent and stirring, and then washing and drying to obtain a hydrophobically modified biomass.
[0009] Furthermore, in step S1, the biomass is one of cotton straw, bamboo, corn straw and wheat straw.
[0010] Further, in step S1, the biomass powder is obtained by passing through a 100-mesh sieve.
[0011] Further, in step S1, the pretreatment is soaking in water or alkaline solution.
[0012] The beneficial effect of adopting the above further scheme is: removing impurities or removing wax on the surface of biomass.
[0013] Furthermore, the alkali solution is one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, potassium carbonate solution and calcium hydroxide solution.
[0014] Further, the concentration of the alkali solution is 3-10wt%.
[0015] Furthermore, the solid-liquid mass ratio of biomass powder to water is 1-2:8-10.
[0016] Furthermore, the solid-liquid mass ratio of biomass powder to water is 1:8.
[0017] Furthermore, the solid-liquid mass ratio of the biomass powder to the alkali solution is 1-2:8-10.
[0018] Furthermore, the solid-liquid mass ratio of the biomass powder to the alkali solution is 1:8.
[0019] Further, in step S1, stirring is performed for 2-24 hours.
[0020] Further, in step S2, the alcohol solution is one of a methanol solution, an ethanol solution, a glycerol solution and an isopropanol solution.
[0021] Furthermore, in step S2, the alcohol solution is selected according to the type of the silane coupling agent, methoxysilane uses methanol solution as the solvent, and ethoxysilane uses ethanol solution as the solvent.
[0022] Furthermore, in step S2, the concentration of the alcohol solution is 40-80 vt.%.
[0023] Furthermore, in step S2, the concentration of the alcohol solution is 75 vt.%.
[0024] Furthermore, in step S2, the solid-liquid mass ratio of the pretreated biomass to the alcohol solution is 1-2:10-40.
[0025] Furthermore, in step S2, the solid-liquid mass ratio of the pretreated biomass to the alcohol solution is 1:10.
[0026] Further, in step S2, the silane coupling agent is at least one of octyltrimethoxysilane, n-octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrihexyloxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, docosyltriethoxysilane and docosyltrimethoxysilane.
[0027] Furthermore, in step S2, the solid-liquid mass ratio of the pretreated biomass to the silane coupling agent is 5-50:1-2.
[0028] Furthermore, in step S2, the solid-liquid mass ratio of the pretreated biomass to the silane coupling agent is 10:1.
[0029] Furthermore, in step S2, stirring is performed at 15-60° C. and 300-400 rpm for 3-36 hours.
[0030] Furthermore, in step S2, the mixture was stirred at 350 rpm and 50°C for 12 h.
[0031] The hydrophobically modified biomass is prepared by the method for improving the hydrophobic properties of biomass.
[0032] The above hydrophobically modified biomass is used in municipal gardening, home decoration building materials, papermaking, food packaging, craft products, fireproof materials or medical devices.
[0033] The present invention has the following beneficial effects:
[0034] 1. The present invention uses recycled farm waste straw or bamboo as raw materials, which are reacted with silane after pretreatment. The method is simple, the reaction is mild, safe and pollution-free. The raw materials used are simple and have great significance for resource recycling. The modified biomass obtained has significant hydrophobic effect and stable hydrophobic performance, and has a very broad application prospect.
[0035] 2. The present invention obtains the method and key parameters of modifying the hydrophilicity and hydrophobicity of biomass by using long-chain coupling agents by adjusting the reaction system and controlling the solubility and reactivity of the long-chain coupling agent. The silane coupling agent used in the present invention is a long-chain one, which reduces the amount of the silane coupling agent used and reduces the cost.
[0036] 3. The present invention utilizes hydrolysis and condensation reactions, wherein the alkoxy groups in the silane chemically condense with water to cause the siloxane bridge (Si-O-Si) to be grafted onto the biomass surface through the Si-OC bond, thereby establishing a stable three-dimensional network structure (Si-OC) on the biomass surface. The hydrophobic properties of the biomass modified by silane are significantly improved, which has important scientific significance and significant prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 is the dodecyltrimethoxy modification mechanism diagram;
[0038] Figure 2 This is the octyl trimethoxy modification mechanism diagram;
[0039] Figure 3 This is the hexadecyltrimethoxy modification mechanism diagram;
[0040] Figure 4 This is the contact angle measurement result of the straw fiber modified with dodecyltrimethoxy;
[0041] Figure 5 This is the contact angle measurement result of the straw fiber modified with octyltrimethoxy;
[0042] Figure 6 This is the contact angle measurement result of the straw fiber modified with hexadecyltrimethoxy;
[0043] Figure 7 This is a comparison chart of infrared spectrum test results of straw fiber after modification with dodecyltrimethoxy;
[0044] Figure 8 This is a comparison chart of infrared spectrum test results of straw fiber modified with octyltrimethoxysilane;
[0045] Fig. 9 This is a comparison chart of infrared spectrum test results of straw fiber modified with hexadecyltrimethoxysilane. DETAILED DESCRIPTION
[0046] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific conditions are specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.
