Reaction Kinetics of Carbon Dioxide in Aqueous Blends of N-Methyldiethanolamine and L-Arginine Using the Stopped-Flow Technique

• Main Authors: Nafis Mahmud, Abdelbaki Benamor, Mustafa Nasser, Muftah H. El-Naas, Paitoon Tontiwachwuthikul
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Processes
• Subjects: Reaction; kinetics; carbon dioxide; N-methyldiethanolamine; L-Arginine; stopped flow technique
• Online Access: https://www.mdpi.com/2227-9717/7/2/81

Reduction of carbon dioxide emission from natural and industrial flue gases is paramount to help mitigate its effect on global warming. Efforts are continuously deployed worldwide to develop efficient technologies for CO₂ capture. The use of environment friendly amino acids as rate promoters in the present amine systems has attracted the attention of many researchers recently. In this work, the reaction kinetics of carbon dioxide with blends of N-methyldiethanolamine and L-Arginine was investigated using stopped flow technique. The experiments were performed over a temperature range of 293 to 313 K and solution concentration up to one molar of different amino acid/amine ratios. The overall reaction rate constant (k_ov) was found to increase with increasing temperature and amine concentration as well as with increased proportion of L-Arginine concentration in the mixture. The experimental data were fitted to the zwitterion and termolecular mechanisms using a nonlinear regression technique with an average absolute deviation (AAD) of 7.6% and 8.0%, respectively. A comparative study of the promoting effect of L-Arginine with that of the effect of Glycine and DEA in MDEA blends showed that MDEA-Arginine blend exhibits faster reaction rate with CO₂ with respect to MDEA-DEA blend, while the case was converse when compared to the MDEA-Glycine blend.