A kind of fast water-absorbing silica gel and its preparation method and application

Abstract

The application belongs to the technical field of silica gel, and particularly relates to fast water-absorbing silica gel, a preparation method and application thereof. The fast water-absorbing silica gel is prepared by a thiol-ene click reaction between coarse-pore silica gel loaded with a polyhydroxy compound and coarse-pore silica gel loaded with polydopamine. The silica gel provided by the application has high water absorption rate while quickly absorbing water, and has good regeneration performance in addition.

Description

Technical Field

[0001] This invention belongs to the field of silicone technology, specifically relating to a fast-absorbing silicone, its preparation method, and its applications. Background Technology

[0002] Silica gel is an amorphous inorganic polymer material that can absorb moisture from the air. Due to its non-toxic, odorless, non-corrosive, and non-polluting properties, it is widely used as a desiccant in food and pharmaceuticals, for moisture protection of electronic devices, and for controlling air humidity. However, the low water absorption rate and slow adsorption speed of ordinary silica gel limit its application in high-humidity environments.

[0003] To improve the water absorption rate of silica gel, Chinese Patent Publication No. CN 118437280 B discloses a composite desiccant and its preparation method. The composite desiccant comprises modified silica gel and activated carbon in a mass ratio of (7-15):(1-5). The modified silica gel prepared by this method has an excellent microporous structure. After treatment with an organic acid solution, it can achieve a certain effect of cleaning and expanding the micropores, thus giving it a high specific surface area, allowing it to load more activated carbon, resulting in a synergistic effect and superior adsorption. Simultaneously, the modified silica gel of this method has a higher number of hydroxyl groups, resulting in high internal structural stability. This not only significantly improves its adsorption performance but also prevents deformation, deterioration, or leakage from the packaging bag after water absorption, thus protecting the product. Furthermore, the recycling and reuse process is simple. However, the composite desiccant prepared by this method only achieves a moisture absorption of about 33% after 48 hours at 90% humidity, indicating a slow adsorption rate.

[0004] To improve the adsorption rate of silica gel, Chinese Patent Publication No. CN 119236889 A discloses a pharmaceutical silica gel desiccant with fast adsorption rate and its preparation method. The fast-adsorption pharmaceutical silica gel desiccant is composed of the following components by weight: 50-65 parts silica gel, 4-8 parts calcium chloride, 3-6 parts magnesium sulfate, 3-7 parts ferric oxide, 1-4 parts antibacterial compound, 5-10 parts modified surfactant, 1-2 parts potassium hydroxide, 10-30 parts ice water, 2-4 parts acrylic acid, 2-4 parts acrylamide, 0.4-0.8 parts sodium carboxymethyl starch, 0.2-0.3 parts dimethyl benzoate, 0.005-0.015 parts polyethylene glycol diacrylate, and 1-2 parts methanol. The silica gel desiccant prepared by this method exhibits excellent antibacterial properties, adsorption rate, and adsorption capacity. However, the moisture absorption rate of this technical solution is approximately 53%, and the water absorption rate can be further improved.

[0005] In addition, none of the aforementioned existing technologies have addressed the regenerative performance of their products. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of low water absorption rate and low water absorption rate of silica gel in the prior art, and to provide silica gel that absorbs water quickly. It is prepared by a mercapto-olefin click reaction of coarse-porous silica gel loaded with polyhydroxy compounds and coarse-porous silica gel loaded with polydopamine. This makes the silica gel have a high water absorption rate while absorbing water quickly, and also has good regeneration performance.

[0007] Another object of the present invention is to provide a method for preparing rapidly absorbent silica gel.

[0008] Another object of the present invention is to provide an application of rapidly absorbent silica gel in desiccants.

[0009] Another object of the present invention is to provide a desiccant.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] One aspect of this invention provides a rapidly absorbent silica gel, which is formed by a click reaction between coarse-porous silica gel loaded with polyhydroxy compounds and coarse-porous silica gel loaded with polydopamine.

[0012] The pore volume of the coarse-pore silica gel of the present invention is preferably 0.6-1 mL / g, more preferably 0.6-0.8 mL / g, and even more preferably 0.65 mL / g-0.78 mL / g.

[0013] The polyhydroxy compounds of the present invention include at least one of glycerol glucoside and konjac glucomannan.

[0014] Furthermore, the polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan in a mass ratio of 3-8:2-4.

