Metal organic framework derived NaCo(x)O(y) for room temperature hydrogen sulfide removal

Novel NaCo(x)O(y) adsorbents were fabricated by air calcination of (Na,Co)-organic frameworks at 700 °C. The NaCo(x)O(y) crystallized as hexagonal microsheets of 100–200 nm thickness with the presence of some polyhedral nanocrystals. The surface area was in the range of 1.15–1.90 m(2) g(−1). X-ray photoelectron spectroscopy (XPS) analysis confirmed Co(2+) and Co(3+) sites in MOFs, which were preserved in NaCo(x)O(y). The synthesized adsorbents were studied for room-temperature H(2)S removal in both dry and moist conditions. NaCo(x)O(y) adsorbents were found ~ 80 times better than the MOF precursors. The maximum adsorption capacity of 168.2 mg g(−1) was recorded for a 500 ppm H(2)S concentration flowing at a rate of 0.1 L min(−1). The adsorption capacity decreased in the moist condition due to the competitive nature of water molecules for the H(2)S-binding sites. The PXRD analysis predicted Co(3)S(4), CoSO(4), Co(3)O(4), and Co(OH)(2) in the H(2)S-exposed sample. The XPS analysis confirmed the formation of sulfide, sulfur, and sulfate as the products of H(2)S oxidation at room temperature. The work reported here is the first study on the use of NaCo(x)O(y) type materials for H(2)S remediation.