Apple Waste Recovery to Remove Phthalate Residues from Water

Phthalates are recognized as emerging environmental contaminants and are classified as endocrine-disrupting chemicals, as they can induce various toxic effects in organisms and interfere with hormonal functions in biological systems, thereby posing significant health risks. In this study, contamination of environmental matrices with phthalate residues—including water, agricultural soils, and grapes—was investigated. In addition, the sorption behavior of dibutyl phthalate (DBP) and di-(2-ethylhexyl phthalate (DEHP) from aqueous solutions onto biochars derived from apple residues and functionalized with metal oxides (Fe3O4 and NiO), green-synthesized using plant extracts from Urtica dioica L. with the aim of their preliminary application in environmental remediation and the reduction of food-chain contamination risks. Several experimental series were conducted, including the determination of the sorption capacity of the biochars as a function of pH (3 - 9), characterization of adsorption isotherms at three temperatures (288 K, 298 K, and 308 K), and the thermodynamic parameters of adsorption. The experimental data were interpreted using the Langmuir and the Freundlich isotherm models. Furthermore, the thermodynamic parameters of the DBP sorption process onto the biochars, namely Gibbs free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0), were calculated.