[0015] Furthermore, the polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan in a mass ratio of 5:3.

[0016] The coarse-porous silica gel loaded with polyhydroxy compounds of the present invention is preferably coarse-porous silica gel with polyhydroxy compounds loaded inside.

[0017] Furthermore, the method for preparing the coarse-porous silica gel loaded with polyhydroxy compounds includes the following steps: stirring and dispersing the aqueous solution of the polyhydroxy compound and the coarse-porous silica gel evenly, placing them in a sealed container, drawing a vacuum, releasing the vacuum, repeating this process 3-5 times, and drying to obtain intermediate A; mixing intermediate A, mercaptosilane coupling agent, and an aqueous ethanol solution, stirring the reaction, filtering, washing, and drying to obtain the final product.

[0018] Furthermore, the mass concentration of the aqueous solution of the polyhydroxy compound is 2-5%.

[0019] Furthermore, the mass ratio of the polyhydroxy compound to the coarse-porous silica gel is 0.3-0.8:1.

[0020] Furthermore, the mass ratio of intermediate A to mercaptosilane coupling agent is 1:2-4.

[0021] Furthermore, the ratio of intermediate A to the aqueous ethanol solution is 1g:30-50mL.

[0022] Furthermore, the mass ratio of ethanol to water in the ethanol-water solution is 1-3:97-99.

[0023] Furthermore, the mercaptosilane coupling agent is selected from at least one of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, or γ-mercaptopropyltriethoxysilane, and is more preferably γ-mercaptopropyltrimethoxysilane.

[0024] Furthermore, the method for preparing the coarse-porous silica gel loaded with polyhydroxy compounds includes the following steps: stirring and dispersing the aqueous solution of the polyhydroxy compound and the coarse-porous silica gel evenly, placing them in a sealed container, evacuating to 0.1-0.3 atm, releasing the vacuum, repeating 3-5 times, and drying to obtain intermediate A; mixing intermediate A, mercaptosilane coupling agent and aqueous ethanol solution, stirring and reacting at 60-80℃ for 3-5 hours, filtering, washing, and drying to obtain the final product.

[0025] The coarse-porous silica gel loaded with polydopamine of the present invention is preferably coarse-porous silica gel with polydopamine loaded on its surface.

[0026] Furthermore, the method for preparing the polydopamine-loaded coarse-porous silica gel includes the following steps: dispersing the coarse-porous silica gel in a Tris (tris(hydroxymethyl)aminomethane hydrochloride) buffer solution, adding an aqueous solution of dopamine hydrochloride, stirring, filtering, washing, and drying to obtain intermediate B; mixing intermediate B, a vinylsilane coupling agent, and an aqueous ethanol solution, filtering, washing, and drying to obtain the final product.

[0027] Furthermore, the mass concentration of the Tris buffer solution is 0.5-1%.

[0028] Furthermore, the mass concentration of the dopamine hydrochloride aqueous solution is 0.5-1%.

[0029] Furthermore, the mass-to-volume ratio of the coarse-porous silica gel to the Tris buffer solution is 5-10 mg: 1 mL.

[0030] Furthermore, the volume ratio of the Tris buffer solution to the dopamine hydrochloride aqueous solution is 1-1.5:1.

[0031] Furthermore, the mass ratio of intermediate B to vinylsilane coupling agent is 1:3-5.

[0032] Furthermore, the ratio of intermediate B to the aqueous ethanol solution is 1g:30-50mL.

[0033] Furthermore, the vinyl silane coupling agent is selected from at least one of vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyltrimethoxysilane, and vinyl-tris(2-methoxyethoxy)silane, preferably vinyltrimethoxysilane.

[0034] Further, the preparation method of the polydopamine-loaded coarse-porous silica gel includes the following steps: dispersing the coarse-porous silica gel in a Tris (tris(hydroxymethyl)aminomethane hydrochloride) buffer solution, adding an aqueous solution of dopamine hydrochloride, stirring at 300-500 rpm for 20-24 h, centrifuging, filtering, washing, and drying to obtain intermediate B, mixing intermediate B, a vinylsilane coupling agent, and an aqueous ethanol solution, stirring and reacting at 60-80°C for 3-5 h, filtering, washing, and drying to obtain the final product.

