Preparation method of hydrophobic adsorption type emulsion separation material based on charge demulsification mechanism

Abstract

The application discloses a preparation method of a hydrophobic adsorption type emulsion separation material based on a charge demulsification mechanism. First, a copolymer monomer, a crosslinking agent, an initiator, a surfactant and a pore-forming agent are fully mixed and dissolved to obtain an oil phase, then a calcium chloride aqueous solution is slowly added into the oil phase under mechanical stirring to obtain a water-in-oil high internal phase emulsion, and then a polymerization reaction is carried out at 70 DEG C, and after a Soxhlet extraction with anhydrous ethanol and vacuum drying, a hydrophobic porous material is obtained. The hydrophobic porous material is immersed in a long-chain tertiary amine for a quaternary ammoniation reaction, and after methanol washing and vacuum drying, a positively charged hydrophobic porous material is obtained. By adjusting the proportion of the copolymer monomer in the polymerization reaction, the quaternary ammoniation degree and the pore structure of the emulsion separation material are controlled, a series of hydrophobic adsorption type materials based on the charge demulsification mechanism are prepared, and the materials are successfully applied to emulsion separation.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation technology, specifically relating to a method for preparing a hydrophobic adsorption emulsion separation material based on a charge demulsification mechanism. Background Technology

[0002] In recent years, with the vigorous development of industry, the large amount of oily wastewater generated has posed a great threat to the ecological environment and human health. Efficient treatment of this oily wastewater has long been a goal for countries around the world. In oily wastewater, emulsion separation is the most difficult and challenging process because emulsions have a stable oil-water interface, and some emulsions also contain surfactants that can stabilize them.

[0003] Currently, most emulsion separation materials are filtration-type materials. However, when performing emulsion separation, it is necessary to first collect the emulsion and then use a self-made filtration device for separation. Furthermore, membrane clogging and fouling are prone to occur after repeated use, limiting their practical applications. Adsorption-type materials have significant advantages in this regard due to their high porosity, strong absorption capacity, and ease of use. However, research on adsorption-type emulsion separation materials is relatively limited. Adsorption-type materials cannot easily utilize the pore size sieving effect to achieve emulsion separation, requiring stronger demulsification capabilities. Therefore, designing adsorption-type materials with excellent demulsification performance is a current research challenge.

[0004] The water-in-oil emulsion template method is a simple and effective approach for preparing hydrophobic porous materials. This method uses a high-internal-phase emulsion as a template to polymerize the external phase and remove the internal phase, thereby forming pores within the material. This method is simple to operate and produces materials with a hierarchical porous structure and high porosity, offering significant advantages in the preparation of porous materials.

[0005] Electrostatic effects, a novel concept proposed in recent years, have been proven to effectively enhance demulsification capabilities, especially for emulsions stabilized by ionic surfactants. This is achieved by utilizing the electrostatic attraction between the material and the emulsion. Studies have found that most emulsions are typically electronegative; therefore, positively charged separation materials can be designed, and efficient demulsification can be achieved through the electrostatic attraction between the positively charged separation material and the negatively charged emulsion droplets. This invention first prepares a hydrophobic porous material containing chloromethyl groups using a water-in-oil emulsion template method. Then, through a quaternization reaction, tertiary amines with long-chain alkyl groups are grafted onto the surface of the material's pores, giving the material a positive charge. Utilizing this charge-based demulsification mechanism, efficient emulsion separation is achieved. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing hydrophobic adsorption emulsion separation materials based on a charge-induced demulsification mechanism. This invention first prepares a hydrophobic porous material containing chloromethyl groups using a water-in-oil high internal phase emulsion template method. Then, through a quaternization reaction, tertiary amines with long-chain alkyl groups are grafted onto the surface of the material's pores, giving the material surface a positive charge. Utilizing the charge-induced demulsification mechanism, efficient emulsion separation is achieved. By adjusting the ratio of comonomers in the polymerization reaction, the degree of quaternization and the pore structure of the material can be controlled.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a hydrophobic adsorption emulsion separation material based on a charge-induced demulsification mechanism, specifically including the following steps:

