Preparation of TiO2-pillared montmorillonite as photocatalyst Part I. Microwave calcination, characterisation, and adsorption of a textile azo dye

Abstract Two photocatalysts based on TiO 2 -pillared intercalated montmorillonite have been prepared by microwave for 10 min at 700 W or by furnace heating at 673 K. Montmorillonite pillaring with TiO 2 increased the basal spacing to 14.7 A (conventional heating) and 17.6 A (microwave heating). XRD patterns of both materials showed the presence of 100% anatase with a slightly higher rate of crystallinity obtained through microwave calcination than by conventional heating at 673 K. The BET specific surface area of the microwave prepared photocatalyst (151 m 2 g − 1 ) was 3 fold higher than those of the Degussa TiO 2 P25. At pH = 5.8, the maximum adsorption capacity of Solophenyl red 3BL (a textile azo dye) on the TiO 2 -pillared montmorillonite calcined by microwave was 185 mg g − 1 , whereas it was 1.4 and 3 fold lower on the TiO 2 -pillared montmorillonite calcined at 673 K, and on the Degussa TiO 2 P25 respectively. The influence of pH on the adsorption of the dye depended on the pH ZPC of the pillared montmorillonites.