A solid adsorbent for separating an oil-water mixture, and a preparation method and application thereof

Abstract

This invention discloses a solid adsorbent for separating emulsified oil-water mixtures. The raw materials include an oil phase and an aqueous phase. The oil phase comprises, by weight, 1-6 parts octadecyl methacrylate, 5-15 parts methyl methacrylate, 6-12 parts butyl acrylate, 0.5-1 parts modified silica, 0.5-1.5 parts initiator, and 0.5-1 parts crosslinking agent. The aqueous phase comprises, by weight, 0.1-1 parts dispersant and 20-100 parts water. This invention introduces inorganic modified silica into an acrylate-based oil-absorbing resin, thereby significantly increasing the specific surface area of ​​the solid adsorbent and reducing its internal pore size. This increases the contact area with oil contaminants, thereby improving the oil absorption rate and separation efficiency, which is beneficial for the adsorption of oil contaminants and the separation and adsorption of O / W type emulsified oils.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a solid adsorbent for separating emulsified oil-water mixtures and its applications. Background Technology

[0002] With the acceleration of industrialization, oil spills and their pollution problems are becoming increasingly prominent. Oil spills entering water bodies not only disrupt the ecological balance but also directly or indirectly affect human health and threaten the survival of plants and animals. Emulsified oil-water mixtures are particularly difficult to degrade and adsorb, making them the most challenging type of oil-water mixture to treat. Therefore, how to efficiently separate and adsorb emulsified oil-water mixtures is a key research focus and challenge.

[0003] Traditional natural and low-cost inorganic materials, such as mineral clay, sand, expanded graphite, diatomaceous earth, carbon-based materials, and porous membrane materials, are gradually being replaced by new synthetic materials because they cannot achieve efficient separation of oily wastewater. Conventional acrylate oil-absorbing resins are currently the most researched oil-absorbing materials, but traditional acrylate oil-absorbing resins are only suitable for separating and adsorbing layered oil-water mixtures, and their application is limited because they cannot separate and adsorb emulsified oil-water mixtures.

[0004] By introducing grafting materials into acrylate oil-absorbing resins, a novel solid adsorbent is obtained that can separate and adsorb both layered oil-water mixtures and emulsified oil-water mixtures, and has high potential application value.

[0005] Therefore, providing a solid adsorbent with emulsified oil separation and adsorption functions, and its preparation method, is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a solid adsorbent for the separation of emulsified oil-water mixtures, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A solid adsorbent for separating emulsified oil-water mixtures, the raw materials of which include an oil phase and an aqueous phase;

[0009] The oil phase comprises, by weight, 1-6 parts of octadecyl methacrylate, 5-15 parts of methyl methacrylate, 6-12 parts of butyl acrylate, 0.5-1 part of modified silica, 0.5-1.5 parts of initiator and 0.5-1 part of crosslinking agent;

[0010] The aqueous phase comprises, by weight, 0.1-1 parts of dispersant and 20-100 parts of water.

[0011] Preferably, the specific preparation steps of the modified silica are as follows: add the silane coupling agent alcohol solution to the silica alcohol solution, adjust the pH value to 10, stir the reaction for 4 hours, and then wash and dry to obtain the modified silica.

[0012] Preferably, the silane coupling agent alcohol solution is made by dissolving vinyltrimethoxysilane in anhydrous ethanol at a concentration of 200 mg / L.

[0013] Modified silica is a product obtained by hydrophobically modifying hydrophilic nano-silica nanoparticles with vinyltrimethoxysilane.

[0014] Preferably, the mass ratio of the silane coupling agent to the silicon dioxide is 9:1.

[0015] Compared to other silane coupling agents, vinyltrimethoxysilane has a double bond structure, which allows inorganic nanoparticles modified with this silane coupling agent to participate in acrylate polymerization reactions; similarly, it can be replaced by γ-(methacryloyloxy)propyltrimethoxysilane.

[0016] Preferably, the concentration of the silanol dioxide solution is 10 g / L;

[0017] The amount of silica should not be too much or too little. When the amount is too much, the cross-linked network inside the polymer is too tight, which reduces the interaction between the lipophilic group and the oil molecule, resulting in a decrease in the solubilization of the polymer. When the amount is too little, its supporting effect on the polymer network structure, as well as the space and pores provided by the polymer for adsorbing organic solvents, will be less.

