Adsorption of Phthalates on Activated Carbons in Monosolute Solution and in Mix Within Complex Matrices

Abstract

Phthalates are considered as dangerous priority pollutants, several effects being attributed to them: foetal deformations, cancers, and endocrine disruptions. Activated carbons are highly efficient materials for the adsorption of numerous organic molecules. Before their use, it is important first to determine both textural and chemical properties and to study kinetics and thermodynamics adsorption, to understand and to optimize the interactions between material and molecules. The aim of this work was to study the kinetics and the adsorption isotherms of three phthalates (dimethylphthalate, diethylphthalate, and diethylhexylphthalate) currently found in industrial effluents, on two different activated carbons. The co-adsorption of these molecules in a synthetic mix and in complex matrices was modeled. The kinetic study and adsorption isotherms of dimethylphthalate and diethylphthalate in monosolute and bisolute were first investigated, followed by a similar study with a mix of the three molecules in complex matrices (surface water (Loire and Loiret Rivers near Orleans city) and municipal wastewater treatment plant outflow). The pseudo-second-order kinetic model was used to determine the kinetic adsorption parameters. The Langmuir equation was used to calculate the surface occupied. Results showed that non-electrostatic interactions are predominant in phthalate adsorption in complex matrices, mainly due to dispersion forces and hydrophobic interactions.