Preparation Of Biogenic Manganese Oxides And Treatment Performance Of17α-ethynylestradiol

In the water treatment realm, as the detecting method make progress every day,more and more environmental endocrine disrupting chemicals are detected. This kind oforganic can disrupt normal hormone function and endocrine system at very lowconcentration, people get more attention about its hazard in the environment. Biogenicmanganese oxides are produced by manganese oxidizing bacteria, it has oxidativecapacity, also has high specific surface areas and high catalytic reactivity. To removeEDCs, the advanced oxidation processes may produce toxic by-products and expensive,while the microbiological processes has the substrates selective disadvantage andgenerations long. The biogenic manganese oxides have not only the advantages of theAOPs which are fast and efficient but also the microbiological processes which arestable and complete. Thus, to investigate utilizing manganese oxidizing bacteria toproduce biogenic manganese oxides to remove EDCs in the aquatic environment issignificantly promising.In this course, manganese oxidizing bacterium MnB6was studied of its growthproperties and best growing conditions. Two addition methods of MnCl2werecompared to investigate the influence on biogenic manganese oxides preparation. Thebiogenic manganese oxides could be only produced in the stable phase of the bacterium.The influence of environmental factors on biogenic manganese oxides preparationshowed that the best pH for MnB6to produce biogenic manganese oxides is7.4, andwhen the concentration of Mn2+was below20mg/L the biogenic manganese oxidespreparation was not inhibited.The MnB6could oxidize the Mn(II) on the solid medium into brown-blackbacterial plaque, and the NH2OHCl could fade this color away. This method could beused to detect whether there is biogenic manganese oxides are produced. The FTIRanalysis showed that protein and Mn-O bonds were synthesized during the formation ofbiogenic manganese oxides. The SEM and EDXs analysis showed that EPS wereproduced onto the wall of MnB6, while it has the element of manganese.In the study of treatment performance of EE2by manganese oxides, we chose EE2as the presentative of EDCs. The results showed that make pH lower was favorable forthe remove of EE2. Because the pHzpcof biogenic manganese oxides is higher than thatof MnO2, biogenic manganese oxides could remove EE2at pH=6or7, which the rangeof pH was wider than that of MnO2. The influence of concentration of substrates andMn(IV) on EE2remove performance confirmed that the key of manganese oxidesremove EE2is solid-liquid mass transfer process。EE2was firstly combined to thevacant sites of manganese oxides, then the electron transfer could be occurred. While there was existing of metal ions, the manganese adsorption effect of metal ions occupiedthe vacant sites of manganese oxides, inhibiting the mass transfer process of EE2tosurface of manganese oxides and remove performance of EE2.