Two-dimensional layered composite film and preparation method and application thereof

Abstract

The invention discloses a two-dimensional layered composite film and a preparation method and application thereof. The two-dimensional layered composite film comprises a base film; two-dimensional nanosheets which are vertically arranged on the surface of the base film to form a nanosheet layer; and nanospheres which are dispersed among the nanosheet layers. According to the prepared two-dimensional layered composite film, the stability of the layered channel of the film is improved through positive and negative electrostatic assembly, and then the stable nanofiltration separation performance is guaranteed; the size of the layered channel can be effectively regulated and controlled by utilizing the nanospheres with different sizes, so that the film pores can just intercept ions and molecules, the problem of poor molecular ion interception effect when the water flux is large is effectively solved, and the energy consumption in the separation process can be reduced; meanwhile, the hydrophilic nanospheres are introduced to enhance the anti-dirt and antibacterial capabilities, so that the film pollution and film degradation are effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of separation membranes, and in particular relates to a two-dimensional layered composite membrane and its preparation method and application. Background technique [0002] Population growth and environmental degradation have forced people to develop advanced water treatment technologies to produce drinking water and purify industrial wastewater with high efficiency and low energy consumption. Membrane separation includes reverse osmosis, forward osmosis, membrane distillation, microfiltration, ultrafiltration, nanofiltration and other technologies, among which nanofiltration is a pressure-driven membrane separation technology between ultrafiltration and reverse osmosis. At present, reverse osmosis has achieved sewage purification and seawater desalination, but reverse osmosis is a high-consumption technology with low water recovery rate. Compared with reverse osmosis, nanofiltration can remove divalent ion...

AI Technical Summary

Problems solved by technology

These processes include dopamine modification, in situ growth of metal-organic covalent framework materials, or two different two-dimensional assemblies to prepare composite two-dimensional layered films, but the preparation process of these two-dimensional layered films is complicated, and it is difficult to finely control the size of the layered channel

Moreover, the stability of the material is poor. Organic materials are easily degraded by microorganisms in water and have no antibacterial ability. After a long period of use, the surface of the membrane is prone to biofouling, which seriously leads to membrane pore blockage and membrane biodegradation, thereby affecting membrane separation performance and use cost.

In addition, most known two-dimensional materials are easy to fall off and are not suitable for large-scale use

The current practice has proved that nanoparticles and nanosheets can self-assemble into films at the nanometer level, which can realize the regulation of sub-nanometer layered channels, and the preparation process is simple. The self-assembly of nanoparticles and two-dimensional nanosheets can also effectively enhance the physical properties of the film. Stability, to ensure stable membrane separation performance, and nanosheets and nanoparticles also have a certain antibacterial ability, and can effectively reduce energy consumption in the recycling process. More importantly, there is no way to use nanoparticles and two-dimensional nano Self-assembly of sheets to regulate the simple process of layered channels

[0004] The pure two-dimensional material membrane prepared in the related art is easy to compress under the action of external pressure, resulting in the decrease of the layered passage, and finally leads to the continuous attenuation of the water flux; the preparation process of the two-dimensional layered membrane is complicated, and it is difficult to finely control the layered The size of the channel, and the stability of the material is poor. Organic materials are easily degraded by microorganisms in water and have no antibacterial ability. After a long period of use, the surface of the membrane is prone to biofouling, which will seriously cause membrane pore blockage and membrane biodegradation, which will affect membrane separation performance and use. Cost; most 2D materials known to fall off are not suitable for large-scale use

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