The Preparation And Application Of Polymer Modified COFs Based Nanocomposites

In recent years,with the rapid development of the society,the numerous environmental problems were brought and has aroused the widely concentration of the people.The safety of the water environment is related to the safety of human and organisms in nature.At present,the problem of water pollution is becoming more and more serious,which need to be paied close attention and solved.In the process of discharge daily life and hospital medical wastewater,a large number of personal care products（PPCPs）and various antibiotics were not absorbed by the human body often discharged into water,which undoubtedly increased the load of the water environment.The self-clean capacity of the water body would be decreased obviously if abundant of pollutants were discharged into water.Therefore,the control treatment of water pollution is urgent.The core of this research is the removal of pollutants from water.The adsorption method is often used to remove the pollutants from water for the advantage of low cost,high efficiency and so on.This paper focuses on the design and synthesis of new nanocomposites for the application of removal pollutants from wastewater.The morphology,pore volume,specific surface area,crystal structure and element content distribution of the prepared nanocomposites were characterized by XRD,FT-IR,SEM,TEM,bet and XPS.In addition,the adsorption properties of adsorbents under different conditions were explored by investigating batch adsorption experiments such as reaction time,the dosage of adsorbent,initial concentration of pollutants,reaction temperature,different p H and interfering ions.Except for that,the adsorption mechanisms were also discussed.In view of this,the related work has been carried out as following:1.Polypyrrole（Polypyrrole,PPy）modified GO/COF-300 nanocomposite were prepared for the first time.The adsorption properties of the materials with different proportions of GO（Graphene oxide）,COF-300 and PPy were investigated.The results showed that the optimal removal efficiency was obtained when the mass ratio of GO to COF-300 was 1:2,which was named as GO/2COF-300.After PPy modification,the preferable removal efficiency was acquired as the ratio of GO/2COF-300 to PPy is 1:4,which was recorded as GO/2COF-300/4PPy.The characterization of XRD,FT-IR and BET showed that GO/2COF-300/4PPy nanocomposites had regular crystal and porous structures.In addition,indomethacin（IDM）and diclofenac（DCF）were selected as the model pollutants,which were used to investeigate the adsorption performance of the GO/2COF-300/4PPy nanocomposites.The adsorption properities of GO/2COF-300/4PPy nanocomposites were investigated under different conditions such as different reaction time,the dosage of adsorbents,initial concentration of pollutants,reaction temperature and p H.The results showed that the adsorption equilibrium of IDM and DCF with GO/2COF-300/4PPy were reached just only in 60 min.Under natural conditions,GO/2COF-300/4PPy showed high adsorption capacity for IDM and DCF at 114.67 mg/g and 137.73 mg/g respectively.According to the model fitting of adsorption kinetics and adsorption isotherm,the adsorption process conforms to the pseudo second-order model and Langmuir isotherm model,which illustrated that the adsorption process was a chemical process and monolayer adsorption.In addition,the effect of humic acid（HA）on the adsorption performance of GO/2COF-300/4PPy was investigated.The results declared that the removal efficiency of GO/2COF-300/4PPy for IDM and DCF didn’t decrease significantly with the concentration of HA at 5-25mg/L.After 8 adsorption-desorption processes,GO/2COF-300/4PPy still maintains high removal efficiency for IDM and DCF at 89.1%and 89.4%respectively.This phenomenon illustrated that the prepared GO/2COF-300/4PPy nanocomposites obained good reusability and stability.The biological toxicity of GO/2COF-300/4PPy was investigated.The bacterial activity experiments showed that GO/2COF-300/4PPy can effectively remove IDM and DCF from water solution and had little effect on the organisms.Finally,the removal of IDM and DCF by GO/2COF-300/4PPy in Yellow River water and medical wastewater was investigated.Meanwhile,the removal efficiency of IDM and DCF by GO/2COF-300/4PPy were 52.1%and 38.37%in hospital wastewater and Yellow River,respectively.The phenomenon illustrated that GO/2COF-300/4PPy had certain removal effect and potential application value in practical application ability.2.In order to further reduce the cost of adsorbent,the use low-cost microcrystalline cellulose（MCC）was selected as the raw material for the preparation of the adsorbent.A novel MCC/COF-300/PANI nanocomposites were prepared by modifying MCC/COF-300 with polyaniline（PANI）.The characterization of XRD,FT-IR and BET illustrated that MCC/COF-300/PANI nanocomposites had regular crystal and porous structure.The characterization of BET showed that the specific surface area of MCC/COF-300/PANI nanocomposites increased greatly from 8.83 m~2/g to 69.86 cm~2/g after PANI modification,which was more conducive to the adsorption process.In addition,IDM and diclofenac DCF were selected as the model pollutants,which were used to investeigate the adsorption performance of the MCC/COF-300/PANI nanocomposites.The removal of IDM and DCF by MCC/COF-300/PANI was investigated under different conditions such as different reaction time,the dosage of adsorbents,initial concentration of pollutants,reaction temperature and p H.The results showed that the adsorption equilibrium of IDM and DCF with MCC/COF-300/PANI were reached just only in 30 min.Under natural conditions,MCC/COF-300/PANI showed high adsorption capacity for IDM and DCF at 149.1 mg/g and 112.5 mg/g,respectively.According to the model fitting of adsorption kinetics and adsorption isotherm,the adsorption kinetics of MCC/COF-300/PANI for IDM and DCF conforms to the pseudo second-order model,the adsorption process of MCC/COF-300/PANI for IDM conforms to the Langmuir isotherm model,and the adsorption process for DCF conforms to the Freundlich isotherm model.The results showed that the adsorption process of MCC/COF-300/PANI for IDM and DCF mainly belongs to chemical adsorption,and the adsorption of IDM was monolayer adsorption,the adsorption of DCF was multilayer adsorption.The interference of the adsorption performance of MCC/COF-300/PANI for IDM and DCF with different coexisting ions were investigated.The experimental results showed that the high concentrations of Na⁺,Ca²⁺,SO₄^2-,H₂PO₄^-,NO₃^-and CO₃^2-in water were conducive to the adsorption process.After5 adsorption-desorption cycles,MCC/COF-300/PANI still still maintains high removal efficiency for IDM and DCF at 76.8%and 76.6%respectively.This phenomenon illustrated that the prepared MCC/COF-300/PANI nanocomposites obained good reusability and stability.In addition,Chlorella was cultured in water samples before and after MCC/COF-300/PANI adsorption.The experimental results illustrated that the biological toxicity of water samples treated with MCC/COF-300/PANI was significantly reduced.The results demonstrated that the IDM/DCF water samples treated by MCC/COF-300/PANI reduced the biological toxicity of the water significantly.Finally,the removal of IDM and DCF in Yellow River water,tap water and lake water by MCC/COF-300/PANI was investigated.The results decleared that MCC/COF-300/PANI could be applied to the removal of typical antibiotics in actual water.The research showed that MCC/COF-300/PANI possessed the potential application for the adsorption and removal of antibiotics in from wastewater.