Construction Of Novel Bimetallic Nanocomposite Electrode Materials And The Studies On The Determination Of Environmental Pollutants

The analysis and detection of environmental pollutants are of great importance to environmental protection and the health of mankind.Compareing with traditional analytical methods,electrochemical method has a lot of advantages such as fast response,high sensitivity,low cost and the ability to be miniaturized,which has attracted much attention in the aspects of food safety and environmental protection.In this paper,ILs-CaFe₂O₄/MWCNTs ? ZnFe₂O₄/SWCNTs and ILs@NiCo₂O₄-P nano-hybrids have been fabricated to construct new-type sensors.The proposed electrochemical sensors were successfully applied to the analysis of CBZ?TBZ and toxic metals Tl⁺?Pb²⁺?Cu²⁺.The main research work is as follows:A simple and sensitive electrochemical analysis method for CBZ using ILs-CaFe₂O₄/MWCNTs/GCE was developed.ILs-CaFe₂O₄/MWCNTs nano-hybrid exhibited good dispersibility and conductivity.The electrochemical behavior of CBZ was investigated using cyclic voltammetry?CV?.The results showed that the reaction of CBZ at the ILs-Ca Fe₂O₄/MWCNTs/GCE was a totally irreversible process.The number of electron transfer was 2.Based on the synergistic effect between ILs-CaFe₂O₄ and MWCNTs,the modified electrode exhibited an obvious electrocatalytic activity toward the oxidation of CBZ.The influence of various factors were studied.In the pH 4.0 PBS,the electrochemical responses of CBZ were linear in the concentrations range of 0.03¹05.0 ?mol/L,and the detection limit?LOD?was 9.41 nmol/L?S/N=3?.The method was successfully applied to the detection of CBZ in paddy water and commercial fruits with satisfied results.Moreover,ILs-CaFe₂O₄/MWCNTs/GCE showed good stability and reproducibility.Zn Fe₂O₄/SWCNTs nanocomposite was synthesized through a facile one-step hydrothermal method and used as a modified electrode material for simultaneous determination of CBZ and TBZ.The modified electrode exhibited high conductivity and large surface area,which could increased the electroactive sites and accelerated electron transfer.The electrochemical behaviors of CBZ and TBZ were investigated using cyclic voltammetry?CV?and differential pulse voltammetry?DPV?.The influence of various factors and the electrochemical reaction mechanism were studied.The results showed that the reaction of CBZ/TBZ was controlled by adsorption/diffusion and was a quasi-reversible/an irreversible process at the Zn Fe₂O₄/SWCNTs/GCE.In the pH 7.0 PBS,the liner range of CBZ was 0.5¹00.0 ?mol/L,and the LOD?S/N=3?was 0.09 ?mol/L.The liner range of TBZ was 0.5¹00.0 ?mol/L,and the LOD?S/N=3?was 0.05 ?mol/L.Moreover,Zn Fe₂O₄/SWCNTs/GCE showed good stability and anti-interferential ability.Satisfied results indicated that the proposed electrode was successfully applied to the determination of CBZ and TBZ in the real samples.The different morphologies of NiCo₂O₄,consisting of nanoparticles?NiCo₂O₄-N?,nanoplates?NiCo₂O₄-P?and microspheres?NiCo₂O₄-S?were fabricated.It was found that the electrocatalytic properties of the sensing materials were strongly dependent on morphology and specific surface area.The porous NiCo₂O₄ hexagonal nanoplates coupled with ILs as modified materials for the simultaneous determination of Tl⁺,Pb²⁺ and Cu²⁺ exhibited enhanced electrocatalytic activity due to large specific surface area,excellent electronic conductivity,and unique porous nanostructure.The analytical performance of the ILs@NiCo₂O₄-P/GCE was examined using differential pulse anodic stripping voltammetry?DPASV?.In the pH 4.0 HAc-NaAc,the electrode showed a good linear response to Tl⁺,Pb²⁺ and Cu²⁺ in the concentration range of 0.1¹00.0,0.1¹00.0 and 0.05¹00.0 ?g/L,respectively.The LODs?S/N=3?were 0.046,0.034 and 0.029 ?g/L,respectively.The fabricated sensor was successfully applied to detect trace Tl⁺,Pb²⁺ and Cu²⁺ in various water and soil samples with satisfactory results.