[0035] This invention creatively crosslinks coarse-porous silica gel loaded with polyhydroxy compounds and coarse-porous silica gel loaded with polydopamine through a mercapto-olefin click reaction to form stable silica gel. The polyhydroxy compounds are loaded inside the coarse-porous silica gel, and the polydopamine is loaded on the outer surface of the coarse-porous silica gel. The two work together to achieve rapid water absorption and a high water absorption rate. In addition, the presence of the mercapto-olefin crosslinking network improves its regeneration rate.

[0036] During this process, the inventors discovered that: (1) when the polyhydroxy compound includes glycerol glucoside and konjac glucomannan, the moisture absorption rate, moisture absorption rate and regeneration rate of the obtained silica gel are better than those of the same mass of a single polyhydroxy compound. It is speculated that this is because the hydroxyl groups of glycerol glucoside and konjac glucomannan accelerate capillary penetration and enhance the multilayer adsorption of water molecules through hydrogen bond network, thus exhibiting a synergistic effect; (2) when polyhydroxy compounds are loaded on the surface of coarse-porous silica gel, the moisture absorption rate, moisture absorption rate and regeneration rate of the obtained silica gel may be poor due to the low pore utilization rate of coarse-porous silica gel and the poor structural stability of coarse-porous silica gel; (3) when preparing coarse-porous silica gel loaded with polyhydroxy compounds, the reaction of other thiol compounds with coarse-porous silica gel loaded with polydopamine may be poor due to insufficient crosslinking density, resulting in poor moisture absorption rate, moisture absorption rate and regeneration rate of the obtained silica gel.

[0037] Another aspect of the present invention provides a method for preparing the above-mentioned rapidly absorbent silica gel, comprising the following steps: dispersing coarse-porous silica gel loaded with polyhydroxy compounds in dimethylformamide, adding coarse-porous silica gel loaded with polydopamine and an initiator, reacting under ultraviolet light, filtering, washing, and drying to obtain the product.

[0038] Furthermore, the initiator is selected from at least one of benzoin dimethyl ether or 2-hydroxy-2-methyl-1-phenyl-1-propanone, preferably benzoin dimethyl ether.

[0039] Furthermore, the ratio of the coarse-porous silica gel loaded with polyhydroxy compounds, the coarse-porous silica gel loaded with polydopamine, the initiator, and dimethylformamide is 2-3g:1g:0.2-0.3g:30-50mL.

[0040] Furthermore, the method for preparing the rapidly absorbent silica gel includes the following steps: dispersing coarse-porous silica gel loaded with polyhydroxy compounds in dimethylformamide, adding coarse-porous silica gel loaded with polydopamine and an initiator, reacting under ultraviolet light (wavelength 365nm) for 1-2 hours, filtering, washing, and drying to obtain the product.

[0041] Another aspect of the present invention provides the application of the aforementioned rapidly absorbing silica gel in desiccants.

[0042] Another aspect of the present invention provides a desiccant, comprising the aforementioned rapidly absorbing silica gel.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. This invention creatively crosslinks coarse-porous silica gel loaded with polyhydroxy compounds and coarse-porous silica gel loaded with polydopamine through a mercapto-olefin click reaction to form stable silica gel. The two work together to achieve rapid water absorption while having a high water absorption rate and regeneration rate.

[0045] 2. In this invention, when the polyhydroxy compound includes glycerol glucoside and konjac glucomannan, the moisture absorption rate, moisture absorption speed, and regeneration rate of silica gel are improved.

[0046] 3. This invention uses a specific thiol compound to react with coarse-porous silica gel loaded with polydopamine, which improves the moisture absorption rate, moisture absorption speed and regeneration rate of the silica gel. Detailed Implementation

[0047] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0048] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0049] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available or prepared by conventional methods in the art.

[0050] The coarse-pore silica gel has a pore volume of 0.78 mL / g and was purchased from Qingdao Century Marine Environmental Protection New Materials Co., Ltd. It is type C-1 and of superior quality.

[0051] Example 1: A fast-absorbing silica gel

[0052] Step 1: Preparation of coarse-porous silica gel loaded with glycerol glucoside:

[0053] Glyceryl glucoside aqueous solution and coarse-pore silica gel were stirred and dispersed evenly, placed in a sealed container, and vacuumed to 0.2 atm. The vacuum was released and repeated 4 times to obtain intermediate A. Intermediate A, γ-mercaptopropyltrimethoxysilane and ethanol aqueous solution were mixed and stirred at 70°C for 4 h. The mixture was filtered, washed and dried to obtain the final product.

