The calcium base bentonite was modified by aluminum and silver salts. By means of optimizing the Al or Ag loading, calcination temperature and calcination time, the modified bentonite with high performance of treating dye wastewater was obtained. The modified bentonite was characterized by XRD, SEM. FT-IR and N2 adsorption techniques. The results showed that polyhydroxy-aluminum entered into the interlayer of the modified bentonite and Si—O—Al bond was formed between the framework of bentonite ([Si4O10]n) and [Al3O4(OH)24(H2O)12]7+ in the modified bentonite. The interlayer spacing, surface area and pore volume were evidently improved by the modification. The modified bentonite was used to treat three types of dye wastewater with a concentration of 500 mg/L. The decolorization ratio for the dye wastewater was 90%-96 % and the ratio of COD elimination was 75%-90%.
