Oil-absorbing material, method for preparing the same and use thereof

Abstract

The application discloses an oil-absorbing material and a preparation method and application thereof, and belongs to the technical field of functional materials. The oil-absorbing material is prepared from a solution containing hydroxypropyl methyl cellulose and a proppant and an oil phase containing a surfactant; the proppant is at least one of xanthan gum, alginic acid and chitosan. On the basis of preparing the oil-absorbing material from the hydroxypropyl methyl cellulose, the microfluidic device is used to prepare the oil-absorbing material with uniform size, large specific surface area and high oil absorption rate, and the oil-absorbing material has good oil-water selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional materials, in particular to an oil absorption material and a preparation method and application thereof. BACKGROUND

[0002] Hydroxypropyl methyl cellulose (HPMC) is a kind of biological macromolecular material with low price, wide source, no irritation to skin and mucous membrane contact, good biocompatibility and biodegradability, which can be used as food additive. It contains a large number of hydroxyl groups in structure, which can be combined with other materials to provide a structural framework, thereby improving the mechanical strength of the material.

[0003] Microfluidic technology is a powerful tool for manufacturing structural materials. Microfluidic devices usually use the interaction between flow shear force and surface tension in microscale channels to divide continuous fluids into discrete droplets. This technology enables precise manipulation of the generated droplets, enabling the production of a large number of microstructures such as particles, fibers and sheets without the use of complex equipment and facilities. The prior art DOI number: 10.1016 / j.foodchem.2021.131357 provides a method for preparing porous cryogels using hydroxypropyl methyl cellulose and structural enhancers (such as flaxseed gum, kappa-carrageenan, carboxymethyl cellulose, gum arabic and guar gum) by freeze gel template method. It is found through experiments that the cryogel prepared by the method has a large material volume and will decompose in a 37℃ aqueous solution, which is not conducive to its oil absorption in an oil-water mixture. It is necessary to prepare an oil absorption material with high oil absorption efficiency and good oil-water selectivity in an oil-water mixture. SUMMARY

[0004] The purpose of the present application is to provide an oil absorption material and a preparation method and application thereof. The present application prepares an oil absorption material with uniform size, large specific surface area and high oil absorption rate through a microfluidic device on the basis of preparing an oil absorption material from hydroxypropyl methyl cellulose, which has good oil-water selectivity.

[0005] The present application first provides an oil absorption material prepared from a solution containing hydroxypropyl methyl cellulose (HPMC) and a supporting agent and an oil phase containing a surfactant.

[0006] The supporting agent is at least one of xanthan gum (XG), alginic acid (Alg) and chitosan (CS).

[0007] In the oil-absorbing material, the mass-volume ratio of the hydroxypropyl methyl cellulose and the solvent is 0.5-2.0 g:100 mL; specifically, 1.0 g:100 mL; the mass-volume ratio of the proppant and the solvent is 0.3-1.0 g:100 mL; specifically, 0.3 g:100 mL or 0.5 g:100 mL.

[0008] In the oil-absorbing material, the surfactant is at least one of Krytox-PEG-Krytox, polyoxyethylene (10) cetyl ether, polyoxyethylene (20) cetyl ether, sorbitan oleate, and polyoxyethylene sorbitan trioleate;

[0009] The solvent in the oil phase is any one of fluorinated oil, liquid paraffin, and vegetable oil;

[0010] The mass-volume ratio of the surfactant and the solvent in the oil phase is 0.5-2.0 g:100 mL; specifically, 0.5 g:100 mL.

[0011] The oil-absorbing material is prepared by microfluidic technology.

[0012] The solvent of the solution containing hydroxypropyl methyl cellulose and proppant is water.

[0013] The particle size of the oil-absorbing material is 0.8-1.2 mm; specifically, 1.06±0.049 mm, 0.99±0.021 mm, or 0.95±0.035 mm.

[0014] In the oil-absorbing material, the surface of the oil-absorbing material is also alternately coated with chitosan and alginic acid.

[0015] The application also provides a preparation method of the oil-absorbing material, comprising the following steps:

[0016] (1) loading the solution containing hydroxypropyl methyl cellulose and proppant and the oil phase containing a surfactant into a microfluidic device, adjusting the flow rate of the solution containing hydroxypropyl methyl cellulose and proppant and the oil phase containing a surfactant, and preparing monodisperse water-in-oil droplets;

[0017] (2) collecting the water-in-oil droplets and freeze-drying to obtain the oil-absorbing material.

