Table 2.

Input Parameters used for equilibrium calculation of manganese and iron solution with NaHCO₃, NaHS, NaOH and sodium gluconate.

Parameters	Value	Reference
•pKa1a H2S	7.02	[28]
•pKa2a H2S	12.87 & 19	[28]
•pKa1a H2CO3	6.3	[33]
•pKa2a H2CO3	10.32	[33]
•pKa2a HGH	3.7	[15]
•pKspa ${\text{MnCO}}_3$/${\text{FeCO}}_3$	9.17 & 11.37/10.54	[30, 33]
•pkspa ${\text{MnS}}_2$/${\text{FeS}}_2$	3.7∗/7	[33]
•pKspa ${\text{Mn}\left(\text{OH}\right)}_2$/${\text{Fe}\left(\text{OH}\right)}_2$	-15.2∗∗/13.79	[33, 38]
Stability Constants log (βa)
•$\text{Mn}{\left(\text{OH}\right)}^{+}$/$\text{ Fe}{\left(\text{OH}\right)}^{+}$	3.4/4.5	[33]
•$\text{Mn}{\left(\text{OH}\right)}_2^{\text{o}}$/$\text{Fe}{\left(\text{OH}\right)}_2^{\text{o}}$	5.8/7.4	[33]
•$\text{Mn}{\left(\text{OH}\right)}_3^{-}$/$\text{Fe}{\left(\text{OH}\right)}_3^{-}$	7.7/11	[33]
•$\text{Mn}{\left(\text{OH}\right)}_4^{=}$/$\text{Fe}{\left(\text{OH}\right)}_4^{=}$	7.7/8.9	[33]
•Stability Constants log (βa)
•$\text{Fe}{\left({\text{HCO}}_3\right)}^{+}$	2.17	[36]
•$\text{Fe}{\left({\text{CO}}_3\right)}^{\text{o}}$	4.73	[36]
•$\text{Fe}\left(\text{II}\right)\left({\text{GH}}_4\right){\left(\text{OH}\right)}_4^{-2}$	17.8	[37]
•${\text{E}}_{{\text{Mn}}^{2+}/\text{Mn}}^{\text{o}}$(volt SHE)	-1.431	[39]
•$\text{Mn}{\left({\text{HCO}}_3\right)}^{+}$	1.95	[36]
•$\text{Mn}{\left({\text{CO}}_3\right)}^{\text{o}}$	4.1	[36]
•$\text{Mn}\left(\text{II}\right){\left({\text{GH}}_3\right)}_2^{-2}$	11.0	this work
•$\text{Mn}\left(\text{III}\right){\left({\text{GH}}_3\right)}_2{\left(\text{OH}\right)}^{2-}$	42.1	this work
•$\text{Mn}\left(\text{IV}\right){\left({\text{GH}}_3\right)}_2{{\left(\text{OH}\right)}_3}^{3-}$	17.2	this work
•$\text{Fe}\left(\text{II}\right){\left({\text{GH}}_4\right)}^{+}$	10	[16]
•$\text{Fe}\left(\text{III}\right)\left({\text{GH}}_4\right){\left(\text{OH}\right)}_3^{-1}$	37.9	[37]
•$\text{Fe}\left(\text{III}\right)\left({\text{GH}}_4\right){\left(\text{OH}\right)}_4^{-2}$	37.2	[16]

^∗Based on reaction of ${\text{MS}}_{2\left(\text{s}\right)}+{\text{ H}}^{+}\leftrightharpoons {{\text{M}}^{2+}}_{\left(\text{aq}\right)}+\text{H}{{\text{S}}^{-}}_{\left(\text{aq}\right)}+{\text{S}}^{\text{o}}$.

^∗∗Based on reaction of ${\text{Mn}\left(\text{OH}\right)}_{2\left(\text{s}\right)}+2{\text{H}}^{+}\leftrightharpoons \text{ M}{{\text{n}}^{2+}}_{\left(\text{aq}\right)}+2{\text{H}}_2\text{O}$.