Study On The Efficiency And Mechanism Of Membrane Filtration-photocatalysis System For Removing Trace Sulfadiazine In Water

As a new class of"pseudo persistent"organic pollutants,sulfanilamide antibiotics have attracted wide attention from scientists and all walks of life.Although it is in the range of trace concentration in water environment,its characteristics?large quantity,low stability,strong persistence,potential bioaccumulation,etc.?will bring great risks to aquatic environment and human health.Therefore,the environmental behavior and pollution removal of sulfanilamide antibiotics have become a hot topic.Conventional water treatment process can not completely remove the trace concentration of sulfadiazine in water,membrane filtration-photocatalysis coupling process in the treatment of drinking water trace concentration of sulfadiazine has a greater advantage.Recently,TiO₂photocatalysts have attracted much attention due to their low price,high catalytic efficiency and commercial availability.Two types of PVDF modified ultrafiltration membranes with TiO₂ photocatalysts as additives were prepared to explore the application potential of their respective membrane filtration-photocatalysis systems to remove trace concentrations of sulfadiazine in water.Addition of Fe³⁺to TiO₂ is one of the effective methods to improve the photocatalytic activity.This paper evaluated the effect and mechanism of PVDF-PVP-TiO₂-FeCl₃?PPTFe?membrane filtration-photocatalysis system for the removal of sulfadiazine?SD?with trace concentrations in water.A 2-factor-4 horizontal orthogonal experiment was established to optimize 16 self-made modified membranes,the optimal membrane was then characterized in seven terms?electron microscope scanning,energy spectrum analysis,membrane pure water flux,contact angle,porosity,average pore size,fourier attenuated total reflection infrared broad spectrum analysis?to verify the accuracy of the orthogonal experimental results.The treatment efficiency of PPTFe membrane filtration-photocatalysis system for SD was investigated,the reaction rate between SD and·OH was also determined according to the pseudo-first-order kinetic model.The effects of membrane types,pH,water quality parameters(Cl^-,SO₄^2-,NO₃^-,HA)on the removal performance of PPTFe membrane filtration-photocatalysis system were also investigated.Moreover,the removal efficiency was closely tracked using three real water.Finally,the possible photocatalytic degradation mechanism was proposed.As a biological adhesive,dopamine not only has strong adhesion function but also has strong hydrophilicity.the PVDF-PVP-TiO₂-dopamine blend ultrafiltration membrane?PPTD?was successfully prepared and the removal of SD in water was achieved by using PPTD membrane filtration-photocatalytic system.The effect of water quality parameters(Cl^-,SO₄^2-,NO₃^-,HA)on SD removal was quite different.Simulated degradation experiments of real water bodies showed that PPTD membrane filtration-photocatalysis system had significant potential in controlling water bodies with SD as pollutants.Moreover,·OH played a major role in SD removal,suggesting possible photocatalytic removal mechanisms.