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71.
The electrochemical oxidation of 2-naphthol has been studied by galvanostatic electrolysis, using a range of electrode materials such as lead dioxide, boron-doped diamond (BDD) and Ti-Ru-Sn ternary oxide anodes. The influence of some operating parameters, such as current density, flow-rate and chloride concentration on naphthol oxidation has been investigated in order to find the optimum experimental conditions. Measurements of chemical oxygen demand, HPLC and total organic carbon have been used to follow the oxidation. The experimental data indicate that on PbO2 and BDD, naphthol oxidation takes place by reaction with electrogenerated hydroxyl radicals and is favoured by low current density and high flow-rate. On the contrary, on a Ti-Ru-Sn ternary oxide the mineralisation of naphthol occurs only in the presence of chloride ions that act as redox mediators and COD removal is affected by chloride concentration and is not significantly influenced by the current density and mass-transfer coefficient. From a comparison of the results of the three electrodes it has been found that boron-doped diamond gives a faster oxidation rate and better current efficiency. 相似文献
72.
Poly(methylphenylene) (PMeP) films were prepared by direct oxidation of toluene in the mixed electrolytes of boron trifluoride diethyl etherate (BFEE) and trifluoroacetic acid (TFA). The oxidation potential of toluene in pure BFEE was measured to be 1.52 V versus saturated calomel electrode (SCE). This value was much lower than that determined in a neutral medium such as acetonitrile (2.13 V versus SCE). The introduction of TFA into BFEE decreased the oxidation potential of toluene and also improved the properties of as‐formed polymer films. Infrared and Raman spectra confirmed the formation of PMeP films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 189–195, 2004 相似文献
73.
A novel perforated bipole trickle-bed electrochemical reactor is investigated for the electro-synthesis of alkaline peroxide.
The process uses a relatively simple cell configuration in which a single electrolyte flows with oxygen gas in a flow-by graphite
felt cathode, sandwiched between a micro-porous diaphragm and a perforated bipolar electrode plate. The graphite felt cathodes
are 120 mm high by 25 mm wide and have a thickness of 3.2 mm. The reactor is operated at current densities in the range 1–5 kA m−2, ca. 800 kPa (abs) pressure and temperature (In/Out) 20–45 °C with one and two-cells. The reactor shows good performance
(current efficiency ∼78% at 2 kA m−2 and a specific energy of 5 kWh per kg of peroxide generated) with peroxide concentrations from 0.02 to 0.15 M in 1 M NaOH. 相似文献
74.
该文利用多壁碳纳米管(MWCNTs)和聚(2-乙酰基-5-溴噻吩)复合纳米材料修饰电极,用于同时检测对苯二酚(HQ)、邻苯二酚(CC)和对甲苯酚(PC)。通过循环伏安法(CV),示差脉冲伏安法(DPV)和透射电镜(TEM)表征了该复合纳米材料的电化学性能和表面形貌。结果表明该电极对HQ、CC和PC具有较高的灵敏度和选择性。DPV峰电流与HQ、CC和PC的浓度在1.0×10-5~8.0×10-4mol/L,5.0×10-6~5.5×10-4mol/L和5.0×10-6~7.5×10-4mol/L范围内分别呈良好的线性关系,且检测限分别为3.0×10-6 mol/L,1.7×10-6 mol/L和2.0×10-6mol/L。 相似文献
75.
Hiba Messaoudi Fayçal Djazi Mohamed Litim Bahadır Keskin Maamar Slimane Djillali Bekhiti 《Journal of Adhesion Science and Technology》2020,34(20):2216-2244
AbstractCorrosion inhibitors based on environmentally friendly and harmless products are currently being studied and developed. The corrosion inhibition properties of caffeine (1,3,7-trimethylxanthine) on copper corrosion in aqueous chloride solution (3.5?wt.% NaCl) are analysed here using stationary and transient electrochemical methods, and a theoretical study based on density functional theory is carried out. Caffeine is a very competitive compared to the chemical inhibitors that are often used for copper protection. Electrochemical and impedance experiments reveal that the protective efficiency of caffeine reaches a value of 96% at a concentration of 10?2?mol L?1. Based on these results, the Langmuir model appears to be the best representation of the adsorption of caffeine onto the copper surface. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD) were used to determine the surface morphology and the chemical composition of the copper surface in chloride media, in the absence and presence of caffeine. The results show the development of a mechanism of corrosion inhibition. In order to confirm the correlation between the inhibitory effect and the molecular structure of caffeine, quantum chemical parameters are used to calculate its electronic properties. 相似文献
76.
环境污染物的电化学处理技术 总被引:4,自引:0,他引:4
对电化学技术在环境污染物治理中的应用进行了综述,分析了应用中可能存在的问题,提出了相应的对策。 相似文献
77.
78.
The processes occurring in aprotic electrolyte on a lithium electrode in the steady state conditions and under polarization
are studied using the method of electrochemical noise characterization. The evidence of the electro-chemical noise measurements
on polarized lithium electrodes indicates that the discharge of lithium ions under cathodic polarization, as well as lithium
anodic dissolution, is localized under the passive film rather than on its surface. An increase in the polarizing current
results in local breakdown of the film; in this case, the electrochemical process emerges on the electrode surface affecting
the character of potential fluctuations. The intensity of electrochemical noise significantly increases in the course of cathodic
polarization with high currents. The reason is that lithium metal crystals, which are formed under the passive film, perforate
the film, and dendrites grow on its surface. The method shows the dependence of electrochemical noise intensity on the nature
of the electrolyte and establishes the correlation between the stability of the lithium electrode in the course of cycling
and the intensity of fluctuations. This offers an opportunity of using the method of electrochemical noise for screening organic
electrolytes for lithium batteries. 相似文献
79.
Deconvolution of the electrolytic manganese dioxide (EMD) discharge curve has indicated the presence of a number of energetically different reduction processes. This has been used to determine the contribution of each reduction process to the total discharge. Using step potential electrochemical spectroscopy (SPECS), the i-t data were modelled as the sum of the discharge of the individual reduction processes. From this, A√ D for each reduction process as a function of degree of discharge was determined. The maximum A√ D values for each process ranged from 2.3×10−2 to 4.0×10−4 cm3 s−1/2 g−1 values are consistent with previously reported values for A√ D, although in this case we have determined values for the entire compositional range. 相似文献
80.
The influence of electrode potential on pentachlorophenol (PCP) oxidation on boron doped diamond (BDD) electrodes in a 0.1 mol L–1 Britton–Robinson buffer (pH 5.5) is described. Controlled potential electrolyses were carried at 0.9, 2.0 and 3.0 V vs Ag/AgCl and the solutions analysed by square wave voltammetry, high performance liquid chromatography, chloride ion selective electrode and spectroscopy in the ultraviolet–visible region. At low positive potential (0.9 V), the formation of an adherent film on the electrode surface involving the transference of 1 electron per PCP molecule was observed. The film was identified as the dimer 2,3,4,5,6-pentachloro-4-pentachlorophenoxy-2,5-cyclohexadienone and the current efficiency was as high as 90%. At potentials close to the onset of O2 evolution (2.0 V), the formation of the corresponding quinone (p-tetrachlorobenzoquinone) was detected at the beginning of the process. This was followed by further oxidation to the hydroxy-benzoquinone with a practically quantitative yield. Electrolyses carried out well into the region of oxygen evolution (3.0 V) lead to the electrochemical combustion of PCP to CO2 and H2O as well as to the release into solution of 5 Cl– ions per PCP molecule destroyed. 相似文献