An ultra-high surface area mesoporous carbon prepared by a novel MnO-templated method for highly effective adsorption of methylene blue.

Mesoporous carbon is considered as the most effective adsorbent for dyes with large molecule diameter. In this study, an ultra-high surface area mesoporous carbon was derived using a kind of new template precursors (manganese salts), i.e. manganese carbonate (MC), manganese oxalate (MO) and manganese acetate (MA). The XRD results demonstrated that after the pyrolysis of the mixture of manganese salts and poly(vinyl alcohol) (PVA) over 500 °C, MnO was only the Mn species on carbon and the particle sizes of the generated MnO were in the range of 1.92-15.11 nm, with the lowest value derived from MO. All prepared carbons presented evident mesoporous characteristics, with higher specific surface areas (SBET) at 2138 m2/g, mesopore volume (Vmeso) at 3.56 cm3/g, and mesopore ratios > 95%, together with the lowest and narrowest mesopore size distribution, for the MO-templated sample. The sample had high adsorption capacities for methylene blue, up to 1791 mg/g, and extremely fast adsorption rates with the adsorption equilibrium time within 1 min, which was significantly higher than previous studies. The results demonstrated that the novel MnO-templated method is very promising for the preparation of high surface area mesoporous carbon for highly effective adsorption of methylene blue.