Preparation And Performance Study Of Modified Polyacrylonitrile And Functionalized Polystyrene Membranes

Water treatment has always been an important issue for scientists in engineering research.The treatment of pollutants in water was time-consuming and laborious.This paper focused on improving membrane separation and separation performance,aiming at solving the problem of low adsorption capacity of heavy metals for existing membranes,low membrane’s reusability,inhomogeneous pore size and unmodifiable pore size.The main work and conclusions were as follows:1.The polyacrylonitrile（PAN）hollow fiber membrane was modified based on a layer-by-layer self-assembly method using ethylenediaminetetraacetic acid disodium（EDTA）.A modified membrane that efficiently adsorbed heavy metal ions was prepared by grafting EDTA onto the surface of the membrane through electrostatic adsorption and photocrosslinking.The experimental results showed that the maximum adsorption capacity of copper ions for polyacrylonitrile membranes（PAN-（DR-EDTA）₃）grafted with three layers of EDTA reached 47.6 mg/g.And lead ions,mercury ions and cadmium ions could be adsorbed.Compared with the traditional modified membrane,the modified membrane had a high adsorption amount of copper ions.It could be reused after being eluted and has good performance.and the preparation method was simple and highly efficient.2.The PAN hollow fiber membrane was modified based on layer self-assembly method using graphene oxide（GO）,and the graphene oxide was grafted to the surface of the membrane by electrostatic adsorption and optical cross-linking.The experimental results showed that the maximum adsorption capacity of the modified membrane to copper ions reaches 73.69 mg/g after polyacrylonitrile grafted three layers of graphene oxide（PAN-（DR-GO）₃）,which was much higher than the maximum adsorption of PAN-（DR-EDTA）₃.The modified membrane had high copper adsorption and could be reused after elution.The modified membrane could be further applied in the treatment of heavy metal ions in water.3.A highly ordered temperature response intelligent filter was synthesized using silica colloidal crystal as a template.The membrane exhibited a good temperature responsiveness by adding PNIPAM to the membrane.The permeability of the membrane was investigated by measuring the electrical conductivity of the potassium chloride solution.The experimental results showed that when the temperature rises from 20°C to 40°C,the polymer chains aggregated with each other and a volumetric phase transition occurs,which increased the conductivity of the channel.After the temperature was lowered,the polymer chain returns to its original state and the electrical conductivity decreased.This research and development could be further applied in microfiltration,separation and other aspects.