[0054] The mass concentration of the glycerol glucoside aqueous solution is 4%.

[0055] The mass ratio of the glycerol glucoside to the coarse-porous silica gel is 0.5:1.

[0056] The mass ratio of intermediate A to γ-mercaptopropyltrimethoxysilane is 1:3.

[0057] The ratio of intermediate A to the aqueous ethanol solution is 1 g: 40 mL.

[0058] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0059] Step 2: Preparation of coarse-porous silica gel loaded with polydopamine:

[0060] Coarse-porous silica gel was dispersed in Tris buffer solution, and dopamine hydrochloride aqueous solution was added. The mixture was stirred at 400 rpm for 24 h, centrifuged, filtered, washed, and dried to obtain intermediate B. Intermediate B, vinyltrimethoxysilane, and ethanol aqueous solution were mixed and stirred at 70 °C for 4 h. The mixture was then filtered, washed, and dried to obtain the final product.

[0061] The Tris buffer solution has a mass concentration of 0.5%.

[0062] The mass concentration of the dopamine hydrochloride aqueous solution is 0.5%.

[0063] The mass-to-volume ratio of the coarse-porous silica gel to the Tris buffer solution is 8 mg: 1 mL.

[0064] The volume ratio of the Tris buffer solution to the dopamine hydrochloride aqueous solution is 1:1.

[0065] The mass ratio of intermediate B to vinyltrimethoxysilane is 1:4.

[0066] The ratio of intermediate B to the aqueous ethanol solution is 1 g: 40 mL.

[0067] Step 3: Prepare silica gel for rapid water absorption:

[0068] Coarse-porous silica gel loaded with glycerol glucoside was dispersed in dimethylformamide, and then coarse-porous silica gel loaded with polydopamine and benzoin dimethyl ether were added. The reaction was carried out under ultraviolet light (wavelength 365 nm) for 1.5 h, and the product was obtained by filtration, washing and drying.

[0069] The ratio of the coarse-porous silica gel loaded with glycerol glucoside, the coarse-porous silica gel loaded with polydopamine, the benzoin dimethyl ether, and the dimethylformamide is 2g:1g:0.2g:40mL.

[0070] Example 2: A fast-absorbing silica gel

[0071] Step 1: Preparation of coarse-porous silica gel loaded with konjac glucomannan:

[0072] Konjac glucomannan aqueous solution and coarse-pore silica gel were stirred and dispersed evenly, placed in a sealed container, and vacuumed to 0.2 atm. The vacuum was released and repeated 4 times to obtain intermediate A. Intermediate A, γ-mercaptopropyltrimethoxysilane and ethanol aqueous solution were mixed and stirred at 70°C for 4 hours. After filtration, washing and drying, the product was obtained.

[0073] The mass concentration of the konjac glucomannan aqueous solution is 4%.

[0074] The mass ratio of konjac glucomannan to coarse-porous silica gel is 0.5:1.

[0075] The mass ratio of intermediate A to γ-mercaptopropyltrimethoxysilane is 1:3.

[0076] The ratio of intermediate A to the aqueous ethanol solution is 1 g: 40 mL.

[0077] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0078] Step 2: Preparation of coarse-porous silica gel loaded with polydopamine: Same as step 2 in Example 1.

[0079] Step 3: Prepare silica gel for rapid water absorption:

[0080] Coarse-porous silica gel loaded with konjac glucomannan was dispersed in dimethylformamide, and coarse-porous silica gel loaded with polydopamine and benzoin dimethyl ether were added. The reaction was carried out under ultraviolet light (wavelength 365nm) for 1.5h, and then filtered, washed and dried to obtain the final product.

[0081] The ratio of the coarse-porous silica gel loaded with konjac glucomannan, the coarse-porous silica gel loaded with polydopamine, the benzoin dimethyl ether and the dimethylformamide is 2g:1g:0.2g:40mL.

[0082] Example 3: A fast-absorbing silica gel

[0083] Step 1: Preparation of coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan:

[0084] The aqueous solution of the polyhydroxy compound and coarse-porous silica gel were stirred and dispersed evenly, placed in a sealed container, and evacuated to 0.2 atm. The vacuum was released and repeated 4 times to obtain intermediate A. Intermediate A, γ-mercaptopropyltrimethoxysilane and aqueous ethanol solution were mixed and stirred at 70°C for 4 hours. The mixture was then filtered, washed and dried to obtain the final product.

