| Graphite carbon nitride(g-C3N4)is a promising two-dimensional conjugate polymer with moderate band gap(about 2.7 e V),stable chemical properties,non-toxic,large specific surface and excellent photoelectric properties.Due its cheap materials,simple synthesis,and the wide range of applications from photo-catalysis to biosensors,it has aroused great interest.At present,g-C3N4-based biosensors are mainly limited to single-channel response mode.It is of great significance to extract multi-channel information from g-C3N4 single material to develop new multi-channel biosensors for rapid and accurate substance identification.On the other hand,the application of g-C3N4 material as a catalyst for photodegradation of antibiotic organic pollutants due to its own limitations,such as high carrier recombination rate,poor dispersion in most solvents,narrow visible light absorption range,etc.The efficiency of photocatalytic degradation of antibiotics is low.The development of g-C3N4 with a new structure is of great significance to the degradation of organic matter and environmental management.The main research content and results of this paper are as follows:1.Three optical properties of g-C3N4(fluorescence,light scattering,and light-induced nanozyme activity)were used as the three-channel response mode of the biosensor for signal output,a three-dimensional sensor was constructed to identify proteins.g-C3N4 was characterized by XRD,TEM,LRS,FTIR and zeta-potential,g-C3N4 structure and surface functional group carboxyl group give g-C3N4 high biological affinity,based on the difference in structure and properties of target protein molecules,different proteins have different responses to the three optical properties of g-C3N4,which is equivalent to the fingerprint of the protein.In order to show the distribution of proteins more intuitively,LDA is used to process the response data to obtain an intuitive two-dimensional discriminant plot.The experiment explored the stability of the three-channel optical sensor,and randomly selected proteins in the matrix to verify the unknown protein,and the accuracy of two different concentrations(1?M and 10?M)reached 95.0%and 97.5%,respectively.The experiment further studied the identification of different concentrations of protein and different ratios of protein mixtures,in order to verify its practicability,the proteins in real biological fluids were accurately identified.The g-C3N4 three-channel optical sensor enables qualitative and quantitative analysis of proteins.The establishment of this sensor not only broadens the application of nano-layered materials,but also has potential prospects in the diagnosis of diseases related to changes in protein levels.2.Trimellitic acid is a promising precursor material,which can convert the original tri-s-triazine condensation pathway of g-C3N4 to s-triazine,thereby adjusting the structure and photoelectric properties of g-C3N4.The obtained s-triazine g-C3N4 is hydrothermally oxidized at a certain temperature to make it have better dispersion and adsorption of organic pollutant molecules,and the modified s-triazine g-C3N4 was characterized by FT-IR and XRD.By comparing the adsorption and illumination kinetics of triazine g-C3N4 on antibiotics before and after hydrothermal treatment,the experiment studied the modified triazine-based g-C3N4 photo-oxidation to remove antibiotics influencing factors(time,p H and LED lights of different wavelengths)and the mechanism.It is obvious that the modified triazine-based g-C3N4 can better adsorption and photosensitive degradation of cefixime(CFX).The interaction of?-?conjugation and hydrogen bonding between g-C3N4 and antibiotic contaminants is used to adsorb the contaminants on its surface.Under the illumination of white LED lamp,g-C3N4 and the dissolved oxygen in the solution generate strong oxidative reactive oxygen species(ROS)substances such as ~1O2,?OH,etc.through electron transfer and energy transfer,thereby the photosensitive oxidation removes the antibiotic cefixime(CFX),and the removal effect can reach 99%.This thechnique for degradation of antibiotics is simple,fast,and efficient,and has a wide range of applications.It is potiential to use sunlight for the treatment of actual wastewater.Hence,the thechnique has practical appicability for the treatment of water pollutions. |
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