The formation of thick anodic oxide films on antimony in diluted solutions of oxalic acid (CO(OH) 2 ) was studied under galvanostatic and isothermal conditions. The film formation was always accompanied by a dissolution process which strongly depended on the growth conditions. The formation efficiency, as determined by the dissolved metal amount, was affected by the CO(OH) 2 concentration, the current density and the anodization time. The dissolved antimony amount increased with higher CO(OH) 2 concentrations and anodization time, and with lower current densities. The analysis of the total current density suggests the occurrence of a formed film and a dissolving component. According to the calculations, the anodic oxides composition is close to Sb 2 O 3 . The growth of anodic Sb 2 O 3 took place at high electric fields within the oxide film. The thicknesses of the formed films were calculated by taking into account their dissolution. The film formation efficiency was determined at various current densities.
{"title":"Efficiency of the Galvanostatic Formation of Anodic Antimony Oxide in Oxalic Acid Solutions","authors":"C. Girginov, E. Lilov, S. Kozhukharov, V. Lilova","doi":"10.4152/pea.2022400203","DOIUrl":"https://doi.org/10.4152/pea.2022400203","url":null,"abstract":"The formation of thick anodic oxide films on antimony in diluted solutions of oxalic acid (CO(OH) 2 ) was studied under galvanostatic and isothermal conditions. The film formation was always accompanied by a dissolution process which strongly depended on the growth conditions. The formation efficiency, as determined by the dissolved metal amount, was affected by the CO(OH) 2 concentration, the current density and the anodization time. The dissolved antimony amount increased with higher CO(OH) 2 concentrations and anodization time, and with lower current densities. The analysis of the total current density suggests the occurrence of a formed film and a dissolving component. According to the calculations, the anodic oxides composition is close to Sb 2 O 3 . The growth of anodic Sb 2 O 3 took place at high electric fields within the oxide film. The thicknesses of the formed films were calculated by taking into account their dissolution. The film formation efficiency was determined at various current densities.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70919950","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 ionic liquid (IL) based pencil graphite electrode (PGE) sensor was electrochemically fabricated for hydroquinone (HQ), catechol (CC) and resorcinol (RS) simultaneous detection and estimation in aqueous media. PGE surface was modified by 1-hexylpyridinium hexafluorophosphate (HPHP) using cyclic voltammetry (CV). The modified surface was characterized by scanning electron microscope (SEM) and energy dispersive X-ray microanalysis (EDX). The modified electrode showed an excellent electro-analytical activity towards simultaneously HQ, CC and RS, at pH 6.8 in aqueous media. The scan rate effect was diffusion controlled and the concentration effect was linear with current. The limit of detection (LOD) for HQ, CC and RS was found to be 6.38 μmol L¹, 4.56 μmol L¹ and 19.6 μmol L¹, respectively. The sensitivity for HQ, CC and RS was found to be 448.49 μAmM -1 cm -2 , 627.35 μAmM -1 cm -2 and 146.10 μAmM −1 cm −2 , respectively, in a ternary mixture of dihydroxybenzene isomers (DHBIs). The cost of using PGE was lower than that of the conventional electrodes. isomers, ionic liquid, pencil graphite electrode and differential pulse voltammetry.
