An irreversible electrode reaction influenced by the reversible potential dependent inhibition is theoretically analysed. The consequence of reactivation of the electrode surface is the continuation of electro-oxidation and the appearance of the second anodic peak in cyclic voltammetry. An indicator of the change of the electrode kinetics caused by the inhibitor is proposed.
{"title":"Simulation of Irreversible Electro-oxidation on a Partially Blocked Electrode","authors":"M. Lovrić, Š. Komorsky-Lovrić","doi":"10.4152/pea.202003165","DOIUrl":"https://doi.org/10.4152/pea.202003165","url":null,"abstract":"An irreversible electrode reaction influenced by the reversible potential dependent inhibition is theoretically analysed. The consequence of reactivation of the electrode surface is the continuation of electro-oxidation and the appearance of the second anodic peak in cyclic voltammetry. An indicator of the change of the electrode kinetics caused by the inhibitor is proposed.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"165-174"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917661","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}
Molecular modelling approach has been used for the pr diction of anticorrosion properties of 1, 2, 4-triazole derivatives on steel in acidic medium by the quantum chemical calculation and molecular dynamics (MD) si mulation methods. Quantum chemical parameters such as the highest occupied mo lecular orbital (E-HOMO), the energy of the lowest unoccupied molecular orbital ( E-LUMO), energy band gap ( ΔE), dipole moment, global electronic chemical potential (μ), chemical softness ( σ), chemical hardness ( η) and electrophilicity ( ) have been calculated and discussed. The reactive sites of the inhibitor molecules were found to be o n the nitrogen-atom of the Triazolic ring and on the π-electron centers. Furthermore, molecular dynamics s mulation was applied to search for the best inhibitor adsorption c figuration over Fe (110) surface. The best adsorption energy was found to be -430.27 kcal/mol (inhibitor 3). The adsorptions occurred via chemisorption.
{"title":"Evaluation of Anticorrosion Properties of 1, 2 ,4-triazole Derivatives on Steel in Acidic Media using Quantum Chemical Calculation and Molecular Dynamic Simulation Methods","authors":"A. U. Bello, A. Uzairu, Gideon Adamu Shallangwa","doi":"10.4152/pea.202006377","DOIUrl":"https://doi.org/10.4152/pea.202006377","url":null,"abstract":"Molecular modelling approach has been used for the pr diction of anticorrosion properties of 1, 2, 4-triazole derivatives on steel in acidic medium by the quantum chemical calculation and molecular dynamics (MD) si mulation methods. Quantum chemical parameters such as the highest occupied mo lecular orbital (E-HOMO), the energy of the lowest unoccupied molecular orbital ( E-LUMO), energy band gap ( ΔE), dipole moment, global electronic chemical potential (μ), chemical softness ( σ), chemical hardness ( η) and electrophilicity ( ) have been calculated and discussed. The reactive sites of the inhibitor molecules were found to be o n the nitrogen-atom of the Triazolic ring and on the π-electron centers. Furthermore, molecular dynamics s mulation was applied to search for the best inhibitor adsorption c figuration over Fe (110) surface. The best adsorption energy was found to be -430.27 kcal/mol (inhibitor 3). The adsorptions occurred via chemisorption.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"377-386"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70918292","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}
Nisha Saini, Rajeev Kumar, Priti Pahuja, Reena Malik, Rinki Malik, S. Singhal, Suman Lata
Polyvinylpyrrolidone Oxime (PVPO) was synthesized a nd studied for mild steel (MS) corrosion inhibition in 1 M H2SO4, at different concentrations and temperatures. The corrosion inhibition efficiency was studied using w eight loss method, polarization technique, electrochemical impedance spectroscopy ( EIS), scanning electron microscopy (SEM) and quantum chemical calculations. The results from weight loss, potentiodynamic polarization and EIS showed that th e inhibition efficiency (I. E.) increased with gradual increments in the inhibitor c ncentration, and decreased at higher temperatures. The polarization study also re veal d that PVPO acted as a mixed type inhibitor, and Langmuir adsorption isotherm fi tted well for the adsorption behavior. The highest corrosion efficiency was found to be 88.39%, with a concentration of 1000 ppm, and a temperature of 303 K. The corrosion inhibition mechanism has been further proposed, including the support from the theoretical study. SEM images also verified the MS surface smoothening in PVPO presence, and, hence, it has shown to be a good corrosion inhibitor.
