Molecular modeling study of the aggregation behavior of nickel(II), cobalt(II), lead(II) and zinc(II) bis(2-ethylhexyl) phosphate complexes

Characterization of reversed micelles formed in solvent extraction of thorium(IV) by bis(2-ethylhexyl) phosphoric acid. Transforming from rodlike to wormlike morphology

“…Steytler et al studied the aggregation of various metal salts of HDEHP in cyclohexane, and found that the aggregate structures depend markedly upon the state of hydration of metal ions [31]. Ibrahim and Neuman further proved that the aggregate structures are "open" water channels rodlike reversed micelles, rodlike reversed micelles without channels and ellipsoidal reversed micelles for nickel(II), cobalt(II) and lead(II) bis(2-ethylhexyl) phosphate, respectively, which are in accordance with the known extraction behaviors of HDEHP toward the metal ions [32][33][34][35]. Nash et al examined the structures and aggregations of the organic phase in Trivalent Actinide-Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexes (TALSPEAK) process, and concluded that uniform oblate spheroid particles form in the organic phase with an increase in the load of lanthanide metal ions, accompanied by the change of complex structures from Ln(DEHP ⋅ HDEHP) 3 to Ln 2 L 2 (DEHP) 4 (L is lactate) [26,36,47].…”

“…Kolarik et al stated that the metal-extractant species in the organic phase are polymers where HDEHP acts as a bridge between the metal ions through coordination bonds [29,30]. In recent years, however, investigators have explained these from reversed micelle aspect [7,[31][32][33][34][35][36].…”

Role of water molecules in sodium bis(2-ethylhexyl) phosphate reversed micelles in n-heptane

“…In addition, they demonstrated the formation of giant NaDEHP reversed micelles under ''dry'' conditions in n-heptane [4]. Ibrahim and Neuman [16,17] utilized molecular modeling in order to clarify the molecular structure of the metal-extractant species for which information is very difficult to obtain from direct experimental measurement. In this paper, molecular modeling was used to investigate the molecular structure and role and effect of water molecules on the NaDEHP reversed micelles.…”