Preparation of bentonite modified by Al-TiO₂ with microwave radiation and its structure characterization

In order to prepare a new composite of water treatment adsorbent, modified bentonite was prepared under microwave radiation by using doped Al-TiO₂ as modifier. The best condition of microwave radiation was investigated. The samples were characterized by EDS, SEM, FTIR, XRD, N₂ adsorption-desorption, differential scanning calorimetry and thermal gravity analysis (DSC-TGA). The results show that the best condition of microwave radiation are microwave power 260 W and microwave time 8 min. The modifier enters into the interlayer of bentonite and Ti—O—Si bond is formed between the framework of bentonite in the modified bentonite. The interlayer spacing increases from 1.280 nm to 1.533 nm, the surface area increases from 39.66 m²·g^-1 to 72.05 m²·g^-1, the pore volume increases from 0.103 4 cm³·g^-1 to 0.140 5 cm³·g^-1, while the saturated adsorption capacity of methylene blue increases from 32.56 g/100 g to 57.96 g/100 g, and the thermal stability is evidently improved by modification.