An improved CO2 sequestration method is proposed that uses new catalysts, specifically a series of tertiary amine nitrate salts, in an aqueous tertiary amine medium.

Nirmala Grace A

Centre for Nanotechnology Research

Vellore Campus

Sivanesan D

Kim Y.E

Youn M.H

Park K.T

Kim H.-J

Jeong S.K.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

RSC Advances

Amine-based postcombustion CO2 capture technology has a great potential to control CO2 emissions but is expensive because a huge amount of thermal energy is required for solvent regeneration due to poor CO2 desorption kinetics. Tertiary amines can be efficiently regenerated, but the poor CO2 absorption kinetics are a major limitation to its large-scale deployment. Here, we synthesized tripodal nitrate salt and its metal catalysts and investigated catalytic activity in a highly concentrated tertiary amine medium, N-methyldiethanolamine (MDEA), for the CO2 capture process. To analyze the catalytic performance, the rate constant for CO2 hydration, CO2 absorption rate, and CO2 desorption rate were experimentally studied. The gathered results suggest that catalyst 2 can improve the CO2 absorption and CO2 desorption efficiencies by 35% and 21%, respectively. On the basis of the obtained results, the possible reaction mechanism is also presented. These findings can provide a new route for energy-efficient CO2 capture using tertiary amines. © 2019 American Chemical Society.

ACS Sustainable Chemistry & Engineering

Catalytic Characteristics of Metal Catalysts and Nitrate Salt of a Tripodal Ligand in a Basic Medium for Postcombustion CO2 Capture Process

Globally, the elevation of carbon dioxide (CO2) levels due to the anthropogenic effect poses a serious threat to the ecosystem. Hence, it is important to control and/or mitigate the level of CO2 in the atmosphere, which necessitates novel tools. Herein, it is proposed to improve CO2 sequestration by using model complexes based on the enzyme carbonic anhydrase (CA) in aqueous tertiary amine medium. The effect of substituents on the model CA model complexes on CO2 absorption and desorption was determined by using a stopped-flow spectrophotometer to follow pH changes through coupling to pH indicator and a continuous stirred-tank reactor (CSTR). The CO2 hydration rate constants were determined under basic conditions and compound 6, which contained a hydrophilic group, showed the highest absorption or hydration levels of CO2 (2.860×103 L mol-1 s-1). In addition, CSTR results for the absorption and desorption of CO2 suggest that simple model CA complexes could be used in post-combustion processing. © 2015 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

ChemSusChem

Carbon Dioxide Sequestration by Using a Model Carbonic Anhydrase Complex in Tertiary Amine Medium

One aspect of the attempt to restrain global warming is the reduction of the levels of atmospheric CO2 produced by fossil fuel power systems. This study attempted to develop a method that reduces CO2 emissions by investigating the absorption of CO2 into sterically hindered amine 2-amino-2-methyl-1-propanol (AMP), the acceleration of the absorption rate by using the enzyme carbonic anhydrase (CA), and the conversion of the absorption product to stable carbonates. CO2 absorbed by AMP is converted via a zwitterion mechanism to bicarbonate species; the presence of these anions was confirmed with 1H and 13C NMR spectral analysis. The catalytic efficiency (kcat/Km), CO2 absorption capacities, and enthalpy changes (ΔHabs) of aqueous AMP in the presence or absence of CA were found to be 2.61 × 106 or 1.35 × 102 M-1 s-1, 0.97 or 0.96 mol/mol, and -69 or -67 kJ/mol, respectively. The carbonation of AMP-absorbed CO2 was performed by using various Ca2+ sources, viz., CaCl2 (CAC), Ca(OOCCH3)2 (CAA), and Ca(OOCCH2CH 3)2 (CAP), to obtain various polymorphs of CaCO 3. The yields of CaCO3 from the Ca2+ sources were found in the order CAP &gt; CAA &gt; CAC as a result of the effects of the corresponding anions. CAC produces pure rhombohedral calcite, and CAA and CAP produce the unusual phase transformation of calcite to spherical vaterite crystals. Thus, AMP in combination with CAA and CAP can be used as a CO 2 absorbent and buffering agent for the sequestration of CO 2 in porous CaCO3. © 2013 American Chemical Society.

Langmuir

CO2Absorption and Sequestration as Various Polymorphs of CaCO3Using Sterically Hindered Amine

The rate of carbon dioxide (CO2) absorption by monoethanol amine (MEA), diethanol amine (DEA), N-methyl-2,2′-iminodiethanol (MDEA), and 2-amino-2-methyl 1-propanol (AMP) solutions was found to be enhanced by the addition of bovine carbonic anhydrase (CA), has been investigated using a vapor-liquid equilibrium (VLE) device. The enthalpy (-ΔHabs) of CO2 absorption and the absorption capacities of aqueous amines were measured in the presence and/or absence of CA enzyme via differential reaction calorimeter (DRC). The reaction temperature (ΔT) under adiabatic conditions was determined based on the DRC analysis. Bicarbonate and carbamate species formation mechanisms were elucidated by 1H and 13C NMR spectral analysis. The overall CO2 absorption rate (flux) and rate constant (kapp) followed the order MEA &gt; DEA &gt; AMP &gt; MDEA in the absence or presence of CA. Hydration of CO2 by MDEA in the presence of CA directly produced bicarbonate, whereas AMP produced unstable carbamate intermediate, then underwent hydrolytic reaction and converted to bicarbonate. The MDEA &gt; AMP &gt; DEA &gt; MEA reverse ordering of the enhanced CO2 flux and kapp in the presence of CA was due to bicarbonate formation by the tertiary and sterically hindered amines. Thus, CA increased the rate of CO2 absorption by MDEA by a factor of 3 relative to the rate of absorption by MDEA alone. The thermal effects suggested that CA yielded a higher activity at 40 C. © 2013 American Chemical Society.

The Journal of Physical Chemistry B

Carbonic Anhydrase Promotes the Absorption Rate of CO2in Post-Combustion Processes

Environmental Science & Technology

Mechanisms of CO2 Capture into Monoethanolamine Solution with Different CO2 Loading during the Absorption/Desorption Processes

Journal of Chemical Technology & Biotechnology

The use of carbonic anhydrase to accelerate carbon dioxide capture processes

The salt-based catalytic enhancement of CO2 absorption by a tertiary amine medium

Journal	Data powered by TypesetRSC Advances
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	20462069
Open Access	0