Temperature-induced phase separation of nonionic polyoxyethylated surfactant and application to extraction of metal thiocyanates

Clouding behaviour in surfactant systems

“…Addition of thiocyanato salt to the poly(oxyethy1ene) (7.5) nonylphenyl ether exhibited an unusual behaviour on the cloud point (Table 4) [99]. In the presence of thiocyanate cloud point was found to increase, which is not a typical phenomenon as many workers have already reported that the cloud point decreases in the presence of a salt due to salting out effects as seen in the case of NaCl [100,101].…”

“…Okada [99] utilized Poly(oxyethy1ene) (7.5) nonylphenyl ether for the cloud point ion-pair extraction of thiocyanato complexes of six transition metal ions on surfactant-rich pseudoorganic phase. The complexation ability, the low cloud point and the high solubility in water of POE(7.5)NP was found to be advantageous for this extraction.…”

Formation of Copper(II) Thiocyanato and Cadmium(II) Iodo Complexes in Micelles of Nonionic Surfactants with Varying Poly(ethylene oxide) Chain Lengths

“…This property, so called solubilization, is widely used in the field of analytical chemistry such as solvent extraction (3-7) temperature-induced phase separation (8), and micellar electrokinetic chromatography (9). However, specific interaction of species with each functional group of surfactants in micelles has yet not been clarified.…”

Cloud Point Extraction of Pesticide Residues

“…The greatest analyte preconcentration factor is reached when the CPE process is conducted with equilibration temperatures well above the cloud point temperature of the system. Moreover, by increasing the equilibration temperature, a reduction in the surfactant rich phase has been observed (Okada, 1992). Thereby, the preconcentration factor increases with increasing temperature depending on the surfactant concentration.…”