Fabrication of multilayer composite hollow fiber membrane comprising NH2-MIL-125 (Ti) for CO2 removal from CH4

Abstract

The presence of CO2 has created significant challenges in natural gas processing in order to meet consumer's specifications and pipeline transportation. Membrane separation is among the most effective approaches in CO2 separation from natural gas mainly to its energy efficiency. This study investigates the alternate technique for enhancing the performance of hollow fiber membrane in CO2 removal from CH4. A new type of composite hollow fiber membrane is fabricated by dip-coating of polymer solution comprising various loadings of NH2-MIL-125 (Ti) in PEBAX onto PDMS coated-polysulfone (PSf) hollow fiber. The morphology and elemental mapping analysis of the resultant membranes were characterized via scanning electron microscope (SEM) and energy dispersive X-ray (EDX), respectively. SEM images showed that no major voids or clusters were observed between the two phases of polymer and filler. Improved CO2 and CH4 gas permeance were found for composite membranes, as compared to PSf membrane coated only by PDMS and PEBAX solutions. Besides, highest improvement of CO2/CH4 ideal selectivity was obtained for composite membrane loaded with 10 wt% of filler. High porosity and high CO2 affinity of NH2-MIL- 125 (Ti) are the main reasons for the enhancement of CO2 removal from CH4. Hence, further research work is necessary to explore the performance of this membrane at various operating conditions such as temperature, flow rate, and CO2 feed concentration.