Preparation and characterization of novel composite AlCr-pillared clays and preliminary investigation for benzene adsorption

Abstract In this study, a one-step high-temperature and high-pressure method was used to synthesize AlCr composite pillaring agents. Compared to conventional methods, the method greatly reduced the steps and material consumption. A series of composite AlCr-pillared clays (AlCr-PILC) were synthesized by ion exchange. The structure of the AlCr composite pillaring agent could be altered by changing the Al/Cr molar ratio, reaction temperature, and reaction time, thereby affecting the structure and properties of AlCr-PILC (including surface area, pore volume, pore diameter, and basal spacing). The structure and properties of the experimental materials were characterized by X-ray diffraction, N 2 adsorption, high-resolution electron microscopy, and benzene adsorption and desorption experiments. The results indicated that after 4 h of calcination at 550 °C, the specific surface area, pore volume, and maximum basal spacing of AlCr-PILC reached 266–362 m 2 /g, 0.16–0.22 cm 3 /g, and 2.06 nm, respectively. The benzene adsorption capacity of the synthesized AlCr-PILC was much larger than the capacity of the starting clays, reaching 48.3 μmol/g. In addition, complete desorption could be achieved at 250 °C. Therefore, the synthesized AlCr-PILC was a good material for adsorption.