Redox performance of trivalent iron iminodisuccinic acid in converting hydrogen sulfide to sulfur: A new complexed iron catalyst

Abstract

A novel iron complex formed with tetrapotassium iminodisuccinate (IDSK4) was developed for catalytic conversion of hydrogen sulfide from industrial gases to monomeric sulfur, and a small-scale apparatus for the conversion of hydrogen sulfide in the laboratory was set up.The voltammetric curves of the system were generated with an electrochemical workstation, which indicated a quasireversible process. The catalytic capacity of the catalyst was saturated at 93.8% of the theoretical value for the trivalent iron complex.The open-circuit potential of the system was in the range −0.3 to −0.2 V, which provided full conversion of hydrogen sulfide, and after regeneration by air, it was restored to the initial potential.Full-cycle experiments showed that with increasing numbers of cycles, the open-circuit potential of the regenerated system was not fully restored to the initial value, thus requiring the design of a continuous absorption–regeneration system for industrial use. For safe treatment of hydrogen sulfide in industrial exhaust gases, a single-tower unit with absorption–regeneration cycles was used, and for safe treatment of hydrogen sulfide in combustible industrial gases, a double-tower unit with absorption–regeneration separation was used. The oxidation performance of the system was quickly monitored by measuring the open-circuit potential.