The Preparation Of Mesoporous Materials Coated Glassy Carbon Electrode And The Detection Of Heavy Metal IONS

Incidents of heavy metal ions poisoning multiplied in recent years. Such as excess chromium poison capsule events, thallium poisoning events from zhu ling, wuxi panasonic cadmium poisoning events. So how to detect and remove heavy metal ions is a very important problem. The frequently-used analytical techniques for heavy metal ions measurement are inductively coupled plasma-atomic emission spectroscopy (ICP-AES), atomic absorption spectroscopy(AAS), inductively coupled plasma-mass spectrometry(ICP-MS) and high-performance liquid chromatography. Although it is a good way to detect heavy metal ions, these methods are limited by high cost and time consumption. But electrochemical method is relatively simple device, convenient automatic operation. Because of its high sensitivity and good selectivity, it becomes a good method to detect heavy metal ions.One of the key problems of testing heavy metal ions is the design of the working electrode. So choosing the right working electrode is very important. Because mesoporous materials have high specific surface area, uniform tunable pore size and easy surface functionalization etc, it can be modified on the electrode surface, thus improvement of electrode primitive properties can be achieved,for the sake of realizing the functional design of electrode, using mesoporous materials modified electrode, not only can greatly improve the detection sensitivity and selectivity of heavy metal ions of the modified electrodes, and can be easy to eliminate the interference of coexisting component and broaden the linear range with normal materials. So the modified glassy carbon electrode with mesoporous materials were choosed. This paper is the inorganic and organic functionalized MCM-48mesoporous materials synthetized through the direct synthesis or co-condensation method,And they are used to detect heavy metal ions after the mesoporous materials were coated on them.Based on the previous reports, three innovative works were carried out in this paper. The conclusions are as follows:1. Using triblock poly(ethylene oxide)poly(propylene oxide)poly(ethylene oxide)P123) and hexadecyltrimethyl ammonium bromide(CTAB) as co-template to synthesize MCM-48. The stuff was proved by XRD, FTIR and SEM. Electrochemical workstation(CHI650a) was used to study MCM48, and discuss the best conditions to detect Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ). Take Cd(Ⅱ) for example choosing the optimum experiment conditions from electrolyte, pH value, different potential and enrichment time.The electrode gives a best peak for Cd(Ⅱ) in1.2v potential,180s deposition time and PH=7NH3H2O-NH4Cl buffer solution.The detection limit(LOD)(S/N=3) of Cd(Ⅱ), Cu(Ⅱ), Pb(Ⅱ) are0.2nM,13.34nM and31nM respectively, and linear ranges are0.003125-12.00μM,0.2422-107.2μM,0.377-28.88μM respectively. Moreover, the mesoporous materials was applied in environmental samples triumphantly.2. With cetyltrimethylammonium bromide(CTAB) and poly(ethylene glycol)block-poly(propylene glycol)block-poly(ethylene glycol)(P123) as a template agent, and Tetraethylorthosilicate(TEOS) as silica source, and has3-[2-(2-aminoethylanimo)ethylamino]-propyl-trimethoxysilane (DTES) mesoporous materials NH2-MCM48were directly synthesized,and the products obtained were characterized by XRD,TGA and SEM. NH2-MCM48was studied by electrochemical workstation(CHI650a) and probes into the the best conditions of the detection of Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) the detection limits and linear ranges of Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) were detected, and use it to analysis Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) in water samples. Cu(Ⅱ) was the injecting ionic, the electrolyte, pH and enrichment time conditions is discussed to choose the best experimental conditions. As a result, the optimal experimental conditions is that the enrichment time is180s, and pH=7NH3H2O-NH4Cl is the best buffer solution. The detection limit(LOD)(S/N=3) of Cd(Ⅱ), Cu(Ⅱ) and Pb(Ⅱ) is0.23nM,11.2nM and0.696nM respectively. And the linear range is0.0015-17.2μM,0.125-154.9μM,0.01-17.0μM respectively. The method was applied in water detection successfully.3.Thiol-functionalized MCM-48(SH-MCM-48) was synthesized by co-condensation method, with co-templates of cetyltrimethylammonium bromide (CTAB) and nonionic poly(ethylene oxide)poly(propylene oxide)poly(ethylene oxide)triblock copolymer(Pluronic P123) together with (3-sulphur propyl) triethoxy silane (MPTMS)The resulting material was characterized by XRD, TGA, FTIR and SEM. Electrochemical workstation (CHI650a) was used to study the synthesis of SH-MCM48, and probes the best conditions to detect Pb (Ⅱ), Cu (Ⅱ), Hg (Ⅱ) and Cd (Ⅱ), the detection limits and linear ranges of Pb (Ⅱ), Cu (Ⅱ), Hg (Ⅱ) and Cd (Ⅱ) were detected. Take Pb (Ⅱ) as the injecting ionic, the optimum experiment conditions was choosed from electrolyte, pH value, different potential and enrichment time. The suitable experimental conditions are0.4v potential from the results,180s deposition time and pH=7NH3H2O-NH4Cl buffer solution. And the detection limits are3.78nM,4.09nM,21nM and0.363nM, the amperometric response to Pb(Ⅱ), Cu(Ⅱ), Hg (Ⅱ) and Cd (II) are linears in the ranges from0.04454to31.52μM,0.2422to94.67μM,0.07295to52.85μM,0.00313to36.2μM, at a signal-to-noise ratio of3. And has been used for quantitative detecting Pb (Ⅱ), Cu (Ⅱ), Hg (Ⅱ) and Cd(Ⅱ) in real samples.