Metal organic framework derived NaCoxOy for room temperature hydrogen sulfide removal
Nishesh Kumar Gupta, Jiyeol Bae, Kwang Soo Kim
Abstract
Abstract 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.