A sensitive voltammetric method for trace measurements of hydroquinone in the sewage water is described. The poly-L-histidine is prepared to modify the glassy carbon electrode in order to improve the electrochemical catalysis of interesting substances such as hydroquinone. The influence of the base solution, pH value, and scanning speed on the tracing of hydroquinone is discussed, and the experimental procedures and conditions are optimized. The laboratory results show that it is possible to construct a linear calibration curve between the peak current of hydroquinone on modified electrode and its concentration at the level of 0.00001 mol/L. The potential limitation of the method is suggested by a linear peaking shift model as well. The method was successfully applied to the determination of hydroquinone in the actual sample of industrial waste water.
{"title":"Using Poly-L-Histidine Modified Glassy Carbon Electrode to Trace Hydroquinone in the Sewage Water","authors":"Bin Wang, Jun Steed Huang","doi":"10.1155/2014/701284","DOIUrl":"https://doi.org/10.1155/2014/701284","url":null,"abstract":"A sensitive voltammetric method for trace measurements of hydroquinone in the sewage water is described. The poly-L-histidine is prepared to modify the glassy carbon electrode in order to improve the electrochemical catalysis of interesting substances such as hydroquinone. The influence of the base solution, pH value, and scanning speed on the tracing of hydroquinone is discussed, and the experimental procedures and conditions are optimized. The laboratory results show that it is possible to construct a linear calibration curve between the peak current of hydroquinone on modified electrode and its concentration at the level of 0.00001 mol/L. The potential limitation of the method is suggested by a linear peaking shift model as well. The method was successfully applied to the determination of hydroquinone in the actual sample of industrial waste water.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"2014 1","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/701284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64625218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Myoglobin was immobilized with poly(methyl methacrylate)-block-poly[(2-dimethylamino)ethyl methacrylate]PMMA-block-PDMAEMA polymer synthesized by reversible addition-fragmentation chain transfer technique (RAFT). Cyclic voltammograms gave direct and slow quasireversible heterogeneous electron transfer kinetics between Mb-PMMA-block-PDMAEMA modified electrode and the redox center of the protein. The values for electron rate constant () and transfer coefficient () were ·s−1 and , respectively. The reduction potential determined as a function of temperature (293–328 K) revealed a value of reaction center entropy of of J·mol−1·K−1 and enthalpy change of kJ·mol−1, suggesting solvent effects and charge ionization atmosphere involved in the reaction parallel to hydrophobic interactions with the copolymer. The immobilized protein also exhibits an electrocatalytical response to reduction of hydrogen peroxide, with an apparent Km of μM. The overall results substantiate the design and use of RAFT polymers towards the development of third-generation biosensors.
{"title":"Electron Transfer of Myoglobin Immobilized in Au Electrodes Modified with a RAFT PMMA-Block-PDMAEMA Polymer","authors":"C. N. Toledo, F. Florenzano, J. Schneedorf","doi":"10.1155/2014/184206","DOIUrl":"https://doi.org/10.1155/2014/184206","url":null,"abstract":"Myoglobin was immobilized with poly(methyl methacrylate)-block-poly[(2-dimethylamino)ethyl methacrylate]PMMA-block-PDMAEMA polymer synthesized by reversible addition-fragmentation chain transfer technique (RAFT). Cyclic voltammograms gave direct and slow quasireversible heterogeneous electron transfer kinetics between Mb-PMMA-block-PDMAEMA modified electrode and the redox center of the protein. The values for electron rate constant () and transfer coefficient () were ·s−1 and , respectively. The reduction potential determined as a function of temperature (293–328 K) revealed a value of reaction center entropy of of J·mol−1·K−1 and enthalpy change of kJ·mol−1, suggesting solvent effects and charge ionization atmosphere involved in the reaction parallel to hydrophobic interactions with the copolymer. The immobilized protein also exhibits an electrocatalytical response to reduction of hydrogen peroxide, with an apparent Km of μM. The overall results substantiate the design and use of RAFT polymers towards the development of third-generation biosensors.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"2014 1","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2014-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/184206","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64380937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrochemical behavior of the anticancer drug doxorubicin hydrochloride was studied using cyclic voltammetry in aqueous medium using Hepes buffer (pH~7.4). At this pH, doxorubicin hydrochloride undergoes a reversible two-electron reduction with value − mV (versus Ag/AgCl, saturated KCl). Depending on scan rates, processes were either quasireversible (at low scan rates) or near perfect reversible (at high scan rates). This difference in behavior of doxorubicin hydrochloride with scan rate studied over the same potential range speaks of differences in electron transfer processes in doxorubicin hydrochloride. Attempt was made to identify and understand the species involved using simulation. The information obtained was used to study the interaction of doxorubicin hydrochloride with calf thymus DNA. Cathodic peak current gradually decreased as more calf thymus DNA was added. The decrease in cathodic peak current was used to estimate the interaction of the drug with calf thymus DNA. Nonlinear curve fit analysis was applied to evaluate the intrinsic binding constant and site size of interaction that was compared with previous results on doxorubicin hydrochloride-DNA interaction monitored by cyclic voltammetry or spectroscopic techniques.