合成了聚乙烯吡咯烷酮肟(PVPO)，研究了PVPO在1 M H2SO4中不同浓度和温度对低碳钢(MS)的缓蚀作用。采用w - 8损耗法、极化技术、电化学阻抗谱(EIS)、扫描电镜(SEM)和量子化学计算等方法对其缓蚀效果进行了研究。失重、动电位极化和EIS实验结果表明，缓蚀剂c的缓蚀效率随浓度的增加而增加，温度越高缓蚀效率越低。极化实验也表明PVPO作为混合型缓蚀剂，Langmuir吸附等温线符合其吸附行为。当腐蚀浓度为1000 ppm，温度为303 K时，腐蚀效率最高，为88.39%。进一步提出了缓蚀机理，包括理论研究的支持。SEM图像也证实了PVPO存在下的MS表面平滑，因此，PVPO已被证明是一种良好的缓蚀剂。
{"title":"Exploring the Capability of Synthesized PVP-Oxime for Corrosion Inhibition of a Mild Steel Surface in a 1 M H2SO4 Solution","authors":"Nisha Saini, Rajeev Kumar, Priti Pahuja, Reena Malik, Rinki Malik, S. Singhal, Suman Lata","doi":"10.4152/pea.202001043","DOIUrl":"https://doi.org/10.4152/pea.202001043","url":null,"abstract":"Polyvinylpyrrolidone Oxime (PVPO) was synthesized a nd studied for mild steel (MS) corrosion inhibition in 1 M H2SO4, at different concentrations and temperatures. The corrosion inhibition efficiency was studied using w eight loss method, polarization technique, electrochemical impedance spectroscopy ( EIS), scanning electron microscopy (SEM) and quantum chemical calculations. The results from weight loss, potentiodynamic polarization and EIS showed that th e inhibition efficiency (I. E.) increased with gradual increments in the inhibitor c ncentration, and decreased at higher temperatures. The polarization study also re veal d that PVPO acted as a mixed type inhibitor, and Langmuir adsorption isotherm fi tted well for the adsorption behavior. The highest corrosion efficiency was found to be 88.39%, with a concentration of 1000 ppm, and a temperature of 303 K. The corrosion inhibition mechanism has been further proposed, including the support from the theoretical study. SEM images also verified the MS surface smoothening in PVPO presence, and, hence, it has shown to be a good corrosion inhibitor.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"43-58"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917358","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}
Surface laser treatments of commercially pure titanium plates (CP-Ti grade 4) were performed in air using a Nd:YAG laser source of short pulse duration about 5 ns. Attention is drawn to the following laser-processing parameters: laser-power interaction time and surface of the irradiated zone. The morphology, structure and chemical composition of the formed layers were analyzed by different characterization techniques providing physico-chemical and structure information. The objective of this research was to study the influence of laser fluence on the composition of the CP-Ti grade 4. Additionally, it was pretended to evaluate the surface modification of obtained layers. The electrochemical response of modified surface in Ringer’s physiological solutions at varying pH values was studied. Fretting test has been investigated in order to study the tribological behavior of the laser treated surface. Results showed that the laser treatments induce the insertion of light elements such as O2 and N2. Laser surface processing shifted the corrosion potential of CP-Ti grade 4 towards the noble side, as compared to the untreated one. After fretting tests, it was found that the steady friction coefficient was similar for all the layers, and quite lower than that measured for the untreated CP-Ti.