采用电化学方法制备了离子液体铅笔石墨电极(PGE)传感器，用于水中对苯二酚(HQ)、儿茶酚(CC)和间苯二酚(RS)的同时检测和估计。采用循环伏安法(CV)对PGE表面进行了六氟磷酸1-己基吡啶(HPHP)修饰。用扫描电镜(SEM)和能谱x射线微分析(EDX)对改性后的表面进行了表征。在pH为6.8的水溶液中，改性电极同时对HQ、CC和RS具有良好的电分析活性。扫描速率效应受扩散控制，浓度效应与电流呈线性关系。检测限(LOD)分别为6.38 μmol L¹、4.56 μmol L¹和19.6 μmol L¹。在二羟基苯异构体(DHBIs)的三元混合物中，HQ、CC和RS的灵敏度分别为448.49 μAmM -1 cm -2、627.35 μAmM -1 cm -2和146.10 μAmM -1 cm -2。使用PGE的成本低于传统电极。异构体，离子液体，铅笔石墨电极和差分脉冲伏安法。
{"title":"Low Cost Electrochemical Sensor for Simultaneous Detection and Estimation of Dihydroxybenzene Isomers","authors":"N. T. Tonu, M. A. Yousuf","doi":"10.4152/pea.2022400105","DOIUrl":"https://doi.org/10.4152/pea.2022400105","url":null,"abstract":"An ionic liquid (IL) based pencil graphite electrode (PGE) sensor was electrochemically fabricated for hydroquinone (HQ), catechol (CC) and resorcinol (RS) simultaneous detection and estimation in aqueous media. PGE surface was modified by 1-hexylpyridinium hexafluorophosphate (HPHP) using cyclic voltammetry (CV). The modified surface was characterized by scanning electron microscope (SEM) and energy dispersive X-ray microanalysis (EDX). The modified electrode showed an excellent electro-analytical activity towards simultaneously HQ, CC and RS, at pH 6.8 in aqueous media. The scan rate effect was diffusion controlled and the concentration effect was linear with current. The limit of detection (LOD) for HQ, CC and RS was found to be 6.38 μmol L¹, 4.56 μmol L¹ and 19.6 μmol L¹, respectively. The sensitivity for HQ, CC and RS was found to be 448.49 μAmM -1 cm -2 , 627.35 μAmM -1 cm -2 and 146.10 μAmM −1 cm −2 , respectively, in a ternary mixture of dihydroxybenzene isomers (DHBIs). The cost of using PGE was lower than that of the conventional electrodes. isomers, ionic liquid, pencil graphite electrode and differential pulse voltammetry.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920080","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}
Novel sulphur (S)-containing Schiff’s bases, N-((1H-indol-3-yl)methylene)thiazol-2-amine (I3A2AT) and(13E)-N1,N2-bis((thiophene-2-yl)methylene) cyclohexane-1,2-diamine (T2CDACH), were synthesized. The structures were deep-rooted by mass, UV-visible, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analyses. The ligands inhibition efficiency ( w%) on carbon steel (CS) corrosion in 1 M hydrochloric acid ( HCl) was studied using gravimetric analysis, electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation (PDP), electrochemical noise (ECN), quantum chemical and surface studies. Both Schiff’s bases acted as excellent inhibitors on CS corrosion in 1 M HCl. The excellent inhibitors performance was confirmed by the formation of protective adsorption films onto the CS surface. The inhibitors adsorption onto the CS surface followed Langmuir’s adsorption isotherm. Energies of the highest and lowest occupied molecular orbitals (E HOMO and E LUMO) , number of electrons transferred (∆N), electronegativity, chemical hardness, and so forth, were evaluated by quantum chemical studies. An acceptable correlation was observed between the results of quantum chemical calculations and other corrosion monitoring techniques. corrosion inhibitors.
