New Amines for the Reversible Absorption of Carbon Dioxide from Gas Mixtures

Abstract

This chapter discusses the use of new amines as a medium for the capture of CO2 from a gas mixture. Anthropogenic carbon dioxide is considered to be the greenhouse gas that contributes most to global warming. Its concentration in the atmosphere is considerably increased and the control of CO2 immission has been agreed at the international level. The capture of carbon dioxide from flue gases may be used as a mitigation technology. Several technologies have been developed for separating carbon dioxide: absorption by liquid amines or solid materials, or membrane separation. The study was carried out comparing the absorption of carbon dioxide by two alkyl-di-amines with that of amines used so far at industrial level, namely mono-ethanolamine (MEA). A known mono silyl-alkyl-amine was also studied for comparison. The absorption of carbon dioxide was studied at different temperatures, in water solution, in organic solvents and using the neat amine. Several cycles of absorption/desorption were carded out. Xerogel solidified amines were also used. A separation technology can be exploited at industrial level if it is reliable and cheap. CO2 separation by amines is more economically convenient than the use of membranes. Therefore, the amount of CO2 absorbed per unit of absorbent is a key factor. Consequently, finding new amines able to capture a higher amount of carbon dioxide per mol has a great economic interest.