Degradation Of Azithromycin Wastewater By Photocatalysts Based Bismuth-based Oxysalts

With the development of human science and technology,a variety of antibiotics have been developed for the treatment of a large number of medical diseases.However,the large-scale manufacture of antibiotics could lead to environmental pollution;antibiotic wastewater is discharged into the water environment,resulting in water pollution,especially.Antibiotic pharmaceutical wastewater cannot be effectively treated due to its complex composition,which is difficult to be degraded and of high toxicity.As a result,residual antibiotics in water have a great impact on human health and environment.Azithromycin,as a kind of macrolide antibiotic,has been detected in different water environments.Photocatalytic technology has the potential to solve the problem of water environment purification,and has become one of the advanced oxidation pretreatment processes for high concentration organic wastewater.It has attracted extensive attention of wastewater treatment researchers in recent decades.Two kinds of bismuth oxyacid salts,bismuth tungstate(Bi2WO6)and bismuth molybdate(Bi2MoO6)have important research value in photocatalytic degradation of antibiotic wastewater due to their unique structure,physical and chemical properties and good response to visible light.In this paper,based on the synthesis research of barium tungstate and barium molybdate nanomaterials,photocatalysts of barium tungstate and barium molybdate synthesized with different surfactants were prepared for the degradation and removal of azithromycin.The main work of this paper includes:(1)The bismuth tungstate(Bi2WO6)photocatalyst with round cake structure,diameter 2-3?m,thickness about 600 nm and smooth surface was prepared by hydrothermal method.BWCA+SDBS photocatalyst modified by sodium dodecylbenzene sulfonate(SDBS)was prepared by using hydrothermal method under optimized reaction conditions including the surfactant type and pH.The obtained photocatalyst has flower-like structure with a size of 3 ?m,which was assembled from two-dimensional Nano plates.The crystal structure and micro-morphology of the prepared nano-photocatalysts were characterized by XRD,SEM and FT-IR.The photocatalytic performance of the synthesized catalyst and the removal rate of azithromycin under visible light irradiation were evaluated by the degradation experiment of azithromycin wastewater.The results showed that BWCA+SDBS(SDBS=0.15 g;CA=2.5 mmol;pH=7)prepared by a facile hydrothermal method with surfactant SDBS had the great photocatalytic activity.When the dosage was 0.5 g/L,the removal rate of azithromycin wastewater with 100 mg/L was 1.39 times as high as that of pure Bi2WO6,reaching 82.82%.(2)The photocatalysts of bismuth molybdate(Bi2MoO6)?BMSDBS?BMCTAB were prepared by using hydrothermal method under the optimized synthesis conditions including the type of surfactants and the adding amount of surfactants..Pure photocatalyst of bismuth molybdate(Bi2MoO6)has a thickness of about 50 nm and a two-dimensional flower-like flaky structure;BMSDBS photocatalyst has a smooth surface,sheet structure and modified with sodium dodecylbenzene sulfonate(SDBS);BMCTAB photocatalyst has fine nano-particles and modified with cetyltrimethylammonium bromide(CTAB).The crystal phase composition,bond characteristics,grain morphology and grain size of the photocatalysts were tested by XRD,SEM and FT-IR characterization techniques.The azithromycin degradation efficiency of bismuth molybdate prepared by different synthesis conditions was investigated to disclose the synthetic condition effect.Meanwhile,the photocatalytic activity of the prepared catalyst for degrading azithromycin under simulated visible light irradiation was well evaluated.The results showed that BMCTAB(CTAB=0.05 g;pH=7)prepared by hydrothermal method with typical cationic surfactant CTAB had the best removal effect on azithromycin.When the dosage was 0.5 g/L,the removal rate of 100 mg/L azithromycin wastewater was 1.27 times as high as that of pure Bi2MoO6,reaching 59.28%.