Effect of preparation methods on morphology of active manganese dioxide and 2,4-dinitrophenol adsorption performance

Herein active manganese dioxide was prepared by different methods using KMnO4 and MnSO4·H2O as inorganic precursors. The impact of preparation methods on morphology and adsorption performance of the synthesized products was investigated. The experimental results show that the reaction temperature and pressure had a great effect on the morphology and adsorption performance of active manganese dioxide. The shape of active manganese dioxide prepared at room temperature and pressure was short rod-like while active manganese dioxide synthesized by hydrothermal method was mesoporous fibers and had better adsorption performance. The adsorption behavior of 2,4-dinitrophenol on mesoporous manganese dioxide was well described by Langmuir and Freundlich isotherm equation (R2>0.99) and pseudo-second-order kinetic equation (R2>0.99), so the adsorption process maybe a chemical and monolayer adsorption. The pH of solution had significant effect on the adsorption performance of 2,4-dinitrophenol on mesoporous manganese dioxide. The adsorption capacity was 2.539 mg/g in the condition of pH = 7.