[0085] The polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan in a mass ratio of 5:3.

[0086] The mass concentration of the aqueous solution of the polyhydroxy compound is 4%.

[0087] The mass ratio of the polyhydroxy compound to the coarse-porous silica gel is 0.5:1.

[0088] The mass ratio of intermediate A to γ-mercaptopropyltrimethoxysilane is 1:3.

[0089] The ratio of intermediate A to the aqueous ethanol solution is 1 g: 40 mL.

[0090] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0091] Step 2: Preparation of coarse-porous silica gel loaded with polydopamine: Same as step 2 in Example 1.

[0092] Step 3: Prepare silica gel for rapid water absorption:

[0093] Coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan was dispersed in dimethylformamide, and then coarse-porous silica gel loaded with polydopamine and benzoin dimethyl ether were added. The reaction was carried out under ultraviolet light (wavelength 365 nm) for 1.5 h, filtered, washed and dried to obtain the final product.

[0094] The ratio of the coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan, the coarse-porous silica gel loaded with polydopamine, benzoin dimethyl ether and dimethylformamide is 2g:1g:0.2g:40mL.

[0095] Comparative Example 1: A fast-absorbing silica gel

[0096] Step 1: Preparation of coarse-pore silica gel:

[0097] The coarse-porous silica gel, γ-mercaptopropyltrimethoxysilane and an aqueous ethanol solution were mixed and stirred at 70°C for 4 hours. The mixture was then filtered, washed and dried to obtain the final product.

[0098] The mass ratio of the coarse-porous silica gel to γ-mercaptopropyltrimethoxysilane is 1:3.

[0099] The ratio of coarse-porous silica gel to ethanol aqueous solution is 1g:40mL.

[0100] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0101] Step 2: Preparation of coarse-porous silica gel loaded with polydopamine: Same as step 2 in Example 3.

[0102] Step 3: Prepare silica gel for rapid water absorption:

[0103] Coarse-porous silica gel was dispersed in dimethylformamide, and then polydopamine-loaded coarse-porous silica gel and benzoin dimethyl ether were added. The mixture was reacted under ultraviolet light (wavelength 365 nm) for 1.5 h, filtered, washed, and dried to obtain the final product.

[0104] The ratio of the coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan, the coarse-porous silica gel loaded with polydopamine, benzoin dimethyl ether and dimethylformamide is 2g:1g:0.2g:40mL.

[0105] Comparative Example 2: A fast-absorbing silica gel

[0106] Step 1: Preparation of coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan:

[0107] An aqueous solution of a polyhydroxy compound and coarse-porous silica gel were stirred at 400 rpm for 5 h to obtain intermediate A. Intermediate A, γ-mercaptopropyltrimethoxysilane and an aqueous solution of ethanol were mixed and stirred at 70 °C for 4 h. The mixture was then filtered, washed and dried to obtain the final product.

[0108] The polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan in a mass ratio of 5:3.

[0109] The mass concentration of the aqueous solution of the polyhydroxy compound is 4%.

[0110] The mass ratio of the polyhydroxy compound to the coarse-porous silica gel is 0.5:1.

[0111] The mass ratio of intermediate A to γ-mercaptopropyltrimethoxysilane is 1:3.

[0112] The ratio of intermediate A to the aqueous ethanol solution is 1 g: 40 mL.

[0113] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0114] Step 2: Preparation of coarse-porous silica gel loaded with polydopamine: Same as step 2 in Example 3.

[0115] Step 3: Prepare rapidly absorbent silica gel: Same as step 3 in Example 3.

[0116] Comparative Example 3: A fast-absorbing silica gel

[0117] Step 1: Same as step 1 in Example 3;

[0118] Step 2: Preparation of coarse-pore silica gel:

[0119] The coarse-pore silica gel, vinyltrimethoxysilane, and aqueous ethanol solution were mixed and stirred at 70°C for 4 hours. The mixture was then filtered, washed, and dried to obtain the final product.

[0120] The mass ratio of intermediate B to vinyltrimethoxysilane is 1:4.

[0121] The ratio of intermediate B to the aqueous ethanol solution is 1 g: 40 mL.

[0122] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0123] Step 3: Prepare rapidly absorbent silica gel: Same as step 3 in Example 3.