[0018] In the preparation method, the flow rate of the solution containing hydroxypropyl methyl cellulose and proppant is 1000-2000 μL / h; specifically, 1600 μL / h.

[0019] The flow rate of the oil phase containing a surfactant is 10-20 mL / h; specifically, 12 mL / h.

[0020] The preparation method further comprises the steps of soaking the oil-absorbing material in a chitosan solution and then in an alginate solution.

[0021] Specifically, the step of soaking the oil-absorbing material in the chitosan solution and then in the alginate solution can be repeated for multiple times; more specifically, 2 to 6 times or 3 times.

[0022] In the preparation method, specifically, the oil-absorbing material is soaked in the chitosan solution, taken out and placed in water, then soaked in the alginate solution, and taken out and placed in water.

[0023] In the alginate solution, the mass-volume ratio of alginate and solvent is specifically 0.2 to 1.0 g:100 mL; more specifically, 0.5 g:100 mL.

[0024] In the chitosan solution, the mass-volume ratio of chitosan and solvent is specifically 0.2 to 1.0 g:100 mL; more specifically, 0.5 g:100 mL.

[0025] The soaking time can be 3 to 10 minutes each time; specifically, 5 minutes.

[0026] In the preparation method, the material is freeze-dried after soaking.

[0027] In the preparation method, the temperature of freeze-drying is -50 to -80°C; specifically, -80°C.

[0028] Finally, the application provides the use of the oil-absorbing material in adsorbing oil or oil in an oil-water mixture.

[0029] In the application, the oil absorbed by the oil-absorbing material is at least one of soybean oil, flaxseed oil and n-decane.

[0030] The application has the following advantages:

[0031] (1) The oil-absorbing material prepared by the application has uniform size and large specific surface area; the oil absorption rate of HPMC / XG oil-absorbing material is 9.66 g / g, the oil absorption rate of HPMC / Alg oil-absorbing material is 10.39 g / g; HPMC / Alg / CS oil-absorbing material has a rich pore structure on the surface, can spontaneously transfer from the water phase to the oil phase and suspend in the oil phase; it can be applied to an oil-water mixed solution for oil absorption, and the oil absorption rate is 12.51 g / g.

[0032] (2) The preparation method of the application is simple to operate and has high practical value; the oil-absorbing material can be widely used for oil absorption, and also widens the application range of microfluidic technology. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Structure diagram of microfluidic device used in the examples; in the diagram, 1 is a syringe pump, 2 is a syringe, 3 is an input tube, 4 is a coaxial needle, 5 is an output tube, and 6 is a collection tube;

[0034] Figure 2 Scanning electron microscope image of the oil absorption material prepared in Example 1;

[0035] Figure 3 Test diagram of the oil absorption material prepared in Example 1 suspended in soybean oil-water two-phase medium. DETAILED DESCRIPTION

[0036] The application will be further described in detail below with reference to the specific embodiments, and the examples given are only for the purpose of illustrating the application, but not for limiting the scope of the application.

[0037] In the following examples, the experimental methods are conventional methods, unless otherwise specified.

[0038] In the quantitative test in the following examples, three repeated experiments are set, and the average value is taken.

[0039] In the following examples, the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels.

[0040] The Krytox-PEG-Krytox surfactant used in the following examples is purchased from RAN Biotechnologies, item number 008-FluoroSurfactant.

[0041] The schematic diagram of the microfluidic device used in the following examples is shown in Figure 1 The main reference (DOI: 10.1002 / adma.201300656) is self-assembled. The microfluidic device includes a syringe pump, a syringe, a coaxial needle, and a tetrafluoroethylene tube. The coaxial needle is a commercially available integrated double-needle seat coaxial needle, with an outer needle of 16G (inner diameter of 1.2mm, outer diameter of 1.6mm) and an inner needle of 20G (inner diameter of 0.6mm, outer diameter of 0.9mm). The connection mode is: the syringe is placed on the syringe pump, and is connected with the coaxial needle for injecting solution; and the needle end of the coaxial needle is connected with the tetrafluoroethylene tube (inner diameter of 1mm, outer diameter of 2mm) for forming microdroplets.

