Dynamics of pH on the oxidation of HS- with iron(III) chelates in anoxic conditions

Effect of Water Content on Properties of Homogeneous [bmim]Fe(III)Cl4–H2O Mixtures and Their Application in Oxidative Absorption of H2S

“…Therefore, it is likely that after oxidation of H 2 S, H + and Cl − present in homogeneous mixtures becomes HCl. The existence of HCl is also strengthened by Equation (5) Previous studies demonstrated that the oxidation of H 2 S by Fe 3+ or an iron(III) chelate is a fast chemical reaction [20,32]. As soon as H 2 S was absorbed, it was oxidized.…”

“…Even when the water content of the mixtures increases to 80%, the pH only reaches 1.17. However, a highly acidic environment was disadvantageous to the solubility of H 2 S [20,32]. Consequently, the weight percent of absorbed H 2 S in mixtures was very low in comparison with iron concentrations.…”

“…Table 1 shows an increase in weight percent of absorbed H2S and a decrease in volatile HCl emissions with increasing water concentration were seen. Previous studies demonstrated that the oxidation of H2S by Fe 3+ or an iron(III) chelate is a fast chemical reaction [20,32]. As soon as H2S was absorbed, it was oxidized.…”

“…Solution pH is widely recognized as a key variable for H2S oxidation process using iron chelates [20]. Acidity is also a key variable for oxidation of H2S by [bmim]Fe(III)Cl4 [21].…”

One-Electron Oxidation of Hydrogen Sulfide by a Stable Oxidant: Hexachloroiridate(IV)

“…Stock solutions of Na 2 S (pH > 12) were freshly prepared daily from sodium sulfide nonahydrate crystals after rinsing their surfaces to remove colored polysulfide impurities. These solutions were standardized with a UV–vis spectrometer at 230 nm (ε = 7910 M –1 cm –1 ) near pH 9.5 and protected from oxygen by bubbling with argon gas. Working solutions of Na 2 S were prepared by dilution of the stock solutions with deoxygenated water.…”