Study On The Mechanism Of Inhibition And Decomposition Of Biofilms In Water System By D-amino Acids

The environment in the water system creates favorable conditions for the reproduction of microorganisms,causing microbiologically influenced corrosion?MIC?,which has become a very thorny problem in the field of oil and gas and water treatment industries.The key and foundation to solve the problem is biofilm treatment.D-amino acid has the function of inhibi-ting the formation of biofilms and promoting the disintegration of mature biofilms.It has been widely used in the synthesis of antibiotics,physiological active skin in medicine,food and additives,and is absolutely harmless to the environment.Therefore,this paper studies the mechanism of inhibition and decomposition of D-amino acids on biofilms in water system.As a new green sterilization technology,it provides theoretical basis and practical technical supp-ort for the treatment of microbial corrosion in later water system.The action mechanisms and bactericidal effects of composite bactericides made up of various D-amino acids and bactericides?tetrakis hydroxymethyl phosphonium sulfate-THPS,glutaraldehyde,cecropin?under different concentration ratios were researched to prevention and removal of biofilms.Finally select the high quality fungicide and D-amino acid concentration.The results showed that:50ppmTHPS+1-5ppmD-Tyrosine or 50ppmTHPS+1-5ppmD-ty-rosine+1-10ppmD-Valine+1-10ppmD-Tryptophane being added in three kinds of mediums with SRB,IOB and SRB+IOB can effectively inhibit Q235B steel MIC.The maximum fungicidal rates for SRB,IOB were 99%,97%respectively.In three bacteria culture mediums,the maximum corrosion inhibition rates were 81%,42%,61%respectively,and the main corrosion products were Fe₂C,Fe₇S₈ and FeSO₃·3H₂O;Fe?OH?₃ and Fe₂O₃;Fe₂C,Fe₇S₈ and Fe₂O₃ respectively.50ppmglutaraldehyde+20-40ppmD-Leucine being added in three kinds of mediums with SRB,IOB and SRB+IOB can effectively inhibit Q235B steel MIC.The maximum fungicidal rates for SRB,IOB were 99%,91%respectively.In three bacteria culture mediums,the maximum corrosion inhibition rates were 61%,45%,60%respectively,and the main corrosion products were Fe₂C,Fe₇S₈ and FeSO₄·4H₂O;Fe?OH?₃ and Fe₂O₃;Fe₂C,Fe₇S₈and Fe₂O₃ respectively.50ppmcecropin+20-40ppmD-Serine being added in three kinds of mediums with SRB,IOB and SRB+IOB can effectively inhibit Q235B steel MIC.The maximum fungicidal rates for SRB,IOB were 99%,97%respectively.In three bacteria culture mediums,the maximum corrosion inhibition rates were 68%,25%,64%respectively,and the main corrosion products wereFe₂CandFe₇S₈;Fe?OH?₃ and Fe₂O₃;Fe₂C,Fe₇S₈andFe₂O₃respectively.