[0018] Preferably, the silanol dioxide solution is a mixture of equal masses of 30nm, 50nm, 100nm and 500nm silanol dioxide solutions.

[0019] Silica is an inorganic material with good physicochemical stability, biocompatibility, low toxicity, and high porosity. As a carrier material, it can improve the storage capacity and stability of composites. The presence of a nanoscale porous structure within the polymer gives it the potential to separate emulsified oil-water mixtures. Furthermore, the nanoscale porous structure is determined by the particle size of the nano-silica; the particle size should not be too large or too small. If the particle size is too small, it is easy to form aggregates during synthesis, blocking the polymer pores and hindering the entry of oil into the polymer, resulting in a lower adsorption rate. If the particle size is too large, the graft chains between silica and acrylate monomers become shorter, failing to form an effective network structure and reducing the polymer's adsorption performance.

[0020] Ammonia water was used to adjust the pH value.

[0021] The reaction temperature is 40-45℃.

[0022] The temperature for hydrophobic modification of silica should not be too high. Excessive temperature can lead to over-reaction on the surface, resulting in cross-linking and preventing effective dispersion of silica particles, thus affecting the modification effect and performance. Furthermore, excessively high temperatures can also cause surface cracks and particle deformation, reducing the modification effect and material stability.

[0023] Preferably, the initiator is benzoyl peroxide;

[0024] The crosslinking agent is N,N-dimethylbisacrylamide;

[0025] The dispersant is hexadecyltrimethylammonium bromide.

[0026] Hexadecyltrimethylammonium bromide is an amphiphilic surfactant. When added to the synthesis system, it causes the oil phase to be suspended and stabilized in the dispersed water phase as spherical droplets under mechanical stirring, and polymerization occurs at the droplet level. Alternatively, amphiphilic organic compounds such as polyvinyl alcohol, which do not participate in acrylate-based polymerization systems and can be easily removed by physical or chemical methods after polymerization, can be used as substitutes.

[0027] The method for preparing the solid adsorbent for separating emulsified oil-water mixtures described above includes the following specific steps:

[0028] (1) Weigh the raw materials by weight: 1-6 parts of octadecyl methacrylate, 5-15 parts of methyl methacrylate, 6-12 parts of butyl acrylate, 0.5-1 part of modified silica, 0.5-1.5 parts of initiator, 0.5-1 part of crosslinking agent, 0.1-1 part of dispersant, and 20-100 parts of water;

[0029] (2) After uniformly mixing the octadecyl methacrylate, methyl methacrylate, butyl acrylate, modified silica, initiator and crosslinking agent, an oil phase is obtained;

[0030] (3) Dissolve the dispersant in the water and stir to obtain an aqueous phase;

[0031] (4) The oil phase is added dropwise to the aqueous phase, and the mixture is stirred to form uniform droplets in the aqueous phase. After reacting for 5.5-6.5 hours, the mixture is washed and dried to obtain the solid adsorbent.

[0032] Preferably, the dropping rate is 1-3 s / drop.

[0033] Preferably, the reaction temperature is 75-80°C, under a nitrogen atmosphere.

[0034] The application of solid adsorbents in oil-water separation as described above.

[0035] Preferably, the oil and water are O / W type emulsified oil-water mixtures.

[0036] The solid adsorbent for emulsified oil adsorption prepared in this invention exhibits rapid oil absorption and high separation efficiency. Under conditions of an oil-to-water ratio of 1:60 and a separation time of 7 hours, the solid adsorbent achieves separation efficiencies of 86.90% and 94.70% for Tween 80 and CTAB-stabilized water-in-toluene emulsified oils, respectively. Furthermore, after four consecutive separations of these two types of emulsified oils, the separation efficiencies remain at 32.31% and 47.83%, respectively. In addition, this solid adsorbent can separate and adsorb O / W type emulsified oils containing multiple miscible organic solvents, with no significant change in separation efficiency compared to O / W type emulsified oils containing a single organic solvent.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention discloses a solid adsorbent with O / W type emulsified oil-water mixture separation and adsorption capabilities, its preparation method, and its application. Based on an acrylate-based oil-absorbing resin, this invention introduces inorganic modified silica, which significantly increases the specific surface area of ​​the solid adsorbent and reduces its internal pore size, thereby increasing its contact area with oil contaminants. This improves the oil absorption rate and separation efficiency of oil contaminants, facilitating the adsorption of oil contaminants and the separation and adsorption of O / W type emulsified oil. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in this description are merely embodiments of the present invention.

