CN-119701685-B - Preparation method and application of hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic membrane

CN119701685BCN 119701685 BCN119701685 BCN 119701685BCN-119701685-B

Abstract

The invention relates to the technical field of membrane distillation, in particular to a preparation method of a hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic membrane, which comprises the following steps that S1, water, ethanol and 1H, 2H-perfluoro decyl triethoxysilane are mixed to obtain a hydrophobic modifier; S2, mixing carbon nano tubes, ammonia water and a hydrophobic modifier to obtain a black suspension, centrifuging, washing and drying the black suspension to obtain hydrophobic carbon nano tube powder, S4, mixing acetone and N, N-dimethylformamide, adding polyvinylidene fluoride and the hydrophobic carbon nano tube powder to obtain a spinning solution, and S5, carrying out electrostatic spinning on the spinning solution to form a film and drying to obtain the hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic film. The modified carbon nano tube can be used as photo-thermal particles to increase the photo-thermal utilization rate of the hydrophobic membrane, and polyvinylidene fluoride is used as a main body structure of the hydrophobic membrane to provide mechanical strength and certain hydrophobicity, so that the photo-thermal utilization rate is coordinated in the solar membrane distillation application, and the comprehensive performance is improved.

Inventors

LEI HUI
ZHU MINGYANG
YU WEI
HU JIE
YUE TINGTING
He Xuanying
YUAN JIACHENG

Assignees

上海第二工业大学

Dates

Publication Date: 20260512
Application Date: 20250219

Claims (3)

1. A preparation method of a hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic membrane is characterized by comprising the following steps: S1, mixing water, ethanol and 1H, 2H-perfluoro decyl triethoxysilane, and stirring at room temperature for 15 minutes to obtain a hydrophobic modifier, wherein the mass ratio of the water to the ethanol to the 1H, 2H-perfluoro decyl triethoxysilane is 50:5:1; S2, adding the carbon nano tube and a certain amount of ammonia water into the hydrophobic modifier in the step 1, and stirring for 12 hours at 65 ℃ to obtain black suspension, wherein the mass ratio of the carbon nano tube to the 1H, 2H-perfluoro decyl triethoxysilane in the step S1 is 1:2, and the addition amount of the ammonia water is 3mL; S3, centrifuging the black suspension solution obtained in the step2, washing with ethanol and water, and drying in a blast drying oven at 80 ℃ for 12-24 hours to obtain hydrophobic carbon nanotube powder; s4, mixing acetone and N, N-dimethylformamide according to a mass ratio of 9:1, adding a certain amount of polyvinylidene fluoride and the hydrophobic carbon nanotube powder obtained in the step 3, and stirring for 6 hours at 50 ℃ to obtain spinning solution, wherein the mass fractions of the polyvinylidene fluoride and the hydrophobic carbon nanotube powder are respectively 12wt% and 1.0wt%; S5, pumping the spinning solution obtained in the step 4 by a certain amount by using a syringe, putting the syringe into a syringe pump, adjusting liquid amount, liquid pushing speed, spinning distance, rotating speed and voltage parameters, putting the obtained spinning film into a vacuum drying oven, and drying at 80 ℃ for 12 hours to obtain the hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic film, wherein the liquid amount of the spinning solution is 10-20 mL, the liquid pushing speed is 0.5-1.0 mL/h, the spinning distance is 10-20 cm, the rotating speed is 300-1000 rpm, and the voltage is 10.0-16.0 kV.
2. The method for preparing the composite polyvinylidene fluoride photo-thermal hydrophobic membrane of the carbon nano tube according to claim 1, wherein the rotational speed of the centrifugal treatment in the step S3 is 3000-8000 rpm, and the washing times are 3-5 times.
3. The use of a hydrophobic carbon nanotube composite polyvinylidene fluoride photo-thermal hydrophobic membrane prepared by the preparation method according to any one of claims 1-2 in solar membrane distillation.

