Amphilic Water‐Lean Carbon Capture Solvent Wetting Behavior through Decomposition by Stainless‐Steel Interfaces

• Published in: ChemSusChem 2021-12, Vol.14 (23), p.5283-5292
• Main Authors: Nguyen, Manh‐Thuong, Grubel, Katarzyna, Zhang, Difan, Koech, Phillip K., Malhotra, Deepika, Allec, Sarah, Rousseau, Roger, Glezakou, Vassiliki‐Alexandra, Heldebrant, David J.
• Format: Article
• Language: English
• Subjects: Alcohols; Amines; Carbon sequestration; Chemical composition; CO2 capture; Decomposition; Hydrophilic surfaces; Hydrophilicity; Hydrophobicity; Hydroxides; Imines; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Leaching; Molecular dynamics; Molecular structure; oxidation; solvent effects; Solvents; Stainless steels; Steel; Wetting
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202101350

A combined experimental and theoretical study has been carried out on the wetting and reactivity of water‐lean carbon capture solvents on the surface of common column packing materials. Paradoxically, these solvents are found to be equally able to wet hydrophobic and hydrophilic surfaces. The solvents are amphiphilic and can adapt to any interfacial environment, owing to their inherent heterogeneous (nonionic/ionic) molecular structure. Ab initio molecular dynamics indicates that these structures enable the formation of a strong adlayer on the surface of hydrophilic surfaces like oxidized steel which promotes solvent decomposition akin to hydrolysis from surface oxides and hydroxides. This decomposition passivates the surface, making it effectively hydrophobic, and the decomposed solvent promotes leaching of the iron into the bulk fluid. This study links the wetting behavior to the observed corrosion of the steels by decomposition of solvent at steel interfaces. The overall affect is strongly dependent on the chemical composition of the solvent in that amines are stable, whereas imines and alcohols are not. Moreover, plastic packing shows little to no solvent degradation, but an equal degree of wetting. Lean in: A combined experimental and theoretical study is carried out on the wetting and reactivity of water‐lean carbon capture solvents on the surface of common column packing materials. The amphiphilic nature of water‐lean solvents allows them to wet cheaper and more chemically durable materials of construction, bypassing catalytic decomposition of solvent molecules on stainless‐steel interfaces.