{"title":"Structural Characterization and Surface Modification of Titanium Plates After Nd:YAG Laser Treatment","authors":"A. Bahloul, M. Sahour, R. Oumeddour, G. Pillon","doi":"10.4152/pea.202004215","DOIUrl":"https://doi.org/10.4152/pea.202004215","url":null,"abstract":"Surface laser treatments of commercially pure titanium plates (CP-Ti grade 4) were performed in air using a Nd:YAG laser source of short pulse duration about 5 ns. Attention is drawn to the following laser-processing parameters: laser-power interaction time and surface of the irradiated zone. The morphology, structure and chemical composition of the formed layers were analyzed by different characterization techniques providing physico-chemical and structure information. The objective of this research was to study the influence of laser fluence on the composition of the CP-Ti grade 4. Additionally, it was pretended to evaluate the surface modification of obtained layers. The electrochemical response of modified surface in Ringer’s physiological solutions at varying pH values was studied. Fretting test has been investigated in order to study the tribological behavior of the laser treated surface. Results showed that the laser treatments induce the insertion of light elements such as O2 and N2. Laser surface processing shifted the corrosion potential of CP-Ti grade 4 towards the noble side, as compared to the untreated one. After fretting tests, it was found that the steady friction coefficient was similar for all the layers, and quite lower than that measured for the untreated CP-Ti.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"215-228"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917476","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}
This work reports the development of a glassy carbon electrode (GCE), modified with an oxidized poly diphenylamine/multi-walled carbon nanotubes-β-cyclodextrin (OPDPA /MWCNT-β-CD) composite film, for ceftazidime determination. The OPDPA/MWCNT-β-CD film surface morphology was investigated using field emission scanning electron microscopy (FESEM) and cyclic voltammetry (CV). Ceftazidime was adsorbed onto the OPDPA/MWCNT-β-CD, at open circuit, for 240 seconds, and then oxidized in acidic media. The electrochemistry of ceftazidime oxidation was investigated using cyclic voltammetry and differential pulse voltammetry (DPV). Under optimum conditions, the peak current linearly increased with ceftazidime concentration, in the range of 5×10 M to 1×10 M. The obtained detection limit was 1.0×10 M. This sensor was employed for ceftazidime determination in the biological and pharmaceutical samples.
本文报道了用氧化聚二苯胺/多壁碳纳米管-β-环糊精(OPDPA /MWCNT-β-CD)复合膜修饰的玻璃碳电极(GCE)，用于头孢他啶的测定。采用场发射扫描电镜(FESEM)和循环伏安法(CV)研究了OPDPA/MWCNT-β-CD膜的表面形貌。将头孢他啶在OPDPA/MWCNT-β-CD上开路吸附240秒，然后在酸性介质中氧化。采用循环伏安法和差分脉冲伏安法(DPV)研究了头孢他啶氧化的电化学过程。在最佳条件下，峰电流随头孢他啶浓度在5×10 M ~ 1×10 M范围内线性增加，得到的检出限为1.0×10 M。该传感器可用于头孢他啶在生物和医药样品中的检测。
{"title":"Partially Oxidized Polydiphenylamine for Sensitive Electrochemical Determination of Ceftazidime","authors":"K. Zarei, M. Lesani","doi":"10.4152/pea.202004229","DOIUrl":"https://doi.org/10.4152/pea.202004229","url":null,"abstract":"This work reports the development of a glassy carbon electrode (GCE), modified with an oxidized poly diphenylamine/multi-walled carbon nanotubes-β-cyclodextrin (OPDPA /MWCNT-β-CD) composite film, for ceftazidime determination. The OPDPA/MWCNT-β-CD film surface morphology was investigated using field emission scanning electron microscopy (FESEM) and cyclic voltammetry (CV). Ceftazidime was adsorbed onto the OPDPA/MWCNT-β-CD, at open circuit, for 240 seconds, and then oxidized in acidic media. The electrochemistry of ceftazidime oxidation was investigated using cyclic voltammetry and differential pulse voltammetry (DPV). Under optimum conditions, the peak current linearly increased with ceftazidime concentration, in the range of 5×10 M to 1×10 M. The obtained detection limit was 1.0×10 M. This sensor was employed for ceftazidime determination in the biological and pharmaceutical samples.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"229-241"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917599","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}
P. Chooto, W. A. Tappachai, S. Duangthong, S. Manaboot
Certain N, O, S-ligating ring compounds and thioureas were investigated to understand their role of copper corrosion inhibition in acetonitrile. For 5 quinones under study, including xanthone, xanthene, thioxanthone, acridone and 1,4-naphthoquinone, acridone was the best inhibitor, with Cu corrosion rate of 4.495 × 10 mm/year, whereas 1,4naphthoquinone exhibited the lowest inhibition, due to a lower number of nitrogen groups. With the presence of sulphur, to form a stronger bond with Cu, thioureas had better inhibiting behavior than quinones. Of 4 thioureas, namely thiourea (tu), diphenylthiourea (dptu), phenylthiourea (ptu), and ethylenethiourea (etu), the fourth shows the highest inhibition – with Cu corrosion rate of 2.27 × 10 mm/year – and the third shows the lowest one, due to the steric effect from the phenyl group. When halide ions are present, the inhibition efficiency of thioureas decreases, due to more preferable Cu complexation to halides; the strongest copper-halide bond formation occurred by the freest iodide ion, which is consistent with the results from X-ray crystallography and electrochemistry.
