Property Study On Adsorption-Photocatalytic Degradation Of Oxytetracycline Wastewater By TiO₂ Composites

With the large-scale production and use of antibiotics,the pollution of antibiotics in the water has become a hot spot in current research.Tetracycline antibiotics are widely used in medical treatment and livestock breeding,and are one of the most widely used antibiotics currently.Due to the biodegradability of antibiotics and shortage of conventional antibiotic wastewater treatment technologies,it is necessary to develop new and efficient antibiotic wastewater treatment technologies without secondary pollution.This study takes the combination of adsorption and photocatalysis technology as the theoretical basis and takes hydrothermal synthesis of TiO2 composite materials as the direction.Dilute sulfuric acid and graphene oxide?GO?are co-doped to synthesize SO₄^2-/TiO₂/GO composite materials,supplemented by a variety of characterization methods to investigate the performance of TiO2 composite materials under different conditions and explore the mechanism of adsorption-photocatalysis synergy to achieve efficient removal of oxytetracycline?OTC?in wastewater.The main content is as follows:?1?By using tetrabutyl titanate as a precursor,using absolute ethanol as a dispersant,adding dilute sulfuric acid as an modification,the SO₄^2-/TiO₂ composite materials are synthesized via hydrothermal method,then TiO₂/GO and SO₄^2-/TiO₂/GO composite materials are synthesized by using pure TiO₂ or SO₄^2-/TiO₂ as the precursor to compound with different ratios of GO via hydrothermal method.The microstructure and appearance of the synthesized samples are analyzed by various characterization methods.The results show that pure TiO₂,SO₄^2-/TiO_2,TiO₂/GO and SO₄^2-/TiO₂/GO are all anatase type,and SO₄^2-is successfully mixed into TiO₂ crystals and combined with a double-bridge coordination structure,GO is also successfully modified into TiO2crystals.?2?Taking the removal rate of oxytetracycline as the evaluation index,the effects of different environmental factors and modification on sample performances are studied.The results show that for the adsorption of oxytetracycline,the optimal initial concentration is determined to be 25mg·L^-1,the optimal dosage of TiO₂ is 1.0g·L^-1,and the optimal pH range is 4-10.The adsorption removal of oxytetracycline is a rapid adsorption process.In addition,the optimal GO ratio of TiO₂/GO and SO₄^2-/TiO₂/GO is1:40.The samples are recycled four times and its adsorption and photocatalytic activity are relatively stable.At 15 minutes of photocatalytic reaction,the adsorption-photocatalytic removal rates of pure TiO₂ and SO₄^2-/TiO₂,TiO₂/GO and SO₄^2-/TiO₂/GO to oxytetracycline are 66.80%,76.74%,75.91%and 77.77%respectively;when the dark reaction reachs adsorption equilibrium,the adsorption removal rate of SO₄^2-/TiO₂/GO is 1.24 times of SO₄^2-/TiO₂,1.46 times of TiO₂/GO,and 2.05 times of pure TiO2,indicating that the combination of dilute sulfuric acid and GO improves the adsorption performance and photocatalytic activity of SO₄^2-/TiO₂/GO composites.?3?Isothermal adsorption model and adsorption kinetics model of pure TiO₂ and SO₄^2-/TiO₂ to oxytetracycline are investigated.The results show that the adsorption on the surface of pure TiO₂ and SO₄^2-/TiO₂ is mainly Langmuir monolayer adsorption,and the adsorption process is a chemical adsorption process,the adsorption rate is influenced by the surface chemical properties of samples and oxytetracycline.The results of this study show that the adsorption and photocatalytic properties of TiO₂ material modified by dilute sulfuric acid and GO(SO₄^2-/TiO₂/GO)to oxytetracycline is obviously strengthened,and its stability is good and it could be recycled,which has a good application value in the field of antibiotic wastewater treatment...