| The technology of microbial fuel cell (MFC) can deal with most organic and partial inorganic pollutants in sewage,and simultaneously produce power energy. Manganese dioxide (MnO2) modified anode studied in this dissertation aims to increase microorganism's electricity producing quantity and store electricity energy on electrode, which can enlarge electricity current.MnO2 is synthesized via hydro-thermal method on carbon felt,and the whole material acts as the anode of MFC. Scanning electron microscopy reveals that each of carbon felt's fiber is coated by MnO2. Compared with the bare carbon felt, the maximum output power of MnO2/carbon felt electrode is improved from 640mW·m-2 to 1030mW·m-2. When the modified electrode discharges for 10mins after being charged for 10mins and 20mins, it can release more electric power (131.2C·m-2 and 177.3 C·m-2, respectively) than the same electrode in stable operation. From the perspective of discharging current, the modified electrode, after being charged for 20mins, can release the current density of 0.187mA·cm-2 when it discharges at 10mins. Compared with the the same electrode in stable operation, the increasement of electric current is 0.017mA-cm-2.Reduced graphene oxide (RGO) is added on carbon felt firstly and then MnO2/RGO/carbon felt electrode is synthesized as MFC's anode. Scanning electron microscopy indicates that every carbon fiber is coated by MnO2, and that RGO and MnO2 are dotted among those fibers. When this electrode discharges for 10mins under constant potentialafter being charged for 10mins and 20mins,it can release more electric power (310.OC·m-2 and 455.0C·m-2,respectively) than the same electrode in stable operation. From the perspective of discharging current, the modified electrode, after being charged for 20mins,can release the current density of 0.143mA·cm-2 when it discharges at 10mins. Compared with same electrode in stable operation, the increasement of electric current is 0.018mA·cm-2.As the matrix, a sponge is coated by carbon nanotubes (CNTs), RGO and MnO2 successively to prepare an electrode, among which the sponge morphology is kept. Make this electrode as MFC' s anode and MFC' s maximum output power is 210mW·m-2. When this electrode discharges for 10mins after being charged for 10mins and 20mins, it can release more electric power (585.0C·m-2 and 662.5C·m-2, respectively) than the same electrode in stable operation. From the perspective of discharging current, this electrode, after being charged for 20mins, can release the current density of 0.123mA·cm-2 when it discharges at 10mins. Compared with the same electrode in stable operation, the increasement of electric current is 0.041mA·cm-2. |
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