Influence of NH2-MOF addition into PVDF and estimation of CO2 gas transport through membrane

Abstract

Polyvinylidene fluoride (PVDF) had been vastly utilised for CO2/CH4 gas separation application. Nevertheless, pure polymeric membranes always suffer from a trade-off between permeability and selectivity as proven by Robeson in upper bound curves developed in gas separation applications. Thus, alternative modification like incorporating filler into polymer matrix to develop mixed matrix membranes (MMMs) is required. Besides, estimation of CO2 permeance of MMMs via unsuitable theoretical models would result in mismatch between experimental and predicted CO2 permeance data, subsequently causing troubles in membrane separation system designation. In the current work, PVDF hollow fiber mixed matrix membranes (HFMMMs) had been developed using NH2-MIL-125 (Ti) loadings of 1, 1.5, 2.5, and 3 wt%. The synthesized NH2-MIL-125 (Ti) and spun NH2-MIL-125 (Ti)/PVDF HFMMMs were characterized using Fourier transform infrared (FTIR). Furthermore, the Maxwell, Pal, modified Pal, Lewis–Nielson, Bruggeman and Bottcher model, were utilised to estimate the CO2 permeance of developed membranes. The additional FTIR peaks appeared at around 3440, 3358, 1478, 1430 cm−1 for developed HFMMMs when compared with pure PVDF indicate the presence of NH2-MIL-125 (Ti) in the HFMMMs. CO2 permeance estimation of 1.5 wt% PVDF HFMMM using all selected models yields around 1 absolute average relative error percent (AARE%). The remaining membranes displayed a high deviation, with an AARE% exceeding ± 5. AARE% obtained in the current work suggested that all the selected models can fit 1.5 wt% PVDF HFMMM.