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Studies on Determination of Heavy Metal Cd(Ⅱ) Pb(Ⅱ) Based on Lonic Liquid Composite Chemically Modified Electrodes

Author: GuoJing
Tutor: FeiJunJie
School: Xiangtan University
Course: Analytical Chemistry
Keywords: Ionic liquids Chemically modified electrode Electrochemical sensors Cadmium Lead
CLC: O657.1
Type: Master's thesis
Year: 2011
Downloads: 117
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Abstract

Heavy metal ions (such as mercury, cadmium, lead, chromium and metals arsenic) has teratogenic, carcinogenic effects, and accumulation of poison, non-biodegradable nature, fate in the water, soil and biota, through the food chain human and animal health. Therefore, the establishment of a sensitive, rapid and simple detection of heavy metal ions is very necessary. The ionic liquid substance that is entirely composed of ions. Its low toxicity, high chemical and thermal stability, almost no vapor pressure, good electrical conductivity, wide potential window, etc., so that a wide range of applications in the field of electrochemistry. Based on these excellent properties of ionic liquids, the paper several new materials and preparative chemistry of ionic liquid composite modified electrode and used to study the electrochemical behavior of heavy metals Pb (II) and Cd (II), and on this basis to establish their analysis of detection methods. These findings expand the ionic liquid chemically modified electrode in Electroanalytical Chemistry, has a very important significance. The main content of the thesis are: (1) titanium silicalite and ionic liquid composite prepared a Titanosilicalite - ionic liquid composite film modified glassy carbon electrode, constructed a linear sweep stripping voltammetry determination of Cd (II ) electrochemical sensing platform. The characteristics of this composite film modified electrode. The prepared Titanosilicalite - ionic liquid composite film modified glassy carbon electrode for the determination of Cd (II) good selectivity and sensitivity. In the optimal experimental conditions, the oxidation peak current and the concentration of Cd (II) in 6.8 × 10 ^{-8 ^{1.6 × 10 ^{-5 mol / L, showed a good linear relationship (R = 0.998) and a detection limit of 1.0 × 10-9 mol / L (S / N = 3). Finally, this approach successfully applied to the determination of Cd (II) in water samples. (2) new thiolated mesoporous molecular sieves and ionic liquid composite prepared a voltammetry electrochemical sensor. Preparation of a new type of chemically modified electrodes can greatly increase the stripping peak current of Cd (II) has a high sensitivity. In optimum conditions, the oxidation peak current and the concentration of Cd (II) in 2.9 × 10 ^{-8 ^{8.7 × 10 ^{-4 mol / L range, a good linear relationship (R = 0.995). -1.1 V at the enrichment of 4 min, the detection limit as low as 1.0 × 10-9 mol / L (S / N = 3). Finally, this method is successfully applied to the determination of Cd (II) in water samples. The electrochemical sensor has many excellent properties, such as the electrically active surface area of ??the fast electron transfer and low background current, for the construction of electrochemical sensing of other substances (such as heavy metal ions and environmental pollutants) to provide a good pass sense platform. (3) the establishment of an acetylene black (AB) and ionic liquids (ILs) composite film modified electrode by linear sweep stripping voltammetry sensitive electrochemical method for the determination of Cd (II). Experimental results show that the the AB / ILS composite modified glassy carbon electrode can significantly improve the sensitivity of the determination of Cd (II). Under optimum conditions, Cd (II) concentration of 1.5 × 10 ^{-8 ^{7.7 × 10 ^{-5 mol / L within the scope of its anodic stripping peak current showed a good linear relationship between the detection limit is 1.0 × 10 ^{-8 mol / L. Finally, this approach successfully applied to the determination of the actual water samples. (4) the establishment of an acetylene black (AB) and ionic liquids (ILs) composite film modified electrode by linear sweep stripping voltammetry sensitive electrochemical method for determination of Pb (II). Experimental results show that the the AB / ILS composite modified glassy carbon electrode can significantly improve the sensitivity of the determination of Pb (II). Under optimum conditions, Pb (II) concentration of 2.8 × 10 ^{-8 ^{2.5 × 10 ^{-5 mol / L range of its anodic stripping peak current showed a good linear relationship between the detection limit is 1.0 × 10-9 mol / L. Finally, this approach successfully applied to the determination of the actual water samples.}}}}}}}}}}}}}

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