Study On The Mechanism Of Iron And Antimony Oxidizing Bacteria Coupled To Mediate The Dissolution And Oxidation Of Antimonite

In recent years,with the continuous mining of antimony ore,the problem of antimony pollution in antimony mining areas has become more and more serious.The dissolution and oxidation release of antimonite is considered to be the key process for Sb to enter the soil and water environment and cause antimony pollution.Typical antimony-oxidizing bacteria play an important role in the dissolution and oxidation of antimonite and affect the geochemical cycling behavior of antimony.Analyzing the mechanism of antimony dissolution and release from the source provides a new idea for solving the problem of antimony pollution in antimony mining areas.Therefore,this paper intends to explore the relationship between iron-mediated and iron-and typical antimony-oxidizing bacteria from the perspective of pH（3-10）,iron form（iron filings,iron sulfate Fe₂（SO₄）₃,pyrite Fe S₂）and iron concentration.Pseudomonas sp.AO-1 coupling-mediated study on the dissolution and oxidation of stibnite in order to establish the dissolution and oxidation mechanism of stibnite mediated by the coupling of iron and antimony oxidizing bacteria.The main work and achievements of this subject are as follows:1.The influencing factors and influencing process of stibnite dissolution oxidation are summarized and analyzed.pH is an important parameter to control the rate of dissolution and oxidation of stibnite,which mainly shifts the dissolution balance by changing the composition of sulfur products;iron oxides can undergo electron transfer and catalytic reaction with stibnite to promote its dissolution and oxidation;antimony oxidation The antimony oxidation mechanism of bacteria can accelerate the dissolution and oxidation of antimonite,which dissolves very slowly.Therefore,pH,Fe and antimony oxidizing bacteria play an important role in the dissolution and oxidation of antimonite,and the impact mechanism needs to be further studied.2.The dissolution and oxidation of antimonite under the influence of pH（3-10）,different forms of iron（iron filings,iron sulfate Fe₂（SO₄）₃,pyrite Fe S₂）and iron concentration were studied.The results show that pH is an important parameter affecting the rate of dissolution and oxidation of stibnite.In the range of pH=3～10,the dissolution and oxidation rate of antimonite increases with the increase of pH,and the proportion of dissolution and oxidation varies with pH.Sb（Ⅲ）dominates,and Sb（Ⅲ）accounts for 53.2%of Sb_TOT;when pH is 4～10,the dissolution and oxidation process of stibnite is dominated by Sb（Ⅲ）oxidation;when pH=10,Sb（V）can account for up to 98.6%of Sb_TOT.Iron filings,ferric sulfate and pyrite can all promote the dissolution and oxidation of stibnite,among which ferric sulfate has obvious promotion effect,while iron filings and pyrite have similar promotion effects.With the increase of iron concentration,the dissolution and oxidation rate of antimonite was further improved,but the promotion and enhancement of the three showed differences with the change of pH value.3.Under the influence of pH（3-10）,iron form（iron filings,iron sulfate Fe₂（SO₄）₃,pyrite Fe S₂）and iron concentration,the coupling of typical antimony oxidizing bacteria AO-1 to mediate stibnite was investigated.The dissolution and oxidation law.The results show that AO-1 can promote the dissolution and oxidation of stibnite by changing the pH of the solution to alkaline.At the same time,its promoting effect is negatively correlated with the pH value,and the promoting effect is most obvious when the pH value is 4-7.Different forms of Fe can The microbial dissolution and oxidation of antimonite was promoted,in which iron filings and pyrite had similar promoting effects,and iron sulfate had the strongest promoting effect;increasing the concentration of iron-containing substances increased the microbial dissolution and oxidation rate of antimonite again.4.Preliminary construction of the dissolution oxidation model of antimony mediated by iron and antimony oxidizing bacteria:iron mediated dissolution oxidation mechanism of antimony and iron and typical antimony oxidizing bacteria AO-1 mediated dissolution oxidation mechanism of antimonite.The iron-mediated dissolution and oxidation mechanism of antimonite is mainly the physicochemical release process under the influence of pH and Fe;the key processes of iron and typical antimony oxidizing bacteria AO-1 mediating the dissolution and oxidation mechanism of antimonite mainly include:AO-1 Coupling with Fe promotes the dissolution and oxidation of antimonite,the dissolution of mineral surfaces mediated by AO-1,the oxidation of Sb³⁺,and the formation of secondary minerals containing antimony.