Publicação
Development of polymeric ionic liquid-based materials for CO2 capture and conversion: The ionic liquid tour through the periodic table
| Resumo: | The imperative of addressing CO2 capture and utilization arises from the pressing concerns surrounding global climate change. Existing commercial technologies for CO2 capture, either require substantial energy consumption or suffer performance degradation in the presence of impurities. Consequently, mitigating greenhouse gas emissions poses persistent challenges that call for advancements in materials and technologies. This study focused on developing highly regenerable materials tailored for CO2 capture and subsequent conversion into higher-value products, such as cyclic carbonates. The effectiveness of CO2 capture and utilization in ionic liquids (ILs) and poly(ILs) (PILs) depends on multiple factors including ion pair nature, anion basicity, buffering capacity, and hydrogen bond-forming sites, with no single property emerging as the most crucial due to their synergistic interplay, which illustrates the complexity of these materials. Herein, novel porous materials based on PILs-chitosan aerogels (AEROPILs) were successfully obtained, boasting high porosity and surface areas. PILs were incorporated into the aerogel matrix through a simple and straightforward procedure, advancing the aerogel formulation methodology. Generally, the inclusion of PILs in chitosan aerogels augmented the CO2 sorption capability of these materials, with the highest CO2 capture capacity observed for the pyrrolidinium-based AEROPIL (C:P230%) with 0.70 mmol g−1, at 25 °C and 1 bar. After evaluating CO2 capture capacity, AEROPILs were optimized as metal-free heterogeneous catalysts for CO2 conversion. In batch reactions, catalysts such as pyrrolidinium-based cross-linked AEROPIL (C:E:M1:P280%) and ammonium-based cross-linked AEROPIL (C:G:P430%) exhibited superior CO2 conversion capacities and high selectivity. Transitioning AEROPILs to continuous flow systems was explored as a pivotal step toward process scalability. Optimal reaction conditions were identified as a temperature of 120 °C, a liquid flow rate of 0.05 mL min-1, and a CO2 flow rate of 0.15 mL min-1. The most efficient catalyst, C:E:M1:P280%, demonstrated a noteworthy productivity of 21.18 gprod h-1 L-1 and maintained stability over 60 hours. Notably, the catalyst preserved its morphology and porosity, underscoring the feasibility of industrial-scale implementation of this process. |
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| Autores principais: | Barrulas, Raquel |
| Assunto: | Polymeric ionic liquids Chitosan Aerogels CO2 capture Catalysis |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | The imperative of addressing CO2 capture and utilization arises from the pressing concerns surrounding global climate change. Existing commercial technologies for CO2 capture, either require substantial energy consumption or suffer performance degradation in the presence of impurities. Consequently, mitigating greenhouse gas emissions poses persistent challenges that call for advancements in materials and technologies. This study focused on developing highly regenerable materials tailored for CO2 capture and subsequent conversion into higher-value products, such as cyclic carbonates. The effectiveness of CO2 capture and utilization in ionic liquids (ILs) and poly(ILs) (PILs) depends on multiple factors including ion pair nature, anion basicity, buffering capacity, and hydrogen bond-forming sites, with no single property emerging as the most crucial due to their synergistic interplay, which illustrates the complexity of these materials. Herein, novel porous materials based on PILs-chitosan aerogels (AEROPILs) were successfully obtained, boasting high porosity and surface areas. PILs were incorporated into the aerogel matrix through a simple and straightforward procedure, advancing the aerogel formulation methodology. Generally, the inclusion of PILs in chitosan aerogels augmented the CO2 sorption capability of these materials, with the highest CO2 capture capacity observed for the pyrrolidinium-based AEROPIL (C:P230%) with 0.70 mmol g−1, at 25 °C and 1 bar. After evaluating CO2 capture capacity, AEROPILs were optimized as metal-free heterogeneous catalysts for CO2 conversion. In batch reactions, catalysts such as pyrrolidinium-based cross-linked AEROPIL (C:E:M1:P280%) and ammonium-based cross-linked AEROPIL (C:G:P430%) exhibited superior CO2 conversion capacities and high selectivity. Transitioning AEROPILs to continuous flow systems was explored as a pivotal step toward process scalability. Optimal reaction conditions were identified as a temperature of 120 °C, a liquid flow rate of 0.05 mL min-1, and a CO2 flow rate of 0.15 mL min-1. The most efficient catalyst, C:E:M1:P280%, demonstrated a noteworthy productivity of 21.18 gprod h-1 L-1 and maintained stability over 60 hours. Notably, the catalyst preserved its morphology and porosity, underscoring the feasibility of industrial-scale implementation of this process. |
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