Research On Biosynthesis And Catalytic Performance Of Palladium-based Nanomaterials

The traditional method of preparing metal nanoparticles can synthesize a catalyst with high purity and good catalytic effect,but it is easy to produce pollution during the synthesis process,and the microbial approach can be used as a sustainable and environmentally harmless alternative method.Therefore,the development of an environmentally friendly method for the synthesis of metal nanoparticles is of great significance in the current nanotechnology research.There have been reports showing that the chemical synthesis of single metals,bimetals and other nanomaterials has been very mature,but there are few reports on the use of microorganisms to synthesize nanomaterials.In this project,the gram-positive bacterium Staphylococcus sp.JJ-1 was reduced to nano-palladium and gold-palladium alloy materials in situ,and applied to the catalytic reduction and degradation of triphenylmethane dye wastewater.In addition,palladium plating of Candida guilliermondii is also used in the yeast season and applied to the toxin-like patulin for catalytic degradation,which has high catalytic efficiency.The main research contents and experimental results are as follows:(1)Staphylococcus sp.JJ-1 was used to reduce the bio-nano-palladium with sodium formate as an electron donor,and the Pd(II)reduction process was further analyzed by chemical characterization.Staphylococcus sp.JJ-1 cooperates with Bio-Pd to greatly increase the rate of methyl green reduction.In the case of high salt and high methyl green concentration,Bio-Pd still has a high catalytic reduction effect on the decolorization of methyl green.After the bacteria were inactivated,it was found that there was no catalytic reduction effect on methyl green,indicating that the bacteria played a synergistic role in the reaction process.(2)Using Staphylococcus sp.JJ-1 to reduce to AuPd alloy material through sodium formate as electron donor.This is the first time that the gram-positive bacteria JJ-1 has the ability to reduce AuPd alloy.The chemical characterization data proves the successful synthesis of AuPd.Alloy materials.In the process of synthesizing AuPd alloy materials,it was found that when the concentration of sodium chloropalladate in the current driver remains unchanged,the concentration of chloroauric acid increases.The catalytic effect of the synthesized AuPd alloy material is better,it may be because gold will catalyze the AuPd alloy material.In the dye wastewater degradation experiment,when JJ-1 is loaded with Au₂Pd₁alloy material,it can be completely degraded within 12 hours.Electrochemical characterization experiments show that Au₂Pd₁alloy material has the largest integral area in the entire reaction system,has redox peaks,and has the best activity.(3)Using Candida guilliermondii and nano-palladium to synthesize nano-palladium Candida guilliermondii,chemical characterization further analyzed the morphology of Candida guilliermondii nano-palladium.After Candida guilliermondii was plated with nano-palladium,the degradation of patulin by Candida guilliermondii with nano-palladium was greatly improved,and the most suitable concentration combination for catalyzing the degradation of patulin was explored.The catalytic degradation time of patulin in this experimental system is shorter and the efficiency is higher.