Determination of anionic surface-active substances in waters

Association and colloid-chemical properties of humic acids in aqueous solutions

“…The equilibrium concentrations of free dissolved AS and that bound with HAs were determined by the sorption photometric procedure [19] and standard extraction photometric procedure using Methylene blue [20], respectively. The applicability of these pro cedures for the determination of ASs bound and unbound with HAs was experimentally confirmed and described in detail in [21].…”

Evaluation of Efficacy of Anionic Surfactant Degradation in the Presence of Concomitant Impurities of Natural Waters

“…Change in ABS concentration during oxidation was monitored by standard extraction-photometric method with methylene blue (EPh) or advanced sorption-photometric (SPh) technique with methylene blue (determination limit of 0.05 mg/dm 3 and 0.02 mg/dm 3 , resp.) [8,14]. The latter method allows to significantly improve the accuracy of the ASAS control in waters with high content of the NOM.…”

“…through different mechanisms, through formation of strong chemical bonds (such as ionic, hydrogen, and covalent), charge transfer or weak interactions (such as van der Waals forces, ligand exchange, hydrophobic links) [8][9][10][11]; therefore, they may significantly affect the properties and behavior of xenobiotics in the processes of natural water or sewage treatment [12,13]. In particular, HA are able to bind anionic surfactants (ASAS) through hydrophobic interactions, significantly distorting their quantification by standard extractionphotometric method with methylene blue [8,14]. The binding of surfactants with mentioned natural organic matter (NOM) depends on the structure of the substrate and NOM and a number of other factors (such as pH, ionic strength, and duration of exposure) [8,10,11].…”