Dear Jaewan Choi, FeS2 and SrCO3 cannot react directly under formation of strontium sulfate, because pyrite contains reduced sulfur in the form of the disulfide anion, S22–. Thus in any case, oxidation of the disulfide must take place in the first step. This is backed by the following statement which I found in the reference you provided:

"These results show that the SrCO3 nanoparticles are not only effective in neutralizing free sulfates and the acid associated with them, but they also react with the reduced sulfur species present to form sulfoxide (from the oxidation

of methionine) and insoluble and very unreactive SrSO4 (from the oxidation of pyrite and other inorganic sulfur compounds)."

I assume the atmospheric oxygen is the oxidant. Once the sulfur is oxidized to sulfate anion, the driving force is the formation of highly insoluble strontium sulfate.

Thank you very much, Mr. Edelmann. Your answer gave me a big help to me. I really appreciate your kindness. Thank you.

Best regards,

Jaewan.

Dear Jaewan Choi, wou're welcome. I'm glad to hear that my answer was helpful. It was indeed rather interesting to read the attached paper. For me it was completely new and surprising to read about the use of SrCO3 nanoparticles for de-acidification of a historic ship.

Mr. Edelmann may I ask some more inquiries?

I understand that oxidation of FeS2 must take a step first.

FeS2+ O2 + H2O = H:+ + SO4:2- + Fe:2+

FeS2 + O2 + H2O = H2SO4 + FeSO4

I think those chemical reactions will take place first.

So, SO4:2- and H2SO4 will react with SrCO3 to create SrSO4.

Then what will happen to FeSO4 and Fe:2+? will it just remain inside of wood?

in the paper, there is no mention regarding FeSO4 and Fe:2+.

I think if the FeSO4 and Fe:2+ have remained in the wood, SrCO3 is not perfect de-acidification chemical compounds. Fe:2+ might react with S to create more FeS2. Thank you.

Hi Jaewan Choi, sorry for the late response! FeS2 is normally not formed in aqueous systems. The by-product FeSO4 (and other Fe2+ ions) is soluble in water and will certainly go into solution.

thanks for your reply dr. Edelmann