Synthesis Of TiO₂/Carbon And Their Photocatalytic Performance

Antibiotics are widely used as antibacterial agents and growth promoters in the fields of disease treatment and livestock breeding.However,only a small amount of antibiotics can be absorbed and transformed by humans and animal organisms.30-90%of antibiotics are excreted in the form of prototypes and metabolites with feces and urine,which poses potential harm to ecological environment and human health.Among the many antibiotic wastewater treatment methods currently available,the adsorption and photocatalysis treatment methods are relatively faster and more effectively,so many researchers have continuously conducted in-depth research and exploration on these two methods.As a photocatalyst,titanium dioxide is considered to be the best in many catalysts and has a very broad development prospect.However,titanium dioxide has a low quantum efficiency and a wide band gap,resulting in a high recombination rate of photogenerated electron holes and a narrow absorption spectrum range.These disadvantages have imposed certain limitations on its practical application.In this regard,many researchers have conducted a lot of research to explore ways to suppress the recombination of electrons and holes and narrow the band gap.Because of its excellent adsorption performance,carbon materials can adsorb organic pollutants to the catalyst,improving the degradation efficiency of pollutants.Therefore,in this paper,titanium dioxide and carbon spheres were selected as photocatalytic materials and adsorbent materials to improve the photocatalytic degradation of pollutants.The TiO₂/carbon composites were prepared in this paper.The structure,composition and morphology of the prepared materials were characterized by TEM,XRD and BET.The photocatalytic properties of the catalysts were studied.Photocatalytic degradation experiments were studied by degrading ciprofloxacin under ultraviolet light,and the optimum calcination temperature and factors affecting antibiotic degradation were studied.The specific contents are as follows:（1）The RF sphere with good dispersibility was prepared by sol-gel method,and a layer of TiO₂ was coated on the outer surface,then RF@TiO₂ was carbonized under nitrogen protection to obtain C@TiO₂,and the structure,composition and morphology are characterized.The TEM images showed that TiO₂ is uniformly wrapped on the outer surface of RF.The thickness of the titanium dioxide shell is about 30 nm,and the diameter of RF@TiO₂ is about 280 nm.The XRD pattern showed the successful synthesis of C@TiO₂.With the increase of calcination temperature,titanium dioxide gradually changed from anatase phase to rutile phase;The BET analysis showed that C@TiO₂ has a large specific surface area.The sample calcined at 1000℃ had the largest specific surface area of 422 m2/g.（2）The photocatalytic performance of the synthesized C@TiO₂ were studied by degrading methylene blue.The experimental results show that C and TiO₂ are added separately and mechanically mixed,and there is no significant difference in catalytic performance.However,the photocatalytic performance is remarkably enhanced when C@TiO₂ was used as catalyst.Because carbon has very good adsorption performance,it can adsorb organic pollutants to the catalyst,improving the degradation efficiency of pollutants.When the calcination temperature is 900℃,C@TiO₂ has excellent adsorption and photocatalytic performance.The removal rate of methylene blue can reach more than 99%.（3）The degradation of ciprofloxacin solution by C@TiO₂ under UV light were studied.In the system of photocatalytic degradation of antibiotic ciprofloxacin by C@TiO₂,the photodegradation rate of organic matter increased with the increase of catalyst dosage.The degradation rate of antibiotics is greatly affected by the initial pH of the solution.Under acidic conditions,the photocatalytic reaction can be accelerated,while under alkaline conditions,the reaction is inhibited.When the calcination temperature is 900℃,C@TiO₂ has excellent adsorption and photocatalytic performance.