Study On The Determination Of Trace Heavy Metal Ions In Water By G-C₃N₄ Nanosheet Modified Electrode

At present,heavy metal ions are seriously polluted in the water environment,and heavy metal ions are characterized by difficulty in degradation,accumulation,and trace toxicity in the living body,which are serious to human health.Electrochemical detection has received extensive attention in the detection of trace heavy metal ions due to its low cost,high sensitivity,high selectivity and good stability.In recent years,graphite-like phase carbonitride?g-C₃N₄?,as a new type of polymer material,has received extensive attention due to its excellent physical and electrochemical properties,rapid electron transport performance,low cost and environmental friendliness.In this paper,g-C₃N₄ thin-layer nanosheets were prepared by a simple one-step thermal polymerization method by adding a bubble templating agent,and the thickness and microstructure of g-C₃N₄ nanosheets were realized by changing the type and amount of bubble templating agent and thermal polymerization parameters.And then regulation of the electron transport properties and specific surface area of g-C₃N₄nanosheets,to obtain electrode modification materials with good enrichment and detection performance for a variety of heavy metal ions,thereby achieving rapid and accurate detection of heavy metal ions.1.Graphitic carbon nitride?g-C₃N₄?ultrathin nanosheets were synthesized via facile thermal polymerization taking melamine as raw materials and deionized water and acetic acid?AC?as bubble templates.Through square wave anodic stripping voltammetry?SWASV?measurements for Cd²⁺in aqueous solution.The calibration curves for Cd²⁺cover three linear ranges varying from 0.001?M to 0.1?M,0.1?M to 5?M,and 5?M to 18?M.The limit of detection?LOD?is calculated to be 0.35nM for Cd²⁺,which is 76 times lower than the World Health Organization?WHO,26.69 nM?standard for drinking water.2.RGO/g-C₃N₄ composite was prepared by a simple thermal polycondensation process and reduction of hydration hydrazine.Under optimized experimental conditions,there was a linear relationship between the square wave anode stripping voltammetry?SWASV?currents and the concentration of Pb²⁺?0.01-1000 nmol/L?with the detection limit was 1.07×10^-1212 mol/L?S/N=3?,which is lower than the standard value?48.26 nM?specified by the World Health Organization?WHO?.3.Palladium nanoparticles?PdNPs?/modified graphite carbon nitride?g-C₃N₄?porous nanosheets?PdNPs/g-C₃N₄?were synthesized via hydration hydrazine red-uction method.The morphology detection of PdNPs/g-C₃N₄)demonstrated that the surface of PdNPs/g-C₃N₄ nanosheets was uniformly distributed.The PdNPs/g-C₃N₄ modified glassy carbon?GC?electrode?PdNPs/g-C₃N₄/GC?was used for the trace detection Hg²⁺by differential pulse voltammetry?DPV?method.It dis played excellent sensitive and selective determination of trace Hg²⁺with excelle nt anti-interference,repeatability and long term stability under the same optimal experiment conditions.The limit of detection?LOD?for Hg²⁺can reach to be0.009?g/L,which being lower than that of World Health Organization?WHO?standard value for drinking water quality?1.0?g/L?and previous reported.