Study On Preparation Of Manganese-Based Metal Oxides And Their Properties Of Adsorption And Catalytic Degradation

In this paper,manganese dioxide was synthesized by hydrothermal method.The metal ions were used to control the crystal structure and morphology of manganese dioxide.The manganese dioxide catalysts were used to degrade Rhodamine B and Congo red dye wastewater and adsorption heavy metal hexavalent chromium from aqueous solution.The main factors of catalytic degradation and adsorption were examined systematically.For the preparation of?-MnO₂,Fe³⁺-doped led to the formation of?-MnO₂.The morphology changes from a regular rod shape to a short rod shape with poor crystallinity.For the preparation of?-MnO₂,Fe³⁺-doped led to the formation of?-MnO₂.The morphology changes from a sheet to a rod.Fe³⁺-doped?-MnO₂ were used to degrade 100 mL 10 mg·L^-1 Rhodamine B.The result indicated that at 20?,the removal rate of rhodamine B was 99%when the pH value kept 6 and 0.005 g of catalyst and 6 mL of hydrogen peroxide were dispersed in solution.The results in also show successful decolorization in three successive cycles,while maintaining 87%activity.Ag⁺doped?-MnO₂ were used to degrade 100 mL 100 mg·L^-1 Congo red,The result indicated that at 25?,the removal rate of Congo red was 99%when the pH value kept 6and 0.1 g of catalyst and 5 mL of hydrogen peroxide were dispersed in solution.The results in also show successful decolorization in four successive cycles,while maintaining76%activity.Fe³⁺doped?-MnO₂ were used to adsorb hexavalent chromium.The specific surface area,pore volume and pore diameter of the adsorbent were 253.905 m²·g^-1,0.64 cm³·g^-1,and 3.391 nm,respectively.The result indicated that the removal rate of hexavalent chromium was 80%when the solution was alkaline,and the adsorption amount was 38.4mg·g^-1.