Metal-organic framework-derived NaMxOy adsorbents for low-temperature SO2 removal

• Published in: Chemosphere (Oxford) Vol. 291; p. 132836
• Main Authors: Gupta, Nishesh Kumar, Bae, Jiyeol, Baek, Soyoung, Kim, Kwang Soo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2022
• Subjects: Air decontamination; Bimetallic oxides; MOF-Derived; Oxidation; Sulfur dioxide; Bimetallic oxides; Oxidation; MOF-Derived; Sulfur dioxide; Air decontamination
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.132836

This work reported the fabrication of NaMxOy-type adsorbents from air calcination of (Na, M)-trimesate metal-organic frameworks. NaMnxOy (NMO) crystallized as disc-shaped microsheets, whereas NaCoxOy (NCO) crystallized as smooth microsheets with surface deposition of polyhedral nanoparticles. The oxides have a surface area of 1.90–2.56 m2 g−1. The synthesized adsorbents were studied for low-temperature SO2 removal in breakthrough studies. The maximum adsorption capacity of 46.8 mg g−1 was recorded for NMO at 70 °C. The adsorption capacity increased with the increasing temperature due to the chemisorptive nature of the adsorption process. The capacity increased with the increasing bed loading and decreasing flow rate due to the improved SO2 retention time. The elemental mapping confirmed the uniform distribution of sulfur species over the oxide surface. X-ray diffraction showed the absence of metal sulfate nanoparticles in the SO2-exposed samples. The X-ray photoelectron analysis confirmed the formation of surface sulfate and bisulfate. The formation of oxidized sulfur species was mediated by hydroxyl groups over NMO and lattice oxygen over NCO. Thus, the work demonstrated here is the first such report on the use of NaMxOy-type materials for SO2 mineralization. [Display omitted] •NaMxOy microsheets fabricated from calcination of bimetallic MOFs.•The maximum adsorption capacity of 46.8 mg g−1.•XPS analysis confirmed sulfate and bisulfate as SO2 oxidation products.•SO2 oxidation over NMO and NCO occurred through the hydroxyl group and lattice oxygen, respectively.