| The massive use of various antibiotics and organic dyes has caused increasingly serious environmental problems and posed a great threat to human health.The key to solving the environmental pollution problems is to develop a safe and efficient catalytic degradation and antibacterial material that is less likely to cause bacterial resistance.As a result,the safe,green and environmental friendly photocatalytic technology has been applied.Metal/covalent organic frameworks（MOF/COF）have a wide range of applications in catalysis,analytical monitoring and adsorption separation due to their large specific surface area,ordered pore size,easy surface modification and high stability.In this paper,metal/covalent organic framework composites were synthesized by a facile process,and their catalytic degradation and bacterial inhibition properties were investigated.The main studies are as follows.（1）Four different COFs(COFTB-AD,COFTB-DT,COFTB-DC,COFTB-DH)were synthesized by a one-pot reaction using 2,4,6-tricarbonylresorcinol with four dia-minopyrimidine ligands（2,4-diamino-6-methoxy-pyrimidine,4,6-diamino-2-mercaptomidine,2,4-diamino-6-chloropyrimidine,2,4-diamino-6-hydroxy pyrimidine）respectively.Under irradiation of a xenon lamp with a photocurrent of 20μA and a wavelength greater than 400 nm for 20 minutes.The order of the degradation performances of the four COFs is in the following order:COFTB-AD>COFTB-DC>COFTB-DT>COFTB-DH.That of the sterilization performance is in the following order:COFTB-AD>COFTB-DC>COFTB-DT>COFTB-DH,indicating that COFTB-AD containing methoxy has better degradation and antibacterial performance against the dyes.The degradation efficiency of rhodamine B was 95%and the antibacterial rate was up to99%.In addition,COFTB-AD has good recyclability.（2）g-C3N4/COFTR-PY composites were prepared by one-pot method using 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and 4,6-pyrimidinediamine as precursors and homotrimethylbenzene and 1,4-dioxane as solvents in the presence of nano-carbon nitride（g-C3N4）.The ternary composites g-C3N4/COFTR-PY-Mn Fe2O4were prepared by post modification of magnetic manganese ferrate（Mn Fe2O4）nanoparticles.Being irradiated with visible light at a photocurrent of 20μA and a wavelength greater than400 nm for 20 min,the photocatalytic degradation rates of rhodamine B by using g-C3N4/COFTR-PY-Mn Fe2O4,g-C3N4/COFTR-PY,COFTR-PY,Mn Fe2O4and g-C3N4were99%,98%,60%,30%and 42%.respectively,The sterilization rates were:99%,92%,58%,52%and 64%.Therefore,the catalytic degradation or antibacterial ability of COFTR-PY,g-C3N4,g-C3N4/COFTR-PYand g-C3N4/COFTR-PY-Mn Fe2O4 against rhodamine B or E.coli were measured in the following order:g-C3N4/COFTR-PY-Mn Fe2O4≈g-C3N4/COFTR-PY>COFTR-PY>g-C3N4.The experimental results indicate that the magnetic material g-C3N4/COFTR-PY-Mn Fe2O4has excellent dye catalytic degradation and sterilization properties.（3）MOF@ZIF-67 was synthesized from 2-methylimidazole and Co（NO3）2·6H2O.Then Mn2+was added to prepare Mn@ZIF-67 composite material.The morphology and structure of the materials were characterized by scanning electron microscopy（SEM）,X-ray diffraction and infrared spectroscopy.Mn@ZIF-67 composites have excellent enzyme simulation properties in weakly acidic solutions,and can be used for colometric detection of ascorbic acid（AA）and artemisinin（Art）concentrations in the presence of TMB.The optimal experimental conditions for the detection of AA and Art were optimized.The linear range of AA was 0-30μM and the limit of detection was as low as 0.05μM at p H=5.The linear range of Art was 0-22μM and the detection limit was 0.1μM at p H=3.In addition,the Mn@ZIF-67 composite was studied with the inactivation activity of Escherichia coli,and it was found that the composite had good sterilization performance.The effects of different proportions of manganese and cobalt on the sterilization performance were tested.The mechanism of catalytic degradation and sterilization of Mn@ZIF-67 composite was discussed through the free radical trapping experiment. |
