Poly(ethylene glycol) diacrylate Iongel membranes reinforced with nanoclays for CO2 separation

• Autor(a) principal: Francisco, Rute Rita Mendes Cancela Oliveira
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/127531
• topic: Iongel membranes; Ionic Liquids; UV cross-linked polymer network; Montmo-rillonite nanoclay; CO2 separation; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

The continuous consumption of fossil fuels has elevated the concentration of carbon dioxide (CO2) in the atmosphere with severe consequences for the environment. Membrane technology emerged as a potential solution to separate CO2 from light gases, contributing to Carbon Capture and Storage (CCS). Within the several materials studied for the preparation of membranes, ionic liquids (ILs) are some of the most interesting, mainly due to their tunable properties and good affinity towards CO2. In this line, iongel membranes combining high IL loadings (≥ 60 wt%) incorporated into a poly(ethylene glycol) (PEG) based polymer network cross-linked by ultraviolet (UV) radiation have been developed. One of the main challenges faced when fabricating these iongel membranes is their limited mechanical resistance due to a gel-like nature, which becomes more accentuated when the concentration of IL increases. To overcome this problem, the addition of low amounts of nanoclay particles (≤ 1 wt%) into the iongel membranes is suggested in this work as a way to reinforce their structure. Self-standing iongel mixed matrix membranes (MMMs) that were solid yet malleable were prepared in a simple single-pot with different loadings (from 0.2 to 1.0 wt%) of mont-morillonite (MMT) nanoclay particles. The iongel MMMs were characterized by several tech-niques, including attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectros-copy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), differential scan-ning calorimetry (DSC), contact angle and puncture tests in order to assess how their proper-ties affect the CO2 separation performance from nitrogen (N2) and methane (CH4) in pure gas permeation experiments and evaluate their potential to be applied in post-combustion streams and biogas upgrading. The characterization results revealed that the iongel MMMs can withstand temperatures typical of post-combustion streams (around 120 ºC) and that the incorporation of MMT did not have a significant impact on the permeability/selectivity, crystallinity, and hydrophilicity of the iongel MMMs. On the other hand, a concentration of 0.2 wt% MMT evenly dispersed into an iongel MMM was able to increase the mechanical resistance up to 30%, which suggests that future studies focused on the optimization of the preparation of these membranes may allow the addition of higher IL loadings for better CO2 separation performance while the me-chanical stability is maintained.