[0040] Figure 1 This is a scanning electron microscope image of the solid adsorbent prepared in Example 1 of the present invention;

[0041] Figure 2 This is a particle size distribution diagram before demulsification in an application example of the present invention.

[0042] Figure 3 This is a particle size diagram after demulsification in an application example of the present invention. Detailed Implementation

[0043] Embodiments of the present invention are described below, examples of which are shown in the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0044] Example 1

[0045] A method for preparing a solid adsorbent for separating emulsified oil-water mixtures specifically includes the following steps:

[0046] (1) Accurately add 60 mL of distilled water and 0.04 g of hexadecyltrimethylammonium bromide to a three-necked flask, heat to 40 °C and stir to dissolve, thus obtaining an aqueous phase;

[0047] (2) Mix 4.6 mL of octadecyl methacrylate, 6.2 mL of methyl methacrylate, 9.2 mL of butyl acrylate, 0.22 g of benzoyl peroxide, 0.16 g of N,N-methylenebisacrylamide and 0.3 g of modified silica evenly to obtain the oil phase;

[0048] (3) The oil phase is added to the aqueous phase at a rate of 1-3 s / drop, and the temperature is raised to 75°C under nitrogen atmosphere. The oil phase is mechanically stirred to form uniform droplets in the water and reacted for 5 hours. After the product is cooled to room temperature, it is washed with anhydrous ethanol and deionized water and dried under vacuum in an oven at 65°C to constant weight to obtain the solid adsorbent.

[0049] The specific steps for preparing modified silica are as follows:

[0050] 1) Disperse 1g of silica nanoparticles with particle sizes of 30nm, 50nm, 100nm and 500nm into 4 beakers containing 100mL of anhydrous ethanol to prepare silica alcohol solutions with a concentration of 10g / L.

[0051] 2) According to the mass ratio of vinyltrimethoxysilane to silica nanopowder of 9:1, vinyltrimethoxysilane was dissolved in 50 mL of anhydrous ethanol and stirred at room temperature for 30 min to obtain a silane coupling agent solution.

[0052] 3) The silane coupling agent was slowly added to the four silica alcohol solutions obtained in step 1), and then ammonia was added dropwise to adjust the pH of the mixture to 10 to obtain a mixed solution. The mixture was placed in a 40°C constant temperature water bath and stirred for 4 hours. The product was washed 5 times with deionized water and dried in a 60°C oven to obtain modified silica powder.

[0053] Figure 1 The image shows a scanning electron microscope (SEM) image of the prepared solid adsorbent. As can be seen from the image, the polymer modified with silica does indeed exhibit a porous structure.

[0054] Example 2

[0055] A method for preparing a solid adsorbent for separating emulsified oil-water mixtures specifically includes the following steps:

[0056] (1) Accurately add 40 mL of distilled water and 0.05 g of hexadecyltrimethylammonium bromide to a three-necked flask, heat to 40 °C and stir to dissolve, thus obtaining an aqueous phase;

[0057] (2) Mix 3.6 mL of octadecyl methacrylate, 5.6 mL of methyl methacrylate, 9.8 mL of butyl acrylate, 0.2 g of benzoyl peroxide, 0.1 g of N,N-methylenebisacrylamide and 0.2 g of modified silica (prepared in the same way as in Example 1) evenly to obtain the oil phase;

[0058] (3) The oil phase is added to the aqueous phase at a rate of 1-3 s / drop, and the temperature is raised to 75°C under nitrogen atmosphere. The oil phase is mechanically stirred to form uniform droplets in the water and reacted for 5 hours. After the product is cooled to room temperature, it is washed with anhydrous ethanol and deionized water and dried under vacuum in an oven at 65°C to constant weight to obtain the solid adsorbent.

