Electrochemical Sensor Towards Environmental Micropollutants Based On Transition/rare Metal Compounds Nanomaterials

Currently,with increasing of the environmental pollution issue,it is necessary to develop a continuous,online and fast monitoring system.Recently,Electrochemical sensor with operation simple,fast response,high sensitivity and on-line have attracted more attentions from environmental workers.With the development of nanotechnology,various metal compound nano materials with versatility have a key role in the preparation of electrochemical sensor.Therefore,this paper developed environmental micropollutants detection methods based on metal compounds nanomaterials and electrochemical sensing technology.This paper includs the following study:1.The one part,a novel flake MoS₂ was prepared by a convenient and low-cost approach and then its suspension was coated on the surface of carbon paste electrode?MoS2/CPE?to develop electrochemical sensor for the determination of UV-24 and TCS.EIS,CV and DPV were employed to evaluate MoS₂/CPE electrocatalytic oxidation toward UV-24 and TCS.Compared with CPE,their oxidation peaks currents were signifantly improved and the detection limit were repectively 0.8 ?M?S/N = 3?and 0.1 ?M?S/N = 3?.The other one,Ag-MoS₂ composite also was prepared and mixed into IL to form stable composite as platform of Hb immoblization on the CPE.Spectroscopic and electrochemical results demonstrated that the Ag-MoS₂/IL composites were sutible for immobilizing Hb.Based on these studied,a novel NO2-sensor was developed and its exhibited wider linear ranges?0.5-1000 ?M and 1000-3500 ?M?and low detection limits?0.2 ?M?.2.Here,a novel NiCo₂S₄ with reticulated hollow spheres assembled from rod-like structures was prepared by a one-pot solvothermal method and its formation mechanism was discussed.Then the NiCo2S4 from different experiment conditions were used to modify CPE to construct acetylcholinesterase?AChE?-based biosensors.Moreover,comparison of NiCo2S4 materials from different experiment conditions as biosensors was investigated by EIS and DPV,and the best one that was reticulated hollow spheres assembled from rod-like structures NiCo2S4 has been successfully employed as a matrix of AChE immobilization for the special structure,superior conductivity and rich reaction active sites.When using common two kinds of organophosphate pesticides as model analyte,the biosensors demonstrated a wide linear range of 1.0×10-12-1.0×10-8 g·mL-1 with the detection limit of 4.2×10-13 g·mL-1 for methyl parathion,and 1.0×10-13-1.0×10-10 g·mL-1 with the detection limit of 3.5×10-14 g·mL-1 for paraoxon,respectively.The proposed biosensors exhibited many advantages such as acceptable stability and low cost,providing a promising tool for analysis of organophosphate pesticides.3.The bimetal-organic frameworks?BMOFs?were synthesized at room temperature,followed by a pyrolysis process of ZnCo-BMOFs to yield derived materials ZnCo oxidation.Especially,the X-ray powder diffraction?XRD?measurement showed that the Zn3CO3-BMOF derived material was a mixture of ZnO and ZnCo2O4,which had best conductivity in these derived materials.Following,ZnO/ ZnCo2O4 was used to construct electrochemical sensor for the simultaneous detection of naphthol isomers and improved the electron transfer and electrocatalytic capacity toward the oxidation of 1-NAP and 2-NAP.The oxidation peak current was linearly dependent on the 1-NAP and 2-NAP concentrations in the range of 0.4-30 ?M and 0.2-25 ?M and the detection limits for 1-NAP and 2-NAP were 0.2 and 0.1 ?M,respectively.The excellent electrocatalytic performance could be attributed to the high conductivity and more active sites as well as unique structure of ZnO/ ZnCo2O4.4.An effective strategy was developed to construct porous metallic Co embedded N-doped carbon?Co NC?material via annealing ZnCo-BMOFs precursor at 800?under N2 atmosphere during which Co can be reduced by carbonization of the organic linker and Zn is selectively evaporated away.As matrix for Mb immoblization,the Co NC/IL composite showed a good biocompatibility.Compared with ZIF-8 and ZIF-67 derived materials,the BMOFs derived materials with synergistic effect of high surface areas and more active sites enhance the immobilization efficiency of proteins and facilitate the direct electron transfer.Notably,the developed biosensor based on Co NC-5/IL composite demonstrating direct electrochemistry with faster electron-transfer rate?3.76 s-1?and excellent catalytic activity towards tricloroacetic acid TCA.The biosesor exhibited a linear response from 0.2-20 mM with detection limit of 0.08 mM?S/N=3?for TCA.In addition,the biosensor had high reproducibility,selectivityand stability,indicating potential valuable tool for monitoring TCA in enviromental samples.5.A series of metal ions including Fe3+,Zr4+ and La3+ were respectively connected with 2-aminoterephthalate to form three MOFs.Especially,La-MOF-NH2 was firstly reported and had like-wool ball structure formed by many streaky-shaped intertwining each other.The effective strategy was developed to obtain good performance electrode modified materials via annealing three MOFs precursor at 550 oC under N2 atmosphere.The results clearly displayed that carbon-based composites have been formed and remain their orginal structure.As immoblization matrix for enzyme,the three materials all were successfully used to construct AChE biosensor for the detection of organophosphate pesticides.As result,the biosensor based on [La-MOF-NH2]N2 with specical structure have best electrochemical preformance.The linear range was found to be 1.0×10-13-5.0×10-9 g·mL-1 with the detection limit of 5.8×10-14 g·mL-1 for methyl parathion.The proposed method for preparing excellent electrode materials may provide a chance to exploring analysis of enzyme inhibitors.