{"title":"Exploration of Electrochemical Intermediates of the Anticancer Drug Doxorubicin Hydrochloride Using Cyclic Voltammetry and Simulation Studies with an Evaluation for Its Interaction with DNA","authors":"Partha Sarathi Guin, Saurabh Das","doi":"10.1155/2014/517371","DOIUrl":"https://doi.org/10.1155/2014/517371","url":null,"abstract":"Electrochemical behavior of the anticancer drug doxorubicin hydrochloride was studied using cyclic voltammetry in aqueous medium using Hepes buffer (pH~7.4). At this pH, doxorubicin hydrochloride undergoes a reversible two-electron reduction with value − mV (versus Ag/AgCl, saturated KCl). Depending on scan rates, processes were either quasireversible (at low scan rates) or near perfect reversible (at high scan rates). This difference in behavior of doxorubicin hydrochloride with scan rate studied over the same potential range speaks of differences in electron transfer processes in doxorubicin hydrochloride. Attempt was made to identify and understand the species involved using simulation. The information obtained was used to study the interaction of doxorubicin hydrochloride with calf thymus DNA. Cathodic peak current gradually decreased as more calf thymus DNA was added. The decrease in cathodic peak current was used to estimate the interaction of the drug with calf thymus DNA. Nonlinear curve fit analysis was applied to evaluate the intrinsic binding constant and site size of interaction that was compared with previous results on doxorubicin hydrochloride-DNA interaction monitored by cyclic voltammetry or spectroscopic techniques.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"77 1","pages":"1-8"},"PeriodicalIF":1.8,"publicationDate":"2014-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/517371","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64531652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Fujimoto, Yu Lei, Zhenghong Huang, F. Kang, J. Kawamura
LiMnPO4 with olivinestructure which is the promising candidate for high voltage cathode material was synthesized by hydrothermal method. In order to synthesize high purity and well-defined LiMnPO4, several precursors for Li, Mn, and P sources and hydrothermal reaction parameters including temperature and [H2O]/[Mn] value are optimized. By analyzing the structure, Mn valence, morphology, and chemical ratio via XRD, XPS, Raman, SEM, and ICP LiMnPO4 synthesized from manganese acetate tetrahydrate have single phase of LiMnPO4 without impurity and showed charge and discharge reaction caused by Mn2
{"title":"Synthesis and Electrochemical Performance of LiMnPO4 by Hydrothermal Method","authors":"D. Fujimoto, Yu Lei, Zhenghong Huang, F. Kang, J. Kawamura","doi":"10.1155/2014/768912","DOIUrl":"https://doi.org/10.1155/2014/768912","url":null,"abstract":"LiMnPO4 with olivinestructure which is the promising candidate for high voltage cathode material was synthesized by hydrothermal method. In order to synthesize high purity and well-defined LiMnPO4, several precursors for Li, Mn, and P sources and hydrothermal reaction parameters including temperature and [H2O]/[Mn] value are optimized. By analyzing the structure, Mn valence, morphology, and chemical ratio via XRD, XPS, Raman, SEM, and ICP LiMnPO4 synthesized from manganese acetate tetrahydrate have single phase of LiMnPO4 without impurity and showed charge and discharge reaction caused by Mn2","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"76 1","pages":"1-9"},"PeriodicalIF":1.8,"publicationDate":"2014-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/768912","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64664644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitrogen doped carbon, synthesized by a novel way of carbonizing polyaniline in an inert atmosphere at a constant temperature of , exhibits several unique features. The carbon: nitrogen ratio is found to increase with the treatment duration up to 120 minutes and a mass reduction of 60 wt% is observed with an interesting observation of the retention of the bulk polymer morphology, surprisingly, even after the carbonization process. The electrochemical activity evaluated with potassium hexacyanoferrate and hexamine ruthenium redox systems at a regular time interval helps to tune the catalytic activity. This type of nitrogen doped carbon prepared from polyaniline base exhibits excellent electrocatalytic activity as illustrated by the oxidation of ascorbic acid in neutral medium.