[0042] Example 1

[0043] (1) Preparation of dispersed and continuous phase solutions: Weigh 0.02g HPMC (hydroxypropyl methylcellulose) and 0.01g Alg (alginic acid) and dissolve them in 2mL of deionized water to obtain 1.0% HPMC / 0.5% Alg as the dispersed phase; Weigh 0.05g Krytox-PEG-Krytox surfactant and dissolve it in 10mL of fluorinated oil to obtain fluorinated oil containing 0.5% surfactant as the continuous phase.

[0044] (2) The continuous phase and the dispersed phase are injected into the syringe and loaded into the microfluidic device, wherein the flow rate of the dispersed phase is 1600 μL / h and the flow rate of the continuous phase is 12 mL / h, forming monodisperse water-in-oil droplets in the microchannel.

[0045] (3) Collect water-in-oil droplets, then remove the lower oil phase, and freeze-dry the upper droplets at -80℃ to obtain HPMC / Alg oil-absorbing material.

[0046] (4) Weigh 0.01g of CS (chitosan) and dissolve it in 2mL of 0.3% acetic acid solution to obtain a 0.5% CS solution; place the HPMC / Alg oil-absorbing material prepared in step (3) in the 0.5% CS solution for 5min, then take out the HPMC / Alg oil-absorbing material and place it in water; then place the HPMC / Alg oil-absorbing material in the 0.5% Alg solution for 5min, then take out the HPMC / Alg oil-absorbing material and place it in water;

[0047] Repeat step (4) three times, then remove the oil-absorbing material from the water and freeze-dry it at -80°C to obtain HPMC / Alg / CS oil-absorbing material.

[0048] The surface morphology and microstructure of the HPMC / Alg / CS oil-absorbing material prepared in Example 1 were observed under a scanning electron microscope, as follows: Figure 2 As shown. The HPMC / Alg / CS oil-absorbing material prepared in this embodiment has a diameter of 0.95±0.035 mm, a rich porous structure on its surface, and a porosity of 70.4±0.54%. Figure 3 In this embodiment, the oil-absorbing material is prepared in an oil-water mixture. When two phases are present, the upper layer is soybean oil and the lower layer is water. The HPMC / Alg / CS oil-absorbing material is suspended in the upper layer.

[0049] Example 2

[0050] (1) Prepare the dispersed and continuous phase solutions: 0.02 g HPMC and 0.006 g XG (xanthan gum) were dissolved in 2 mL deionized water to obtain 1.0% HPMC / 0.3% XG as the dispersed phase; 0.05 g Krytox-PEG-Krytox surfactant was dissolved in 10 mL fluorinated oil to obtain fluorinated oil containing 0.5% surfactant as the continuous phase.

[0051] (2) The continuous and dispersed phases were injected into syringes and loaded into the microfluidic device, where the dispersed phase had a flow rate of 1600 μL / h and the continuous phase had a flow rate of 12 mL / h, forming monodisperse water-in-oil droplets in the microchannel.

[0052] (3) The water-in-oil droplets were collected, and the lower oil phase was then aspirated. The upper droplets were placed in a freeze dryer at -80°C to obtain HPMC / XG oil-absorbing materials.

[0053] Example 3

[0054] (1) The dispersed and continuous phase solutions were prepared, which were the same as in Example 1.

[0055] (2) The continuous and dispersed phases were injected into syringes and loaded into the microfluidic device, where the dispersed phase had a flow rate of 1600 μL / h and the continuous phase had a flow rate of 12 mL / h, forming monodisperse water-in-oil droplets in the microchannel.

[0056] (3) The water-in-oil droplets were collected, and the lower oil phase was then aspirated. The upper droplets were placed in a freeze dryer at -80°C to obtain HPMC / XG oil-absorbing materials.

[0057] Performance test: The mass of the oil-absorbing material itself was first measured and recorded, and then it was immersed in soybean oil, flaxseed oil, n-decane, or an oil-water mixture (soybean oil: water mixed at a ratio of 1:1 to form an emulsion) at 37°C for 2 h. After the oil absorption process was completed, the oil-absorbing material saturated with oil was taken out, and the excess oil on the surface of the material was gently wiped off. Then the mass of the saturated oil-absorbing material was measured and recorded. The oil absorption capacity of the oil-absorbing material was calculated by the following formula: oil absorption rate = (M-M0) / M0 (g / g), M (g) is the mass of the oil-absorbing material after oil absorption, and M0 (g) is the initial mass of the oil-absorbing material. The calculation results are shown in Table 1.

