The montmorillonite@carbon (MMT@C) composite was synthesized by the one-step hydrothermal carbonization process. U(VI) sorption on MMT@C from aqueous solution was investigated by using batch experiments. The maximum capacity of MMT@C toward U(VI) was 20.76 mg g(-1) at pH 3.95, which was much higher than that of the raw MMT. The decoration of the functional carbonaceous species on the MMT@C improved its sorption capacity. U(VI) sorption on the MMT@C was an endothermic process. The inner-sphere surface complexation might be the primary sorption mechanism. MMT@C was a promising material for pre-concentration and immobilization of U(VI) from large volumes of aqueous solution. (C) 2015 Elsevier B.V. All rights reserved.