To mitigate the threat of microcystins on the environment and human health, we demonstrate for the first time that porous activated semi-cokes (ASCs) with average pore diameters of 2-20 nm could be used as adsorbents for the fast and efficient removal of microcystin-LR (MC-LR). The surface physicochemical properties of ASCs were carefully investigated and their relations with the adsorption performance were discussed. The results showed that ASCs activated by HNO3 and KOH exhibited excellent adsorption capacities of 4276 and 8430 mu g/g, respectively, which were nearly 5 times and 10 times higher than that of activated carbon (AC). ASCs also showed a fast adsorption property by over 95% recovery of MC-LR in the initial 10 min. The overall adsorption of MC-LR on ASCs might be dominated by both external diffusion and intra-particle diffusion. In addition, ASCs manifested an outstanding reusability and the adsorption of MC-LR was hardly influenced by the coexisting fulvic acid at low concentration. Given the remarkable performance and low cost, activated semi-cokes are expected to present promising potentials for the practical application in removing microcystins from aqueous solutions. (C) 2015 Elsevier B.V. All rights reserved.