{"title":"Synthesis of Nitrogen Doped Carbon and Its Enhanced Electrochemical Activity towards Ascorbic Acid Electrooxidation","authors":"S. Mutyala, Mathiyarasu Jayaraman","doi":"10.1155/2014/246746","DOIUrl":"https://doi.org/10.1155/2014/246746","url":null,"abstract":"Nitrogen doped carbon, synthesized by a novel way of carbonizing polyaniline in an inert atmosphere at a constant temperature of , exhibits several unique features. The carbon: nitrogen ratio is found to increase with the treatment duration up to 120 minutes and a mass reduction of 60 wt% is observed with an interesting observation of the retention of the bulk polymer morphology, surprisingly, even after the carbonization process. The electrochemical activity evaluated with potassium hexacyanoferrate and hexamine ruthenium redox systems at a regular time interval helps to tune the catalytic activity. This type of nitrogen doped carbon prepared from polyaniline base exhibits excellent electrocatalytic activity as illustrated by the oxidation of ascorbic acid in neutral medium.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"2014 1","pages":"1-11"},"PeriodicalIF":1.8,"publicationDate":"2014-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/246746","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64402748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Chorbadzhiyska, M. Mitov, G. Hristov, Nina Dimcheva, L. Nalbandian, A. Evdou, Y. Hubenova
Pd-Au codeposits with different ratio of both metals were electrodeposited on carbon felt, characterized by scanning electron microscopy, and investigated as electrocatalysts towards hydrogen evolution reaction in neutral phosphate buffer solution. The quantities of the produced hydrogen gas with different electrocatalysts, estimated from data obtained by chronoamperometry, were confirmed by mass spectrometry analysis. The highest hydrogen evolution rate was achieved with the electrocatalysts, produced from electrolyte with equal Pd and Au content.
{"title":"Pd-Au Electrocatalysts for Hydrogen Evolution Reaction at Neutral pH","authors":"E. Chorbadzhiyska, M. Mitov, G. Hristov, Nina Dimcheva, L. Nalbandian, A. Evdou, Y. Hubenova","doi":"10.1155/2014/239270","DOIUrl":"https://doi.org/10.1155/2014/239270","url":null,"abstract":"Pd-Au codeposits with different ratio of both metals were electrodeposited on carbon felt, characterized by scanning electron microscopy, and investigated as electrocatalysts towards hydrogen evolution reaction in neutral phosphate buffer solution. The quantities of the produced hydrogen gas with different electrocatalysts, estimated from data obtained by chronoamperometry, were confirmed by mass spectrometry analysis. The highest hydrogen evolution rate was achieved with the electrocatalysts, produced from electrolyte with equal Pd and Au content.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"28 1","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2014-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/239270","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64398369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Ponmani, S. Durga, A. Arun, S. Kiruthika, B. Muthukumaran
This paper reports the media flexibility of membraneless sodium perborate fuel cell (MLSPBFC) using acid/alkaline bipolar electrolyte in which the anode is in acidic media while the cathode is in alkaline media, or vice versa. Investigation of the cell operation is conducted by using formic acid as a fuel and sodium perborate as an oxidant for the first time under “acid-alkaline media” configurations. The MLSPBFC architecture enables interchangeable operation with different media combinations. The experimental results indicate that operating under “acid-alkaline media” conditions significantly improves the fuel cell performance compared with all-acidic and all-alkaline conditions. The effects of flow rates and the concentrations of various species at both the anode and cathode on the cell performance are also investigated. It has been demonstrated that the laminar flow based microfluidic membraneless fuel cell can reach a maximum power density of 28.2 mW cm−2 with a fuel mixture flow rate of 0.3 mL min−1 at room temperature.
