Preparation Of Ternary Titanium Dioxide-based Magnetic Composite Material For Wastewater Treatment

With the development of society and the improvement of human living standards,more and more pollutants are discharged into the natural environment.Energy shortage and environmental pollution have become issues that humans need to solve urgently.Due to water pollution and other reasons,the composition of surface water is complicated,organic components are increased,and water pollution treatment is becoming more and more difficult.Moreover,traditional processing methods have many equipments,complicated management and high equipment maintenance costs.In recent years,the development of photocatalytic technology has provided new possibilities for dealing with water pollution.The recent trend titanium dioxide is widely used in wastewater treatment due to its chemical stability,low cost and non-toxicity.However,there are some unfavorable factors in the practical application of titanium dioxide,such as low photocatalytic efficiency,poor adsorption capacity to target pollutants,and difficulty in separation.In this paper,TiO₂ was used as the matrix to synthesize ternary titanium dioxide-based magnetic composites by solvothermal method.The magnetic composites were studied in the photocatalytic treatment of methyl orange and ciprofloxacin in wastewater under visible light.This paper mainly includes the following three aspects:?1?Preparation of ternarymagnetic composite nanomaterial Ag-TON/g-C₃N₄/Fe₃O₄Ag?N codoped TiO₂?Ag-TON??Ag-TON/g-C₃N₄?Ag-TON/g-C₃N₄/Fe₃O₄photocatalytic materials were prepared by solvothermal method.These visible light photocatalysts were characterized by X-ray diffraction?XRD?,scanning electron microscopy?SEM?,UV–vis diffuse reflectance spectra?DRS?and vibrating sample magnetometer?VSM?.The effects were studied the doping amount of N,g-C₃N₄ and Fe₃O₄,TiO₂ doping ratios on photocatalytic performance of composites.The results showed that the optimum doping ratio of the optimum doping ratio of N was 25%?molar ratio to TiO₂?,the optimal reaction condition was40wt%of g-C₃N₄?mass ratio of TiO₂?,and the optimal reaction condition was1wt%of Fe₃O₄?molar ratio of TiO₂?.On the basis of this,the best absorption of the ternary magnetic composite nanomaterial Ag-TON/g-C₃N₄/Fe₃O₄ was obtained.It was found that Ag-TON/g-C₃N₄/Fe₃O₄ magnetic composite material had excellent magnetic properties,strong stability,easy dispersion and recovery.The maximum saturation magnetization can reach 29.6733 emu·g^-1.After 180min of visible light irradiation,the degradation rate of the methy orange solution can reach 71.4%.The main active species were h⁺and·O₂^-.?2?Preparation of ternarymagnetic composite nanomaterial Ag-TON/FAC/Fe₃O₄Ag-TON/FAC?Ag-TON/FAC/Fe₃O₄ were synthesized by solvothermal method.These visible light photocatalysts were characterized by X-ray diffraction?XRD?,scanning electron microscopy?SEM?,infrared spectra?FT-IR?UV–vis diffuse reflectance spectra?DRS?and vibrating sample magnetometer?VSM?.The effects were studied the Ag doping amount,FAC and Fe₃O₄,TiO₂doping ratios.The results showed that the optimum doping ratio of Ag was determined to be 15%,TiO₂:FAC=2:1,and the optimal reaction condition was 10wt%of Fe₃O₄?molar ratio of TiO₂?.The ternary composite nanomaterial Ag-TON/FAC/Fe₃O₄ had the lowest electron-hole recombination rate and exhibited good superparamagnetism.After 180 min of visible light irradiation,the degradation rate of the methy orange and ciprofloxacin solution can reach71.4%and 63.9%.After 5 cycles of experiments,the degradation rate of simulated wastewater by Ag-TON/FAC/Fe₃O₄ remained above 60%.The catalytic mechanism of Ag-TON/FAC/Fe₃O₄ under visible light was preliminarily investigated by active species capture experiments.It was preliminarily determined by active substance capture experiments that the active substances of Ag-TON/FAC/Fe₃O₄ are h⁺,·O₂^-and e^-.?3?Preparation of ternarymagnetic composite nanomaterial Ag@AgX-TON/FAC/Fe₃O₄Ag@AgX-TON/FAC and Ag@AgX-TON/FAC/Fe₃O₄ composites were synthesized by solvothermal method and photoreduction method.These visible light photocatalysts were characterized by X-ray diffraction?XRD?and UV–vis diffuse reflectance spectra?DRS?.The effects were studied the different halogens and Fe₃O₄,TiO₂ doping ratios on the photocatalytic properties of composites.The results showed that when the doping amount of X=Br and the optimum doping ratio of Fe₃O₄ was 1%,the obtained samples degrades the simulated wastewater best.The degradation rate of methyl orange reached 96.9%after 60min of light,which was 4.8 times that of TiO₂.Through active species capture experiments,it showed that the main active species are h⁺and e^-.