Preparation Of Polypyrrole Composite Hydrogel And Its Performance In Microbial Fuel Cell

As a renewable,sustainable,simultaneous wastewater treatment and high-efficiency energy technology,microbial fuel cell(MFC)has a wide range of application potential.The anodic material was the key factor that affecting the efficiency of MFC.The three-dimensional(3D)conductive polypyrrole composite hydrogel material has good conductivity,biocompatibility and capacitancity performance.The improvement of MFC power generation and energy storage performance was due to these excellent characteristics.For this reason,this article prepared the 3D conductive polypyrrole composite hydrogel anode material for MFC.The polypyrrole-carbon nanotube composite(PPy-CNT)hydrogel with 3D macroporous structure,good conductivity and biocompatibility was successfully prepared by slow oxidation method and this self-supporting material could be directly used as electrode in MFCs.The SEM results showed that the prepared PPy-CNT hydrogel had a uniform 3D macroporous network structure with rich porosity.It was beneficial to the adhesion of exoelectrogens on the surface and inside of the material,as well as the formation of biofilms.The PPy-CNT in mass ratio of 10:1 showed best performance,including the largest output voltage,power density and storage capacity of 618 m V,3844 m W/m³,and 6533 C/m²,while it also exhibited the smallest electrochemical reaction resistance and apparent internal resistance of 34?and 148?.Then,a binder-free PPy-CS-CNT hydrogel was prepared using Fe(NO₃)₃ as the initiator and the hydrogel was used in the MFC as anode.The as-prepared electrode possessed a rich three-dimensional pore structure,good water retention and electrochemical performance.The MFC with PPy-CS-CNT exhibited a high stable output of 617 m V,which was 147 m V higher than that of the MFC with PPy anode;while the maximum power density was improved by 36%higher than the MFC with unmodified anode.Through the high-throughput analysis of the microbial community on the anodes,the prepared hydrogel exhibited better biocompatibility,while the Rhodopsedomonas and Geobacterwere the dominant electro-producing bacteria.Thirdly,the PEDOT:PSS hydrogel was crosslinked on the surface of spherical polypyrrole particles by the secondary crosslinking method to form PPy-PEDOT:PSS composite hydrogel with pleated morphology particles on the surface.Due to its 3D porous structure,good conductivity and biocompatibility,the power density of MFC with PPy-PEDOT:PSS anode exhibited an enhancement by 44.3%than the MFC with PPy anode.And the storage and total released capacity of PPy-PEDOT:PSS anode was increased by 2520C/m²and 1909 C/m²,respectively,while the protein content on the anode was also increased by 77%.The high-throughput sequencing analysis exhibited that the most dominant strain of anode biofilm was changed,from Pseudomonas to Rhodobacter.The 3D PPy-GH hydrogel with good mechanical performance was prepared through two-step method.First,the graphene oxide was reduced by hydrothermal method with pyrrole to prepare a 3D graphene hydrogel structure;then,the polypyrrole was intercalated into the blooming flower-like graphene hydrogel layer through chemical oxidation polymerization.The MFC with PPy-GH anode exhibited good performance on power generation and energy storage.The maximum power density could reach 4867 m W/m³,the storage and total discharge capacity were 7268 C/m² and 12146 C/m²,respectively.And the protein content on the anode was 82.38 mg/cm³.The high-throughput sequencing analysis showed that the optimal genus of anode biofilm was Pseudomonas(56.08%)and Thiobacillus(9.32%).