Dry Scrubbing of Hydrogen Sulfide Gas Using Nano Zinc Oxide Coated Glass Beads

Hydrogen sulfide (H2S) is one of the most toxic and smelly gases emitted from animal production facilities, which also acts as a catalyst poison in many industrial processes. The principal objective of this research was to develop a dry scrubber to adsorb H2S gas efficiently from airstreams mimicking air exhausts of animal and poultry barns at the ambient atmospheric condition. Nano zinc oxide (nZnO) coated 3-mm sized glass beads were investigated to adsorb H2S gas in a vertical dry scrubber setting. Colloids of nZnO were prepared and thin films of nZnO were grown on the surfaces of commercially available glass beads following a sol-gel method. The sizes of nZnO on glass bead surfaces ranged from nm to µm and found to be clustered due to the repeated coatings on the same surfaces. The energy dispersion spectroscopy (EDS) analysis confirms the presence of sulfur (S) compound that indicated a conversion of H2S into zinc sulfide (ZnS) on nZnO coated bead surfaces. The highest H2S breakthrough capacity of 2.54 mg H2S g-1 sorbent was observed. Heating the beads at 550°C regenerated glass beads effectively but experienced a gradual loss of reactivity as a number of regeneration cycles progressed. This research demonstrated that nZnO supported on glass beads are promising adsorbents for capturing H2S gas from airstreams at ambient temperature. Keywords: Airstreams, Breakthrough capacity, Hydrogen sulfide, Nano zinc oxide, Regeneration.