合成了新型含硫席夫碱N-((1h -吲哚-3-基)亚甲基)噻唑-2-胺(I3A2AT)和(13E)- n1, n2 -二((噻吩-2-基)亚甲基)环己烷-1,2-二胺(T2CDACH)。通过质量、紫外可见、傅里叶变换红外光谱(FTIR)和核磁共振(NMR)分析，对其结构进行了深入分析。采用重量分析、电化学阻抗谱(EIS)、动电位极化(PDP)、电化学噪声(ECN)、量子化学和表面研究等方法研究了配体在1 M盐酸(HCl)中对碳钢(CS)的缓蚀效果。两种希夫碱在1 M HCl溶液中对CS腐蚀均有良好的抑制作用。在CS表面形成保护性吸附膜，证实了其优异的抑制剂性能。抑制剂在CS表面的吸附遵循Langmuir吸附等温线。采用量子化学方法对其最高和最低已占据分子轨道(E HOMO和E LUMO)的能量、转移电子数(∆N)、电负性、化学硬度等进行了评价。在量子化学计算结果和其他腐蚀监测技术之间观察到可接受的相关性。腐蚀抑制剂。
{"title":"Screening of Two Sulphur-Containing Schiff’s Bases Corrosion Inhibition Properties on CS: Gravimetric, Electrochemical and Quantum Chemical Studies","authors":"J. Reeja, K. Thomas, K. Ragi, M. P. Binsi","doi":"10.4152/pea.2022400401","DOIUrl":"https://doi.org/10.4152/pea.2022400401","url":null,"abstract":"Novel sulphur (S)-containing Schiff’s bases, N-((1H-indol-3-yl)methylene)thiazol-2-amine (I3A2AT) and(13E)-N1,N2-bis((thiophene-2-yl)methylene) cyclohexane-1,2-diamine (T2CDACH), were synthesized. The structures were deep-rooted by mass, UV-visible, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analyses. The ligands inhibition efficiency ( w%) on carbon steel (CS) corrosion in 1 M hydrochloric acid ( HCl) was studied using gravimetric analysis, electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation (PDP), electrochemical noise (ECN), quantum chemical and surface studies. Both Schiff’s bases acted as excellent inhibitors on CS corrosion in 1 M HCl. The excellent inhibitors performance was confirmed by the formation of protective adsorption films onto the CS surface. The inhibitors adsorption onto the CS surface followed Langmuir’s adsorption isotherm. Energies of the highest and lowest occupied molecular orbitals (E HOMO and E LUMO) , number of electrons transferred (∆N), electronegativity, chemical hardness, and so forth, were evaluated by quantum chemical studies. An acceptable correlation was observed between the results of quantum chemical calculations and other corrosion monitoring techniques. corrosion inhibitors.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920627","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 high toxicity of industrial metal corrosion inhibitors raises various environmental and health problems. Thus, the study of metals and alloys corrosion inhibition, in acidic media, by eco-compatible organic compounds, has become a very attractive research field. In this paper, garlic ( Allium Sativum ) extract inhibition efficiency (IE) against API X60 carbon steel (CS) and 316L stainless steel (SS) corrosion, in a 1 M sulphuric acid (H 2 SO 4 ) solution, has been investigated using electrochemical techniques, including potentiodynamic polarization (PPD) and electrochemical impedance spectroscopy (EIS). The experimental results showed the remarkable corrosion inhibitive performance of garlic extract (GE). The corrosion IE, which depends on the inhibitor concentration, increased up to 90%, for SS, and 67% for CS, as shown from the PPD tests. EIS analysis showed that the corrosion resistance (CRST) was increased in the medium with GE, indicating the properties improvement of the passive films formed on the steels surfaces.
{"title":"Garlic Extract as an Environmentally Corrosion Inhibitor of API X60 Carbon Steel and 316L Stainless Steel in Sulphuric Acid","authors":"S. Belkaid, S. Hamdani, D. Mansour","doi":"10.4152/pea.2022400403","DOIUrl":"https://doi.org/10.4152/pea.2022400403","url":null,"abstract":"The high toxicity of industrial metal corrosion inhibitors raises various environmental and health problems. Thus, the study of metals and alloys corrosion inhibition, in acidic media, by eco-compatible organic compounds, has become a very attractive research field. In this paper, garlic ( Allium Sativum ) extract inhibition efficiency (IE) against API X60 carbon steel (CS) and 316L stainless steel (SS) corrosion, in a 1 M sulphuric acid (H 2 SO 4 ) solution, has been investigated using electrochemical techniques, including potentiodynamic polarization (PPD) and electrochemical impedance spectroscopy (EIS). The experimental results showed the remarkable corrosion inhibitive performance of garlic extract (GE). The corrosion IE, which depends on the inhibitor concentration, increased up to 90%, for SS, and 67% for CS, as shown from the PPD tests. EIS analysis showed that the corrosion resistance (CRST) was increased in the medium with GE, indicating the properties improvement of the passive films formed on the steels surfaces.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920751","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}
Metals and alloys corrosion is one of the most challenging and damaging occurrence that is linked with enormous economic and safety losses, and it becomes more severe during some manufacturing processes by which metallic surfaces are treated for other industrial application processes. The use of corrosion inhibitors is one of the best way to protect metals and alloys against damage. The problem of the environmental toxicity of some of the employed inhibitors and the high cost involved in controlling and preventing corrosion have prompted this review. Computational chemistry methods are mostly significant in reducing the cost of protecting metals and alloys against corrosion. This review article begins with the summary of the most used computational methods, parameters and, finally, summarizes the results of some studies made by different authors in the field of corrosion science and engineering. 5-sulfamethoxazoleazo-3-phenyl-2-thioxo-4-thiazolidinone), as corrosion inhibitors for MS in an acidic medium, using DFT at the B3LYP/6-31G (d, p) and B3LYP/6-311G (d, p) basis set levels. Ab initio calculations using the HF/6-31G (d, p) and HF/6-311G (d, p) methods for quantum chemical parameters/descriptors, namely, E HOMO , E LUMO , ΔE, μ, A, I, X, η, , polarizability (α), Mulliken charges and fraction of electrons transferred (ΔN) from the inhibitors to Fe, were calculated and correlated with the experimental IE%. Quantitative structure activity relationship (QSAR) approach and a composite index of some quantum chemical parameters/descriptors were also considered to characterize the studied molecules IE. The results showed that the IE% of the studied rhodanine azosulfa drugs was closely related to their theoretical IE%, but with varying degrees of the correlation coefficient (R 2 ). The IE% also increased in E HOMO and decreased in E HOMO -E LUMO , and the areas containing N and S atoms were the most possible sites for bonding to the Fe surface, by donating the lone pair electrons to its empty d-orbital.
金属和合金腐蚀是最具挑战性和破坏性的事件之一，它与巨大的经济和安全损失有关，并且在某些制造过程中变得更加严重，这些过程是金属表面处理的其他工业应用过程。使用缓蚀剂是保护金属和合金免受损害的最好方法之一。一些所采用的缓蚀剂的环境毒性问题以及控制和防止腐蚀所涉及的高成本问题促使本文进行综述。计算化学方法在降低保护金属和合金免受腐蚀的成本方面具有重要意义。本文首先对腐蚀科学与工程领域中常用的计算方法、参数进行了综述，最后对不同作者的研究结果进行了总结。在B3LYP/6-31G (d, p)和B3LYP/6-311G (d, p)基组水平下，采用DFT对5-磺胺甲氧恶唑啉偶氮-3-苯基-2-硫氧-4-噻唑烷酮)作为MS在酸性介质中的缓蚀剂。用HF/6-31G (d, p)和HF/6-311G (d, p)方法从头计算了E HOMO、E LUMO、ΔE、μ、A、I、X、η、、极化率(α)、Mulliken电荷和从抑制剂转移到Fe的电子分数(ΔN)等量子化学参数/描述符，并与实验IE%进行了相关计算。采用定量构效关系(QSAR)方法和一些量子化学参数/描述符的复合指数来表征所研究的分子IE。结果表明，所研究的罗丹宁偶氮磺胺类药物的IE%与其理论IE%密切相关，但存在不同程度的相关系数(r2)。E HOMO -E LUMO的IE%增加，E HOMO -E LUMO的IE%减少，含有N和S原子的区域最有可能与Fe表面成键，将孤对电子提供给空的d轨道。
