The effect of pH on thiosulfate formation in a biotechnological process for the removal of hydrogen sulfide from gas streams

P.L.F. van den Bosch, D.Y. Sorokin, C.J.N. Buisman, A.J.H. Janssen

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38 Citations (Scopus)

Abstract

In a biotechnological process for hydrogen sulfide (H2S) removal from gas streams, operating at natronophilic conditions, formation of thiosulfate (S2O32¿) is unfavorable, as it leads to a reduced sulfur production. Thiosulfate formation was studied in gas-lift bioreactors, using natronophilic biomass at [Na+]+[K+] = 2 mol L¿1. The results show that at sulfur producing conditions, selectivity for S2O32¿ formation mainly depends on the equilibrium between free sulfide (HS¿) and polysulfide (Sx2¿), which can be controlled via the pH. At pH 8.6, 21% of the total dissolved sulfide is present as Sx2¿ and selectivity for S2O32¿ formation is 3.9¿5.5%. At pH 10, 87% of the total dissolved sulfide is present as Sx2¿ and 20¿22% of the supplied H2S is converted to S2O32¿, independent of the H2S loading rate. Based on results of bioreactor experiments and biomass activity tests, a mechanistic model is proposed to describe the relation between S2O32¿ formation and pH.
Original languageEnglish
Pages (from-to)2637-2642
JournalEnvironmental Science and Technology
Volume42
Issue number7
DOIs
Publication statusPublished - 2008

Keywords

  • biologically produced sulfur
  • dissolved sodium sulfide
  • aqueous sulfide
  • alkaline conditions
  • oxidizing bacteria
  • soda lakes
  • oxidation
  • kinetics
  • polysulfide
  • autoxidation

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