title: Experimental-Theoretical Approach to the Adsorption Mechanisms for Anionic, Cationic, and Zwitterionic Surfactants at the Calcite-Water Interface.
abstract: The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite-water interface was studied through surface zeta potential measurements and multiscale molecular dynamics. The ground-state polarization of surfactants proved to be a key factor for the observed behavior; correlation was found between adsorption and the hard or soft charge distribution of the amphiphile. SDS exhibits a steep aggregation profile, reaching saturation and showing classic ionic-surfactant behavior. In contrast, DTAB and CAPB featured diversified adsorption profiles, suggesting interplay between supramolecular aggregation and desorption from the solid surface and alleviating charge buildup at the carbonate surface when bulk concentration approaches CMC. This manifests as an adsorption profile with a fast initial step, followed by a metastable plateau and finalizing with a sharp decrease and stabilization of surface charge. Suggesting this competition of equilibria, elicited at the CaCO3 surface, this study provides atomistic insight into the adsorption mechanism for ionic surfactants on calcite, which is in accordance with experimental evidence and which is a relevant criterion for developing enhanced oil recovery processes.
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Ingeniería Química/USIP, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.|Universidad Nacional Autónoma de México , Facultad de Ingeniería, Departamento de Ingeniería Petrolera, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Agustín
authors.initials: A
authors.lastname: Durán-Álvarez
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Química Orgánica, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Maldonado-Domínguez
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Química Orgánica, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Oscar
authors.initials: O
authors.lastname: González-Antonio
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Ingeniería Química/USIP, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Durán-Valencia
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Química Orgánica, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Margarita
authors.initials: M
authors.lastname: Romero-Ávila
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Ingeniería Química/USIP, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Fernando
authors.initials: F
authors.lastname: Barragán-Aroche
authors.affiliation: Universidad Nacional Autónoma de México , Facultad de Química, Departamento de Ingeniería Química/USIP, Ciudad Universitaria, México, Distrito Federal C.P. 04510, México.
authors.forename: Simón
authors.initials: S
authors.lastname: López-Ramírez