| dc.creator | Santos, Francisco Klebson Gomes dos | |
| dc.creator | Barros Neto, Eduardo Lins | |
| dc.creator | Moura, Maria Carlenise Paiva de Alencar | |
| dc.creator | Dantas, Tereza Neuma de Castro | |
| dc.creator | Dantas Neto, Afonso Avelino | |
| dc.date | 2021-12-01T17:09:10Z | |
| dc.date | 2021-12-01T17:09:10Z | |
| dc.date | 2009 | |
| dc.identifier | MOURA, Maria Carlenise Paiva de Alencar; SANTOS, Francisco Klebson Gomes; BARROS NETO, Eduardo Lins; DANTAS NETO, Afonso Avelino; DANTAS, Tereza Neuma de Castro. Molecular behavior of ionic and nonionic surfactants in saline medium. Colloids and Surfaces A: Physicochemical and Engineering Aspects, v. 333, p. 156-162, 2009. Disponível em: https://www.sciencedirect.com/science/article/abs/pii/S0927775708006456?via%3Dihub. Acesso em: 28 jul. 2021. DOI: https://doi.org/10.1016/j.colsurfa.2008.09.040 | |
| dc.identifier | 0927-7757 | |
| dc.identifier | https://repositorio.ufrn.br/handle/123456789/45113 | |
| dc.description | The aim of this study was to investigate the molecular behavior of ionic and nonionic surfactants at differ ent salt concentrations. The nonionic surfactants used in this work were nonylphenol 20 EO, nonylphenol
100 EO, lauryl alcohol 10 EO, and lauryl alcohol 23 EO, being EO the number of ethene oxide groups. The
ionic surfactants were synthesized through saponification reactions using the following vegetable oils:
coconut oil and castor oil. The cmc (critical micelle concentration) of each surfactant was determined
using surface tension measurements at different surfactant and salt concentrations. The study of surfac tant adsorption, using the Gibbs equation with factor n = 1 for nonionic surfactants and n = 2 for ionic
ones, allowed to obtain the packing area per surfactant molecule, the surface excess, and the Gibbs free
energy of micellization. The obtained results were compared and discussed in view of the hole of the
type of surfactant and electrolyte influence. From the obtained results, it can be concluded that the ionic
surfactants, due to electrostatic repulsion between ionic head groups, showed higher cmc values than
those obtained for nonionic ones. When salt ions were added to the ionic surfactant solution, the cmc
values were decreased due to the existence of electrostatic interactions between the ionic head groups of
these molecules with the electrolytes. For nonionic surfactants, the increasing ethoxylation degree, the
hydrophilic portion of surfactant molecule, and electrolyte addition diminishes cmc values. Concerning
to the Gibbs free energy of micellization, the obtained results showed that the adsorption process was
spontaneous for all studied surfactants, but it was thermodynamically more favorable for nonionic ones | |
| dc.description | The aim of this study was to investigate the molecular behavior of ionic and nonionic surfactants at differ ent salt concentrations. The nonionic surfactants used in this work were nonylphenol 20 EO, nonylphenol
100 EO, lauryl alcohol 10 EO, and lauryl alcohol 23 EO, being EO the number of ethene oxide groups. The
ionic surfactants were synthesized through saponification reactions using the following vegetable oils:
coconut oil and castor oil. The cmc (critical micelle concentration) of each surfactant was determined
using surface tension measurements at different surfactant and salt concentrations. The study of surfac tant adsorption, using the Gibbs equation with factor n = 1 for nonionic surfactants and n = 2 for ionic
ones, allowed to obtain the packing area per surfactant molecule, the surface excess, and the Gibbs free
energy of micellization. The obtained results were compared and discussed in view of the hole of the
type of surfactant and electrolyte influence. From the obtained results, it can be concluded that the ionic
surfactants, due to electrostatic repulsion between ionic head groups, showed higher cmc values than
those obtained for nonionic ones. When salt ions were added to the ionic surfactant solution, the cmc
values were decreased due to the existence of electrostatic interactions between the ionic head groups of
these molecules with the electrolytes. For nonionic surfactants, the increasing ethoxylation degree, the
hydrophilic portion of surfactant molecule, and electrolyte addition diminishes cmc values. Concerning
to the Gibbs free energy of micellization, the obtained results showed that the adsorption process was
spontaneous for all studied surfactants, but it was thermodynamically more favorable for nonionic ones | |
| dc.language | en | |
| dc.publisher | ELSEVIER | |
| dc.subject | Anionic surfactant | |
| dc.subject | Nonionic surfactant | |
| dc.subject | Critical micelle concentration | |
| dc.subject | Salinity | |
| dc.subject | Molecular behavior | |
| dc.title | Molecular behavior of ionic and nonionic surfactants in saline medium | |
| dc.type | article | |