{"title":"Corrosion Inhibition of Copper by Thioureas and N, O, S-Ligating Ring Compounds","authors":"P. Chooto, W. A. Tappachai, S. Duangthong, S. Manaboot","doi":"10.4152/pea.202005343","DOIUrl":"https://doi.org/10.4152/pea.202005343","url":null,"abstract":"Certain N, O, S-ligating ring compounds and thioureas were investigated to understand their role of copper corrosion inhibition in acetonitrile. For 5 quinones under study, including xanthone, xanthene, thioxanthone, acridone and 1,4-naphthoquinone, acridone was the best inhibitor, with Cu corrosion rate of 4.495 × 10 mm/year, whereas 1,4naphthoquinone exhibited the lowest inhibition, due to a lower number of nitrogen groups. With the presence of sulphur, to form a stronger bond with Cu, thioureas had better inhibiting behavior than quinones. Of 4 thioureas, namely thiourea (tu), diphenylthiourea (dptu), phenylthiourea (ptu), and ethylenethiourea (etu), the fourth shows the highest inhibition – with Cu corrosion rate of 2.27 × 10 mm/year – and the third shows the lowest one, due to the steric effect from the phenyl group. When halide ions are present, the inhibition efficiency of thioureas decreases, due to more preferable Cu complexation to halides; the strongest copper-halide bond formation occurred by the freest iodide ion, which is consistent with the results from X-ray crystallography and electrochemistry.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"343-350"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917882","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}
Bello Abdullahi Umar, A. Uzairu, Gideon Adamu Shallangwa
The inhibition performance of twenty-five amino acids and related compounds was studied by theoretical techniques. The effect of the acidic solution was considered on the molecular dynamics simulation, and the calculated binding energies for most of the inhibitors was ˃100 kcal mol, suggesting chemisorptive interactions. Density Functional Theory (B3LYP/6-31G*) quantum substance chemical study was utilized to discover the upgraded geometry of the inhibitors. Also, a linear quantitative structureactivity relationship (QSAR) model was built by Genetic Function Approximation (GFA) method, to run the regression analysis and build up connections between various descriptors and the experimental inhibition efficiencies. The prediction of corrosion efficiencies of these inhibitors nicely matched the experimental measurements. The statistical parameters are: 0.973421, which indicates that the model was excellent. The proposed model has great dependability, strength, and consistency on checking, with inward and outside approval.
