The effect of microwave irradiation and conventional acid activation on the textural properties of smectite: Comparative study

Abstract

In this work, the activation clay employing “traditional or conventional” heating and microwave (MW) irradiation is reported. This paper is an extension of a previous paper where the natural and purified clay in the homoionic Na form were activated by microwave irradiation and physico-chemically characterized (Korichi et al., 2009).The influence of conventional and microwave irradiation on smectite activation was investigated. Preparation time of the conventional activation took about 8h, whereas a highly porous structure is obtained, when operating at a power of 500W for 20min in case of microwave irradiation. To find changes in physicochemical properties, the following techniques were used: Laser granulometry, N2 adsorption/desorption, Mercury porosimetry, X-ray diffraction, Chemical analysis, FT-IR spectroscopy, Scanning Electron Microscopy (SEM), Thermo Gravimetric (TGA) and Differential Thermal Analysis (DTA). Characterization results confirm the general smectite character of the natural sample.The properties of the compounds obtained by these two methods are comparable. The clay materials were composed of microporous and mesoporous structures. The total surface area and pore volume of samples prepared with conventional method are 173.17m2/g and 0.1597cm3/g, respectively. The total surface area and pore volume of samples prepared under microwave are 165.80m2/g and 0.1919cm3/g, respectively. The results of this study showed that small pores were created in the prepared materials with both methods: conventional heating and microwave irradiation.