Sodium benzyl sulfonate functionalized-bentonite as a novel adsorbent for water softening process

Abstract

In this work, novel Sodium benzyl sulfonate functionalized-bentonite (SBSB) adsorbent was synthesized through the reaction of bentonite with benzyl alcohol and chlorosulfonic acid. The prepared adsorbent was characterized using Low-angle XRD, FT-IR and TGA methods, and applied for the removal of calcium and magnesium ions from water solutions. The effect of contact time and initial hardness concentration on the hardness removal efficiency of the prepared adsorbents were studied. It was found that the adsorption was reached the equilibrium condition within about 60 min, and the maximum adsorption capacity (52.5 mg g−1) was achieved in the hardness of 150 mg L−1. Compared to pristine bentonite, the adsorption efficiency of SBSB was significantly enhanced, which is ascribed to the presence of benzyl sulfonate functional groups on its surface. The adsorption isotherm of calcium and magnesium ions on SBSB was described by Langmuir and its adsorption kinetic behavior followed pseudo-second-order model.