Influence of organic and inorganic precipitators on the efficiency of surfactants extraction from wastewater by flotation

Abstract

The chemical structure of surfactants causes their accumulation on the surface of water sources and leads to the formation of stable foam, which prevents the access of oxygen to the water and leads to the death of hydrobionts and deterioration in water quality. Therefore, the extraction of surfactants from wastewater is an urgent task. Increase the efficiency of flotation extraction of cationic surfactants, namely hexadecyl pyridinium chloride [C 16 H 33 NC 5 H 5]Cl (CHDP) and surfactants based on it - cetazol, by introducing organic – (sodium alkyl sulfate (SAS), CnH 2n+1 OSO 3 Na, n=10-16), and inorganic - potassium hexacyanoferrate (II, III) precipitators. The solubility of the products of interaction of cationic surfactants with SAS (sublates) was determined, which are extracted from solutions at different temperatures and impurities of electrolytes. The Gibbs free energy (), enthalpy (), and entropy (), which take place in the process of dissolution, are calculated. The low value of the heat of dissolution (2.1-16.6 kJ/mol) indicates a small effect of temperature on the solubility of sublates. The thermodynamic analysis of the process of formation of sublates allows determining the optimal length of the hydrocarbon radical of the precipitator. It is established that the extraction of the studied cationic surfactants should be extracted from water solutions and wastewater by the method of precipitation flotation using organic and inorganic precipitators. The presence of electrolytes and an increase in temperature leads to an increase in the degree of extraction hexadecyl pyridinium alkyl sulphonates sublates.