Removing aromatic organic pollutants by cloud point extraction using biodegradable nonionic surfactants: equilibrium constants and diffusion kinetics

• Published in: International journal of environmental analytical chemistry 2024-12, Vol.104 (17), p.5552-5573
• Main Authors: Duarte, Lindemberg de Jesus Nogueira, Bezerra Lopes, Francisco Wendell, Araújo, Elayne Andrade, Melo, Ricardo Paulo Fonseca, Neto, Eduardo Lins de Barros, Canselier, Jean Paul
• Format: Article
• Language: English
• Subjects: Alcohol; Alcohols; Amines; analytical chemistry; Aniline; Aromatic compounds; Aromatic organic pollutants; Benzyl alcohol; biodegradability; Biodegradation; Chemical bonds; Chemical equilibrium; Cloud point curves; cloud point extraction, diffusion kinetics, equilibrium constants; Diffusion; Economics; Effluents; Electrostatic properties; Environmental management; Equilibrium; human health; hydrogen; Hydrogen bonding; Hydrogen bonds; Hydrophobicity; Industrial areas; Industrial wastes; Industrial wastewater; ionization; Kinetics; Mass transfer; micellar solubilisation; Miscibility; non-ionic surfactants; Nonionic surfactants; Organic compounds; p-Toluidine; Phase diagrams; phenol; Phenols; phenylethyl alcohol; Pollutants; Solubility; Solubilization; Surfactants; Toluidine; van der Waals forces; Wastewater
• ISSN: 0306-7319; 1029-0397; 1029-0397
• DOI: 10.1080/03067319.2022.2125314

The impacts of inadequate disposal of industrial wastewater cause environmental, economic, social and human health damage. The search for innovative and viable methodologies from a technical and economic standpoint aims to promote suitable management of effluents produced by different industrial activities. The objective of this paper was to study phenol, aromatic alcohol and aromatic amine removal using cloud point extraction based on analysis of extraction capacity, miscibility curves, equilibrium lines, distribution coefficients and mass transfer solubilisation diffusion. The oxo-C 10 E 3 P 4 E 2 surfactant produced the best results, exhibiting smaller coacervate volume fractions, low concentration in the diluted phase and efficient extraction (E%) of phenol (81.79%), 1-phenylethanol (67.88%), 2-phenylethanol (65.41%), benzyl alcohol (57.01%), aniline (56.91%), p-toluidine (73.96%) and 2,4-dimethylaniline (84.87%). The ternary phase diagrams revealed a large miscibility area favourable to extraction, with equilibrium lines showing a pronounced slope in favour of the coacervate, indicating high compound concentration factors. Equilibrium isotherms were used to obtain the distribution and solubilisation constants (Log K C/D K S ), in the following order: aniline (1.05; 9.15) < p-toluidine (1.35; 20.40) < 2,4-dimethylaniline (1.76; 45.10) and benzyl alcohol (1.07; 8.19) < 2-phenylethanol (1.22; 14.04) < 1-phenylethanol (1.28; 15.23) < phenol (1.59; 36.72). These parameters show a linear correlation with Log K O/W , revealing that micellar solubilisation is governed by the hydrophobic nature of aromatic organic compounds. The evolution of pH demonstrated that the ionised forms of phenol and 2,4-dimethylaniline do not establish interactions (electrostatic, van der Waals, hydrogen bonds) with surfactants. Mass transfer diffusion is governed by hydrophobic compounds, slightly compromising phenol due to its high solubility in water.