LAUSR

Abstract Transition metal oxides with hierarchical porous nanostructure have attracted tremendous attention in removal organic pollutants and heavy metal due to their high adsorption efficiency and versatile properties. In this work, a CoO/MoO2/Mo2C composite was obtained via a one-pot hydrothermal method. The CoO/MoO2/Mo2C composite showed a core-shell structure with enhanced adsorption performance. Batch adsorption experiments indicated that adsorbent type, solution pH, dosage and pollutant concentration affected the adsorption performance of CoO/MoO2/Mo2C. The adsorption of methyl orange (MO), methylene blue (MB), Congo red (CR) and Cr(VI) fitted the Pseudo-second-order kinetic model. The Langmuir model was more suitable to describe the adsorption isotherm, and the theoretical maximum adsorption capacities were 555.6, 384.6, 219.8 and 294.1 ​mg ​g−1 @ 25 ​°C, respectively, which marched well with the experimental data (472.7, 328.0, 213.0 and 263.9 ​mg ​g−1, respectively). The adsorption capacity of CoO/MoO2/Mo2C maintained more than 80% after three adsorption-desorption cycles, which confirmed that the CoO/MoO2/Mo2C was stable and could be considered to be a potential versatile adsorbent.