Removal of Bisphenol from Aqueous Solution by Surfactant-Modified Bentonite

Abstract

In this study surfactant-modified natural bentonite was examined for the adsorption of bisphenol A [2,2-bis(4-hydroxyphenyl)propane; BPA] from aqueous solutions. Batch experiments were performed to investigate the adsorption kinetics, equilibrium and thermodynamics between the adsorbent surfaces and BPA. At acidic pH conditions, removal of BPA was increased due to a neutral molecule form of BPA and hydrophobic surface created by the loaded surfactant molecules. The adsorption of BPA on modified bentonite was enhanced when the ionic strength was increased. The adsorption behavior of BPA onto surfactant-modified bentonite followed the pseudo-second order kinetic model. Langmuir isotherm provided the best fit for adsorption. The adsorption of BPA on modified bentonite is more favorable at lower temperature. According to the experimental results, a physical adsorption is responsible mechanisms for adsorption of BPA on modified bentonite.