New strategies for treatment and reuse of spent sulfidic caustic stream from petroleum industry

Abstract

This work examines traditional and new routes for removal of H 2S and other sulfur compounds from spent sufidic caustic (SSC). SH- (hydrogenosulfide) and S 2- (sulfide) ions were quantitatively oxidized at 25 °C using H 2O 2, NaOCl or a spent sulfochromic mixture. SH-/S 2- ions were also removed via reaction with freshly prepared iron or manganese hydroxides, or after passing the SSC through strong basic anion exchange resins (OH- form). The treated caustic solution, as well as iron/manganese hydroxides, removed H 2S from diesel samples at 25 °C. SSC treatment via strong basic anion-exchange resins produced the treated caustic solution with the highest free alkalinity.