Micellar extraction concentration of microcomponents by phases of nonionic SAS at the cloud point

Room temperature cloud point extraction: An application to preconcentration and spectrophotometric determination of copper(II)

“…It is known that the cloud point phenomenon occurs due to the destruction of hydrogen bonds and the dehydration of oxygen atoms of surfactant molecules, which leads to the aggregation of micelles when the solution is heated to a cloud point temperature. [1][2][3][4] In our opinion, a similar effect can be achieved by introducing organic substances, for example, certain aromatic carboxylic acids. A high content of benzoic or salicylic acids will make it possible to dehydrate large surfactant molecules and their micelles by more profitable hydration of comparatively small molecules of acids and lead to the generation of a surfactant rich phase.…”

“…The cloud point extraction (CPE) is a modern, environmentally friendly and an effective alternative to classical liquid-liquid extraction (LLE). 1 The CPE is easily combined with various analytical methods, such as spectrophotometry, atomic absorption spectroscopy, atomic emission spectroscopy, ICP-MS and other. The CPE is based on heating a solution that contains an analyte, a complexing agent and a surfactant to the cloud point temperature.…”

“…[2][3][4] Nonionic surf-90 SNIGUR et al actants are the most commonly used for CPE. 1,4 For CPE intensification the ultrasonic or microwave irradiation was used. [5][6][7][8] In most cases, with the help of physical influence on the system, there is only an opportunity to slightly lower the cloud point temperature and shorten the time of the surfactant rich phase generation.…”

“…Chemical methods for initiating CPE are more typical when anionic surfactants are used. 1,9 In the case of non-ionic surfactants, the chemical initiation of CPE has been little studied. A number of studies have described that sodium sulfate introduction leads to immediate formation of the surfactant rich phase.…”

“…10,11 In turn, in many studies was noted that the introduction of sodium sulfate and other electrolytes leaded to a more or less significant decrease in the cloud point temperature. 1,11 In this case, the positive effect of salts (salting out effect) does not completely avoid heating the solution to initiate CPE. Thus, one can point out that one of the directions of development of CPE is the search for ways to initiate it.…”