Influence of Natural Water Components on the Sorption of Dodecyl Sulfate Anions on Kaolinite

• Published in: Journal of water chemistry and technology Vol. 44; no. 1; pp. 1 - 9
• Main Authors: Dolenko, S. O., Trifonova, M. Yu, Ivanova, Z. G.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.02.2022; Springer Nature B.V
• Subjects: Adsorption; Anions; Aquatic ecosystems; Aquatic Pollution; Calcium ions; Cations; Chemical precipitation; Chemical properties; Chemicophysical properties; Colloid chemistry; Components; Confined groundwater; Contamination; Distilled water; Earth and Environmental Science; Environment; Industrial Chemistry/Chemical Engineering; Ions; Isotherms; Kaolinite; Micelles; Multilayers; Physical Chemistry of Water Treatment Processes; Pollutants; Polyelectrolytes; Salts; Sodium; Sodium dodecyl sulfate; Sodium lauryl sulfate; Solutions; Sorbents; Sorption; Sulfates; Surface activity; Surface chemistry; Surfactants; Waste Water Technology; Water; Water Industry/Water Technologies; Water Management; Water Pollution Control; Water Quality/Water Pollution; precipitation; isotherm; kaolinite; associates; dodecyl sulfate; humate; artesian water; sorption
• ISSN: 1063-455X; 1934-936X
• DOI: 10.3103/S1063455X22010027

To better understand the physicochemical processes occurring in natural reservoirs upon their contamination with the most common organic pollutants (anionic surfactants), the interaction of sodium dodecyl sulfate (DDSNa), sodium humate (HNa), and kaolinite from the Glukhiv deposit in distilled and natural artesian water is investigated. The influence of the natural water components on the states of the sorbent and sorbate is determined by a set of methods. The influence of Ca 2+ ions and pH on the mechanism and value of adsorption of HNa on kaolinite is discussed. Increases in the adsorption capacity of the monolayer and the specific surface area of kaolinite are detected during the adsorption of humates from both distilled and artesian water. The influence of the formation of more surface-active than DDSNa but less soluble dodecyl sulfate salts with double-charged cations on the colloidal chemical properties of a solution of DDSNa in artesian water is demonstarted. Substantial leveling of the influence of mineral components on the surface activity and solubility of DDSNa upon the introduction of humates (natural polyelectrolytes) is established. The concentration ranges of the existence of different forms of the anionic surfactant (anions, insoluble salts, self-associates, intermolecular associates with humates, and micelles) in the studied systems and their influence on the sorption of the anionic surfactant on natural kaolinite are determined. It is shown that the isotherm of adsorption of anionic surfactants from artesian water is characterized by the presence of a maximum, which indicates a substantial effect of the precipitation of sparingly soluble salts of the dodecyl sulfate anion with doubly charged cations from artesian water. Moreover, the stepwise nature of the isotherm of adsorption of the anionic surfactant from artesian water in the presence of 5 mg/dm 3 HNa may indicate the occurrence of multilayer adsorption, which is associated with following changes in the state of dodecyl sulfate upon changing its concentration in a solution: intermolecular associates with HNa and polyvalent ions with different DDSNa/HNa ratios in the surfactant associates and micelles. It is found that the addition of 5 mg/dm 3 HNa to solutions of DDSNa in artesian water almost doubles the adsorption of DDSNa from its micellar solutions. It is established that low residual concentrations of DDSNa at the level of maximum permissible concentration (MPC) in water (DDSNa = 0.5 mg/dm 3 ) ensure almost complete ( R = 97%) removal of the humate from natural water, which is very important from the standpoint of environmental safety for understanding the influence of anionic surfactant pollutions on the state of aquatic ecosystems.