Preparation Of G-C₃N₄/PAN/PANI@LaFeO₃ Nanofiber Membrane And Its Organic Wastewater Treatment And Antibacterial Properties

Water pollution has become increasingly severe as modern industrialization progresses,resulting in a shortage of water resources.Therefore,the effective treatment and regeneration of water resources have become emergent problems that cannot be ignored.Conventional wastewater treatment methods include activated sludge,precipitation,oxidation-reduction,and membrane separation.Membrane separation refers to the use of membrane filtration,bioreactors,and other technologies to separate pollutants from wastewater for treatment purposes.As a new type of selective treatment technology,membrane separation has been widely used in the fields of pharmaceuticals,food,chemical engineering,and environmental protection due to its advantages of simplicity,high efficiency,and low energy consumption.However,in traditional membrane separation processes,pollutants easily deposit on the membrane surface,resulting in a decrease in membrane flux,a shortened service life,and the need for regular cleaning and replacement,which increases operating costs and restricts its application and development in the field of water purification.Therefore,achieving self-cleaning membranes,increasing membrane flux and prolonging membrane service life are always important research topics in traditional membrane separation technology.Recently,photocatalytic technology has gained high focus for its efficient,green properties and environmentally friendly characteristics in wastewater treatment.However,the shortcomings of photocatalysts,such as a high rate of photogenerated carrier recombination,poor cycling stability,and difficult catalyst recovery,severely affect its widespread application and development.Fenton oxidation is widely used to treat wastewater in the papermaking,printing,dyeing and pharmaceutical industries owing to its advantages of strong oxidation ability,simplicity,easy operation and low operating costs.Herein,the research and development of composite photocatalytic membranes with good photocatalytic degradation,high membrane flux,long service life and self-cleaning performance have become the focus of membrane separation technology research.This study utilizes porous polyaniline（PANI）/polyacrylonitrile（PAN）fibers as a carrier and employs electrospinning to prepare a coaxial composite photocatalytic membrane（g-C₃N₄/PAN/PANI@LaFeO₃）by loading nitrogen-doped carbon（g-C₃N₄）and lanthanum ferrite（LaFeO₃）in spatially separated.The membrane is applied to adsorption-filtration-photocatalytic degradation of methylene blue（MB）,methyl violet（MV）,ciprofloxacin（CIP）,imidacloprid（AP）,as well as antibacterial and disinfection research on Escherichia coli/golden staphylococcus（E.coli and S.aureus）.The results demonstrate that LaFeO₃ and g-C₃N₄ nanoparticles are loaded on the inner and outer layers of the PAN/PANI composite fiber,respectively,forming a Z-type heterojunction system with spatial separation and site-specificity.The PANI in cable not only possesses abundant exposed amino/imino functional groups for adsorption of contaminant molecules but also due to the excellent electrical conductivity works as a redox medium for collecting and consuming the electrons and holes from LaFeO₃ and g-C₃N₄,which can efficiently promote photo-generated charge carriers separation and improve the catalytic performance.Additionally,LaFeO₃ in PC@PL catalyzes/activates the H₂O₂generated in situ by LaFeO₃/g-C₃N₄,further enhancing the decontamination efficiency of the PC@PL.The porous,hydrophilic,anti-fouling,flexible and reusable properties of the PC@PL membrane significantly improve the mass transfer efficiency of reactants during the filtration process and increase the amount of dissolved oxygen,thus producing massive·OH for degradation of pollutants,which maintains the high water flux(1184 L·m^-2·h^-1（LMH）)and rejection rate（98.5%）.Profiting from its unique synergy of adsorption,photocatalysis,and filtration,the PC@PL membrane exhibits excellent self-cleaning performance and distinguished removal rate for MB（97.0%）,MV（94.3%）,CIP（87.6%）and AP（88.9%）within 75 min,disinfection（100%E.coli and 80%S.aureus inactivation）and excellent cycle stability.