Based On The Fe @ Fe < Sub > 2 < / Sub > O < Sub > 3 < / Sub > Electrode Degradation Of Organic Matter (methylene Blue And Rhodamine B)

Nowadays, with the rapid growth of our science and technology, living andecological environment are getting worse. An increasing number of people arebeginning to realize that environment pollution is a serious problem. In view of theseriousness of this problem, effective measures should be taken before things getworse. So how to deal with the pollutants has been the primary concern over theworld. There is no denying the fact that water pollution is an extremely seriousProblem. Organic pollution in water is a global problem, its nature, severity andharmful are changed with the development of science and technology. Dye wastewater,which is the main source of industrial waste water and hard to be degradate, hascaused wildly public concern. However, traditional technology and methods havebecome less useful at the degradation of organic pollutants. So, seek a more effectiveapproach to degradate the organic matter in the waste water has become a hotspotrecently.The treatment of organic wastewater by Fenton-like reaction, which is on thebasis of traditional Fenton reaction, though introduce of Fenton reagent （Fe2+and/orH2O2） indirectly to generate the extremely reactive hydroxyl radical （OH）. Comparedwith other chemical oxidation, Fenton-like oxidation technology not only have manyadvantages such as simple equipment, mild reaction conditions, easy to operate,efficient, no secondary pollution, but also overcome the traditional Fenton reactiondisadvantages such as the cost of high consumption of hydrogen peroxide, and thenarrow scope of pH and iron ions can’ t be reused.With greatly enhances on theoxidative capacity, Fenton-like reaction is widely used in organic wastewatertreatment technology. Recently, the iron core-shell nanostructures, which containedmetal with good magnetic iron nanoparticles can prevent the nanoparticles to beoxidized, had became more and more popular. The core-shell structure of Fe@Fe₂O₃nanowires own the function of both iron and iron oxide, and elemental iron core cancontinue to provide the electronics, iron oxide shell in the liquid phase catalysis canbe used to achieve reduction or as Fenton iron reagents. The paper includes three sections as followed:1. This article was based on a novel electro-Fenton （E-Fenton） methods, theelectrode modified by Fe@Fe₂O₃/Au-MCNTs/PDDA/GCE composite was used forthe degradation of cationic azo dyes of methylene blue （MB）. The basic principle wasthat H2O2and Fe Fe2+produced continue by the electrochemical method formed theFenton reagent, hydroxyl radical （OH） was generated by the decomposition of H2O2under the catalyst of Fe2+can attack the methylene blue （MB） molecules. Cyclicvoltammetry（CV）、Electrochemical impedance spectroscopy （EIS）、X-ray diffraction（XRD）, scanning electron microscopy （SEM）, UV-visible spectrophotometry（UV-vis）、Fourier transform infrared spectroscopy（FT-IR）and other methods wereused to characterize the results. At the same time, we explored the optimalexperimental conditions and analyzed the concentrations of Fen+、H2O2and OH atdifferent time in the experiment. The degradation rate of MB under this E-Fentonreaction system reached71.7%in two hours, which indicated that the system in thesewage treatment process would have a good prospect.2. This experiment was also based on the principle of E-Fenton reaction, theFe@Fe₂O₃/MCNTs/Au/PDDA/GCE composites electrode as prepared used for thedegradation of Rhodamine B. Cyclic voltammetry（CV）, electrochemical impedancespectroscopy（EIS）, x-ray diffraction （XRD）, scanning electron microscopy （SEM）,fourier transform infrared spectra （FT-IR） and other electro-chemical techniques hadbeen used to characterize the results. Furthermore, we explored the optimalexperimental conditions, and analyzed the concentrations of Fen+、H2O2and OH inthe solution under the optimum conditions. The results show that the system for thedegradation of Rhodamine B would have a good prospect.3. The single-walled carbon nanotubes （SWNT）, functionalized with carboxylicacid groups, modified glassy carbon electrode （GCE） and its application for thevoltammetric differentiation of dopamine （DA） and ascorbic acid （AA） had beendescribed. Scanning electron microscope （SEM）, fourier transform infrared spectra（FT-IR）, electrochemical impedance spectroscopy （EIS） and other electrochemicaltechniques had been used to characterize the SWNT modified GCE （SWNT/GCE）. Using different charged catecholates and ascorbic acid in PBS pH7.0, the changes inelectrode processes and accumulation or exclusion of analytes at the electrode surfacewere shown to be controlled by electrostatic interactions with the surface groups. Atneutral pH, the amine group of DA is positively charged （pKb=8.87）, whereas thehydroxyl next to the carbonyl group of AA is negatively charged. As a negativelycharged linker at pH7.0（the carboxylic acid groups on the surface of SWNT aredeprotoned at neutral pH）, the SWNT film combined with the positively charged DAto induce the accumulation of DA and thus promoted the electron transfer reaction ofDA. However, due to the electrostatic repulsion, the negatively charged SWNT filmrestrained the electro-oxidation of the negatively charged AA. Based on the differentelectrochemical behaviors of DA and AA at SWNT/GCE, the modified electrode canbe used for the voltammetric differentiation of DA and AA. In the presence of AA, thedifferential pulse voltammetric （DPV） peak current for the oxidation of DA increasedlinearly with DA concentration over the range of6.0×10-6and1.65×10-4mol L-1witha correlation coefficient of0.998. The detection limit （S/N=3） for the determination ofDA was4.7×10^-7mol L^-1.