Study On The Preparation And Application Of Schiff Base Covalent Organic Framework Membrane

The shortage of traditional energy sources and environmental pollution during energy mining and transportation have had a huge impact on human production and life.Renewable energy has many obvious advantages and can be used as a supplement to traditional energy at this stage.Salinity gradient energy is a renewable energy produced when two solutions with different salt concentrations are mixed.Reverse electrodialysis（RED）technology can use ion exchange membranes to convert salinity gradient energy into electrical energy,but the technology’s low power generation efficiency and serious membrane pollution restrict its practicality.In addition,traditional treatment technologies have encountered bottlenecks in the leakage of crude oil during energy extraction and transportation,as well as oily wastewater generated in human production and life.Covalent organic framework（COF）membranes have potential applications in the fields of salinity gradient energy conversion and oil-water separation due to their excellent stability,permanent porosity,and easy functionalization.The COF membrane material designed in this paper had excellent performance and controllable structure,which can realize the efficient conversion of salinity gradient energy and the rapid separation of oil-in-water emulsions.The main innovative research results were as follows:1.The COF was simply prepared by the one-step reaction in-situ growth method,and the influence of different reaction conditions and different substituents on the membrane-forming properties of COF was explored.TpPa-SO₃H COF membrane was flexible,adjustable in thickness,easy to prepare in large areas,and had excellent stability and mechanical properties.2.TpPa-SO₃H COF membrane with one-dimensional nanochannels and high charge density exhibits high ionic conductivity and selectivity,and can effectively collect salinity gradient energy.Its power density reached up to 5.9W/m² by mixing artificial seawater and river water.The TpPa-SO₃H COF membrane can operate in a wide p H and high salinity environment,and had wide applicability.3.The copper mesh modified by TpPa-2SO₃H COF was hydrophilic and had a simple gravity-driven oil-water separation performance.The oil-water separation efficiency of COF-modified copper mesh was as high as 99%,and the water flux was above 70 L m^-2 s^-1.It can separate various oil-in-water emulsions quickly and efficiently,and had certain application value.