Influence And Mechanism Of Inorganic Anions In Advanced Oxidation Catalysis Via Amorphous Alloys For Waste Water Treatment

Amorphous alloys are excellent catalysts for the treatment of wastewater by advanced oxidation processes due to their metastable properties and widely adjustable components.Among them,ferromagnetic amorphous alloys exhibiting several advantages,including high catalytic activity,corrosion resistance,low price,easy preparation,easy recycling and good durability,have become a research hotspot.Currently,most research studies on amorphous alloy catalysts focus on improving their catalytic activity,such as improving the surface morphology and composition state via dealloying,nanocrystallisation,etc.,and preparing new amorphous alloys through 3D printing,changing the element composition and ratio,etc.Although inorganic anions are widely used in wastewater treatment with a significant impact on the advanced oxidation catalysed by amorphous alloys,there is a lack of systematic research in this aspect.Therefore,this article aims to study the influence of various inorganic anions on the catalytic performance of amorphous alloys.In this paper,a single roller melting-spinning equipment was used to prepare amorphous ribbons.The influence of inorganic salt ions（Cl^-）on the catalysis of amorphous alloy ribbons(Fe₇₈Si₉B₁₃)with different oxidation reagents（H₂O₂,peroxydisulfate（PDS）and peroxymonosulfate（PMS））and the influence and mechanism of different inorganic anions(Cl^-,HCO₃^-,H₂PO₄^-,SO₄^2-and NO₃^-)on the degradation performance of the amorphous alloy(Fe₄Co₆₇Mo_1.5Si_16.5B₁₁)in the catalytic advanced oxidation process were studied.The main findings are listed below:（1）For the Fe₇₈Si₉B₁₃ amorphous alloy catalysed by three common oxidants to degrade Orange II,Cl^-inhibits the degradation performance of the Fe₇₈Si₉B₁₃/H₂O₂ and Fe₇₈Si₉B₁₃/PDS systems by consuming free radicals.However,Cl^-directly reacts with PMS to produce Cl₂/HCl O and improve the degradation performance of the Fe₇₈Si₉B₁₃/PMS system.And the degradation effect increases with the increase in Cl^-concentration.The addition of Cl^-also affected the surface morphology and element valence of the Fe₇₈Si₉B₁₃ amorphous ribbons.（2）The catalytic mechanism of Fe₇₈Si₉B₁₃ amorphous ribbons was also revealed through quenching and electron paramagnetic resonance experiments.The degradation process occurs via three pathways:（i）Fe₇₈Si₉B₁₃ amorphous ribbons themselves reducing the pollutants;（ii）Fe₇₈Si₉B₁₃ amorphous ribbons catalysing oxidants and generating free radicals to degrade pollutants,which is a free radical pathway;（iii）Fe₇₈Si₉B₁₃ amorphous ribbons and oxidants synergistically producing ¹O₂ to oxidise and degrade pollutants,which is a non-radical path.The addition of Cl^-affects the free radical pathway（ii）to bring about an inhibitory effect or reacts with PMS to generate new active substances and pathways to promote degradation performance.（3）The Fe₄Co₆₇Mo_1.5Si_16.5B₁₁/PMS system showed high efficiency degradation of Orange II in the p H range of 5-9.The impact of experimental parameters,such as ribbon dosage,PMS concentration,Orange II concentration and temperature have been studied.Under the same conditions,the catalytic activity is better than Fe₇₈Si₉B₁₃ amorphous ribbon.After 24 repeated uses,an oxide layer is formed on the ribbon surface,but the amorphous ribbon still has an excellent degradability.（4）After adding various inorganic anions,sporadic particle products were formed on the ribbon surface.Cl^-inhibited degradation in low concentrations,but as the concentration of Cl^-increased,the inhibitory effect weakened;HCO₃^-severely inhibited degradation,but the inhibitory effect weakened with the increase in the concentration;H₂PO₄^-,SO₄^2-and NO₃^-inhibited degradation,and the degree of inhibition increased with the concentration.