{"title":"The Role of Computational Chemistry in Corrosion Inhibition: a Review","authors":"F. Abeng, B. Nyong, M. E. Ikpi, M. E. Obeten","doi":"10.4152/pea.2022400402","DOIUrl":"https://doi.org/10.4152/pea.2022400402","url":null,"abstract":"Metals and alloys corrosion is one of the most challenging and damaging occurrence that is linked with enormous economic and safety losses, and it becomes more severe during some manufacturing processes by which metallic surfaces are treated for other industrial application processes. The use of corrosion inhibitors is one of the best way to protect metals and alloys against damage. The problem of the environmental toxicity of some of the employed inhibitors and the high cost involved in controlling and preventing corrosion have prompted this review. Computational chemistry methods are mostly significant in reducing the cost of protecting metals and alloys against corrosion. This review article begins with the summary of the most used computational methods, parameters and, finally, summarizes the results of some studies made by different authors in the field of corrosion science and engineering. 5-sulfamethoxazoleazo-3-phenyl-2-thioxo-4-thiazolidinone), as corrosion inhibitors for MS in an acidic medium, using DFT at the B3LYP/6-31G (d, p) and B3LYP/6-311G (d, p) basis set levels. Ab initio calculations using the HF/6-31G (d, p) and HF/6-311G (d, p) methods for quantum chemical parameters/descriptors, namely, E HOMO , E LUMO , ΔE, μ, A, I, X, η, , polarizability (α), Mulliken charges and fraction of electrons transferred (ΔN) from the inhibitors to Fe, were calculated and correlated with the experimental IE%. Quantitative structure activity relationship (QSAR) approach and a composite index of some quantum chemical parameters/descriptors were also considered to characterize the studied molecules IE. The results showed that the IE% of the studied rhodanine azosulfa drugs was closely related to their theoretical IE%, but with varying degrees of the correlation coefficient (R 2 ). The IE% also increased in E HOMO and decreased in E HOMO -E LUMO , and the areas containing N and S atoms were the most possible sites for bonding to the Fe surface, by donating the lone pair electrons to its empty d-orbital.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920686","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}
Ethylenediamine (EDA), diethylenetriamine (DETA) and N,N,N',N'-tetrakis (2-hydroxypropyl) ethylenediamine (THPrED) are used relatively often in galvanic processes. Tetra-substituted derivatives, such as N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine, (THEtED) are quite biologically stable and hardly degradable. In recent years, much attention has been devoted to electrochemical oxidation, using anodes with a high over-potential of O2 evolution, such as the boron-doped diamond (BDD). DETA and THPrED electrochemical treatment using a BDD anode was herein studied. The degradation efficiency of the amines was evaluated under different current intensities and reaction times. To determine the products formed in the oxidation process, ion chromatography (IC) was used. A high decrease in the current between the first and the second CV scan indicated the polymer film formation on the BDD electrode surface. Hydroxyl radicals formed at a potential of about 2 V and higher caused further oxidation of the electrode reaction products. It was found that NH4, CH3-COOH, N2, EDA, CO2 and NO3were formed in a short reaction time, and at low current intensity. The mineralization occurred during substrates electrolysis, due to rapid DETA and THPrED decomposition. After 180 min of reaction, αTOC and αN values for DETA were 94% and 18%, respectively. For THPrED, αTOC was 98.6% and αN was 43.6%. Therefore, the electrochemical approach was considered a very promising method in practical application for the treatment of wastewater containing amines.
