Adsorption of metallic ions from aqueous solution on surfactant aggregates: a molecular dynamics study

TL;DR

This study uses molecular dynamics simulations to analyze how metallic ions like lead and aluminum adsorb onto surfactant micelles, revealing preferential adsorption patterns influenced by electrostatic interactions.

Contribution

It provides detailed molecular insights into metal ion adsorption on SDS micelles, highlighting differences in adsorption efficiency for lead versus aluminum.

Findings

SDS micelles adsorb lead more effectively than aluminum.

Electrostatic interactions drive metal ion capture on micelle surfaces.

Adsorption efficiency varies with salt concentration and micelle size.

Abstract

Metallic ion adsorption on surfactant aggregates were studied with Molecular dynamics simulations. Using ionic salts, such as lead sulfate (PbSO$_4$) and aluminum sulfate [Al$_2$(SO$_4$)$_3$], adsorption of lead and aluminum were investigated at different salt concentrations and different surfactant aggregates (micelles) sizes. The micelles were constructed with spherical shapes composed of sodium dodecyl sulfate (SDS) anionic surfactants. The electrostatic interactions between the positive ions and the negative SDS headgroups promote capture of the metal particles on the aggregate surface. Metal adsorption was analyzed in terms of radial density profiles, partial pair distribution functions and adsorption isotherms. It is showed that SDS micelles adsorb better lead than aluminum ions regardless of the size of the aggregates and salt concentrations.