Polypyrrole (PPy) films were electrochemically synthesized on an Au/TiO 2 coated quartz crystal electrode in solutions with different heparin (Hep) concentrations. The PPy films morphology was determined by tapping a mode atomic force microscopy (AFM). The influence of the dopant concentration on the coating surface roughness was studied. Electrochemical quartz crystal microbalance (EQCM) results suggest that Hep retained in the PPy films was bound to thrombin. The adsorbed thrombin amount increased with a higher coating surface roughness. PPy films doped with Hep are electroactive and show cation exchange properties under oxidation or reduction conditions in a Ringer solution. The pre-oxidized PPy film adsorbed a greater thrombin amount than the freshly one and even more than the pre-reduced film.
{"title":"Synthesis and Characterization of Heparin-Doped Polypyrrole Coatings Using an Electrochemical Quartz Crystal Microbalance (EQCM)","authors":"D. Flamini, M. B. González, S. Saidman","doi":"10.4152/pea.2022400104","DOIUrl":"https://doi.org/10.4152/pea.2022400104","url":null,"abstract":"Polypyrrole (PPy) films were electrochemically synthesized on an Au/TiO 2 coated quartz crystal electrode in solutions with different heparin (Hep) concentrations. The PPy films morphology was determined by tapping a mode atomic force microscopy (AFM). The influence of the dopant concentration on the coating surface roughness was studied. Electrochemical quartz crystal microbalance (EQCM) results suggest that Hep retained in the PPy films was bound to thrombin. The adsorbed thrombin amount increased with a higher coating surface roughness. PPy films doped with Hep are electroactive and show cation exchange properties under oxidation or reduction conditions in a Ringer solution. The pre-oxidized PPy film adsorbed a greater thrombin amount than the freshly one and even more than the pre-reduced film.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920212","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}
S. Mehtab, M. Zaidi, P. Bhatt, P. Joshi, T. Agarwal
The use of pesticides has been increased in recent years, to enhance crops productivity, which may lead to a serious global concern of environmental pesticides monitoring. Isoproturon (IPU: 3-(4-isopropylphenyl)-1,1-dimethylurea) is an herbicide widely used in wheat crops. However, when it enters in the ecosystem, it is heavily toxic to humans. Thus, there is an urgent need to develop sensitive and selective IPU detection methods. In the present work, a novel polymethylmethacrylate/ferrite (PMMA/M(FexOy)) polymer nanocomposite (PNC) modified glassy carbon electrode (GCE) was developed for IPU detection. The PNC/GCE surface morphology was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). PNC electrochemical characterization (EC) was performed by cyclic voltammetry (CV) that showed a quasi-reversible redox behavior. PNC/GCE demonstrated an excellent square wave voltammetric (SWV) response towards IPU, with a limit of quantification (LOQ) of 1.98 × 10 M, and a limit of detection (LOD) of 6.5 × 10 M, in 1 M HClO4 (perchloric acid), at pH 2.0. EC investigations reflected a peak current that was linearly related to IPU concentrations, with a high detection sensitivity. It also showed much better CV and SWV IPU responses than those of a bare GCE, and further environmental stability, without a high influence of common interfering ions.
{"title":"Isoproturon (IPU) Electrochemical Sensing Based on a Polymethylmethacrylate Ferrite (PMMA/M(FexOy)) Nanocomposite Modified Electrode","authors":"S. Mehtab, M. Zaidi, P. Bhatt, P. Joshi, T. Agarwal","doi":"10.4152/pea.2022400305","DOIUrl":"https://doi.org/10.4152/pea.2022400305","url":null,"abstract":"The use of pesticides has been increased in recent years, to enhance crops productivity, which may lead to a serious global concern of environmental pesticides monitoring. Isoproturon (IPU: 3-(4-isopropylphenyl)-1,1-dimethylurea) is an herbicide widely used in wheat crops. However, when it enters in the ecosystem, it is heavily toxic to humans. Thus, there is an urgent need to develop sensitive and selective IPU detection methods. In the present work, a novel polymethylmethacrylate/ferrite (PMMA/M(FexOy)) polymer nanocomposite (PNC) modified glassy carbon electrode (GCE) was developed for IPU detection. The PNC/GCE surface morphology was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). PNC electrochemical characterization (EC) was performed by cyclic voltammetry (CV) that showed a quasi-reversible redox behavior. PNC/GCE demonstrated an excellent square wave voltammetric (SWV) response towards IPU, with a limit of quantification (LOQ) of 1.98 × 10 M, and a limit of detection (LOD) of 6.5 × 10 M, in 1 M HClO4 (perchloric acid), at pH 2.0. EC investigations reflected a peak current that was linearly related to IPU concentrations, with a high detection sensitivity. It also showed much better CV and SWV IPU responses than those of a bare GCE, and further environmental stability, without a high influence of common interfering ions.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920577","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}
A. El-khlifi, M. Saadouni, R. Ijoub, A. Oubihi, Y. ElAoufir, S. Boukhriss, M. Ouhssine
Ethyl 3-hydroxy-2-(p-tolyl)-3,4-dihydro-2H-benzo[b][1,4]thiazine-3-carboxylate (EHBT) inhibition effect and its adsorption onto a mild steel surface in phosphoric acid (2 M H 3 PO 4 ) was investigated, at temperatures varying between 298 and 328 K, by weight loss, EIS and potentiodynamic polarization techniques. The tested compound showed an inhibition efficiency that was superior to 88 % for a concentration equal to 5 × 10 -3 M. Polarization measurements indicated that the examined EHBT acted as a mixed inhibitor. The protection efficiency increased with higher inhibitor concentrations and decreased with an increase in temperature. EHBT adsorption onto the mild steel surface obeyed Langmuir adsorption isotherm. EHBT inhibition action was also evaluated by surface SEM images.
