Silica mesophases intercalated by cross-linked micelles of a sustainable oleyl diamine surfactant and metal ion uptake properties thereof

Abstract

Sustainable plant-derived N-oleyl-1,3-diaminopropane surfactant micelles cross-linked by divinylbenzene (DVB) have been intercalated in the pores of mesostructured silica and the resulting functionalized mesophases were used to immobilize heavy metal ions through complexation by the diamine head groups. Two methods were used to form the composite surfactant–silica compositions. In the “pre-assembly” approach, the unsaturated amine micelles were first cross-linked in aqueous solution and subsequently used as a structure-directing agent to form the composite silica–polymeric amine mesophase. In the second “post-assembly” approach, the unsaturated amine micelles were used to template the silica mesophase and then cross-linked in situ with DVB within the pores of the composite mesophase. The accessibility of the amine functional groups in the mesophases prepared by both assembly methods was demonstrated through the uptake of Cu(II) and Pb(II) ions from aqueous solution.