Investigation On Preparation Of Modified TiO₂ And Photocatalytic Degradation For Aniline Aerofloat

In recent years,with the development requirements of the country’s proposed construction of green mines,many mining enterprises are facing a huge pressure on environmental protection,so it is particularly important to deal with the mine’s important source of pollution-beneficiation wastewater.Usually beneficiation wastewater contains more ore dressing agents and is of complex nature and difficult to handle.Aniline aerofloat is widely used as a kind of fine flotation collector of sulfide ores,and it belongs to toxic and refractory aniline-like organic compounds.TiO2 photocatalytic technology is widely used in the degradation of organic pollutants,which is safe,stable and non-toxic,and has good chemical properties and inexpensive application.In this study,aniline aerofloat was used as the degradation object,with TiO2 as the base,rare earth doping and semiconductor composite modification to enhance the photocatalytic activity of the catalyst.The stability and mechanism of the catalyst were investigated at the same time.The photocatalytic degradation process of aniline aerofloat was deduced by the analysis of the degradation products of HPLC.The contents and conclusions of the study are summarized as follows:(1)The Sm-TiO2 with different Sm doping ratio,different calcination temperature and the g-C3N4/TiO2 with different g-C3N4 composite ratio,different heating rate,different calcination temperature and time were prepared by Sol-gel method and pyrolytic process.The structure and physicochemical properties of Sm-TiO2 and g-C3N4/Ti0O were characterized by XRD,UV-Vis DRS,SBET and SEM.The results indicate that there are different catalyst crystal phase under different conditions.The transformation of TiO2 anatase to rutile was inhibited because of the doping of Sm and g-C3N4,which improve the ultraviolet light absorption intensity of TiO2.The results of FT-IR indicate that Sm was doped to lattice of TiO2,and g-C3N4 failed to be tested because of too low composite ratio.(2)The photodegradation activity of TiO2 with different preparation conditions were examined by the degradation of aniline aerofloat by orthogonal experiment and single factor experiment under the irradiation.The 0.25%Sm-TiO2 powder with 0.6 g/L calcined at 500 °C shows the highest photocatalytic activity of 91.9%and the factors affecting photocatalytic activity are as follows:doping ratio>temperature>dosage in the orthogonal experiment of Sm doped TiO2 which was consistent with the highest photocatalytic activity in the single factor experiment.The U40T600R5H6-g-C3N4/TiO2 powder with 0.6 g/L shows the highest photocatalytic activity and the factors affecting photocatalytic activity are:calcination temperature>dosage>heaTting rate>composite ratio>soaking time in the orthogonal experiment of g-C3N4/TiO2,which was different with the single factor experiment where the U20T550R10H6-g-C3N4/TiO2 powder with 0.8 g/L shows the highest photocatalytic activity.(3)The results of quenching experiment indicate that the photocatalytic activity of 0.25%Sm-TiO2 and U20T550R10H6-g-C3N4/TiO2basd on the synergistic reaction between h+and OH while the OH acts as the major role.In addition,the 0.25%Sm-TiO2 and U20T550R10H6-g-C3N4/TiO2 still has a great photocatalytic activity for the photodegradation of aniline aerofloat after 4-times recycling,showing the stability of Sm-TiO2 and g-C3N4/TiO2.