The structural feature of Ni–Al-LDH nanosheets and their adsorption performance for ethyl mercaptan from methane gas

Abstract

Two-dimensional nanomaterials of Ni–Al layered double hydroxide nanosheets (Ni–Al-LDH-NS) were fabricated using an exfoliation process with formamide as the pillaring agent. XRD, FT-IR, LRS, N₂ adsorption–desorption, XPS, and SEM were used to study their structure and morphology. The adsorption of ethyl mercaptan (EM) on Ni–Al-LDH-NS was investigated by an adsorption experiment on a fixed bed adsorption apparatus and density functional theory calculations (DFT). The characterization analysis indicates that Ni–Al-LDH-NS presents a uniform sheet structure with a specific surface area of 266.94 m² g⁻¹. An EM breakthrough adsorption capacity up to 229.95 mg g⁻¹ was found in the absorption experiment using the Ni–Al-LDH-NS. DFT calculations indicate that EM is mainly adsorbed on Ni–Al-LDH-NS through coordination bonds, in which the S → Ni coordination bond plays a major role, and its coordination bonds interact with the Ni 3d orbital through the S 3p orbital. In addition, differences in adsorption performance between Ni–Ti-LDH-NS and Ni–Al-LDH-NS were investigated via studying host–guest interactions and structural properties.