[0059] Example 3

[0060] A method for preparing a solid adsorbent for separating emulsified oil-water mixtures specifically includes the following steps:

[0061] (1) Accurately add 40 mL of distilled water and 0.2 g of hexadecyltrimethylammonium bromide to a three-necked flask, heat to 40 °C and stir to dissolve, thus obtaining an aqueous phase;

[0062] (2) Mix 3.3 mL of octadecyl methacrylate, 6.7 mL of methyl methacrylate, 10 mL of butyl acrylate, 0.15 g of benzoyl peroxide, 0.2 g of N,N-methylenebisacrylamide and 0.1 g of modified silica (prepared by the same method as in Example 1) evenly to obtain the oil phase;

[0063] (3) The oil phase is added to the aqueous phase at a rate of 1-3 s / drop, and the temperature is raised to 75°C under nitrogen atmosphere. The oil phase is mechanically stirred to form uniform droplets in the water and reacted for 5 hours. After the product is cooled to room temperature, it is washed with anhydrous ethanol and deionized water and dried under vacuum in an oven at 65°C to constant weight to obtain the solid adsorbent.

[0064] Comparative Example 1

[0065] A method for preparing a solid adsorbent specifically includes the following steps:

[0066] (1) Accurately add 60 mL of distilled water and 0.04 g of hexadecyltrimethylammonium bromide to a three-necked flask, heat to 40 °C and stir to dissolve, thus obtaining an aqueous phase;

[0067] (2) Mix 4.6 mL of octadecyl methacrylate, 6.2 mL of methyl methacrylate, 9.2 mL of butyl acrylate, 0.22 g of benzoyl peroxide, and 0.16 g of N,N-methylenebisacrylamide evenly to obtain the oil phase;

[0068] (3) The oil phase is added to the aqueous phase at a rate of 1-3 s / drop, and the temperature is raised to 75°C under nitrogen atmosphere. The oil phase is mechanically stirred to form uniform droplets in the water and reacted for 5 hours. After the product is cooled to room temperature, it is washed with anhydrous ethanol and deionized water and dried under vacuum in an oven at 65°C to constant weight to obtain the solid adsorbent.

[0069] Application examples

[0070] Five parts of surfactant Tween 80 or cetyltrimethylammonium bromide (CTAB) were dispersed in 250 parts of water. After complete dissolution, one part of oil was added and stirred continuously at room temperature for 2-3 hours at a stirring speed of 1000-2000 rpm to obtain surfactant-stable O / W emulsion oil.

[0071] The solid adsorbents prepared in Examples 1-3 and Comparative Example 1 were respectively placed in non-woven bags and completely immersed in oil-water mixtures. After dripping for hours, the bags were weighed until the weight no longer changed. The separation efficiency of the solid adsorbents for Tween 80 and CTAB-stable water-in-toluene emulsions was measured. Simultaneously, the separation efficiency of the solid adsorbents for the above two O / W type emulsion oil-water mixtures was studied after four consecutive separations. The relevant results are as follows:

[0072] Example 1: The solid adsorbent achieved separation efficiencies of 86.90% and 94.70% for Tween 80 and CTAB-stabilized water-in-toluene emulsions, respectively, with a saturation adsorption time of 7 hours. After four consecutive separations, the separation efficiencies remained at 32.31% and 47.83%, respectively. Furthermore, the solid adsorbent's separation and adsorption capacity for O / W type emulsions was restored after desorption by immersion in anhydrous ethanol. Specifically, if... Figure 2 This is a particle size distribution of a solid adsorbent stabilized at Tween 80 for water-coated toluene before demulsification. The figure shows that the oil droplet size before separation from the water-coated toluene emulsion is 300-570 nm. Figure 3 The figure shows the particle size distribution of the solid adsorbent before demulsification of water-in-toluene stabilized at Tween 80. As can be seen from the figure, the particle size of the separated emulsified oil droplets is 4-19 nm.

