Physical and chemical activation of pyrolyzed oil shale residue for the adsorption of phenol from aqueous solutions

Abstract

Batch kinetics and isotherm studies were carried out to evaluate the sorption of phenol by pyrolyzed and activated Jordanian oil-shale. The effects of contact time, initial sorbate concentration, sorbent concentration, temperature, pH and inorganic salts (NaCl and KCl), on the adsorption process by different sorbents were considered. Chemically activated oil shale, pretreated with ZnCl₂, gave the highest uptake of phenol. The isotherm experimental data fit well to Freundlich and Redlich-Paterson models and to a less extent to the Langmuir model. The increase in the initial sorbate concentration resulted in an increase in the uptake. Three kinetics models, namely the Morris-Weber model, the Lagergren model, and the pseudo-second-order model (PSOM), were applied to represent the experimental results for pyrolyzed and ZnCl₂-oil shale sorbents. Pyrolyzed oil shale was prepared using a fluidized bed reactor at 520 °C in the presence of nitrogen. Physical activation was carried out by treating the resulted pyrolyzed oil shale with CO₂ at 830 °C, while chemical activation of oil shale was carried out using KOH and ZnCl₂ as impregnating agents.