Synthesis And Characterization Of Dual-Template Molecularly Imprinted Membrane With High Flux Based On Blending The Inorganic Nanoparticles

Molecularly imprinted membrane which exhibits the advantages of the membrane separation technology and molecule imprinting technique can operate in a continuous way.However,on account of lesser mechanical strength of organic membrane,which makes the membranes spatial deformation of imprinting pore easily and the location of complementary functional groups instable under the pressure in the separation process,as a result,it would reduce separation efficiency substantially.In order to enhance the mechanical strength and water flux,organic-inorganic hybrid membranes were prepared with blending inorganic nanoparticles in the preparation process.In this paper,the membranes were synthesized through in-situ polymerization by UV irradiation,based on PVDF membranes as supporting membranes,the ferulic acid composite molecularly imprinted membrane with blending nanoparticles has been prepared by blending inorganic nanomaterial within membrane casting solution.The structure and morphology of the membranes were characterized by using Fourier Transform Infrared Spectroscopy(FTIR)and Scanning Electron Microscope(SEM).Results showed that blending of nanoparticles is a pure physical way,and they are all scattered around the pore to contribute to maintain the pore structure of membrane.The separation performance,pure water flux and pressure-bearing capacity of the prepared membranes were evaluated by using flat sheet membrane filtration equipment.The results showed that the modified molecularly imprinted composite membrane has high separation efficiency,and the pressure-bearing capacity and water flux were improved obviously.In addition,the modified membranes which blended with 0.5wt%18nm TiO2 present the best properties,with mechanical strength more than 0.4Mpa,the separation factor about 3.4,and the pure water flux 6696 L·m-2·h-1.On the basis of previous experiments,this paper is dedicated to different methods to attempt to synthesize and character the dual-template molecularly imprinted composite membrane.So as to improve mechanical strength and pure water flux of membrane,it explores a-methacrylic acid(MAA)as functional monomer,ethylene glycol dimethacrylate(EGDMA)as crosslinker,ferulic acid and cinnamic acid as the templates,2,2-azobisisobutyronitrile(AIBN)as photoinitiator inducing polymerization reaction and mingles nanoparticles by blending method,consequently,which has synthesized dual-template molecularly imprinted membrane(MIM)with high pure water flux.This paper has researched that the effect of variety of nanoparticles and its quantity,the quantity of photoinitiator,the ratio value of the functional monomer and template molecules(F/T)and synthetic method(one-step method or two-step method)on performance of prepared membrane.The study has founded optimum parameters of synthesis:nanoparticles 18nmTiO2 of lwt%,photoinitiator of 0.3 g,if it was synthesized by one-step method,the ratio value of the functional monomer and template molecules(ferulic acid + cinnamic acid)(F/T)is 1:3.Under the above conditions,dual-template molecularly imprinted membrane(MIM)would present a high separation efficiency of template molecules(ferulic acid and cinnamic acid)and the analogues(caffeic acid and syringic acid)with the permeation rate of about 100%.However,the permeation rate of glucose which has analogous formula weight and extremely different structure is about 60%.From the foregoing,it showed that the separation efficiency of the template molecular and its analogues is relatively high,but the substances which have obvious distinctions in structure would present low separation efficiency.It can be seen that dual-template molecularly imprinted membrane(MIM)can identify the same kind of substance with specificity.Therefore,it can be used in the enrichment and separation of some active ingredients of traditional Chinese medicine,the detection of toxic substances in food and so on.