Hydrosulphide oxidation pathways in oxic alkaline media containing iron/cerium oxide‐hydroxide

Abstract

The oxidation kinetics of hydrosulphide by iron/cerium oxide‐hydroxide (FeCeOx) and dissolved oxygen (DO2) was studied at 0.1 MPa and 298 K in a batch slurry reactor. The oxidation of hydrosulphide by the FeCeOx/DO2 system proceeded via a combined heterogeneous–homogeneous pathway to yield zerovalent sulphur and thiosulphate. The role of dissolved oxygen was twofold: (i) it reoxidized the iron from Fe(II) to active Fe(III), (ii) it prompted the homogeneous oxidation of hydrosulphide to polysulphides and of polysulphides to thiosulphate. The Fe(III) in situ regeneration by DO2 showed that FeCeOx holds promise for a redox scrubbing process targeting the elimination of H2S from the Kraft mill effluents.

Advances in Chemical Oxidation of Total Reduced Sulfur from Kraft Mills Atmospheric Effluents

“…In oxic conditions, Petre and Larachi (2007d) reported that the oxidation of HSby the Fe/CeOx0.9/DO 2 system proceeded with conversions up to 100% to yield zerovalent sulfur and thiosulfate. The role of DO 2 was found to be twofold: i) it reoxidized the ferrous iron (via Eq.6), yielded from HSoxidation, to replenish the surface with Fe(III) sites for restoring full oxidative capability of the material towards HS -, ii) it prompted the homogeneous oxidation of HSto polysulfides and of polysulfides to thiosulfate (see Section 4.4).…”

“…Based on their experimental observations, Petre and Larachi (2007d) proposed a simple kinetic model depicting the early 20 min of the global reaction between HSand Fe/CeOx0.9 in presence of oxygen. The model is adapted on the HSanoxic heterogeneous oxidation kinetics (Eq.…”