本文报道了使用酸/碱性双极电解质的无膜过硼酸钠燃料电池(MLSPBFC)的介质柔性，其中阳极在酸性介质中，阴极在碱性介质中，反之亦然。首次以甲酸为燃料，过硼酸钠为氧化剂，在“酸碱介质”配置下对电池操作进行了研究。MLSPBFC架构支持不同媒体组合的可互换操作。实验结果表明，与全酸性和全碱性条件相比，在“酸碱介质”条件下运行可显著提高燃料电池的性能。本文还研究了流量和阳极、阴极不同物质浓度对电池性能的影响。实验证明，在室温下，当混合燃料流量为0.3 mL min - 1时，层流微流控无膜燃料电池的最大功率密度可达28.2 mW cm - 2。
{"title":"Development of Membraneless Sodium Perborate Fuel Cell for Media Flexible Power Generation","authors":"K. Ponmani, S. Durga, A. Arun, S. Kiruthika, B. Muthukumaran","doi":"10.1155/2014/962161","DOIUrl":"https://doi.org/10.1155/2014/962161","url":null,"abstract":"This paper reports the media flexibility of membraneless sodium perborate fuel cell (MLSPBFC) using acid/alkaline bipolar electrolyte in which the anode is in acidic media while the cathode is in alkaline media, or vice versa. Investigation of the cell operation is conducted by using formic acid as a fuel and sodium perborate as an oxidant for the first time under “acid-alkaline media” configurations. The MLSPBFC architecture enables interchangeable operation with different media combinations. The experimental results indicate that operating under “acid-alkaline media” conditions significantly improves the fuel cell performance compared with all-acidic and all-alkaline conditions. The effects of flow rates and the concentrations of various species at both the anode and cathode on the cell performance are also investigated. It has been demonstrated that the laminar flow based microfluidic membraneless fuel cell can reach a maximum power density of 28.2 mW cm−2 with a fuel mixture flow rate of 0.3 mL min−1 at room temperature.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"2014 1","pages":"164-172"},"PeriodicalIF":1.8,"publicationDate":"2014-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/962161","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64766212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, and PpAP), were performed in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymers were characterized by employing elemental analysis, GPC, UV-VIS-NIR, FT-IR, XRD, and TGA. The corrosion inhibition effect of these three polymers on mild steel in 1 M HCl solution was studied by using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy. These measurements reveal that the inhibition efficiency obtained by these polymers increased by increasing their concentration. The inhibition efficiency follows the order PpAP > PoAP > PmAP. The results further revealed that PpAP at a concentration of 250 mg/L furnishes maximum inhibition efficiency (96.5%). Polarization studies indicated that these three polymers act as the mixed type corrosion inhibitors.
用过硫酸铵作为氧化剂，在0-3°C的水溶液中进行了氨基苯酚的三种异构体，邻位，间位和对位(PoAP, PmAP和PpAP)的氧化化学聚合。采用元素分析、GPC、UV-VIS-NIR、FT-IR、XRD和TGA对合成的聚合物进行了表征。采用动电位极化和电化学阻抗谱等电化学技术研究了这三种聚合物在1 M HCl溶液中对低碳钢的缓蚀效果。这些测量结果表明，这些聚合物的缓蚀效率随着其浓度的增加而增加。抑制效率顺序为PpAP > PoAP > PmAP。结果表明，PpAP浓度为250 mg/L时的抑菌率最高(96.5%)。极化研究表明，这三种聚合物均为混合型缓蚀剂。
{"title":"Isomers of Poly Aminophenol: Chemical Synthesis, Characterization, and Its Corrosion Protection Aspect on Mild Steel in 1 M HCl","authors":"G. Thenmozhi, P. Arockiasamy, R. Santhi","doi":"10.1155/2014/961617","DOIUrl":"https://doi.org/10.1155/2014/961617","url":null,"abstract":"The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, and PpAP), were performed in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymers were characterized by employing elemental analysis, GPC, UV-VIS-NIR, FT-IR, XRD, and TGA. The corrosion inhibition effect of these three polymers on mild steel in 1 M HCl solution was studied by using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy. These measurements reveal that the inhibition efficiency obtained by these polymers increased by increasing their concentration. The inhibition efficiency follows the order PpAP > PoAP > PmAP. The results further revealed that PpAP at a concentration of 250 mg/L furnishes maximum inhibition efficiency (96.5%). Polarization studies indicated that these three polymers act as the mixed type corrosion inhibitors.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"4 1","pages":"1-11"},"PeriodicalIF":1.8,"publicationDate":"2014-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/961617","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64765644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An electroanalytical methodology was developed for the direct determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using a graphite-polyurethane composite electrode and square wave voltammetry (SWV). 2,4-D exhibited one reduction peak with characteristics of an irreversible process at −0.54 V (versus Ag/AgCl), which is controlled by the diffusion of the reagent on the electrode surface. After the experimental parameters optimization (pH 2.0, s−1, V, and V), analytical curves were constructed in the range of 0.66 mg L−1 to 2.62 mg L−1. Detection (LD) and quantification (LQ) limits were 17.6 g L−1 and 58.6 g L−1, respectively. The methodology was successfully applied to measure the percolation of the herbicide 2,4-D in undisturbed soil columns of different granulometric compositions.
