Bi_1-xRe_xFeO₃ Nano-powder Preparation And Study On Photocatalytic Treatment Of Simulated Congo Red Wastewater

In order to deal with the pollution of organic pollutants in water,treat Congo red dye wastewater,and fundamentally solve the problems of organic pollution entering the human body through the food chain.The BFO photocatalytic nano powders with different content of doped Y?La were prepared by gel sol method.The characterization of doped BiFeO₃ nano-powders was made by using XRD?SEM?FT-IR?UV-8000?VSM.The study of Congo red and COD degradation reaction was performed at room temperature.The effects of different Y?La doping on the structure,optical,magnetic and photocatalytic properties of BFO powders were studied.Explore the basic rules and influencing factors of Bi_xRe_1-xFeO₃ photocatalyst for degradation of organic pollutants in water,and elucidate the interaction mechanism between the catalyst and organic pollutants during photocatalytic degradation process.The results show that:(1)The doped BFO photocatalyst is spherical and has a small particle size,which not only affects the magnetism of the BFO,but also reduces its band gap.BFO the photocatalytic degradation of Congo red solution,the degradation rate of pure bismuth ferrate to Congo red is about 30%;86%removal rate of Congo red from Y₅ sample,56%more than pure BFO catalytic effect;20 mg/L 200 m L of Congo red solution can be completely degraded by doping La₅ sample in photocatalytic 60min,85.7%more than pure BFO catalytic effect in the same time.Meanwhile the degradation efficiency of Congo red solution with doping La_7.5 samples can reach 90%at 120 min.To sum up,catalytic effect of doped BFO photocatalysts is obviously improved,The La-doped catalyst has better photocatalytic effect than the Y-doped catalyst.As the ratio of Congo red concentration to its initial concentration(Ct/C0)changes exponentially with time,it accords with the kinetic equation of quasi-first-order reaction.(2)The COD concentration BFO reduced by 17%after photocatalytic degradation of wastewater solution.When Y₅ sample was added,COD concentration decreased by 31%,while the concentration content of COD was reduced by 40%after adding La₅ samples.BFO catalyst also degrades the COD concentration in water according to the results of Congo red degradation experiment,The degradation of COD by the catalyst after doping is better than that of pure bismuth ferrate.Among them,the catalytic effect of La doping is better.(3)The investigation of photocatalytic mechanism shows that:After adding ammonium oxalate,the degradation rate of Congo red was 43.6%and 52%after doping Y?La;the degradation rate of tert-butanol was 87%and 82%respectively;the degradation rate of catalase was 91.6%and 95%respectively.It can be seen that the main active substance in photocatalytic degradation of Congo red by composite photocatalyst is hole.To sum up,Through controlling the doping amount of Y?La,it can enhance the visible light response ability,effectively inhibit the recombination of e^--h⁺pairs,and improve the photocatalytic degradation efficiency.