[0009] (1) A certain amount of comonomer, crosslinking agent, initiator, surfactant and porogen are mixed by ultrasonication to form an oil phase;

[0010] (2) Under mechanical stirring, calcium chloride aqueous solution was slowly added to the oil phase obtained in step (1). After the addition was completed, stirring was continued for 1.5 h to obtain a water-in-oil emulsion with high internal phase.

[0011] (3) After sealing the high internal phase emulsion obtained in step (2), the crude product was obtained by polymerization reaction at 70 °C for 24 h. After Soxhlet extraction with anhydrous ethanol and vacuum drying, hydrophobic porous material was obtained.

[0012] (4) The hydrophobic porous material obtained in step (3) is immersed in a long-chain tertiary amine and quaternized at 60°C for 72 h. After washing with methanol and vacuum drying, a positively charged hydrophobic porous material is obtained.

[0013] The comonomer mentioned in step (1) is an alkyl styrene such as a combination of 4-tert-butylstyrene and 4-vinylbenzyl chloride.

[0014] The crosslinking agent mentioned in step (1) is divinylbenzene, the initiator is azobisisobutyronitrile, the surfactant is Span80, and the porogen is toluene.

[0015] The molar ratio of the comonomer to the crosslinking agent in step (1) is 3:1.

[0016] The molar ratio of the comonomer alkylstyrene and 4-vinylbenzyl chloride in step (1) is 1:2-3:0, preferably 1:2-5.

[0017] The long-chain tertiary amines mentioned in step (4) include, but are not limited to, N,N-dimethylhexadecyl tertiary amine.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) This invention develops a method for preparing hydrophobic adsorption emulsion separation materials based on charge demulsification mechanism, and successfully applies it to emulsion separation. The method first uses an oil-in-water type high internal phase emulsion template method to prepare hydrophobic porous materials containing chloromethyl groups, and then grafts tertiary amines with long-chain alkyl groups onto the surface of the material pores through a quaternization reaction, so that the material surface has a positive charge. The efficient separation of emulsions is achieved by utilizing the charge demulsification mechanism.

[0020] (2) By adjusting the ratio of comonomers in the polymerization reaction, the degree of quaternization and pore structure of the material were controlled, and a series of hydrophobic adsorption emulsion separation materials based on charge demulsification mechanism were prepared and successfully applied to emulsion separation. Attached Figure Description

[0021] Figure 1 Scanning electron microscope (SEM) images of the porous materials prepared in Examples 1-5 and Comparative Example 1; wherein, a1 and a2: Example 1; b1 and b2: Example 2; c1 and c2: Example 3; d1 and d2: Example 4; e1 and e2: Example 5; f1 and f2: Comparative Example 1;

[0022] Figure 2 The water contact angle of the porous materials prepared in Examples 1-5 and Comparative Example 1;

[0023] Figure 3 Photographs of the porous materials prepared from the water-in-toluene emulsions in Examples 1-5 and Comparative Example 1 after separation;

[0024] Figure 4 The separation efficiency of the porous materials prepared in Examples 1-5 and Comparative Example 1 for water-in-toluene emulsion;

[0025] Figure 5 The amount of water-in-toluene emulsion adsorbed by the porous materials prepared in Examples 1-5 and Comparative Example 1. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0027] Example 1