[0047] Example 1
[0048] A method for improving the hydrophobicity of biomass comprises the following steps:
[0049] S1. Put cotton straw into a multifunctional pulverizer and crush it, then sieve to obtain 100-mesh cotton straw powder, then soak the cotton straw powder in a 5wt% sodium hydroxide solution and stir for 3h, the solid-liquid mass ratio of the cotton straw powder to the sodium hydroxide solution is 1:8, then wash and dry the cotton straw powder to obtain pretreated cotton straw fiber;
[0050] S2, add 40 mL of 75 wt% methanol solution to 1 g of the pretreated cotton straw fiber obtained in step S1, then add 0.2 g of dodecyltrimethoxysilane, stir magnetically at 350 rpm for 12 h at 50°C, then wash and dry to obtain hydrophobically modified straw fiber. The modification mechanism is as follows Figure 1 shown.
[0051] Example 2
[0052] A method for improving the hydrophobicity of biomass comprises the following steps:
[0053] S1. Put cotton straw into a multifunctional pulverizer and crush it, then sieve to obtain 100-mesh cotton straw powder, then soak the cotton straw powder in a sodium hydroxide solution with a concentration of 8wt% and stir for 2h, wherein the solid-liquid mass ratio of the cotton straw powder to the sodium hydroxide solution is 1:8, and then wash and dry the cotton straw powder to obtain pretreated cotton straw fiber;
[0054] S2, add 40 mL of 75 wt% methanol solution to 1 g of the pretreated cotton straw fiber obtained in step S1, then add 0.066 g of octyltrimethoxysilane, stir magnetically at 350 rpm for 12 h at 50°C, then wash and dry to obtain hydrophobically modified straw fiber. The modification mechanism is as follows Figure 2 shown.
[0055] Example 3
[0056] A method for improving the hydrophobicity of biomass comprises the following steps:
[0057] S1. Put cotton straw into a multifunctional pulverizer and crush it, then sieve to obtain 100-mesh cotton straw powder, then soak the cotton straw powder in a 5wt% sodium hydroxide solution and stir for 24 hours, the solid-liquid mass ratio of the cotton straw powder to the sodium hydroxide solution is 1:8, then wash and dry the cotton straw powder to obtain pretreated cotton straw fiber;
[0058] S2, add 40 mL of 75 wt% methanol solution to 1 g of the pretreated cotton straw fiber obtained in step S1, then add 0.066 g of hexadecyltrimethoxysilane, stir magnetically at 350 rpm for 12 h at 50°C, then wash and dry to obtain hydrophobically modified straw fiber. The modification mechanism is as follows Figure 3 shown.
[0059] Example 4
[0060] A method for improving the hydrophobicity of biomass comprises the following steps:
[0061] S1. Put corn straw into a multifunctional pulverizer and crush it, then sieve to obtain 100-mesh corn straw powder, then soak the corn straw powder in a 3wt% potassium hydroxide solution and stir for 2h, wherein the solid-liquid mass ratio of the corn straw powder to the potassium hydroxide solution is 2:10, and then wash and dry the corn straw powder to obtain pretreated corn straw fiber;
[0062] S2. Add 40 mL of 70 vt% ethanol solution to 1 g of the pretreated corn straw fiber obtained in step S1, then add 0.1 g of decyltriethoxysilane and 0.1 g of dodecyltriethoxysilane, stir magnetically at 300 rpm for 3 h at 15 °C, then wash and dry to obtain hydrophobically modified corn straw fiber.
[0063] Example 5
[0064] A method for improving the hydrophobicity of biomass comprises the following steps:
[0065] S1. Put wheat straw into a multifunctional pulverizer and crush it, then sieve it to obtain 100-mesh wheat straw powder, then soak the wheat straw powder in a 10wt% potassium hydroxide solution and stir it for 24 hours, the solid-liquid mass ratio of the wheat straw powder to the lithium hydroxide solution is 1:8, then wash and dry the wheat straw powder to obtain pretreated wheat straw fiber;
[0066] S2. Add 40 mL of 80 vt% ethanol solution to 1 g of the pretreated wheat straw fiber obtained in step S1, then add 0.066 g of octadecyltriethoxysilane and stir magnetically at 400 rpm, react at 60°C for 36 h, then wash and dry to obtain hydrophobically modified straw fiber.
