Selective Adsorption of CH₄/N₂ on Ni-based MOF/SBA-15 Composite Materials.

Hong Liu,Xupei Tian,Wei Ding,Fubao Zhou,Shaohua Lei

doi:10.3390/nano9020149

Abstract

Spherical SBA-15-based metal–organic framework (MOF) composite materials were prepared, with nickel as the metal center of MOFs. The materials were characterized via scanning electron microscopy, X-ray fluorescence analysis, X-ray powder diffraction, Fourier-transform infrared spectroscopy, and nitrogen (N2) adsorption–desorption. The methane (CH4) or N2 high-pressure adsorption isotherms of the samples were measured and compared. The specific surface area and adsorption capacity of the composite materials were generally higher than the pristine MOFs, but were much lower than the synthesized SBA-15. The selectivity of the samples toward a binary gas mixture was determined from the Langmuir adsorption equation. The results revealed that, of all the samples, the MOF-2/SBA-15 sample had the best CH4/N2 adsorption selectivity, with an adsorption selection parameter (S) of 11.1. However, the adsorption of MOF-2/SBA-15 was less than that of spherical SBA-15, due to partial plugging of the pores during the synthesis process. Further research is essential for improving the performance of spherical SBA-15-based MOF materials and (in turn) the enrichment of CH4 from the CH4/N2 mixture.

Highlights

Interest in clean energy research has increased owing to the growing threat of global warming resulting from the harmful emissions of greenhouse gases
Coalbed methane (CBM), a type of natural gas adsorbed onto coalbed with huge reserves, consists mainly of methane and nitrogen (N2), and contains minor components such as carbon dioxide (CO2) and water [2]
The concentration of methane plays a vital role in the selection of the CBM approach utilized [3], and an extremely low concentration would limit this utilization

Summary

Introduction

Interest in clean energy research has increased owing to the growing threat of global warming resulting from the harmful emissions of greenhouse gases. Coalbed methane (CBM), a type of natural gas adsorbed onto coalbed with huge reserves, consists mainly of methane and nitrogen (N2), and contains minor components such as carbon dioxide (CO2) and water [2]. Ventilation air methane is usually released directly into the atmosphere, as technology for its use is lacking, which results in a serious greenhouse effect [4]. High-efficiency enrichment and application of methane from low-concentration CBM is essential for remitting the worrisome energy crisis, and could reduce greenhouse gas emissions, with great comprehensive benefits for energy, environmental protection, and society. The separation of methane and nitrogen is the most difficult and important step for the enrichment of low-concentration CBM, because the two components are similar in kinetic diameter (0.381 and 0.364 nm) and their critical temperatures are very low

Methods

Results

Conclusion