A novel adsorbent, HO-CaBen, was prepared by the modification of bentonite, which shows good potential as a cheap and effective adsorbent for anionic contaminants removal from aqueous solutions. The adsorbent HO-CaBen was characterized by XRD and FTIR. The effects of equilibrium time, pH and temperature on adsorption some typical anionic contaminants were studied by the batch adsorption process. The adsorption capacities for fluoride, phosphate, Orange II, and SDBS are 50.07, 29.1, 239.5, and 298.5 mg g(-1), respectively. These values are higher than those reported for low-cost adsorbents. The adsorption mechanism of the anion on HO-CaBen is anion/OH- exchange reaction and is verified by theoretical calculation results. These results indicated that HO-CaBen was a promising adsorbent for anion removal from wastewater treatment by bentonite. (C) 2012 Elsevier B.V. All rights reserved.