[0067] Example 6
[0068] A method for improving the hydrophobicity of biomass comprises the following steps:
[0069] S1, putting bamboo into a multifunctional crusher and crushing it, then sieving to obtain 100-mesh bamboo powder, then soaking the bamboo powder in a 5wt% sodium hydroxide solution and stirring for 3h, the solid-liquid mass ratio of the bamboo powder to the sodium hydroxide solution is 1:8, and then washing and drying the bamboo powder to obtain pretreated bamboo;
[0070] S2. Add 40 mL of 75 wt% methanol solution to 1 g of the pretreated bamboo obtained in step S1, then add 0.2 g of dicosyltrimethoxysilane, stir magnetically at 350 rpm for 12 h at 50° C., then wash and dry to obtain hydrophobically modified bamboo.
[0071] Comparative Example 1
[0072] A method for preparing straw fiber comprises the following steps:
[0073] S1. Put the cotton stalks into a multifunctional grinder, grind them, and then sieve them;
[0074] S2, after sieving, washing and drying to obtain straw fiber.
[0075] Test Example 1
[0076] The contact angles of the hydrophobically modified straw fibers obtained in Examples 1-3 were tested respectively. The results are as follows: Figure 4-Figure 6 As shown. Among them, Figure 4-Figure 6 The contact angle results of the hydrophobically modified straw fibers obtained in Examples 1-3 are shown respectively.
[0077] Depend on Figure 4-Figure 6 It can be seen that the hydrophobic properties of the straw fibers modified with silane coupling agent have been greatly improved, the contact angles are greater than 90°, and they can continue to stay on the surface to exhibit a hydrophobic effect.
[0078] Test Example 2
[0079] The untreated straw fiber prepared in the comparative example was used as a control, and the hydrophobically modified straw fiber prepared in Examples 1-3 was subjected to infrared spectroscopy detection. The results are as follows: Figure 7-Figure 9 As shown. Among them, Figure 7-Figure 9 They are infrared spectra of the hydrophobically modified straw fibers obtained in Examples 1-3, respectively.
[0080] Depend on Figure 7-Figure 9 It can be seen that the hydrophobically modified straw fibers obtained in Examples 1-3 are respectively -1、1420cm -1 、1240cm -1 、700cm -1 Absorption peaks appear near the surface, which are characteristic peaks after modification by silane coupling agent, indicating that the silane coupling agent has been successfully grafted onto the straw fiber.
[0081] In summary, silane coupling agents can be used to modify biomass, thereby improving the hydrophobicity of straw fiber and bamboo.
[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for improving the hydrophobicity of biomass, characterized in that: The following steps are involved: S1, crushing and sieving the biomass, then pre-treating it, stirring, washing and drying it to obtain the pre-treated biomass; S2, adding an alcohol solution to the pretreated biomass obtained in step S1, then adding a silane coupling agent and stirring, and then washing and drying to obtain a hydrophobically modified biomass.
2. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S1, the biomass is one of cotton straw, bamboo, corn straw and wheat straw.
3. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S1, the pretreatment is soaking in water or alkali solution; the alkali solution is one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, potassium carbonate solution and calcium hydroxide solution; the concentration of the alkali solution is 3-10wt%.
4. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S2, the alcohol solution is one of a methanol solution, an ethanol solution, a glycerol solution and an isopropanol solution; and the concentration of the alcohol solution is 40-80 vt.%.
5. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S2, the solid-liquid mass ratio of the pretreated biomass to the alcohol solution is 1-2:10-40.
6. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S2, the silane coupling agent is at least one of octyltrimethoxysilane, n-octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrihexyloxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, docosyltriethoxysilane and docosyltrimethoxysilane.
7. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S2, the solid-liquid mass ratio of the pretreated biomass to the silane coupling agent is 5-50:1-2.
8. The method for improving the hydrophobicity of biomass according to claim 1, characterized in that: In step S2, the mixture is stirred at 15-60°C and 300-400 rpm for 3-36 hours.
9. Hydrophobically modified biomass obtained by the method for improving the hydrophobic properties of biomass according to any one of claims 1 to 8.
10. Use of the hydrophobically modified biomass according to claim 9 in municipal gardening, home decoration building materials, papermaking, food packaging, craft products, fireproof materials or medical devices.