[0124] Comparative Example 4: A fast-absorbing silica gel

[0125] Step 1: Preparation of coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan:

[0126] The aqueous solution of the polyhydroxy compound and coarse-porous silica gel were stirred and dispersed evenly, placed in a sealed container, and evacuated to 0.2 atm. The vacuum was released and repeated 4 times to obtain intermediate A. Intermediate A, β-mercaptoethylamine and aqueous ethanol solution were mixed and stirred at 70°C for 4 hours. The mixture was then filtered, washed and dried to obtain the final product.

[0127] The polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan in a mass ratio of 5:3.

[0128] The mass concentration of the aqueous solution of the polyhydroxy compound is 4%.

[0129] The mass ratio of the polyhydroxy compound to the coarse-porous silica gel is 0.5:1.

[0130] The mass ratio of intermediate A to β-mercaptoethylamine is 1:3.

[0131] The ratio of intermediate A to the aqueous ethanol solution is 1 g: 40 mL.

[0132] The mass ratio of ethanol to water in the ethanol-water solution is 3:97.

[0133] Step 2: Preparation of coarse-porous silica gel loaded with polydopamine: Same as step 2 in Example 3.

[0134] Step 3: Prepare rapidly absorbent silica gel: Same as step 3 in Example 3.

[0135] Comparative Example 5: A fast-absorbing silica gel

[0136] The aqueous solution of the polyhydroxy compound and coarse-porous silica gel are stirred and dispersed evenly, placed in a sealed container, and vacuumed to 0.2 atm. The vacuum is then released, and the mixture is repeated 4 times. After drying, the product is obtained.

[0137] The polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan in a mass ratio of 5:3.

[0138] The mass concentration of the aqueous solution of the polyhydroxy compound is 4%.

[0139] The mass ratio of the polyhydroxy compound to the coarse-porous silica gel is 0.5:1.

[0140] Comparative Example 6: A fast-absorbing silica gel

[0141] Coarse-porous silica gel was dispersed in Tris buffer solution, and dopamine hydrochloride aqueous solution was added. The mixture was stirred at 400 rpm for 24 h, centrifuged, filtered, washed, and dried to obtain the final product.

[0142] The Tris buffer solution has a mass concentration of 0.5%.

[0143] The mass concentration of the dopamine hydrochloride aqueous solution is 0.5%.

[0144] The mass-to-volume ratio of the coarse-porous silica gel to the Tris buffer solution is 8 mg: 1 mL.

[0145] The volume ratio of the Tris buffer solution to the dopamine hydrochloride aqueous solution is 1:1.

[0146] Test case

[0147] The properties of the rapidly absorbent silica gel (10g) prepared in Examples 1-3 and Comparative Examples 1-6 were tested:

[0148] (1) Under the conditions of 25℃, 90% humidity and 24h adsorption time, its moisture absorption rate was tested: Moisture absorption rate = (mass after water absorption - mass before water absorption) / mass before water absorption × 100%;

[0149] (2) Under the conditions of 25℃, 90% humidity and adsorption time of 10min, the moisture absorption rate was tested: Moisture absorption rate = (mass after water absorption - mass before water absorption) / time;

[0150] (3) First, adsorb at 25℃ and 90% humidity for 1 hour, then heat at 100℃ for 4 hours to remove water. This is one cycle. The regeneration rate is tested: regeneration rate = water absorption after 30 cycles / water absorption after the first cycle × 100%.

[0151] Test results:

[0152] Table 1

[0153] Moisture absorption rate (%) <![CDATA[Moisture absorption rate (g·g -1 ·min -1 )]]> Regeneration rate (%) Example 1 53 3.6 98.8 Example 2 48 3.2 98.2 Example 3 55 4.4 99.4 Comparative Example 1 35 2.3 96.4 Comparative Example 2 40 2.5 89.3 Comparative Example 3 31 2.2 87.1 Comparative Example 4 43 2.8 90.2 Comparative Example 5 30 2.2 85.7 Comparative Example 6 39 1.9 90.6

[0154] Results analysis:

[0155] A comparison of Examples 1-3 shows that when the polyhydroxy compound is a mixture of glycerol glucoside and konjac glucomannan, the moisture absorption rate, moisture absorption speed, and regeneration rate of the silica gel prepared by the single polyhydroxy compound are all improved.

