SRB clarification needed (1 Viewer)

[mitch_f1]

Hey
I just needed this calrified, or confirmed.

Is it the action of the SRB reducing sulfate in shipwrecks that causes the oxidation of iron through the transfer of electrons.

Thanks
Mitch

 

[kazan]

im not 100% sure what your asking

but i think what you want to know is,
sulfate reducing bacteria create oxygen through there respiration, they also create small acid enviroments, and according to le chataliers principle, this will force the reaction forward and increase the rate of corrosion.

anyone care to correct me?

 

[dikeymikey]

Ahhh I think the SRB reduce sulfate ions to sulfite ions, which then oxidises the iron.

 

[tristambrown]

if you want to get off syllabus then yes, SRB do cause traditional oxidation of Fe (rusting)

in nice simple terms for the HSC, NO they cause corrosion not rusting

Simple SRB ACTION (energy to reduce SO4 comes from oxididation of iron)

Fe(s) ----SRB----> Fe^2+ + 2e^1

S04^2- -----SRB---> S^2- + H^+

Fe^2+ + S^2- ------> FeS (s) (rusticle - the redish black crud on the titanic) (Iron Sulfite)



The simplest way i can put the following longwinded set of reactions follow. We do not need to know any of this.
In the following n is an amount i do not know off hand because i dont need to know it, X is a number less than n, y is (N-X) and z is a number even smaller than the rest

nFe(s) ----SRB----> nFe^2+ + n2e^1
ySO4^2- +ne^- ---> nOH^- + yS^2-

nOH^- + nFe^2+ yS^2- --> yFeS(s) + xFe(OH)2 + zH+
xFe(OH)2 +O2 ----> xFe2O3.H20 +xH20 (rust + Water)

(the H+ ion may come from a different reaction than exactly what i have put above.the point is that it does appear and that we just need to know that the net result IS the S^2- and the H^+ (which increases acidity , indirectly speeding traditional oxidation in the vacinity)