乙二胺(EDA)、二乙烯三胺(DETA)和N,N,N'，N'-四(2-羟丙基)乙二胺(THPrED)是电偶过程中比较常用的几种。四取代衍生物，如N, N, N'， N'-四基(2-羟乙基)乙二胺(THEtED)具有很好的生物稳定性和难降解性。近年来，电化学氧化研究受到了广泛的关注，主要是利用掺硼金刚石(BDD)等具有高氧析出过电位的阳极。本文研究了BDD阳极的DETA和THPrED电化学处理。在不同的电流强度和反应时间下评价了胺类化合物的降解效率。采用离子色谱法测定氧化过程中生成的产物。第一次和第二次CV扫描之间的电流大幅下降表明BDD电极表面形成了聚合物膜。在约2v或更高的电位下形成的羟基自由基导致电极反应产物进一步氧化。结果表明，在较短的反应时间和较低的电流强度下，NH4、CH3-COOH、N2、EDA、CO2和no3均可生成。矿化发生在底物电解过程中，由于快速的DETA和THPrED分解。反应180 min后，DETA的αTOC和αN值分别为94%和18%。THPrED αTOC为98.6%，αN为43.6%。因此，电化学方法被认为是一种具有实际应用前景的处理含胺废水的方法。
{"title":"Electrochemical Degradation of Ethyleneamines Contained in Galvanic Baths on a BDD Electrode","authors":"M. Socha, J. Rynkowski","doi":"10.4152/pea.2022400303","DOIUrl":"https://doi.org/10.4152/pea.2022400303","url":null,"abstract":"Ethylenediamine (EDA), diethylenetriamine (DETA) and N,N,N',N'-tetrakis (2-hydroxypropyl) ethylenediamine (THPrED) are used relatively often in galvanic processes. Tetra-substituted derivatives, such as N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine, (THEtED) are quite biologically stable and hardly degradable. In recent years, much attention has been devoted to electrochemical oxidation, using anodes with a high over-potential of O2 evolution, such as the boron-doped diamond (BDD). DETA and THPrED electrochemical treatment using a BDD anode was herein studied. The degradation efficiency of the amines was evaluated under different current intensities and reaction times. To determine the products formed in the oxidation process, ion chromatography (IC) was used. A high decrease in the current between the first and the second CV scan indicated the polymer film formation on the BDD electrode surface. Hydroxyl radicals formed at a potential of about 2 V and higher caused further oxidation of the electrode reaction products. It was found that NH4, CH3-COOH, N2, EDA, CO2 and NO3were formed in a short reaction time, and at low current intensity. The mineralization occurred during substrates electrolysis, due to rapid DETA and THPrED decomposition. After 180 min of reaction, αTOC and αN values for DETA were 94% and 18%, respectively. For THPrED, αTOC was 98.6% and αN was 43.6%. Therefore, the electrochemical approach was considered a very promising method in practical application for the treatment of wastewater containing amines.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920827","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. Rodríguez-Yáñez, R. Brenes-Brenes, R. Jimenez-Salas, M. Abdalah-Hernández, J. Sanabria-Chinchilla
The Western Central Valley (WCV) of Costa Rica is an area of interest, due to its high concentration of population and economic activity, presenting itself as a tropical monsoon-type atmospheric basin (AB), with well-defined climatic seasons (dry and rainy). The present study proposes the assessment of low carbon steel (CS) atmospheric corrosion, based on ISO 9223 (2012) and associated standards. A general analysis of the atmospheric basin effect was initially performed on these data, followed by the basic modeling of air pollutants and meteorological parameters. The WCV is an area of low contamination, which corresponds to a C2 or C3 category, according to ISO 9223. It mainly shows significant climatic seasons (dry and rainy) effects on the initial corrosion rates, but obtaining similar annual corrosion results for them. The ISO 9223 annual atmospheric corrosion model overestimated the actual obtained corrosion values, whereas linear or logarithmic models gave better results, especially when time and/or time of wetness (TOW) were considered as variables. ISO 9223 and ISO 9225.
