Study On Treatment Of Acid Mine Drainage Using Sulfate Reducing Bacteria Cooperate With Lignite

Low pH and multiple heavy metal ions can inhibit SRB and the economy of microbial available carbon sources when sulfate reducing bacteria?SRB?treat acid mine drainage?AMD?.Lignite has the advantages of adsorbing heavy metals,lifting pH and as solid organic carbon source.The search for an economical and effective carbon source is of great significance for treatment AMD.Firstly,the adsorption properties and mechanism of lignite with different particle sizes on Cu²⁺and Zn²⁺under monometallic and polymetallic systems were studied.Secondly,in order to improve the utilization of SRB solid organic carbon source of lignite,a coal-soluble bacterium?PSB1?was enriched,separated and purified from Yulong Lake,Fuxin City.After molecular biological identification of coal-soluble bacteria?PSB1?,the growth characteristics,acid resistance and metal resistance were studied.Finally,the feasibility and effectiveness of lignite as a SRB carbon source were explored through SRB cooperative lignite remediation AMD experiments,and the mechanism of SRB cooperative lignite treatment was revealed.The main findings are as follows:?1?The adsorption kinetic fitting model of lignite adsorption Cu²⁺and Zn²⁺is in accordance with the quasi-first-order kinetic model.the isothermal adsorption line types are all L-2 curves in typical L isotherms.The isothermal adsorption line fitting model of lignite adsorption Cu²⁺conforms to the Langmuir model,and the isothermal adsorption line fitting of adsorption Zn²⁺conforms to the Freundlich model.The process of lignite adsorption Cu²⁺in monometallic system involves electrostatic,coordination and ion exchange,Cu²⁺adsorption on lignite surface in Cu²⁺?Cu O?Cu SO₄and Cu CO₃chemical states.The process of lignite adsorption Zn²⁺involves electrostatic interaction,coordination and ion exchange,Zn²⁺Zn O?Zn SO₄and Zn CO₃chemical adsorption on the surface of lignite,and the crystal structure of lignite does not change greatly when it is coordinated with oxygen on lignite aromatics change.The mechanism Cu²⁺lignite adsorption is the same as that of lignite adsorption in Cu²⁺polymetallic system.under the polymetallic system Zn²⁺only the lignite surface is adsorbed by coordination.?2?The liquid cultures PSB1 coal-soluble bacteria were red,and the colonies were yellow,round,with neat edges,smooth and moist,with a diameter of about 1?2 mm,and gram staining was negative,which was pseudomonas,with a similarity of 98.7%to Rhodopseudomonas palustris?wp012495146?.When inoculated PSB1 cultured according to 1:10 inoculation ratio,0?4h were delayed,4?50h were logarithmic growth period,50?60 h were stable period,and 60h entered decline period.PSB1 can grow in the pH range of 4?10,and has good acid resistance.The toxicity of Cu²⁺to coal-soluble bacteria PSB1 is stronger than that of Zn²⁺.?3?At 60min of lignite pretreatment for AMD,the Cu²⁺removal rate was 100%,and the system pH was increased from 4 to 7.12;at 24h,the Zn²⁺removal rate was 100%,and the system pH was 7.94.SRB synergistic PSB1 of the system of dissolved lignite to repair the AMD after pretreatment,the SRB activity was the best,and the removal rate of SO₄^2-was the highest,which was 58.87%.Repairing AMD of lignite system by SRB synergistic PSB1,PSB1 growth metabolism consumes inorganic carbon?Fe CO₃?Ca CO₃?in lignite,and exposed Fe²⁺and Ca²⁺appear on the surface of lignite.The S^2-produced by SRB reduction SO₄^2-can form Fe S precipitate with the Fe²⁺in lignite.The SO₄^2-of the part in the AMD is formed Ca SO₄adsorbed on the surface of lignite with the Ca²⁺in lignite.