Enhanced removal of hydrogen sulfide using novel nanofluid system composed of deep eutectic solvent and Cu nanoparticles.

The H2S removal performances of four deep eutectic solvent (DES) based nanofluid (NF) systems were measured using dynamic absorption experiment. The Cu containing NF system is found to be an excellent absorbent for H2S removal with a significantly enhanced desulfurization performance compared with DES original solution. Besides, the NF systems have relatively high regeneration performance. The NF systems and Cu nanoparticles before and after absorption as well as after regeneration were characterized by Fourier transform infrared (FT-IR) spectra, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrum (EDS). It is found that the ethanolamine, choline cation and sulfur were accumulated on the surface of Cu nanoparticles after absorption, and the bulk elements on the surface were identified as Cu and S after regeneration. The S-2 was existed in the form of Cu2S, and some sulfur was oxidized to zero-valent sulfur after regeneration.