(138f) Measurements of Carbon Dioxide Capture in Various Amines-Ionic Liquids-Water Systems

With the situation of world wide climate change becoming more and more severe, hunting for the new solvent of high efficiency, low energy consumption and environment-friend to capture carbon dioxide (CO2) from coal industries, petrol industries, and other CO2 emission industries turns to be a crucial task. As known, CO2 could be used in many fields, for instance, refrigeration, farming and synthesis of amines and urea industries. Nowadays, the main and effective method for CO2 capture is based on the chemical absorption and this method could fix much more CO2 quickly. The primary chemical absorbents are monoethanolamine (MEA), methylethanolamine (MDEA), diethonalamine (DEA), and triethonalamine (TEA) or mixtures of them. However, there are some shortcomings of these chemical absorbents, such as corrosion, volatility, toxicity and high energy consumption, which make it necessary to design and synthesize a novel and more effective system to scrub CO2. Ionic liquids, as a new kind of low melting point salt, are focused on by many scientific researchers as their outstanding advantages for CO2 capture: low energy consumption, low pollution level and recyclable properties. However, considering their CO2 absorption abilities, most of ionic liquids could fix less CO2 than that of in amines absorption systems. Recently, in light of CO2 capture properties of amines and ionic liquids, some researchers pay more attentions on the new composite solvents containing amines and ionic liquids. It is reported that these composite systems could fix more CO2 due to the function of amines and be easy to be regenerated because of the existence of ionic liquids and low concentration of water, which means low energy will be used. The conventional ionic liquids, BmimBF4, BmimPF6 and BmimCl, are added into amines to form composite capture systems, and some satisfactory results are obtained in our past work. However, price of these ionic liquids is too high, so cheap and effective ionic liquids, monoethanolamine fluoroborate (MEABF4), N-methyl-diethanolamine fluoroborate (MDEABF4), N-methyl-diethanolamine sulfate (MDEASO4), N-methyl-diethanolamine phosphate (MDEAPO4), and N-methyl-diethanolamine hydrochloride (MDEACl), are synthesized in our lab to form composite absorbents to capture CO2. In this work, amounts of further experiments have been carried out at pressure ranging from 0.00-9.00MPa and temperature between 10°C and 90°C, and some expected results have already been obtained. The main composite solvent systems compounded by amines and ionic liquids are investigated, which performs an effective activity in capturing CO2. 1.000g solvent could absorb as high as 0.158g CO2 in 500 minutes at average by some capture systems. Thermodynamics properties of the various systems are also accurately measured. It is also shown in the research that the captured CO2 could be released very easily from the composite systems, which means less energy will be needed in the regeneration process of absorbents. Besides, CO2 absorption and desorption mechanisms of amines and ionic liquids is also studied in this work. Some new and reasonable mechanisms are discovered according to the characterization results of absorption systems before and after CO2 capture. Keywords: Amines, Ionic Liquids, Carbon Dioxide Capture