Jong Kyun You

Characteristics of CO2 absorption into aqueous ammonia

Abstract Aqueous ammonia was investigated as a new absorbent of the chemical absorption process for CO2 capture from combustion flue gas. The effects of the temperature and concentration of aqueous ammonia on CO2 absorption in a semi‐batch reactor were studied by interpreting breakthrough curves. Raman spectroscopy analysis of CO2 loaded aqueous ammonia provided concentration changes of bicarbonate, carbonate, and carbamate as well as CO2 sorption capacity at given time during the absorption with 13 wt% aqueous ammonia at 25°C. It was observed that carbamate formation was dominating at the early stage of absorption. Then, the bicarbonate formation took over the domination at the later stage while the carbonate remained unchanged.

Influence of Additives Including Amine and Hydroxyl Groups on Aqueous Ammonia Absorbent for CO2 Capture

Aqueous ammonia absorbent (10 wt %) was modified with four kinds of additives (1 wt %) including amine and hydroxyl groups, i.e., 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-methyl-1,3-propandiol (AMPD), 2-amino-2-ethyl-1,3-propandiol (AEPD), and tri(hydroxymethyl) aminomethane (THAM), for CO(2) capture. The loss of ammonia by vaporization was reduced by additives, whereas the removal efficiency of CO(2) was slightly improved. These results were attributed to the interactions between ammonia and additives or absorbents and CO(2) via hydrogen bonding, as verified by FT-IR spectra and computational calculation. Molecular structures as well as binding energies were obtained from the geometries of (ammonia + additives) and (ammonia + additives + CO(2)) at the optimized state. These experimental and theoretical findings demonstrate that additives including amine and hydroxyl group are suitable for modifying aqueous ammonia absorbent for CO(2) removal.

Analysis of the CO2 and NH3 Reaction in an Aqueous Solution by 2D IR COS : Formation of Bicarbonate and Carbamate

The two-dimensional (2D) infrared correlation spectra obtained from the reaction time- and concentration-dependent IR spectra elucidates the reaction of CO2 and NH3 in an aqueous solution for CO2 absorption. In the synchronous 2D correlation spectra, the interrelation of the proton with carbamate and bicarbonate indicates that the pH level affected the formation reactions of the two products. Furthermore, the interrelation of carbamate with bicarbonate confirmed the conversion of carbamate into bicarbonate with the release of protons (or the decrease of the pH). From the experimental results including the asynchronous 2D correlation spectra, the reaction of the CO2 and aqueous ammonia proceeded through the following steps: formation of carbamate, formation of bicarbonate, release of protons, and conversion of carbamate into bicarbonate. The analysis of the formation of carbamate and bicarbonate by 2D infrared correlation spectroscopy provides useful information on the reaction mechanism of CO2 and NH3 in aqueous solutions.

Phase separation characteristics in biphasic solvents based on mutually miscible amines for energy efficient CO2 capture

One of the challenges with regard to the aqueous amine-based CO2 capture process is the considerable energy requirement for solvent regeneration. To overcome this challenge, a biphasic solvent was employed in this study. Here, the phase separation behavior of amine blends depending on the characteristic structures of the solvent component was investigated using a turbidity measurement apparatus. Amines were classified as (1) primary/secondary amines or tertiary/sterically hindered amines depending on the CO2 reaction species, such as carbamate and bicarbonate (2) alkyl and alkanolamines, depending on the presence of a hydroxyl group, (3) chain and cyclic amines, and (4) mono- and polyamines depending on the molecular structure. Easy phase separation occurred in solvent blends containing polyamines such as DETA (diethylenetriamine), TETA (triethylenetetramine), and DEEA (2-(diethylamino) ethanol). The types with the greatest potential were the DETA/DEEA blended solvents. A phase separation could be determined based on the difference in the reaction rate with CO2 and the low solubility between the carbamate species of DETA and DEEA.

Sample Clean-up of Red Fluorescent Protein for Analysis Using Electric Field in Microfluidic Device

Microfluidic technology allows the design and operation of effective and simple devices for sample preparation and cleanup. Majority of current sample preparation methods is focused on the complex and combined steps such as solid phase extraction and membrane dialysis. In addition, it is generally recognized that sample treatment often is the bottleneck for the rapid analysis of protein due to performing off-chip in many cases. In this study, for an effective cleaning of protein from a urea-rich protein sample, electro-microfluidic desalting system was applied using the charge characteristics of protein.

1D and 3D Shaped Ionic Liquid/Aluminum Hydroxide Nanohybrids for Electrochemical Device

In this research, ionic liquids are considered as multifunctional components by employing not only templates and co-solvents for fabricating nanostructured materials but also proton conductors for electrochemical devices. Two ionic liquid-aluminum hydroxide nanohybrids obtaining 1D and 3D shape were synthesized via a one-pot ionothermal process. The shape-controlled nanohybrids are expected to be a strong candidate for electrochemical device in terms of reasonable ionic conductivity and thermal stability as a result of the one-pot assembled nano-confinements.