Hi Brian, I've attached two react files. The first, FeS2_Kin_7Jan2016#1.rea, uses the custom rate law you suggested in your previous post; unfortunately, I wasn't able to use "soln_vol" in my GWB version.
In the second file, FeS2_Kin_5Jan2016#11c.rea, I entered a constant value for O2(aq) and set the rate constant equal to k * A/V. In this run, the amount of pyrite that reacts more closely resembles what was observed/measured in the experimental system; however, the system is still saturated with pyrite.
In all of the simulations, I decoupled all relevant redox pairs.
Thanks for your help; I really appreciate it!
Amy
FeS2_Kin_7Jan2016#1.rea
FeS2_Kin_5Jan2016#11c.rea