{"title":"Atmospheric Corrosion in the Tropics: The Costa Rican Central Valley Case","authors":"J. Rodríguez-Yáñez, R. Brenes-Brenes, R. Jimenez-Salas, M. Abdalah-Hernández, J. Sanabria-Chinchilla","doi":"10.4152/pea.2022400602","DOIUrl":"https://doi.org/10.4152/pea.2022400602","url":null,"abstract":"The Western Central Valley (WCV) of Costa Rica is an area of interest, due to its high concentration of population and economic activity, presenting itself as a tropical monsoon-type atmospheric basin (AB), with well-defined climatic seasons (dry and rainy). The present study proposes the assessment of low carbon steel (CS) atmospheric corrosion, based on ISO 9223 (2012) and associated standards. A general analysis of the atmospheric basin effect was initially performed on these data, followed by the basic modeling of air pollutants and meteorological parameters. The WCV is an area of low contamination, which corresponds to a C2 or C3 category, according to ISO 9223. It mainly shows significant climatic seasons (dry and rainy) effects on the initial corrosion rates, but obtaining similar annual corrosion results for them. The ISO 9223 annual atmospheric corrosion model overestimated the actual obtained corrosion values, whereas linear or logarithmic models gave better results, especially when time and/or time of wetness (TOW) were considered as variables. ISO 9223 and ISO 9225.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70921355","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 study investigated one of the chemical compounds taken by diabetic patients as a replacement for natural sugar. Its aim was to identify the electrochemical properties of sodium saccharin in different electrolytes, using a nano-sensor. Sodium saccharine was studied by cyclic voltammetric technique, in different electrolytes, using a modified glassy carbon electrode (GCE) with carbon nanotubes (CNT) as working electrode (CNT/GCE). It was found that the redox current peaks of 0.01 mM sodium saccharine in 1 M Na2SO3 enhanced both redox peaks with the CNT electro-catalyst on the GCE surface. Different concentrations, pH and scan rates of sodium saccharine in Na2SO3 have been studied. Also, the nano sensor showed good reliability and stability towards the chemical compounds in the cyclic voltammetric cell. Other electrochemical parameters were determined, such as the potential peak separation (Epa-Epc≈100 mV), the current ratio (Ipa/Ipc≈1) of the redox peaks and the cathodic-anodic reaction rate. The diffusion coefficient value was determined at different scan rates.
本研究调查了糖尿病患者作为天然糖替代品的一种化合物。其目的是利用纳米传感器识别不同电解质中糖精钠的电化学性质。以碳纳米管(CNT)为工作电极的改性玻碳电极(GCE) (CNT/GCE)为研究对象，采用循环伏安法研究了糖精钠在不同电解质中的作用。结果表明，在1 M Na2SO3溶液中，糖精钠的氧化还原峰为0.01 mM，碳纳米管电催化剂对GCE表面的氧化还原峰均有增强作用。研究了糖精钠在Na2SO3中的不同浓度、pH和扫描速率。此外，纳米传感器对循环伏安电池中的化合物也表现出良好的可靠性和稳定性。测定了电位峰间距(Epa-Epc≈100 mV)、氧化还原峰电流比(Ipa/Ipc≈1)和阴极-阳极反应速率等电化学参数。测定了不同扫描速率下的扩散系数值。
{"title":"Electrochemical Behavior Study of Sodium Saccharin in an Aqueous Electrolyte Solution by a Nano-sensor, Using Cyclic Voltammetric Technique","authors":"M. Radhi, Y. K. A. Amir, A. Ibrahim","doi":"10.4152/pea.202102071","DOIUrl":"https://doi.org/10.4152/pea.202102071","url":null,"abstract":"This study investigated one of the chemical compounds taken by diabetic patients as a replacement for natural sugar. Its aim was to identify the electrochemical properties of sodium saccharin in different electrolytes, using a nano-sensor. Sodium saccharine was studied by cyclic voltammetric technique, in different electrolytes, using a modified glassy carbon electrode (GCE) with carbon nanotubes (CNT) as working electrode (CNT/GCE). It was found that the redox current peaks of 0.01 mM sodium saccharine in 1 M Na2SO3 enhanced both redox peaks with the CNT electro-catalyst on the GCE surface. Different concentrations, pH and scan rates of sodium saccharine in Na2SO3 have been studied. Also, the nano sensor showed good reliability and stability towards the chemical compounds in the cyclic voltammetric cell. Other electrochemical parameters were determined, such as the potential peak separation (Epa-Epc≈100 mV), the current ratio (Ipa/Ipc≈1) of the redox peaks and the cathodic-anodic reaction rate. The diffusion coefficient value was determined at different scan rates.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70918414","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 study reports the evaluation of the anticorrosive performance of polymer epoxy resin, namely, Diglycidyl ether 4, 4’-dihydroxydiphenylsulfone (DGEDDS) and its polymer composite reinforced with Titanium Dioxide (TiO 2 ), for carbon steel (CS) corrosion, in 3% wt. NaCl, using experimental analyses. Thermal, electrochemical and morphological techniques were used to demonstrate the anticorrosive effectiveness of the standard epoxy resin (MP1) and its TiO 2 composite (MP2). The effect of UV irradiation (for 2000 h), on the effectiveness of MP1 and its TiO2 composite (MP2), showed that TiO 2 presence appreciably enhanced the protection efficiency effect of MP1 .
