Removal of sulphur dioxide using palygorskite in a fixed bed adsorber.

This work describes the use of a novel palygorskite, a type of magnesium aluminium silicate clay possessing a high specific surface area and pore surface activity, as a low cost and highly efficient adsorbent for sulphur dioxide (SO2) removal. Dynamic adsorption in a fixed bed adsorber showed that palygorskite pretreated with sodium hydroxide had a higher adsorption capacity at 10% breakthrough than either raw material or that pretreated with acid. The SO2 adsorption capacity increased with increasing inlet SO2 concentration and decreased with increasing temperature. Samples were characterized for: specific surface area using the Brunauer-Emmett-Teller (BET) method, crystal structure by X-ray diffraction (XRD), and surface chemistry by Fourier transform infrared spectroscopy (FTIR). Adsorption equilibrium isotherms were established for samples over an SO2 concentration range from 50 to 460 ppm, at room temperature. The adsorption equilibrium could be described by both the Freundlich and the Langmuir isotherms.