Preparation of CuFe2O4-MOF hybrid materials and their adsorption properties for H2S

Abstract

Hydrogen sulfide (H2S) is one of the major environmental pollutants, and it is one of the most dangerous by-products of oil and gas industry. Therefore, the removal and monitoring of H2S for has gained considerable attention for environmental protection and safety. The main objective of this research was to study the H2S adsorption capacities of several adsorbent materials: copper ferrite, zeolitic imidazolate frameworks-8, and zeolitic imidazolate frameworks-67 nanoparticles. In this research, CuFe2O4, P0.1Cu0.9Fe2O4, ZIF-8, ZIF-67, and their hybrid materials (CuFe2O4@ZIF-8, CuFe2O4@ZIF-67, and P0.1Cu0.9Fe2O4@ZIF-8) were successfully synthesized using different synthesis procedures to investigate the effect of these procedures on the materials properties. The synthesized materials were characterized using various techniques including X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Transmission Electron Microscopy (TEM). The crystallinity, structure, and composition of all the samples were confirmed using XRD, FTIR and EDX. The SEM images indicated that the CuFe2O4 nanoparticles exhibited porous sponge-like morphologies, while the ZIFs particles revealed nanocrystals with rhombic dodecahedral structures. The HR-TEM analysis of hybrid material CuFe2O4@ZIF-8, prepared in heated water, revealed that CuFe2O4 nanoparticles were successfully encapsulated (as cores) in ZIF-8. This hybrid material showed the highest H2S adsorption capacity compared to the other materials, along with a remarkable breakthrough curve. This is possibly due to the combined effect of both CuFe2O4 and ZIF-8 in the core-shell structure of CuFe2O4@ZIF-8. The H2S adsorption capacities were investigated at two temperatures, 25°C and 150°C. For example, the H2S capacity of CuFe2O4 was found to be 3.610 mmol/g at 150°C compared to 0.387 mmol/g at 25°C. On the other hand, the performance of ZIF-67 was not affected by the temperature change, showing 0.161 mmol/g at 150°C and 0.147 mmol/g at 25°C. The higher adsorption capacity of CuFe2O4 at 150°C compared to that at 25°C indicates that the adsorption process is not thermodynamically controlled. The obtained ZIFs breakthrough curves suggested the occurrence of a chemical reaction on the ZIFs surfaces during the H2S adsorption process. Indeed, the gas chromatography measurements revealed the formation SO2 gas due to H2S oxidation during the adsorption experiments.

Date of Award	May 2020
Original language	American English