Zinc Chloride Aqueous Solution Is Used As The Solvent To Prepare PAN-based Filter Membrane And Dye Desalination Research

The casting solution was prepared by grafting acrylonitrile?AN?and acrylamide?AM?onto silk fibroin with high concentration of ZnCl₂ aqueous solution as solvent.The SF-g-P?AN-co-AM?membrane was prepared by using water as coagulation bath.Zinc and chloride ions act as pore-forming agents.The membrane was characterized by scanning electron microscopy?SEM?,Fourier infrared spectroscopy?FTIR?,thermogravimetric analysis?TG?and water contact Angle.The filtration properties of SF-g-P?AN-co-AM?membrane were investigated with dye solutions of different molecular weights.The membrane has a rejection rate of more than 99%for dyes with the molecular weight greater than 660 Da.The stable flux of bovine serum protein?BS A?aqueous solution was about 94.4%of the pure water flux,indicating that the membrane had good anti-pollution performance.The effect of AM on the mechanical properties and the flux of the membrane were also investigated.The results showed that the mechanical properties of SF-g-P?AN-co-AM?filtration membrane gradually increased with the increasing amount of AM.When the amount of AM was 0.5g,the fracture strength of SF-g-P?AN-co-AM?composite filtration membrane reached 1.4 MPa,and the water flux was 43 L/?m²·h?at the pressure of 0.1 MPa.SF-g-PAN solution was obtained by homophase graft of acrylonitrile from silk fibroin,and nano-TiO₂ was added to prepare SF-g-PAN/TiO₂ filtration membrane.The membrane was characterized by SEM,FTIR and 3D ultra depth of field microscope.The hydrophilic,anti-fouling and mechanical properties of the SF-g-PAN/TiO₂ filtration membranes with different TiO₂ contents were researched.The desalination properties of dye solutions with different molecular weights were studied.The results showed that the mechanical properties of SF-g-PAN/TiO₂ filtration membrane increased first and then decreased with the increase of TiO₂ content.The hydrophilic and anti-fouling properties of SF-g-PAN/TiO₂ membrane were significantly improved.When the TiO₂ content was 1 wt.%,the mechanical properties and hydrophilic properties of the membrane were the best.The rejection rate of SF-g-PAN/TiO₂ membrane on 2 g·L^-1 NaCl was less than 5%,and the flux of Brilliant Blue solution containing 0.25?2 g·L^-1 NaCl was higher than 62 L/?m²·h?at 0.1 MPa,and the rejection rate of Brilliant Blue was more than 98,0%.SF-g-PAN/TiO₂ filtration membrane has a good application prospect in the field of dye desalination.SF-g-PAN based composite nanofiltration membrane was prepared by interfacial polymerization of piperazine?PIP?and trimesoyl chloride?TMC?using SF-g-PAN membrane as the matrix membrane.The surface chemical characteristics and morphology of the composite membrane were characterized by SEM,FTIR and water contact angle test.The mechanical properties,dye adsorption,dye filtration properties and desalination properties of the nanofiltration membrane were studied.The experimental results showed that under the operating pressure of 0.1 MPa,the membrane's rejection rates of MgSO₄,MgCl₂,Na₂SO₄ and NaCl were 79.8%,67.3%,67.1%and 39.1%,respectively.The results show that the membrane can still retain inorganic salts well under low operating pressure.