Development of PRIDES – PolymeRIc Deep Eutectic Solvents – for CO2 capture

• Autor(a) principal: Nunes, Débora Clemêncio
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/113517
• topic: CO2 capture; Nuclear Magnetic Resonance Spectroscopy (NMR); Deep Eutectic Solvents (DES); Polymeric Deep Eutectic Solvents (PRIDES); Chitosan; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

One of the main reasons attributed to the climate changes occurring in our planet in recent years is the increase in carbon dioxide emissions resulting from human activity. Since the Industrial Revolution (XVIII century), fossil fuels have played a central role in energy production, which has led to a sharp increase in CO2 emissions, whose concentration went from 280 ppm, in 1750, to the 410 ppm currently found. To minimize the presence of CO2 in the atmosphere, there are several possible strategies, from the search for alternative energy sources, and/or the implementation of technologies to capture and convert the gas during its release. There are currently several technologies for this purpose in different stages of development, including membranes, solid adsorbents and chemical/physical absorbents. Chemical absorbents are currently the most widely used, namely aqueous solutions of monoethanolamine (MEA), however, their corrosive properties and high energy expenditure to carry out recycling, have motivated the search for alternative solutions. One of the alternatives to the use of amines is the use of non-conventional solvents such as Ionic Liquids (ILs) and Deep Eutectic Solvents (DES). The main objectives of this work were to develop Polymeric Deep Eutectic Solvents (PRIDES) and explore their use for CO2 capture, by themselves or in a hybrid system with a biopolymer (chitosan) using Nuclear Magnetic Resonance spectroscopy (NMR) techniques both to study intermolecular interactions and for quantification of captured CO2. The PRIDES system that showed the best results for CO2 capture at atmospheric pressure and temperature was the aqueous solution of tetrabutylammonium bromide (TBAB) with polyethylene glycol 200 (PEG) at 25% w/w, with a capture of 120.44 mmol CO2/Kg DES. The hybrid system which showed the best performance was PRIDES composed of choline chloride, glycerol and citric acid, which presents the best compromise between chitosan solubilization/CO2 capture. A 25% w/w aqueous solution of this system showed to solubilize a maximum of 8% w/w of chitosan and obtained a CO2 capture of 106.35 mmol CO2/Kg DES. This ternary eutectic system in the presence of 1% w/w chitosan reveals the best results of CO2 capture at a pressure of 10 bar (768.74 mmol CO2/Kg DES), but at atmospheric pressure, with CO2 flow,for the capture of CO2, the best results were obtained in the absence of biopolymer (110.11 mmol CO2/Kg DES). This seminal study allowed a proof of concept for new CO2 capture materials, starting from more sustainable compounds that could be an alternative to the solutions currently available.