Preparation of pervaporation composite membrane based on interfacial reaction and study of its desalination performance
Polyvinyl alcohol(PVA)is widely used in desalination membrane materials due to its outstanding hydrophilicity.However,its high hydroxyl content can lead to excessive swelling,thereby affecting membrane separation performance.In this study,we propose a novel method for interfacial crosslinking of ethylene alcohol-ethylene amine copolymers(VA-co-VAm),which contain both amino and hydroxyl groups.A reaction takes place between the amino-rich VA-co-VAm and the hydroxyl-rich epigallocatechin gallate(EGCG)under alkaline conditions,resulting in a crosslinked structure.By adjusting the film-forming parameters,such as deposition time and reaction concentration of the copolymer and EGCG,we can precisely control the structure of the composite membrane.Various analytical techniques,including scanning electron microscopy(SEM)and Fourier-transform infrared spectroscopy(FTIR),were used to investigate the microstructure and physicochemical properties of the modified composite membrane.Experimental results demonstrate that the modified composite membrane exhibits excellent pervaporation performance,with the ability to process 35 g/L NaCl saltwater at a rate of 33.19 kg/(m2·h),while maintaining a salt rejection rate exceeding 99.99％.Furthermore,the composite membrane demonstrates remarkable desalination performance across different temperatures and saltwater concentrations.Particularly,at 70 ℃,the water flux reaches 37.7 kg/(m2·h).Composite membranes prepared through interfacial reactions display exceptional desalination capabilities,offering a novel solution for efficient seawater desalination and presenting significant prospects in the field of wastewater treatment.
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