{"title":"Quantum Modeling and Molecular Dynamic Simulation of some Amino Acids and Related Compounds on their Corrosion Inhibition of Steel in Acidic Media","authors":"Bello Abdullahi Umar, A. Uzairu, Gideon Adamu Shallangwa","doi":"10.4152/pea.202005313","DOIUrl":"https://doi.org/10.4152/pea.202005313","url":null,"abstract":"The inhibition performance of twenty-five amino acids and related compounds was studied by theoretical techniques. The effect of the acidic solution was considered on the molecular dynamics simulation, and the calculated binding energies for most of the inhibitors was ˃100 kcal mol, suggesting chemisorptive interactions. Density Functional Theory (B3LYP/6-31G*) quantum substance chemical study was utilized to discover the upgraded geometry of the inhibitors. Also, a linear quantitative structureactivity relationship (QSAR) model was built by Genetic Function Approximation (GFA) method, to run the regression analysis and build up connections between various descriptors and the experimental inhibition efficiencies. The prediction of corrosion efficiencies of these inhibitors nicely matched the experimental measurements. The statistical parameters are: 0.973421, which indicates that the model was excellent. The proposed model has great dependability, strength, and consistency on checking, with inward and outside approval.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"313-329"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70918235","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 electrochemical degradability of Al-20% Mg and hypereutectic Al-22% Si industrial alloys was evaluated in an aggressive acidic environment, namely 1 M H2SO4, using potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) techniques. The microstructure and constituting phases of the surface alloys were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), coupled with Energy Dispersive X-ray Spectroscopy (EDX). It was found that the two alloys’ corrosion behavior mainly depends on their crystalline phases. The presence of the active intermetallic βAl3Mg2 phase in the Al alloy with high Mg content induced a preferential Mg dissolution, which caused a severe intergranular attack on this alloy by the corrosive solution. Meanwhile, the Al alloy containing high Si content, which presented the eutectic Al-Si phase, showed a uniform and weaker dissolution. It was also observed that a rise in temperature reduced the corrosion performance of the two studied alloys, as these corroded faster than pure aluminum.
采用动电位极化、线性极化电阻(LPR)和电化学阻抗谱(EIS)技术，研究了Al-20% Mg和过共晶Al-22% Si工业合金在1 M H2SO4强酸性环境下的电化学降解性能。采用x射线衍射仪(XRD)、扫描电镜(SEM)和能量色散x射线能谱仪(EDX)对表面合金的微观组织和组成相进行了表征。结果表明，两种合金的腐蚀行为主要取决于其晶相。高Mg含量铝合金中存在活性的金属间相βAl3Mg2，导致Mg优先溶解，腐蚀溶液对合金造成严重的晶间侵蚀。同时，高Si含量的Al-Si合金表现出较弱的均匀溶出，为共晶Al-Si相。研究还发现，温度升高会降低这两种合金的腐蚀性能，因为它们比纯铝腐蚀得更快。
{"title":"Electrochemical Degradability of Al-20% Mg and Al-22% Si Alloys in an Acidic Environment in Relation with their Microstructure","authors":"M. Slimane, F. Kellou-Kerkouche","doi":"10.4152/pea.202002079","DOIUrl":"https://doi.org/10.4152/pea.202002079","url":null,"abstract":"The electrochemical degradability of Al-20% Mg and hypereutectic Al-22% Si industrial alloys was evaluated in an aggressive acidic environment, namely 1 M H2SO4, using potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) techniques. The microstructure and constituting phases of the surface alloys were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), coupled with Energy Dispersive X-ray Spectroscopy (EDX). It was found that the two alloys’ corrosion behavior mainly depends on their crystalline phases. The presence of the active intermetallic βAl3Mg2 phase in the Al alloy with high Mg content induced a preferential Mg dissolution, which caused a severe intergranular attack on this alloy by the corrosive solution. Meanwhile, the Al alloy containing high Si content, which presented the eutectic Al-Si phase, showed a uniform and weaker dissolution. It was also observed that a rise in temperature reduced the corrosion performance of the two studied alloys, as these corroded faster than pure aluminum.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"79-98"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917500","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}
R. Chadli, M. Elazouzi, I. Khelladi, A. M. Elhorri, J. K. Mulangi, B. Hammouti, A. Aouiniti
In this work we made a synthesis of two molecules of the same family, the pyrazole 4(4,5-dihydro-1H-pyrazol-5-yl)-N,N-dimethylaniline D and N,N-dimethyl-4-(3-methyl4,5-dihydro-1H-pyrazol-5-yl)aniline D10. These two molecules have a good inhibiting activity against the corrosion of mild steel in 1 M HCl. This activity has been confirmed by gravimetric and electrochemical studies; we use a potentiodynamic polarization and the impedance spectroscopic technique. From this investigation, we observe that the integration of a methyl group in the pyrazole D allows decreasing slightly the corrosion of steel. For more information about the action mode of our inhibitors, we launched theoretical calculation by DFT method. We used these calculations to discuss the stability, the reactivity, and the adsorption of our pyrazolic inhibitors with iron in acid medium.
