Adsorption was carried out on RhB by mixing 1.0 g of the natural diatomite samples with initial concentrations of 20 mg/dm3, 40 mg/dm3, and 60 mg/dm3. The mixtures were shaken in a thermally controlled automatic shaker at 120 rpm, at temperatures of 303 K, 313 K, and 323 K for 15, 30, 60, 90, and 120 minutes until the equilibrium