Topological Interpenetrative Covalent Anchored Network (TIP CAN) for H2S Detection, Storage, and Remediation Relevance to Shipboard Wastewater

Hydrogen Sulfide (H2S) can be generated on ships from seawater with sulfates storage or oil-bilge tanks containing hydrocarbons with sulfur and sulfur-containing detergents or gray- and blackwater storage tanks, where H2S is generated microbiologically. This workplace hazard requires carefully venting these tanks before inspection and maintenance. Here we report the synthesis and evaluation of iron peroxide (FeOOH), silver reduced with ascorbate [Ag(ASC)], copper tricarboxylate metal–organic framework (CuMOF), chromium terephthalate metal–organic framework doped with silver [MIL101(Cr)Ag) or silver and magnesium [MIL101(Cr)AgMg] demonstrated excellent removal of H2S from an offline slurry reactor, eliminating 100% of 100 ppm H2S under 35 min, at 90 °F. The adsorbents were evaluated for different concentrations of H2S using pulsed injections. The time was taken to reach 0 ppm, including regeneration using hydrogen peroxide to oxidize the surfaces of this catalyst. Regeneration after 5 cycles showed H2S effectiveness of around 75% relative to the new catalyst averaged over the top five adsorbents. The sulfur binding capacity of at least 78 mg/g was shown, and a catalyst mass of even less than 100 mg was effective at removing 100 ppm of H2S. The slurry reactor workflow has the advantages of speed of operation, simplicity of design, and ease of use. It would suit a ship with a general crew who would not require a specialist degree to operate the offline slurry reactor to remove H2S. The kinetics of the reaction were modeled on a shrinking model, and the lowering of the effectiveness of H2S was attributed to the formation of elemental sulfur and sulfate indirectly confirmed using x-ray photon electron spectroscopy which could block active hydroxyl sites that are avenues for attracting the H2S molecule. The surface adsorption of H2S by the exchange with oxygen is suggested as the main mechanism whereby H2S is removed, followed by surface area and catalyst porosity. This study also suggests guidelines for developing filter-based ceramics that could be deployed on ships to remove H2S from tanks without venting or exposing the crew to possible exposure.