H2S(g) removal using a modified, low-pH liquid redox sulfur recovery (LRSR) process with electrochemical regeneration of the Fe catalyst couple

Youri Gendel, No'omi Levi, Ori Lahav*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

A modified pH 1.0 liquid redox sulfur recovery (LRSR) process, based on reactive absorption of H2S(g) in an acidic (pH 1.0) iron solution ([Fe(III)] = 9-8 g L-1, [Fe(II)] = 1-2 g L-1) and electrochemical regeneration of the Fe(III)/Fe(II) catalyst couple, is introduced. Fe(II) was oxidized in a flow-through electrolytic cell by Cl 2(aq) formed on a Ti/RuO2 anode. pH 1.0 was applied to retard the potential precipitation of predominantly jarosite group Fe(III) species. At pH 1.0, the presence of chloride ions at [Cl-] = 30 g L-1 allows for both efficient (indirect) electrochemical oxidation of Fe(II) and efficient H2S(g) reactive absorption. The latter observation was hypothesized to be associated with higher concentrations of Fe(III)-Cl complexes that are more highly reactive toward H2S (aq) than are free Fe(III) ions and Fe-SO4 complexes that otherwise dominate pH 1.0 Fe(III) solutions in the absence of a significant Cl-concentration. At the described operational conditions the rate of Fe(II) oxidation in the experimental system was 0.793 kg Fe h-1 per m2 anode surface area, at a current efficiency of 58%. Electricity cost within the electrochemical step was approximated at $0.9 per kg H2S(g) removed.

Original languageEnglish
Pages (from-to)8315-8319
Number of pages5
JournalEnvironmental Science & Technology
Volume43
Issue number21
DOIs
StatePublished - 1 Nov 2009
Externally publishedYes

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