{"title":"Thermal and Anti-Corrosive Properties of Titanium Dioxide/Epoxy Resin Composite Coating for Steel Preservation in a Marine-Environment","authors":"O. Dagdag, A. El-Harfi, A. EL-BACHIRI, S. Jodeh","doi":"10.4152/pea.2021390303","DOIUrl":"https://doi.org/10.4152/pea.2021390303","url":null,"abstract":"This study reports the evaluation of the anticorrosive performance of polymer epoxy resin, namely, Diglycidyl ether 4, 4’-dihydroxydiphenylsulfone (DGEDDS) and its polymer composite reinforced with Titanium Dioxide (TiO 2 ), for carbon steel (CS) corrosion, in 3% wt. NaCl, using experimental analyses. Thermal, electrochemical and morphological techniques were used to demonstrate the anticorrosive effectiveness of the standard epoxy resin (MP1) and its TiO 2 composite (MP2). The effect of UV irradiation (for 2000 h), on the effectiveness of MP1 and its TiO2 composite (MP2), showed that TiO 2 presence appreciably enhanced the protection efficiency effect of MP1 .","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70918604","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}
I. Kaabi, T. Douadi, D. Daoud, S. Amamra, S. Chafaa
A new inhibitor Schiff base ether ligand, L, di[(4-phenylamino)2,4-dihydroxy salicylaldehyde], was synthesized and characterized using mass spectra, elemental analysis, IR spectra, UV-Vis spectra, H NMR spectroscopy and thermal analysis. Electrochemical properties were investigated using cyclic Voltammetry (CV). The corrosion inhibition effect of the new prepared Schiff base was examined on mild steel (X48) in a 1 M HCl solution, by using gravimetric and electrochemical measurements. The potentiodynamic polarization results showed that the investigated Schiff base acted as a mixed kind inhibitor (cathodic/anodic), with some cathodic predominance. The adsorption procedure on X48 surface obeyed Langmuir isotherm. The associated adsorption activation factors and thermodynamic parameters were evaluated and interpreted. The inhibitor layer formed on the metal surface was characterized by AFM and SEM. The solid-state molecular geometry has been studied with the theoretical data obtained by density functional theory (DFT). Furthermore, the interaction between the inhibitor and Fe (1 1 0) surface was achieved by molecular dynamics simulations.
{"title":"A New Synthesized Schiff Base as Corrosion Inhibitor for Mild Steel in a HCl Medium: Experimental, Density Functional Theory and Molecular Dynamics Simulation Studies","authors":"I. Kaabi, T. Douadi, D. Daoud, S. Amamra, S. Chafaa","doi":"10.4152/pea.2021390504","DOIUrl":"https://doi.org/10.4152/pea.2021390504","url":null,"abstract":"A new inhibitor Schiff base ether ligand, L, di[(4-phenylamino)2,4-dihydroxy salicylaldehyde], was synthesized and characterized using mass spectra, elemental analysis, IR spectra, UV-Vis spectra, H NMR spectroscopy and thermal analysis. Electrochemical properties were investigated using cyclic Voltammetry (CV). The corrosion inhibition effect of the new prepared Schiff base was examined on mild steel (X48) in a 1 M HCl solution, by using gravimetric and electrochemical measurements. The potentiodynamic polarization results showed that the investigated Schiff base acted as a mixed kind inhibitor (cathodic/anodic), with some cathodic predominance. The adsorption procedure on X48 surface obeyed Langmuir isotherm. The associated adsorption activation factors and thermodynamic parameters were evaluated and interpreted. The inhibitor layer formed on the metal surface was characterized by AFM and SEM. The solid-state molecular geometry has been studied with the theoretical data obtained by density functional theory (DFT). Furthermore, the interaction between the inhibitor and Fe (1 1 0) surface was achieved by molecular dynamics simulations.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70919182","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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