Bimetallic Ag–Cu-trimesate metal–organic framework for hydrogen sulfide removal

Abstract

Here, we have fabricated a bimetallic Ag–Cu-trimesate metal–organic framework at room temperature. The MOF showed rod-like morphology with a uniform distribution of Ag and Cu-sites in the MOF. The MOF has a surface area of 27.2 m² g⁻¹ with a mean pore diameter of 3.8 nm. The X-ray photoelectron (XPS) analysis confirmed the presence of Ag(I), Cu(I), and Cu(II) sites in the MOF. Moreover, a minor fraction of Ag as Ag⁰ (27.2%) was confirmed due to the reductive effect of DMF solvent. The synthesized MOF was tested for H₂S removal under ambient conditions, where a maximum adsorption capacity of 69.7 mg g⁻¹ was achieved. A novel regeneration method based on H₂O₂ solution partially regenerated the MOF. The diffraction pattern predicted the exceptional stability of the MOF after the adsorption–regeneration process. The XPS analysis confirmed sulfate/bisulfate (82.6%) and sulfide (17.4%) as the H₂S adsorption/oxidation species. The regeneration process involved the oxidation of Ag⁰ and Cu(I), which resulted in appreciable adsorption capacity in the subsequent cycles. Thus, we have reported a new and economical synthesis of bimetallic MOFs and a method for the partial regeneration of the spent MOF.