Low thermal conductivity hydrophilic-hydrophobic bipolar composite membrane as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of membrane separation materials and discloses a low thermal conductivity hydrophilic-hydrophobic bipolar composite membrane as well as a preparation method and application thereof. The composite membrane is composed of a porous supporting body layer with the thickness of 30-100mu m and an ultrathin skin layer with the thickness of 5-20mu m, wherein the porous supporting body layer is prepared from a hydrophobic polymer and hydrophobic silicon dioxide aerogel, and the ultrathin skin layer is prepared from a hydrophilic polymer and hydrophilic silicon dioxide aerogel. The preparation method of the composite membrane adopts a coating method, technology is simple, and equipment cost is low; and the obtained composite membrane has good permeability and gas selectivity, relatively low thermal conductivity and relatively high strength, can be widely applied to the fields of water treatment technology, air conditioning engineering, energy sources, chemical engineering, metallurgy, biochemical engineering and the like and is especially applicable to sea water desalination and independent air dehumidification.

Description

Technical field [0001] The invention belongs to the technical field of membrane separation materials, and specifically relates to a low thermal conductivity hydrophilic-hydrophobic bipolar composite membrane and a preparation method and application thereof. Background technique [0002] Freshwater resources are one of the most important material foundations for human survival and development. Seawater desalination and wastewater purification technologies are gradually becoming important means to solve the shortage of freshwater resources. [0003] Seawater desalination, also known as seawater desalination, is a process of separating salt and water in seawater. Commonly used seawater desalination methods include thermal method and membrane method. The thermal method mainly uses multi-stage flash evaporation, multi-effect distillation, and pressure steam distillation. The membrane method mainly refers to reverse osmosis. Thermal method usually consumes a large amount of high-grade...

AI Technical Summary

Problems solved by technology

The cooling and dehumidification method needs to cool the temperature of the air below its dew point, and the cooled air needs to be heated before it can be sent into the room. During this process, the temperature and humidity cannot be controlled independently, resulting in low energy efficiency and high energy consumption; Moisture condenses on the surface of the cooler, making the cooler humid all the year round, providing a place for bacteria to grow and multiply, and seriously degrading the indoor air quality; and for conditions where the dew point temperature is too low, it is easy to cause frost on the cooler surface, which requires a special device Perform defrosting treatment on it. Membrane dehumidification is a passive dehumidification method, and its dehumidification capacity is controlled by the side with lower water vapor pressure in the wet exchange gas; membrane material is an important factor affecting membrane dehumidification. Good or bad determines the performance of the entire dehumidification process

Electrochemical dehumidification is a very novel dehumidification method, and its technology is not mature enough; moreover, a DC power supply is required in the dehumidification process, and the energy utilization is not high.

[0006] The disadvantage of existing membranes is that it is difficult to meet the contradiction between high moisture permeability and blocking the penetration of other gas molecules at the same time, and the thermal conductivity of the membrane material itself is too high, resulting in excessive sensible heat transfer and excessive energy loss.

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