Performance And Mechanisms Of Removal Cr(?) And As(?) With Fe₇₈Si₉b₁₃ AmorpHous Alloys

The problem of heavy metal pollution in water been highly concerned by the country.In recent years,studies have found that some iron-based amorphous alloys have excellent chemical reduction and physical adsorption,and this new zero-valent iron material can achieve rapid degradation of organic wastewater.In theory,the new zero-valent iron material could also be used to treat wastewater containing heavy metal ions,but so far it not been reported.Therefore,Cr(?)and As(?)were selected the target heavy metal pollutants in this paper,and the effects of three kinds of iron-based materials with different morphology and size on the removal efficiency and reaction mechanism of Cr(?)and As(?)were mainly studied.It is of great significance to promote the application of Fe-based amorphous alloys in treating heavy metal wastewater.Firstly,the feasibility of removing Cr(?)from water by Fe₇₈Si₉B₁₃ amorphous alloy strip demonstrated.Under acidic conditions(p H=2),the removal performance of Cr(?)by amorphous alloy strip and 300 mesh iron powder compared.It found that under the same conditions,the surface area reduction reaction rate coefficient of Fe₇₈Si₉B₁₃ amorphous alloy strip on Cr(?)removal reaction 47 times that of 300mesh iron powder.The analysis shows that the excellent removal efficiency is rel ated to the unique amorphous structure and the addition of metal-like elements.Because the amorphous structure in metastable state gives higher reactivity to iron atoms,and the addition of metal-like elements reduces the density of the product layer,whi ch protects the inner layer of zero-valent iron from being eroded by oxygen,so that the inner layer of zero-valent iron long-lasting fresh activity.Then,under different environmental conditions(pH=4,5),the combined application of Fe₇₈Si₉B₁₃amorphous alloy strip and H₂O₂ to remove Cr(?)in water studied.The results showed that the lowest Cr(?) removal rate could reach 99.7%.Because in the pollution of chromium and arsenic in water with persistence,concentration,strong toxicity and carcinogenicity.Therefore,the performance of removing As(?)from water by Fe₇₈Si₉B₁₃ amorphous alloy strip and powder finally studied.By contrast,found that amorphous alloy powder Fe₇₈Si₉B₁₃ removal efficiency reached 0.0309min^-1(greater than the amorphous strip and iron powder 300 mesh),and remove process conforms to the pseudo first-order kinetics model.The results show that the removal of As(?)by atomized amorphous powder is mainly through adsorption and reduction,and the increase of metal-like elements on the powder surface protects the matrix from being eroded by oxygen and higher chemical activity.At the same time,it simulates the actual heavy metal polluted water and selects the atomized amorphous powder with the best removal effect to anal yze the simultaneous removal performance of Cr(?),As(?)and Pb(?).Compared with a single solution,it is found that the removal efficiency is slightly lower.Mainly because a variety of heavy metal ions compete for active sites on the powder surface,which limits the final removal efficiency of Cr(?),As(?),and Pb(?).