[0028] First, 4-vinylbenzyl chloride, 4-tert-butylstyrene, divinylbenzene, Span 80, azobisisobutyronitrile, and toluene were ultrasonically mixed to obtain an oil phase. The molar ratio of 4-vinylbenzyl chloride:4-tert-butylstyrene:divinylbenzene was 1:2:1 (total amount added was 7.5 g). The amount of Span 80 added was 3 g, the amount of azobisisobutyronitrile added was 0.3 g, and the amount of toluene added was 7.5 ml. Under a stirring speed of 550 r / min, 60 ml of calcium chloride aqueous solution (10 g / L) was slowly added dropwise to the oil phase. After all the aqueous phase was added, the stirring speed was adjusted to 1100 r / min and stirring was continued for 1.5 h to form a milky white viscous emulsion. The emulsion was sealed and reacted at 70 ℃ for 24 h. After Soxhlet extraction with anhydrous ethanol and vacuum drying, a hydrophobic porous material was obtained. The hydrophobic porous material was immersed in N,N-dimethylhexadecyl tertiary amine and subjected to a quaternization reaction at 60°C for 72 h. After washing with methanol and vacuum drying, a positively charged hydrophobic porous material was obtained.

[0029] Example 2: The specific experimental steps are the same as in Example 1. The molar ratio of 4-vinylbenzyl chloride: 4-tert-butylstyrene: divinylbenzene in the oil phase is 1.5:1.5:1.

[0030] Example 3: The specific experimental steps are the same as in Example 1. The molar ratio of 4-vinylbenzyl chloride: 4-tert-butylstyrene: divinylbenzene in the oil phase is 2:1:1.

[0031] Example 4: The specific experimental steps are the same as in Example 1. The molar ratio of 4-vinylbenzyl chloride: 4-tert-butylstyrene: divinylbenzene in the oil phase is 2.5:0.5:1.

[0032] Example 5: The specific experimental steps are the same as in Example 1. The molar ratio of 4-vinylbenzyl chloride: 4-tert-butylstyrene: divinylbenzene in the oil phase is 3:0:1.

[0033] Comparative Example 1: The specific experimental steps were the same as in Example 1, but the molar ratio of 4-vinylbenzyl chloride: 4-tert-butylstyrene: divinylbenzene in the oil phase was 0:3:1, and there was no subsequent quaternization reaction step.

[0034] Emulsion separation process: The prepared sample was cut into blocks of foam about 0.1 g and immersed in 15 ml of sodium dodecyl sulfate (0.5 g / L) stabilized water-in-toluene emulsion (toluene to water volume ratio of 1:49) and soaked at room temperature for 30 min.

[0035] Table 1. Data on porous materials prepared under different conditions

[0036]

[0037] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a hydrophobic adsorption emulsion separation material based on a charge-induced demulsification mechanism, characterized in that, Includes the following steps: (1) A certain amount of comonomer, crosslinking agent, initiator, surfactant and pore-forming agent are mixed by ultrasonication to form an oil phase; calcium chloride aqueous solution is slowly added to the above oil phase under stirring conditions, and stirring is continued for 1.5 h after the addition is completed to obtain a water-in-oil emulsion with high internal phase. (2) After sealing the high internal phase emulsion obtained in step (1), the crude product was obtained by polymerization reaction at 70 °C for a certain time. After Soxhlet extraction with anhydrous ethanol and vacuum drying, hydrophobic porous material was obtained. (3) The hydrophobic porous material obtained in step (2) is immersed in a long-chain tertiary amine and quaternized at 60°C for 72 hours. After washing with methanol and vacuum drying, a positively charged hydrophobic porous material is obtained. The comonomer mentioned in step (1) is a combination of 4-tert-butylstyrene and 4-vinylbenzyl chloride, and the molar ratio of 4-tert-butylstyrene and 4-vinylbenzyl chloride in the comonomer is 2:1-1:5; The crosslinking agent mentioned in step (1) is divinylbenzene, the initiator is azobisisobutyronitrile, the surfactant is Span 80, and the porogen is toluene; The molar ratio of the comonomer to the crosslinking agent mentioned in step (1) is 3:1; The long-chain tertiary amine mentioned in step (3) is N,N-dimethylhexadecylamine.

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