[0156] A comparison of Example 3 and Comparative Example 1 shows that when no polyhydroxy compound is loaded inside the coarse-porous silica gel, the moisture absorption rate and moisture absorption capacity of the prepared silica gel decrease significantly.

[0157] A comparison of Examples 3, 1, and 2 shows that when polyhydroxy compounds are loaded onto the surface of coarse-porous silica gel, the moisture absorption rate and moisture absorption speed of the prepared silica gel are improved compared to when no polyhydroxy compounds are loaded, but the regeneration rate is reduced. Compared to coarse-porous silica gel loaded with polyhydroxy compounds, the moisture absorption rate, moisture absorption speed, and regeneration rate of the prepared silica gel are all significantly reduced.

[0158] A comparison of Example 3 and Comparative Example 3 shows that when polydopamine is not loaded on the surface of the coarse-porous silica gel, the moisture absorption rate, moisture absorption rate, and regeneration rate of the prepared silica gel all decrease significantly.

[0159] A comparison of Examples 3, 1-2, and 4 shows that when the mercaptosilane coupling agent was replaced with β-mercaptoethylamine in the preparation of coarse-porous silica gel loaded with glycerol glucoside and konjac glucomannan, the resulting silica gel had better moisture absorption rate, moisture absorption speed, and regeneration rate than Comparative Examples 1-2, but not as good as Example 3.

[0160] A comparison of Examples 3, 5, and 6 shows that the moisture absorption rate, moisture absorption speed, and regeneration rate of coarse-porous silica gel loaded with only glycerol glucoside and konjac glucomannan or only polydopamine are far inferior to those of Example 3.

[0161] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A quick water-absorbing silica gel, characterized in that, The fast water-absorbing silica gel is prepared by a thiol-ene click reaction of a coarse-pore silica gel loaded with a polyhydroxyl compound and a coarse-pore silica gel loaded with a polydopamine. The preparation method of the coarse-pore silica gel loaded with the polyhydroxyl compound, The preparation method of the coarse-pore silica gel loaded with the polyhydroxyl compound comprises the following steps: uniformly stirring and dispersing a polyhydroxyl compound aqueous solution and coarse-pore silica gel, placing the mixture in a sealed container, vacuumizing, releasing the vacuum, repeating the vacuumizing and releasing the vacuum for 3-5 times, and drying to obtain an intermediate A; mixing the intermediate A, a thiol silane coupling agent and an ethanol aqueous solution, stirring and reacting, filtering, washing, and drying to obtain the coarse-pore silica gel loaded with the polyhydroxyl compound. The polyhydroxyl compound comprises at least one of glycerol glucoside and konjac glucomannan. The thiol silane coupling agent is at least one of γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyl methyl dimethoxysilane or γ-mercaptopropyl triethoxysilane. The preparation method of the coarse-pore silica gel loaded with the polydopamine comprises the following steps: dispersing coarse-pore silica gel in a Tris buffer solution, adding a dopamine hydrochloride aqueous solution, stirring, filtering, washing, and drying to obtain an intermediate B; mixing the intermediate B, a vinyl silane coupling agent and an ethanol aqueous solution, filtering, washing, and drying to obtain the coarse-pore silica gel loaded with the polydopamine.

2. The quick water absorbing silica gel according to claim 1, characterized in that, The polyhydroxyl compound is a mixture of glycerol glucoside and konjac glucomannan with a mass ratio of 3-8:2-4.

3. The quick water absorbing silica gel according to claim 1, characterized in that, The vinyl silane coupling agent is at least one of vinyl triethoxysilane, γ-methacryloyloxypropyl trimethoxysilane, vinyl trimethoxysilane, and vinyl-tris(2-methoxyethoxy)silane.

4. The method for producing a quick water-absorbing silica gel according to any one of claims 1 to 3, characterized by, The preparation method of the fast water-absorbing silica gel comprises the following steps: The coarse-pore silica gel loaded with the polyhydroxyl compound is dispersed in dimethylformamide, the coarse-pore silica gel loaded with the polydopamine and an initiator are added, and the reaction is carried out under ultraviolet light, and then filtering, washing, and drying are performed to obtain the fast water-absorbing silica gel.

5. Use of the fast water-absorbing silica gel according to any one of claims 1-3 in a desiccant.

6. A desiccant, characterized by, The desiccant comprises the fast water-absorbing silica gel according to any one of claims 1-3.