Preparation Of Ytterbium-doped Titanium Dioxide/activated Carbon Fiber And Its Application In The Removal Of Organic Pollutants

The problem of air pollution caused by the rapid development of the economy has become more and more serious,which has aroused widespread public concern.Therefore,more and more countries have introduced a series of laws and regulations to solve this problem.In order to control the problems caused by VOC emissions effectively,photocatalysis is currently the best choice.At the same time,not only is it necessary to find a material with visible light response to broaden its response range in solar spectrum,but also significant in catalyst modification.Therefore,designing a composite photocatalyst can not only improve the utilization range of sunlight,but also improve the efficiency of photogenerated carriers,which has been an effective way to solve the problem of photocatalysis.In this paper,Yb-TiO₂ composite photocatalyst and Yb-TiACF three-dimensional porous materials were successfully prepared by hydrothermal method.The phase structure,microstructure,pore size distribution,specific surface area and photoreaction ability of composite nanomaterials also were investigated by XRD,SEM,TEM,FTIR,BET,UV-Vis,PL and other characterization.The effects of different catalysts on the removal of toluene at a certain concentration were investigated.The effect of toluene concentration on the reactivity was investigated,and the mechanism of photocatalytic degradation was explored.The specific experimental results are listed below:?1?The Yb-TiO₂ composite was successfully prepared by two times hydrothermal method.The composite was caculated by Scherrer formula with particle size of 11.61 nm through the XRD pattern.The SEM images has indicated that the catalyst has a rod-like structure with length of 3 to 6?m and the diameter of 120 to300 nm.The Yb-TiO₂ material is composed of three elements of Yb,Ti and O,and the element Yb can be well supported on TiO₂ rods.Compared with pure TiO₂,Yb-TiO₂has a large specific surface area,pore size and pore volume,and the band gap is narrower?3.18 eV?,the fluorescence intensity is lower.During photocatalytic acticity of toluene degradation,the material of Yb-TiO₂ exhibited excellent catalytic performance,and the removal rate has reached 88.98%.Compared with pure TiO₂,Yb expands its photoresponse range and improves its catalytic performance.?2?The Yb-TiACF three-dimensional porous material was successfully prepared by three times hydrothermal method.The composite was grown orient along the crystal plane?101?of TiO₂ with a lattice spacing of 0.35 nm.This material consists of C,O,Ti,and Yb four elements.The specific surface area is 762.96 m²·g^-1.The forbidden band width is 2.91 eV,and the PL fluorescence intensity is lower.In the adsorption experiment of toluene,the adsorption efficiency has reached 99.2%and the whole adsorption process is accorded with the pseudo-second-kinetic model,which was also consistent with the conclusion of the adsorption of different concentrations of toluene.In the photocatalytic remecal of toluene with 3 h,the catalytic efficiency reached 100%,The kinetics model of toluene photodegradation 0.05Yb-TiACF matched with CO₂ desorption semi-empirical power-law expression model,while that of TiACF,0.01Yb-TiACF and 0.10Yb-TiACF was fit with apparent first-order reaction kinetics model.During the degradation of 115 ppm,230 ppm toluene,the process on 0.05Yb-TiACF is met with the semi-empirical power exponential model.During the degradation of 460 ppm,690 ppm toluene,the toluene photodegradation processes matched with both the apparent first-order reaction kinetics model and the semi-empirical power-law expression model of CO₂ desorption,demonstrating that the toluene photocatalysis rates and CO₂ desorption rates played an equal role in the whole photodegradation procedure.The excellent findings demonstrated that Yb-TiACF were a promising platform for VOC removal via adsorption and photocatalysis synergetic effects.