Description

Preparation method and application of hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic membrane Technical Field The invention relates to the technical field of membrane distillation, in particular to a preparation method of a hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic membrane. Background Membrane Distillation (MD) is an emerging thermally driven membrane separation process, hydrophobic membranes being the separation medium, the driving force being provided by the difference in solution temperature across the membrane, allowing volatile components (such as water vapor) to pass through the membrane pores and condense on the permeate side while intercepting non-volatile components (such as salts) from passing through the membrane pores to effect the desalination process. MD shows significant advantages over desalination technologies such as reverse osmosis, conventional distillation processes, etc., such as insensitivity to feed solution salt concentration, high salt rejection, simple equipment, modularity, etc. However, the phenomenon of differential temperature polarization is one of the main challenges faced by the current membrane distillation technology, which means that the temperature at the membrane interface on the feed liquid side is lower than the bulk temperature of the feed liquid, resulting in a decrease in the actual transmembrane effective temperature difference, thus reducing flux and increasing energy loss during membrane distillation. Photo-thermal membrane distillation (PMD) technology generally enriches photo-thermal materials into MD membranes, uses solar energy to achieve photo-thermal conversion effects and locally heats the membrane surface, thereby alleviating temperature differential polarization and improving energy utilization efficiency. Among them, carbon-based photothermal nanomaterials such as carbon nanotubes have advantages of relatively low cost and wide spectrum light absorption capability, and are widely used for PMD film preparation. Therefore, how to develop a CNTs material-based high-flux high-liquid inlet pressure durable photo-thermal hydrophobic membrane, and ensure sustainable and stable operation of the membrane in the high-salinity wastewater treatment and sea water desalination processes is a technical problem to be solved by the technicians in the field. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a preparation method of a hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic film, which solves the problem of poor comprehensive performance of the traditional photo-thermal hydrophobic film. The preparation method of the hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic membrane comprises the following steps: S1, mixing water, ethanol and 1H, 2H-perfluoro decyl triethoxysilane, and stirring at room temperature for 15 minutes to obtain a hydrophobic modifier; s2, adding the carbon nano tube and a certain amount of ammonia water into the hydrophobic modifier in the step 1, and stirring for 12 hours at 65 ℃ to obtain black suspension; S3, centrifuging the black suspension solution obtained in the step 2, washing with ethanol and water, and drying in a blast drying oven at 80 ℃ for 12-24 hours to obtain hydrophobic carbon nanotube powder; S4, mixing acetone and N, N-dimethylformamide according to a mass ratio of 9:1, adding a certain amount of polyvinylidene fluoride and the hydrophobic carbon nanotube powder obtained in the step 3, and stirring for 6 hours at 50 ℃ to obtain spinning solution; S5, pumping the spinning solution obtained in the step 4 by a certain amount by using a syringe, putting the spinning solution into a syringe pump, adjusting liquid amount, liquid pushing speed, spinning distance, rotating speed and voltage parameters, and putting the obtained spinning film into a vacuum drying oven to dry for 12 hours at 80 ℃ to obtain the hydrophobic carbon nano tube composite polyvinylidene fluoride photo-thermal hydrophobic film. Preferably, the mass ratio of water, ethanol and 1H, 2H-perfluorodecyl triethoxysilane in the step S1 is 50:5:1. Preferably, the mass ratio of the carbon nano tube in the step S2 to the 1H, 2H-perfluoro decyl triethoxysilane in the step S1 is 1:2, and the addition amount of the ammonia water is 3mL. Preferably, the rotational speed of the centrifugal treatment in the step S3 is 3000-8000 rpm, and the washing times are 3-5 times. Preferably, the mass fractions of the polyvinylidene fluoride and the hydrophobic carbon nanotube powder in the step S4 are 12wt% and 1.0wt%, respectively. Preferably, the spinning solution in the step S5 has a liquid amount of 10-20 mL, a liquid pushing speed of 0.5-1.0 mL/h, a spinning distance of 10-20 cm, a rotating speed of 300-1000 rpm and a voltage of 10.0-16.0 kV. The invention provides a preparation