Sulfur dioxide gas adsorption over ZnO/Zn-based metal-organic framework nanocomposites

We have reported the fabrication of ZnO and Zn-based metal-organic framework (ZnO/Zn-MOF) nanocomposites via a rapid sonication method. The synthesized nanocomposites had ZnO nanoparticles dispersed over the MOF surface. The surface area of nanocomposites was in the range of 12.4–20.6 m2 g−1. These nanocomposites were used for SO2 removal in ambient conditions, where the maximum adsorption capacity of 31.0 mg g−1 was achieved. The adsorption capacity was found to decrease with the increasing temperature due to the removal of adsorbed water and molecular oxygen, which were required for SO2 oxidation after the adsorption process. The elemental mapping confirmed sulfur species over the adsorbent with significant morphological changes. The X-ray diffraction pattern suggested the formation of zinc hydroxide sulfate phases. The sulfate presence in the composite was further confirmed by X-ray photoelectron spectroscopy. Thus, we have reported the room-temperature conversion of toxic SO2 gas to sulfates over ZnO/Zn-MOF nanocomposites.