Preparation And Antibacterial Properties Of Super-hydrophilic Reduced Graphene Oxide Membrane

In order to improve the hydrophilicity and stability of the nanofiltration membrane,this experiment used polyethersulfone ultrafiltration membrane（PES）as the base membrane,and the interfacial polymerization method to prepare the（PIP@rGO/TMC）/PES charged composite membrane with good permeability and stability by using the co-blended solution of piperazine（PIP）and partially reduced graphene oxide（rGO）as the aqueous phase and the N-hexane solution of Trimesoyl chloride（TMC）as the organic phase,and the（PIP@rGO-TP/TMC）/PES antibacterial membrane was prepared by using the binding power of phenolic hydroxyl groups in TMC to cross-link with tea polyphenols.The experiment discussed the influence of the concentration ratio of graphene oxide（GO）and dopamine（DA）,the partial reduction reaction time of GO,the reaction temperature,the activation temperature,the concentration of TP and other factors on the performance of the membrane;Through（Fourier Transform Infrared Spectroscopy（FTIR））characterize the complexes generated by GO and GO/DA to explore the chemical reaction between GO and DA;analyze the structure and properties of the composite membrane by scanning electron microscopy（SEM）,FTIR,contact angle measurement and Zeta potential;determine the composite membrane The pure water permeability,molecular weight cut-off and other parameters;the desalination performance of the charged nanofiltration membrane and its retention effect on organic pollutants PPCPs were studied,and the antibacterial properties of the antibacterial membrane were evaluated.The specific research results are as follows:The optimized membrane forming conditions:the concentration ratio of GO/DA is 0.25,the mass fraction of GO is 0.08%,the partial reduction reaction time is 12 h,and the activation temperature is 60°C.The experiment shows that the pure water permeability coefficient of the（PIP@rGO/TMC）/PES composite membrane is 49.86 L·m^-2·h^-1·MPa^-1,the molecular weight cut-off is 673.6 Da,and the effective pore diameter of the membrane is 0.60 nm.It is negatively charged in the range of 3-10.The order of the retention effect of the rGO modified membrane on inorganic salts is:Na₂SO₄>Mg SO₄>Mg Cl₂>Na₂CO₃>Ca Cl₂>Na Cl,indicating that the membrane has a better removal effect on the dianion SO₄^2-.The membrane has a good removal effect on several drug-like PPCPs:atenolol（ATE）,carbamazepine（CBZ）,ibuprofen（IBU）and amlodipine（AML）,among which the removal rate of negatively charged IBU up to 92.22%.Compared with the unmodified（PIP/TMC）/PES composite membrane,the modified（PIP@rGO/TMC）/PES membrane has a greater improvement in durability and swelling resistance.The preparation conditions of the antibacterial membrane were optimized by response surface software,and the best reaction conditions were obtained as follows:TP concentration0.5 wt%,crosslinking time 3.75 min,crosslinking temperature 32.95℃,corresponding maximum rejection rate 92.10%,maximum antibacterial rate 86.56%.It was observed by SEM that the active layer of the rGO modified composite membrane was slightly thicker.The comparison of the surface SEM morphology characterization results showed that the porosity of the membrane surface decreased and the phenomenon of local wrinkles appeared.It may be that rGO particles have been introduced on the surface of the composite membrane.The characteristic morphology of the polyamide layer indicates that the surface of the composite membrane has been loaded with a polypiperazinamide layer.The contact angle test showed that the hydrophilicity of the rGO modified composite membrane was significantly improved,and it was super-hydrophilic.（PIP@rGO-TP/TMC）/PES antibacterial membrane showed better antibacterial performance against E.coli in the inhibition zone experiment.