| With the continuous development of the global industrialization process,the subsequent heavy metal ion pollution has attracted worldwide attention.As we all know,heavy metal ion pollution has brought serious harm and threat to the living environment of nature and human life and health.Therefore,it is of great significance to seek a simple,convenient and sensitive analytical method for the detection of heavy metal ions.Electrochemical analysis technology has been widely used in the detection of heavy metal ions due to its advantages such as easy operation,strong selectivity,high sensitivity,and low cost.Graphite carbon nitride materials(g-C3N4)have attracted widespread attention in the field of electrochemical sensing due to their excellent physical and chemical properties.In this paper,based on graphite phase carbon nitride materials,three kinds of carbon nitride-based modified electrodes were prepared by electroplating,and the detection of iron and copper ions was studied by differential pulse voltammetry.The main content are listed as follows:1.[BMIM]PF6/g-C3N4/ITO modified electrode was prepared to detect iron ions of different valences.The results show that the sensing mechanism of Fe2+ and Fe3+ by the modified electrode is surface adsorption control mechanism.By means of differential pulse voltammetry,the co-existence of Fe2+ and Fe3+can be successfully identified by the modified electrode without the addition of masking agent or complexing agent,and the quantitative detection of Fe2+ and Fe3+ can be carried out in the concentration range of 5×10-6～3.5×10-4 mol/L when the co-existence of Fe2+ and Fe3+ exists.The electrode also has excellent reproducibility and stability.2.A water-dispersed carbon nitride material with a concentration of 0.5 mg/mL was prepared by chemical oxidation of graphite phase carbon nitride.The water-dispersed carbon nitride modified electrode(W-g-C3N4/ITO)was further prepared and used for the detection of copper ions.The influence mechanism of different buffer solutions on the detection of copper ions was also discussed.The results show that the chemical adsorption between different buffer solutions and W-g-C3N4 and the complexation of different buffer molecules on Cu2+ together affect the DPV response of W-g-C3N4/ITO to copper ions.In addition,within the linear range of 0.322～25.8μmol/L,the detection limit of W-g-C3N4/ITO for Cu2+ is 0.167 μmol/L,or 0.041 mg/L,which is lower than the limit of Cu2+ in drinking water stipulated by the World Health Organization(1 mg/L).3.The polydopamine and water-dispersed carbon nitride composites(PDA@W-g-C3N4)were prepared by combining dopamine(DA)with water-dispersed carbon nitride(W-g-C3N4)at different mass ratios.The modified electrode PDA@W-g-C3N4/ITO was prepared by using the composite material.By cyclic voltammetry(CV)and electrochemical impedance(EIS)analysis,the modified electrode PDA@W-g-C3N4/ITO with the mass ratio of 1:1 between DA and W-g-C3N4 was determined for the detection of Cu2+.The results show that,compared with W-g-C3N4/ITO,PDA@W-g-C3N4/ITO has a lower detection limit for Cu2+.The effects of experimental parameters such as buffer solution,pH,enrichment potential,and enrichment time on the stripping peak current of copper ions were optimized.Under the optimal experimental conditions,the detection limit of Cu2+ is 3.789 nmol/L in the linear range of 0.033～0.933 μmol/L.At the same time,the modified electrode has good reproducibility,anti-interference and long-term stability.Figure[33]Table[9]Reference[125]... |
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