Precipitation phenomena of heavy metal soaps in aqueous solutions

Precipitation and Solubility of Calcium Soaps in Basic Aqueous Media

“…2. The stable value of γ for stearate solutions at low Ca 2+ concentrations and its sharp increase above 2 × 10 −5 mol l −1 of Ca 2+ reflect the fact that below the calcium ion critical transition concentration, γ is constant and equal to that of the corresponding pure anionic fatty acid solution (7). Since the starting solution was near the cmc, it is also possible that no relevant change in surface tension was observed for low concentrations of Ca 2+ , despite the precipitation of the corresponding calcium salt.…”

Surfactant-colligend particle size effects on ion flotation: Influences of mixing time, temperature, and surfactant chain length

“…For all three surfactants, above the "critical M", small, stable particles were observed, with the stability provided by adsorbed surfactant, as evidenced by increases in the Suspension Effect. Analogous behavior has been observed for calcium oleate and thorium oleate, based on light scattering measurements (20,21). The high surfactant adsorption magnified its role as a dispersant, making the particles hydrophilic (probably with the positivelycharged head groups pointing toward the aqueous phase) and less floatable.…”

“…A precipitation reaction between cationic surfactants and Cr(VI) has been reported by several investigators (12,17,18,19), for example, Ci6TA + ÷ HCrOa ~ (C16TA-HCrOa)~ona Before precipitation, molecular clusters which are smaller than the critical cluster or nucleus may be formed, leading to the formation of soluble complexes (19,20),…”

“…Matijevic (20,21) has reported calcium oleate and thorium oleate particles with a negative charge and stabilized (above the "critical transition concentration" of oleate, at a constant calcium or thorium concentration) probably due to being coated with oleate as they were being formed. The surfactant-Cr(VI) particles of this study had a net positive charge, as determined by the Suspension Effect and detailed below, evidently due to the adsorption of simple or complexed surfactant cations.…”

Precipitation and association of silver laurate in aqueous solutions

“…Hydrolysis, precipitation phenomena, and solubilities of some fatty acid salts were also investigated [7][8][9][10][11][12][13][14].…”