[0073] In Example 2, the separation efficiencies of the solid adsorbent for Tween 80 and CTAB-stabilized water-in-toluene emulsions were 64.65% and 76.78%, respectively, with a saturation adsorption time of 5 hours. After four consecutive separations, the separation efficiencies were still 30.31% and 41.83%, respectively. After desorption by soaking in anhydrous ethanol, the separation and adsorption capacity of the solid adsorbent for O / W type emulsions could be restored.

[0074] In Example 3, the solid adsorbent achieved separation efficiencies of 55.97% and 68.97% for Tween 80 and CTAB-stabilized water-in-toluene emulsions, respectively, with a saturation adsorption time of 5 hours. After four consecutive separations, the separation efficiencies remained at 36.56% and 38.47%, respectively. The solid adsorbent's ability to separate O / W type emulsions was restored after desorption by immersion in anhydrous ethanol. Furthermore, the solid adsorbent achieved separation efficiencies of 94.88%, 91.86%, 98.11%, and 94.49% for four emulsions: CTAB-stabilized water-in-toluene, water-in-toluene + styrene (volume ratio of the two organic solvents 1:1, the same below), water-in-chloroform, and water-in-chloroform + carbon tetrachloride, respectively.

[0075] In Comparative Example 1, the solid adsorbent achieved separation efficiencies of 43.47% and 50.43% for Tween 80 and CTAB-stabilized water-in-toluene emulsions, respectively, with a saturation adsorption time of 5 hours. After four consecutive separations, the separation efficiencies remained at 27.31% and 31.83%, respectively. After desorption by soaking in anhydrous ethanol, the solid adsorbent's ability to separate O / W type emulsions was restored.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An application of a solid adsorbent in oil-water separation, characterized in that, The oil and water are an emulsified oil-water mixture; The solid adsorbent comprises an oil phase and an aqueous phase as raw materials. The oil phase comprises, by weight, 1-6 parts octadecyl methacrylate, 5-15 parts methyl methacrylate, 6-12 parts butyl acrylate, 0.5-1 parts modified silica, 0.5-1.5 parts initiator, and 0.5-1 parts crosslinking agent; the specific preparation steps of the modified silica are as follows: adding a silane coupling agent alcohol solution to a silica alcohol solution, adjusting the pH to 10, stirring and reacting for 4-6 hours, washing and drying to obtain the modified silica; the silane coupling agent alcohol solution is vinyltrimethoxysilane dissolved in anhydrous ethanol; The aqueous phase comprises, by weight, 0.1-1 parts of dispersant and 20-100 parts of water; The preparation method of the solid adsorbent includes the following specific steps: (1) Weigh the raw materials by weight: 1-6 parts of octadecyl methacrylate, 5-15 parts of methyl methacrylate, 6-12 parts of butyl acrylate, 0.5-1 part of modified silica, 0.5-1.5 parts of initiator, 0.5-1 part of crosslinking agent, 0.1-1 part of dispersant, and 20-100 parts of water; (2) After uniformly mixing the octadecyl methacrylate, methyl methacrylate, butyl acrylate, modified silica, initiator and crosslinking agent, an oil phase is obtained; (3) Dissolve the dispersant in the water and stir to obtain an aqueous phase; (4) The oil phase is added dropwise to the aqueous phase and stirred to form uniform droplets in the aqueous phase. After reacting for 5.5-6.5 hours, the oil phase is washed and dried to obtain the solid adsorbent.

2. The application according to claim 1, characterized in that, The concentration of the silane coupling agent alcohol solution is 200 mg / L.

3. The application according to claim 1, characterized in that, The concentration of the silanol dioxide solution is 10 g / L; Ammonia water was used to adjust the pH value. The stirring reaction temperature during the preparation of the modified silica is 40-45℃.

4. The application according to claim 1, characterized in that, The mass ratio of the silane coupling agent to the silicon dioxide is 9:

1.

5. The application according to claim 1, characterized in that, The initiator is benzoyl peroxide; The crosslinking agent is N,N-dimethylbisacrylamide; The dispersant is hexadecyltrimethylammonium bromide.

6. The application according to claim 1, characterized in that, The dropping rate is 1-3 s / drop.

7. The application according to claim 1, characterized in that, The reaction in step (4) is carried out at a temperature of 75-80°C under a nitrogen atmosphere.

Images