Research On Azo Dye Degradation Properties Regulation And Its Mechanisms Of Fe-based Amorphous Alloy

Fe-based amorphous alloys have been applied as classical soft magnetic materials for years.Recently,they have been found to show excellent catalytic performance in degrading dye wastewater due to its unique atomic structure,making them a promising new candidate for future wastewater treatment applications.However,the degradation efficiency and mechanisms,degradation pathway and mechanism of degradation factors of Fe-based amorphous alloys are still unclear.Additionally,the catalytic efficiency and stability of currently studied alloys have not yet meet the requirements of commercial use.These obstacles limit the industrial applications of Fe-based amorphous alloys as new catalysts.Therefore,it is of great scientific significance and applicable value to perform researches in the related fields.In this dissertation,the dye degradation properties and mechanisms of the Fe-based amorphous alloy ribbons were systematically studied.And we also explored the comprehensive degradation performance of Fe-based amorphous alloy ribbons with high degradation efficiency in environmental suitability.Moreover,the performance and mechanism of the Fe-based high-entropy amorphous alloys also been systematically investigated.The prepared Fe₇₈?Si,B?₂₂ amorphous alloy ribbons show excellent degradation performance against azo dye,and all degradation processes obey the first-order reaction model of chemical reaction kinetics.At the same reaction conditions,the degradation ability first increase and then decreases with elevating Si/B ratio.As a result,the Fe₇₈Si₁₃B₉ amorphous alloy ribbon shows better degradation ability.The degradation reaction mainly occurs on the surface of the alloy,and the degradation process of azo dyes consists of two steps:surface adsorption and reduction fracture of the azo double bond?-N=N-?.Among them,Fe₇₈?Si,B?₂₂amorphous alloy ribbons act as both electron provider and catalyst.Compared with the B element,the existence of the Si element can promote the formation of a loose oxide layer on the alloy surface that is easy to exfoliate during the reaction.At the same time,the Si element also enhances the surface activity of the alloy,which accelerates the reaction process and improves the degradation ability of the alloy.Based on the above results,we further tuned the comprehensive degradation performances of the Fe-Si-B amorphous alloys ribbons via different alloying strategies.Firstly,we investigated the effects of minor alloying.The results showed that Fe₇₈Si₁₁B₉M₂?M=Zr?Sn?V?Y and P?amorphous alloy ribbons can completely degrade azo dyes in a short time,and the degradation performance of Fe₇₈Si₁₁B₉P₂ amorphous alloy ribbons is more prominent.Through studying the behavior of Fe₇₈Si₁₁B₉P₂ amorphous alloy strips under different environmental conditions,we found that reducing the initial concentration of azo dyes,increasing the solution temperature,lowering the solution's p H,increasing the number of ribbons,and adding an appropriate amount of H₂O₂ can improve the degradation reaction rate of orange?azo dye.These above-mentioned studies show that Fe₇₈Si₁₁B₉P₂?M=Zr,Sn,V,Y,and P?amorphous alloy ribbons have excellent environmental applicability.These outstanding comprehensive performances of Fe78Si11B9P2 amorphous alloy ribbons with low cost,high degradation efficiency,rapid reaction kinetics rate(0.661 min^-1),low reaction activation energy?E_a=15 k J/mol?,excellent reusability?17 times?and high COD removal?90.6%?rate are achieved without any additional conditions,which provide a broad application prospect in wastewater treatment.Secondly,we explored the effects of multi-principal alloying on degradation performances.The results showed that the degradation reaction of?Fe Co Ni?₇₈Si₁₃B₉ series high-entropy amorphous alloy ribbons on azo dyes obey the zero-order kinetic model.The dye molecules can only be absorbed,but not be reduced and degraded in the neutral solution.The degradation reaction rate is much lower than that of Fe₇₈Si₁₃B₉.It was found that the protective passivation film formed on the surface of the high-entropy alloys.It reflects the excellent durability of the high-entropy alloy.However,the protective passivation film hinders the material transportation and electron transfer between the alloy elements and the azo dye molecules,which results in a decrease of active sites on the alloy surface and weakening degradation ability of the alloy.By analyzing the degradation capacity and degradation mechanisms of different Fe-based amorphous alloys system,we found that the specific surface area,the structure of alloy,the actives elements,electronic structure,reaction activated energy,the molecular structure of dye and degradation environment could affect the degradation performance of the alloy.It provides a significant guide for optimizing the composition and electronic control of Fe-based amorphous alloys and process selection during degradation,which can further promote the application of Fe-based amorphous alloys in the treatment of dye wastewater.