| With the development of economy and society, water pollution problem hasbecome a research focus of academe and government. Biological treatmenttechnologies are widely used due to many advantages, such as low cost, high efficiency,multifunction, easy operation and pollution free. In this paper, three nano-composites,LDH/lysozyme, LDH/GO and LDH/GO/FeP were prepared with MgAl-NO3-LDH asthe carrier. As novel biological technologies, they were tried to apply to wastewatertreatment. The properties of composites were characterized by using X-ray diffraction(XRD), infrared spectroscopy (FT-IR), atomic force microscopy (AFM),ultraviolet-visible absorption (UV-vis), cyclic voltammetry (CV) and electrochemicalimpedance spectroscopy (EIS). The experimental study and results are as follows:(1) First, MgAl-NO3-LDH precursor was prepared by the co-precipitation method.XRD showed that LDH has a good single crystal structure. Then, LDH/lysozymecomposite was prepared by inserting lysozyme into MgAl-LDH interlayers withadjusting the appropriate PH. The composite structure characterized by XRD andFT-IR showed that lysozyme was successfully intercalated into LDH. Using thiscomposite material, the antibacterial ability to Staphylococcus aureus was studied. Theresults showed that sterilizing effect is very good and antibacterial performance waseffected by the ratio of LDH/lysozyme and PH of aqueous solution containingbacterium. Further studies found that antibacterial efficiencies of LDH/lysozyme (massratio=1:0.5) nano-composite were always more than94%in the range of PH3~9. Andduring the study period, the material can continue to be used without replacement.Therefore, it would become a potential new disinfectant in the enzymatic treatment ofsewage because of its good bactericidal activity and no pollution.(2) By the layer-by-layer self-assembly technology (LBL), the positively chargedLDH and negatively charged graphene oxide (GO) were modified onto ITO electrodeand LDH/GO composite film electrode was prepared as the anode of the environmentfriendly reactor---two chamber microbial fuel cell (MFC). UV-vis indicated that LDHand GO was successfully modified onto the ITO substrate electrode by self-assemblytechnique. AFM analysis of surface morphology showed that the LDH/GO compositefilm is a smooth and uniform film of nanometer thickness. Electrochemical propertieswere tested by means of CV, EIS and polarization curves, and the results showed that the LDH/GO-modified electrode possessed strong capability to catalytically reduce O2.They can also enhance the electron transfer and reduce interface resistance. Comparedwith the Rct of bare ITO electrode (7028), the Rct of (LDH/GO)n(n=10,20,30)modified electrodes were reduced to1559,2068and1745. The power of MFCincreased by66%.(3) Using the electrostatic interaction between LDH with the positive charge andGO with the negative charge and π-π conjugation between GO and iron porphyrin(FeP), LDH/GO/FeP nano-composite film material was prepared and used as thecathode in MFC. The composite film is a uniform film of nanometer thickness. XRDand UV-vis displayed that LDH, GO and FeP were successfully assembled in ITOelectrode by LBL and π-π interaction. CV, EIS and polarization curves showed thatelectron transfer reaction of LDH/GO/FeP composite film electrode was improved andthe interface resistance was reduced. When LDH/GO/FeP composite film electrodeacted as the cathode of MFC, catalytic reduction rate of O2was accelerated. Theproduction ability of MFC was improved and the power showed an increase of about36%. |
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