Physicochemical Parameters of the Methylparaben Adsorption from Aqueous Solution onto Activated Carbon and Their Relationship with the Surface Chemistry

Abstract

The methylparaben adsorption from aqueous solution onto activated carbon is a relevant topic because of the toxicity of this compound for human and environmental health. The physicochemical parameters allow us to evaluate the performance of the adsorption and the relationship between the surface chemistry and the adsorbed amount of methylparaben. The effect of the solution chemistry on the adsorption was also evaluated. In this work, the methylparaben adsorption on three activated carbons with different physicochemical properties, specifically different contents of oxygenated groups and total basicity, is presented. Kinetic, equilibrium, and calorimetry tests were conducted. The maximum adsorbed amount of methylparaben was achieved on an activated carbon with basic characteristics, Qmax = 1.64 mmol g-1 in the same activated carbon, the initial rate was 0.20 mmol g-1 h-1, and the value determined for the interaction enthalpy was -12.6 × 10-20 J molecules-1, and the Gibbs energy change was close to -14.96 kJ mol-1.