{"title":"Synthesis and comparative study between two pyrazoles in inhibition against the corrosion of steel in 1 M hydrochloric acid","authors":"R. Chadli, M. Elazouzi, I. Khelladi, A. M. Elhorri, J. K. Mulangi, B. Hammouti, A. Aouiniti","doi":"10.4152/pea.202002125","DOIUrl":"https://doi.org/10.4152/pea.202002125","url":null,"abstract":"In this work we made a synthesis of two molecules of the same family, the pyrazole 4(4,5-dihydro-1H-pyrazol-5-yl)-N,N-dimethylaniline D and N,N-dimethyl-4-(3-methyl4,5-dihydro-1H-pyrazol-5-yl)aniline D10. These two molecules have a good inhibiting activity against the corrosion of mild steel in 1 M HCl. This activity has been confirmed by gravimetric and electrochemical studies; we use a potentiodynamic polarization and the impedance spectroscopic technique. From this investigation, we observe that the integration of a methyl group in the pyrazole D allows decreasing slightly the corrosion of steel. For more information about the action mode of our inhibitors, we launched theoretical calculation by DFT method. We used these calculations to discuss the stability, the reactivity, and the adsorption of our pyrazolic inhibitors with iron in acid medium.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"125-138"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917623","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}
This work presents the thermometric and gravimetric analyses of aluminum corrosion control in a HCl medium, using Ricinus communis (castor oil) extract. The obtained plant extract was subjected to phytochemical analys es for the identification of various sample constituents. Applying the thermometric tech nique, reaction values for the aluminum dissolution in free and inhibited HCl media were used to determine the extract inhibition efficiency. The gravimetric meth od was carried out using one factor at a time, and response surface methodology. Thermodyn amic parameters of activation energy, heat of adsorption and free Gibbs energy of the corrosion inhibition process were determined. Central composite design of Design Expert Software was employed in the response surface methodology. The results analy sis revealed that Ricinus communis extract contained phytochemicals of alkaloids, card iac glycosides, flavonoids, phenolics, phytates, saponins and tanins. The extra ct adsorption onto the aluminum surface obeyed the physical adsorption mechanism; t he activation energy was lower than the threshold value of 80 kJ/mol required for chemisorption. A quadratic model adequately described the relationship between the i n ibition efficiency and the inhibitor concentration, temperature and time factors. The th rmometric and gravimetric techniques recorded high inhibition efficiencies of 83.93% and 82.61%, respectively, showing that the Ricinus communis extract can be employed to control aluminum corrosion in an HCl medium.
{"title":"Thermometric and Gravimetric Analyses of Aluminum Corrosion Control in a HCl Medium, Using Ricinus Communis Extract","authors":"O. Onukwuli, M. Omotioma, Obiora-Okafo Ia","doi":"10.4152/pea.202001019","DOIUrl":"https://doi.org/10.4152/pea.202001019","url":null,"abstract":"This work presents the thermometric and gravimetric analyses of aluminum corrosion control in a HCl medium, using Ricinus communis (castor oil) extract. The obtained plant extract was subjected to phytochemical analys es for the identification of various sample constituents. Applying the thermometric tech nique, reaction values for the aluminum dissolution in free and inhibited HCl media were used to determine the extract inhibition efficiency. The gravimetric meth od was carried out using one factor at a time, and response surface methodology. Thermodyn amic parameters of activation energy, heat of adsorption and free Gibbs energy of the corrosion inhibition process were determined. Central composite design of Design Expert Software was employed in the response surface methodology. The results analy sis revealed that Ricinus communis extract contained phytochemicals of alkaloids, card iac glycosides, flavonoids, phenolics, phytates, saponins and tanins. The extra ct adsorption onto the aluminum surface obeyed the physical adsorption mechanism; t he activation energy was lower than the threshold value of 80 kJ/mol required for chemisorption. A quadratic model adequately described the relationship between the i n ibition efficiency and the inhibitor concentration, temperature and time factors. The th rmometric and gravimetric techniques recorded high inhibition efficiencies of 83.93% and 82.61%, respectively, showing that the Ricinus communis extract can be employed to control aluminum corrosion in an HCl medium.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"38 1","pages":"19-28"},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70917143","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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