建立了用石墨-聚氨酯复合电极和方波伏安法直接测定除草剂2,4-二氯苯氧乙酸(2,4- d)的电分析方法。2,4- d在−0.54 V(相对于Ag/AgCl)下表现出一个不可逆还原峰，该还原峰受试剂在电极表面的扩散控制。优化实验参数(pH 2.0、s−1、V和V)后，在0.66 mg L−1 ~ 2.62 mg L−1范围内建立了分析曲线。检测限(LD)为17.6 g L−1，定量限(LQ)为58.6 g L−1。该方法成功地应用于测定除草剂2,4- d在不同颗粒组成的原状土壤柱中的渗透性。
{"title":"Electroanalytical Methodology for the Direct Determination of 2,4-Dichlorophenoxyacetic Acid in Soil Samples Using a Graphite-Polyurethane Electrode","authors":"Fernanda Ramos de Andrade, R. A. Toledo, C. Vaz","doi":"10.1155/2014/308926","DOIUrl":"https://doi.org/10.1155/2014/308926","url":null,"abstract":"An electroanalytical methodology was developed for the direct determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using a graphite-polyurethane composite electrode and square wave voltammetry (SWV). 2,4-D exhibited one reduction peak with characteristics of an irreversible process at −0.54 V (versus Ag/AgCl), which is controlled by the diffusion of the reagent on the electrode surface. After the experimental parameters optimization (pH 2.0, s−1, V, and V), analytical curves were constructed in the range of 0.66 mg L−1 to 2.62 mg L−1. Detection (LD) and quantification (LQ) limits were 17.6 g L−1 and 58.6 g L−1, respectively. The methodology was successfully applied to measure the percolation of the herbicide 2,4-D in undisturbed soil columns of different granulometric compositions.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"75 1","pages":"1-9"},"PeriodicalIF":1.8,"publicationDate":"2014-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/308926","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64432758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. H. Potgieter, P. Olubambi, S. Potgieter-Vermaak
Hardmetals possess excellent wear resistance, making them suitable alloys in several industrial applications. Mine waters with both dissolved chloride and sulphate salts can be severely corrosive and can limit the application of hardmetal tools in the mining industry. Ru additions to these alloys can refine and improve selected mechanical properties, but its influence on the corrosion resistance is unknown. A series of WC-Co-Ru alloys was evaluated in different chloride containing media to investigate their corrosion resistance. Standard electrochemical corrosion tests, chronoamperometric measurements, and surface analyses with Raman spectroscopy were conducted. An increasing amount of Ru improves the corrosion resistance of all the alloys. The effect is not as dramatic as that observed with stainless steels containing Ru in corrosive media. In both corrosive media Ru decreased the cathodic Tafel constant and has a retarding influence on the cathodic part of the corrosion reaction. Raman analyses indicated the presence of tungsten oxide, hydrated tungsten oxide compounds, and CoO and Co3O4 formed on the alloy surfaces during the corrosion process.
{"title":"The Corrosion Behaviour of WC-Co-Ru Alloys in Aggressive Chloride Media","authors":"J. H. Potgieter, P. Olubambi, S. Potgieter-Vermaak","doi":"10.1155/2014/594871","DOIUrl":"https://doi.org/10.1155/2014/594871","url":null,"abstract":"Hardmetals possess excellent wear resistance, making them suitable alloys in several industrial applications. Mine waters with both dissolved chloride and sulphate salts can be severely corrosive and can limit the application of hardmetal tools in the mining industry. Ru additions to these alloys can refine and improve selected mechanical properties, but its influence on the corrosion resistance is unknown. A series of WC-Co-Ru alloys was evaluated in different chloride containing media to investigate their corrosion resistance. Standard electrochemical corrosion tests, chronoamperometric measurements, and surface analyses with Raman spectroscopy were conducted. An increasing amount of Ru improves the corrosion resistance of all the alloys. The effect is not as dramatic as that observed with stainless steels containing Ru in corrosive media. In both corrosive media Ru decreased the cathodic Tafel constant and has a retarding influence on the cathodic part of the corrosion reaction. Raman analyses indicated the presence of tungsten oxide, hydrated tungsten oxide compounds, and CoO and Co3O4 formed on the alloy surfaces during the corrosion process.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":"2014 1","pages":"1-11"},"PeriodicalIF":1.8,"publicationDate":"2014-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2014/594871","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64564912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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