Copper MOFs And Their Derived Porous Materials For Electrochemical Analysis Of Sulfanilamide And Acetaminophen In Water

Currently,with the increasement of environmental issue caused by the existence of emerging pollutants and their potential hazards,the establishment and development of detection systems with on-site monitoring and rapid response are of great importance for preventing pollution and tracing pollution source.Electrochemical analysis technology has received wide attentions from environmentalists because of its facile,responsive,sensitive,cost-effective and easy implementation of online detection.Metal organic frameworks(MOFs)have been developed as a type of ideal electrode substrates for electrochemical sensing due to their unique physicochemical properties.The improvement of their stability,sensitivity,signal-conversion capability,and universality of the related electrochemical sensors is the key to rapidly determinate contaminants.This thesis takes HKUST-1-type copper MOF as electrode substrate material and then adopts several strategies including surfactant modulation,gold nanoparticledoping,dicyandiamide assistance,and one-dimensional fiber augmentation to optimize its morphology,structure,and composition,which intend to enhance the electroanalytic performance of copper MOFs based porous materials in amine/phenolic pollutants determination.Using sulfanilamide(SA)or/and acetaminophen(AP)as the target pollutants,the electroanalytical performances and their structure-activity relationship have been explored to reveal the interfacial reaction mechanism of the target analytes in the sensing layer materials.The main contents as well as the conclusions are as follows:(1)To improve the stability of HKUST-1 in electrochemical analysis process,a polyvinylpyrrolidone(PVP)assisted strategy was developed for the synthesis of regular and homogeneous N-HKUST-1 by using PVP as a structural stabilizer and a heteroatom dopant.In the case of dopamine(DA)and SA as the target contaminants,the electroanalytical performance of constructed N-HKUST-1 sensor was superior to that of the conventional HKUST-1,which is attributed to the heteroatom introduction and good dispersion stability of N-HKUST-1.The constructed N-HKUST-1 sensor exhibited lower limit of detection(LOD)values for the determination of DA(0.15 n M)and SA(3 n M).After the electrochemical tests,the good reproducibility and stable morphological structure indicate the high stability and durability of N-HKUST-1 prepared by introducing PVP.The developed highly stable N-HKUST-1 sensor enables effective detection of DA and SA in water.(2)To solve the problems of the poor conductivity and low sensitivity of HKUST-1 during electrochemical determination process,Au nanoparticles were introduced to prepare NHKUST-1/Au composite.The introduction of exogenous Au materials increased the conductivity and electrochemical active area of HKUST-1,resulting in a 23% reduction of electrochemical impedance and a 300% increase of the electrochemical effective active area,which in turn led to the broadening of the maximum detection concentration of SA to 251.6μM.Meanwhile,N-HKUST-1/Au composite sensor for the determination of AP also exhibited excellent analytical performance with a detection range of 1～4448.4 μM and LOD of 0.16 μM.The highly conductive and sensitive N-HKUST-1/Au composite sensor was developed to achieve accurate detection of SA and AP molecules at low concentrations.(3)To enhance the signal conversion capability of HKUST-1 in electroanalytic process,a dicyandiamide-assisted strategy was utilized to synthesize well-dispersed Cu/N-doped porous carbon nanoarchitecture(Cu-NC)for the electrochemical detection of AP.Owing to the rich hierarchical pore structure,excellent conductive carbon skeleton and uniformly dispersed active Cu species,the signal-conversion capability of Cu-NC sensor was greatly enhanced.The constructed Cu-NC sensor exhibited superior electroanalytic performance for monitoring AP with linear range from 0.01 μM to 921.2 μM,and the LOD of 2.46 n M.The constructed CuNC sensor with high signal conversion capability enables rapid and sensitive detection of AP molecules.(4)To improve the universality of HKUST-1 in the electrochemical detection process,one-dimensional porous Cu/N-doped carbon nanofibers(Cu-NCNFs)were prepared via the coupled process of electrospinning technology and high-temperature pyrolysis.The resulting Cu-NCNFs sensor could simultaneously determinate AP and SA and exhibit excellent electroanalytical performance with the detection range of 0.1～445 μM(AP)and 5～500 μM(SA),the LOD of 0.028 μM(AP)and 1.26 μM(SA).By comparing the SA and AP recovery efficiency of Cu-NCNFs sensor with the N-HKUST-1 sensor,N-HKUST-1/Au sensor,and CuNC sensor in real water samples,the Cu-NCNFs sensor has the best recovery efficiency.The introduction of one-dimensional carbon fibers not only solves the problem of poor universality of HKUST-1 sensor,but also enhances the electroanalytical performance for the actual detection of amine/phenolic PPCPs.The fabricated Cu-NCNFs with high signal amplification effect enables simultaneous determination of low concentration of AP and SA.By rationally designing the modified electrode materials,the electroanalytical performance of the constructed sensors for amine/phenolic pollutants have been improved,which provide effective technical reserves for the detection of amine/phenolic contaminants in actual water environment.