TiO2-coated granular activated carbon was employed for the removal of toxic microcystin-LR from water. Surface areas of the activated carbon in the vicinity of TiO2 particles provided sites for the adsorption of microcystin-LR, and the adsorbed microcystin-LR migrated continuously onto the surface of TiO2 particles which were located mainly at the exterior surface in the vicinity of the entrances of the macropores of the activated carbon. The migrated microcystin-LR was finally degraded into nontoxic products and CO2 very quickly. These combined roles of the activated carbon and TiO2 showed a synergistic effect on the efficient degradation of toxic microcystin-LR. For this purpose, 0.6 wt.% TiO2 loading in the TiO2-coated activated carbon was proved to be the most effective. (C) 2004 Elsevier B.V. All rights reserved.