Preparation Of Pt Supported On Titanium Silicalite-2 Catalyst And Its Properties For Catalytic Oxidation And Reduction Of Organic Pollutants At Room Temperature

Human health and ecological environment are increasingly harmed by indoor air pollution and water pollution,causing widespread concern in society.Formaldehyde?HCHO?in an indoor environment is harmful to human health because of its long-lasting volatilization and toxicity.Nitrophenol?NP?in wastewater has the characteristics of high concentrations and non-biodegradable,threatening the biological safety..The traditional treatment is hard to achieve high removal efficiency for the degradation of refractory and toxicity organic pollutants,more efficient treatments must be developed.In present work,the precious metal Pt was loaded on titanium silicalite-2?TS-2?via one-step hydrothermal method and photoreduction method,respectively.The catalytic oxidation of HCHO by the Pt/TS-2 catalyst and the catalytic reduction of NP by the Pt@TS-2 catalyst were investigated.The main tasks of this work are as follows:?1?Pt/TS-2 catalysts with different Pt loadings were successfully prepared with the reducing agent of organic reactants by using a one-step hydrothermal method.The physicochemical properties of the Pt/TS-2 catalyst were characterized comprehensively.The results of the characterization analysis showed that the structure of Pt/TS-2 was still Mobil eleven?MEL?topology after Pt loading.The Pt particles were uniformly dispersed on the Pt/TS-2 catalyst.?2?The performance of HCHO oxidation by Pt/TS-2 was studied under different experimental conditions and the possible mechanism of the HCHO oxidation by Pt/TS-2 was proposed.The experimental results showed that the removal efficiency of HCHO by the 1 wt.%Pt/TS-2 catalyst reached 90%within 30 min,and the CO₂ and H₂O were produced continuously.The removal efficiency of HCHO by 1 wt.%Pt/TS-2 catalyst could still reach 85%even after 7 cycles,which attributed to the excellent adsorption performance of TS-2 and the catalytic activity of highly dispersed Pt particles.?3?Pt@TS-2 catalyst was successfully synthesised by the photoreduction method.The physicochemical properties of the Pt@TS-2 catalyst were characterized comprehensively.The results of the characterization analysis showed that the Pt loading on the catalyst through photoreduction method had almost no influence on the structure of TS-2,and the status of Ti was tetracoordinated and hexacoordinated in the framework without anatase generated.?4?The performance of 1 wt.%Pt@TS-2 catalyst on NP reduction was investigated through the catalytic reduction for the three isomeric of NP,including o-nitrophenol?ONP?,m-nitrophenol?MNP?and p-nitrophenol?PNP?.The effects of different experimental conditions on the catalytic reduction of PNP by Pt@TS-2 and its possible mechanism was proposed.It could be seen that the three isomers of NP was reduced to the corresponding aminophenols by 1 wt.%Pt@TS-2 in a short time.The average reduction efficiency of 1 wt.%Pt@TS-2 on catalytic reduction of PNP was over 77%after 3 cycles.The kinetic analysis results showed that the process of catalytic reduction of PNP by 1 wt.%Pt@TS-2 catalyst was consistent with the pseudo first-order reaction kinetics equation,and the rate constant was reached 0.1011 min^-1.The efficient catalytic reduction of PNP by 1 wt.%Pt@TS-2 catalyst was mainly due to the efficient transfer of electrons generated between the NaBH₄ and PNP on the catalyst surface.The Pt/TS-2 and Pt@TS-2 catalysts were successfully synthesized with the high catalytic efficiency of HCHO and NP respectively,which due to the TS-2 with excellent adsorption performance and the noble metal Pt with high-efficiency catalytic activity.This study have important implications for the treatment of indoor air pollution and water pollution.