Treatment of Thiols in a GAS Stream Using Adsorption with Electrochemical Regeneration

Abstract

This communication investigates the use of a non-porous, graphite intercalation compound adsorbent for the treatment of malodorous sulfur containing gases by adsorption followed by electrochemical regeneration. Molecular weight was shown to be an important factor for adsorption with breakthrough time increasing as molecular weight increased. The largest thiol studied, sec-butanethiol, had an adsorptive capacity of the order of 0.03 mg · g⁻¹ and showed unfavorable isotherm characteristics. The oxidation of aqueous phase thiols was studied in an electrochemical cell with the adsorbent forming a three-dimensional anode. The oxidation charge efficiency in terms of chemical oxygen demand was measured for sec-butanthiol and was shown to be approximately 5.5%. A mathematical model of the process concluded that the process in this configuration would not be economical for general application but the concept merited further investigation for the selective removal of higher molecular weight contaminants.

Keywords:

• Adsorption
• Electrochemical regeneration
• Mercaptans
• Nyex