Processing Dyeing Wastewater By Acid Birnessite In Different Factors And Its Mechanism Studying

Manganese oxide, especially Acid Birnessite with layered structure, has potentiallyimportant application value in dye wastewater because of its efficient adsorption,oxidation and environmental friendly characteristics. Birnessite is the most common typeof manganese oxide with layered structure in the soil and sediment, which has a largesurface area, low zero charge, high cationic exchange capacity and strong oxidizing,commonly used in treating of refractory organic wastewater. However, in the field oftreating dye wastewater with MnO2, there still exist some problems. For example, Couldmanganese oxide treat anionic and cationic dyes? The process of adsorption dyes by AcidBirnessite. The mechanism of removal dyes byAcid Birnessite.In this dissertation, the manganese oxide was synthesized by reflux method, thencharacterizing of it. Selecting the cationic dye Methylene blue, rhodamine B and anionicdye methyl orange dyes as the experimental object, researching influence of removaldyes byAcid Birnessite under different factors. The results are as follows.1) In the range of1.44-9.66of pH, the removal efficiency of methylene blue byAcid Birnessite was better. The optimum concentration of manganese oxide is500mg/L.Removal rate of MB in the studying range of temperature increases almost linearly.2) The removal rate of Rhodamine B is higher by acid birnessite under acidicconditions, and the removal rate decreased with the increasing pH. The optimumconcentration of manganese oxide is500mg/L of RB. Rising temperature can promotethe removal of RB.3) The methyl orange dye was almost completely removed when the pH value was2.93, and then the removal rate decreased with the increasing pH. Higher concentrationof manganese oxide can promote the removal of MO. The removal rate of MO firstreduced and then increased as the temperature changes.4) The effect of cationic dyes and anionic dyes were good by Acid Birnessite, andthe surface charge did not affect removal rates.5) The sequence of removal rate was Alkaline Birnessite> Acid Birnessite>Todorokite> Cryptomelane when removal MB and RB by different polymorphs ofmanganese. And the order was Alkaline Birnessite> Cryptomelane> Acid Birnessite>Todorokite when removal of MO.6) Removal of MB and RB by Acid Birnessite was mainly based on the oxidationreduction of hydroxyl radicals. MO was mainly removed by physical adsorption.7) When the experiment made Acid Birnessite reused, there is still good for dyeingwastewater.