[0058] Table 1 Particle size and oil absorption rate (g / g) of the oil-absorbing materials prepared in the examples

[0059] Particle size Soybean oil Linseed oil n-Decane Oil-water mixture HPMC / XG 1.06 ± 0.049 mm 9.66 10.07 8.89 / HPMC / Alg 0.99 ± 0.021 mm 10.39 10.54 9.95 8.21 HPMC / Alg / CS 0.95 ± 0.035 mm 14.82 15.63 13.63 12.51

Claims

1. Use of an oil-absorbing material in adsorbing oil, characterized in that: The oil-absorbing material is prepared from a solution containing hydroxypropyl methyl cellulose and a support agent and an oil phase containing a surfactant; The support agent is alginic acid; The preparation method of the oil-absorbing material comprises the following steps: (1) loading the solution containing hydroxypropyl methyl cellulose and a support agent and the oil phase containing a surfactant into a microfluidic device, adjusting the flow rates of the solution containing hydroxypropyl methyl cellulose and a support agent and the oil phase containing a surfactant, and preparing monodisperse water-in-oil droplets; (2) collecting the water-in-oil droplets and freeze-drying to obtain a product; (3) soaking the product obtained in step (2) in a chitosan solution and then in an alginic acid solution.

2. Use of an oil-absorbing material for adsorbing oil from an oil-water mixture, characterized in that: The oil-absorbing material is prepared from a solution containing hydroxypropyl methyl cellulose and a support agent and an oil phase containing a surfactant; The support agent is alginic acid; The preparation method of the oil-absorbing material comprises the following steps: (1) loading the solution containing hydroxypropyl methyl cellulose and a support agent and the oil phase containing a surfactant into a microfluidic device, adjusting the flow rates of the solution containing hydroxypropyl methyl cellulose and a support agent and the oil phase containing a surfactant, and preparing monodisperse water-in-oil droplets; (2) collecting the water-in-oil droplets and freeze-drying to obtain a product; (3) soaking the product obtained in step (2) in a chitosan solution and then in an alginic acid solution.

3. Use according to claim 1 or 2, characterized in that: In the solution containing hydroxypropyl methyl cellulose and a support agent, the mass-volume ratio of the hydroxypropyl methyl cellulose and the solvent is 0.5-2.0 g:100 mL; and the mass-volume ratio of the support agent and the solvent is 0.3-1.0 g:100 mL.

4. Use according to claim 1 or 2, characterized in that: The surfactant is at least one of Krytox-PEG-Krytox, polyoxyethylene (10) cetyl ether, polyoxyethylene (20) cetyl ether, sorbitan oleate and polyoxyethylene sorbitan trioleate; The solvent of the oil phase is any one of fluorinated oil, liquid paraffin and vegetable oil; The mass-volume ratio of the surfactant and the solvent in the oil phase is 0.5-2.0 g:100 mL.

5. Use according to claim 1 or 2, characterized in that: The solvent of the solution containing hydroxypropyl methyl cellulose and a support agent is water.

6. Use according to claim 1 or 2, characterized in that: The flow rate of the solution containing hydroxypropyl methyl cellulose and a support agent is 1000-2000 μL / h; The flow rate of the oil phase containing a surfactant is 10-20 mL / h.

7. Use according to claim 1 or 2, characterized in that: In step (3), the step of soaking the product obtained in step (2) in a chitosan solution and then in an alginic acid solution is repeated for multiple times; In the alginic acid solution, the mass-volume ratio of alginic acid and the solvent is 0.2-1.0 g:100 mL; In the chitosan solution, the mass-volume ratio of chitosan and the solvent is 0.2-1.0 g:100 mL.

8. Use according to claim 7, characterized in that: The step of soaking the product obtained in step (2) in a chitosan solution and then in an alginic acid solution is repeated for 2-6 times.

9. Use according to claim 1 or 2, characterized in that: The oil absorbed by the oil-absorbing material is at least one of soybean oil, flaxseed oil and n-decane.

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