Korean Journal of Chemical Engineering, Vol.33, No.8, 2384-2391, August, 2016
Chelate-modified fenton treatment of sulfidic spent caustic
Spent caustic can be treated by several treatment methods. Among the advanced techniques, Fenton reagent has many advantages. But since spent caustic contains excessive amounts of sulfide compounds, utilizing this technique in treatment of such wastewaters is not economical. The acid neutralization step, which was applied as the pretreatment process, showed an 84% COD abatement at temperature equal to 80 ℃ and a pH equal to 4.0. The acid neutralized wastewater was then introduced to the chelate-modified Fenton system and oxidized. Using a ratio of tartrate/Fe2+=1.1, reaction time=50min, temperature=95 ℃, Fe2+=110mg/l and a ratio of H2O2/COD=1.2 in the chelatemodified Fenton system at an optimum pH value equal to 1.9, total COD abatement of the wastewater reached over 99.4%. Having tartrate added to the Fenton system, a series of photochemical reactions enhanced Fe2+ and hydroxyl radicals’ generation. This method has proved to be the recommended technique for the contamination abatement of spent caustic.
Keywords:Chelate-modified Fenton Reagent;Fractional Factorial Design;Peroxidation;Tartrate;Spent Caustic