Influence Of Sphaerotilus Natans On Antimony (V) Removal From Surfacewater By Microscale Zero-valent Iron And Mechanism Research

Antimony pollution of surface water is serious in mine area,research showed that cheap iron filings is good at antimony removal in the water,but the research of the effect of iron removal from water Sb???and the related mechanism are less.Iron-oxidizing bacteria,which is easy to grow under lean nutrition,is one of the representative microorganism in rust corrosion.Sphaerotilus natans which are easy to grow in poor nutrition and rich was studied in the research;the tolerance of Sphaerotilus natans Sb???and its removal ability was researched.In this experiment,by researching the Sb???removal ability and reaction process of the Sphaerotilus natans–scrap iron coexistence system in poor nutrient solution,and comparing with scrap iron-water systems,the effect of the Sphaerotilus natans on the removal of Sb???by micron grade zero iron?mZVI?was determined;the changes of pH and redox potential in the reaction process were monitored;XRD,SEM,FTIR,TEM were used to characterize biomineralization,the composed and morphology of solid products was analyzed after the reaction,and the influence mechanism of Sphaerotilus natans on the removal of Sb???was explored.Results:At an initial Fe⁰ dose of 0.1g·L^-1,40 mg·L^-1 Sb???was completely removed in abiotic systems.Dissolved oxygen in solution is good for the remove of Sb???used by mZVI.When the pH of solution is 5.0⁸.0,it has little effect on removal efficiency.The main mechanism of Sb???removal by zero-valence iron is that the iron is corroded into iron oxide/hydroxide,and then Sb???is absorbed into the iron oxide.Sphaerotilus natans showed strong tolerance to Sb???,but they were weak to adsorb Sb???.The most important is that the presence of Sphaerotilus natans reduced the Sb???removal ability of the mZVI.With the increase of microbial inoculation,the inhibition effect was more obvious,and the inhibition rate can be as high as 39%.By compared with antimony in non-biological systems,the value of redox potential decreased significantly in the process of Sphaerotilus natans–scrap iron coexistence system,which suggested that the growth of the Sphaerotilus natans consumed a lot of dissolved oxygen and inhibited the formation of iron oxides.At the same time,the presence of a large number of turbidities may inhibit the electron transfer between Sb???and the zero valence iron.The main product after Sb???removal by Sphaerotilus natans–scrap iron coexistence system was FeOOH and FeSb₂O₆.However,the product after Sb???removal by pure zero valence iron is mainly Fe₂O₃.Fe³⁺ions were biomineralized by Sphaerotilus natans in this process,and the sediment was formed around the bacteria,but this bacterium did not play significant role in the removal of Sb???.Conclusion:mZVI can be effectively used to remove Sb???from water.However,the presence of Sphaerotilus natans can inhibit the ability of Sb???removed by mZVI,because the microbe affects the generation of iron oxide minerals and electron transfer during the reaction.