Degradetion Properties Of Co-based Amorphous Alloy For Activateing Hydrogen Peroxide In Treating Dye Wastewater

In recent years,amorphous alloys with both catalytically active and uniquely selective properties have become a new promising and competitive member in the family of catalysts for wastewater remediation,thus receiving a great deal of attention and extensive reports.Herein,Co₇₈Si₈B₁₄ amorphous alloy ribbons are used to degrade dye wastewater by activating hydrogen peroxide（H₂O₂）as Fenton-like catalysts for the first time,and the catalytic degradation process by using Fe₇₈Si₈B₁₄amorphous alloy ribbons are investigated for comparison.The mechanisms of catalytic degradation of Co₇₈Si₈B₁₄ amorphous ribbons under acidic and alkaline conditions were investigated by different characterization methods.At the same time,in order to determine the reusability of the Co-based amorphous alloys,this work tested the as-received Co₇₈Si₈B₁₄ amorphous alloy ribbons in Acid Orange II（AO II）solutions of p H=4 and p H=10,respectively.The results show that Co₇₈Si₈B₁₄amorphous alloy has excellent catalytic activity and reusability under wide p H conditions,which not only provides a new solution for wastewater treatment,but also extends the application fields for Co₇₈Si₈B₁₄ amorphous alloy.The main research contents are as follows:Firstly,the degradation performance of Co₇₈Si₈B₁₄ amorphous alloy ribbons on Rhodamine B（Rh B）by Fenton-like reaction were analyzed by UV-vis,and the degradation performance of Fe₇₈Si₈B₁₄ amorphous alloy ribbons was compared.It was found that under the same reaction conditions,Co₇₈Si₈B₁₄ amorphous alloy ribbons have higher degradation efficiency（degradation efficiency 95%and 53%）,degradation rate(degradation rate 0.057 min^-1 and 0.021 min^-1)and TOC removal rate（TOC removal rate 49.2%and 38.2%）than Fe₇₈Si₈B₁₄ amorphous alloy ribbons.Notably,the Co-based amorphous alloys can effectively decomposition Rh B in both acidic and alkaline environments,which can solve the problem that the activity of the amorphous alloy catalysts are limited by the p H of the solution,and the reaction rate in alkaline environment is higher than that in acidic environment.This is mainly due to:under acidic conditions,the·OH produced by the activation of H₂O₂ by Co-based amorphous alloy plays a leading role in the degradation of Rh B,while under alkaline conditions,·OH and Co³⁺together assist the degradation of Rh B,accelerating the degradation reaction.Secondly,to examine the versatility of the Co-based amorphous alloy catalyst for the degradation of different dye compounds under acidic and alkaline conditions,AO II,which is a representative of azo dyes,is used as pollutant.At the same time,the degradation efficiency and degradation rate of Co₇₈Si₈B₁₄ and Fe₇₈Si₈B₁₄amorphous alloy ribbons by Fenton-like reaction to degrade acid orange II are also compared.It was found that when the solution p H is 10,95%of AO II could be degraded by using Co₇₈Si₈B₁₄ amorphous alloy catalysts in 15 min,and comparative studies showed that AO II degradation efficiency by using Fe₇₈Si₈B₁₄ amorphous alloy catalysts is only 37.2%.The degradation rate by using Co₇₈Si₈B₁₄ amorphous alloy catalysts reaches 0.174 min^-1at p H 10,which is 5.9 times higher than that of the Fe₇₈Si₈B₁₄ amorphous alloy catalysts(0.030 min^-1).In addition,when the solution p H is 4,the degradation rate by using Co₇₈Si₈B₁₄ reached 0.089 min^-1,which is 1.2 times higher than that of the Fe₇₈Si₈B₁₄ amorphous alloy(0.072 min^-1).Whether under acidic or alkaline conditions,a comprehensive comparison of the degradation efficiency and degradation rate of Co-based and Fe-based amorphous alloys to activate H₂O₂ to degrade AO II shows that Co-based amorphous alloys activate H₂O₂to degrade pollutants more effectively and faster.Impressively,the Co-based amorphous alloy catalysts can be reused up to 20-60 times at wide p H conditions,demonstrating fairly good reusability.This is mainly due to:under alkaline conditions,the self-repairing capability of the surface of Co₇₈Si₈B₁₄ amorphous alloy ribbons makes the cracked layers gradually dropped-off,exposing the fresh layers at the bottom,which ensures the long service life of Co₇₈Si₈B₁₄ amorphous alloy ribbons in the degradation process.