{"title":"Synthesis and Corrosion Inhibition of Mild Steel in a Phosphoric Acid Solution of a Novel Benzothiazine Derivative","authors":"A. El-khlifi, M. Saadouni, R. Ijoub, A. Oubihi, Y. ElAoufir, S. Boukhriss, M. Ouhssine","doi":"10.4152/pea.2022400103","DOIUrl":"https://doi.org/10.4152/pea.2022400103","url":null,"abstract":"Ethyl 3-hydroxy-2-(p-tolyl)-3,4-dihydro-2H-benzo[b][1,4]thiazine-3-carboxylate (EHBT) inhibition effect and its adsorption onto a mild steel surface in phosphoric acid (2 M H 3 PO 4 ) was investigated, at temperatures varying between 298 and 328 K, by weight loss, EIS and potentiodynamic polarization techniques. The tested compound showed an inhibition efficiency that was superior to 88 % for a concentration equal to 5 × 10 -3 M. Polarization measurements indicated that the examined EHBT acted as a mixed inhibitor. The protection efficiency increased with higher inhibitor concentrations and decreased with an increase in temperature. EHBT adsorption onto the mild steel surface obeyed Langmuir adsorption isotherm. EHBT inhibition action was also evaluated by surface SEM images.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920009","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}
W. Yassine, S. Akazdam, I. Mechnou, Y. Raji, S. Zyade
Olive mill wastewater (OMW) is the major problem from olive oil extraction, due to its polluting organic and mineral matter and acid pH. This study aims to electrochemically treat OMW in an Al electrode reactor, to oxidize the organic matter, discolor the margins and neutralize the pH, thus reducing the pollutants. Various low cost adsorbents have been studied for the treatment of different types of effluents. In this study, the potential of activated carbon (C) derived from olive stones (OS) was studied for OMW removal. H 3 PO 4 (phosphoric acid) treated OS (AOS), as a low-cost, natural and eco-friendly biosorbent, was investigated for OMW removal from aqueous solutions. This work found that the increase in electrolysis time and current intensity significantly improved the treatment, while energy consumption and electrodes were observed. The results showed thirty-fold diluted margins for effluents with an acid pH of 5.02 and a conductivity of 14.89. The physicochemical parameters evolution during the electrocoagulation (EC) treatment showed that, under the conditions of an electrolysis time of 3 h and a current intensity of 3 A (= 416 A/m -2 ), the margins discoloration diluted ten times (91%), the mass loss of the electrodes was 0.55 kg.m -3 and the chemical oxygen demand (COD) reduction was 50%. These optimal operational levels allowed a good degradation of the margins. Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir’s and Freundlich’s isotherms equations. The best fit was obtained by the Langmuir’s model, with maximum OWM monolayer biosorption capacity of 189.83 mg/g. The biosorption was exothermic in nature (entalphy change: H° = -13.11 kJ/mol). The reaction was accompanied by a decrease in entropy ( S° = -72.91 kJ/mol). The Gibbs energy ( G°) was higher when the temperature was increased from 303 to 318 K, indicating a decrease in the biosorption feasibility at higher temperatures. The results have established good potentiality for EC and ALS to be used for OMW removal.
橄榄厂废水(OMW)是橄榄油提取过程中存在的主要问题，其污染有机物、矿物质和酸碱度。本研究的目的是在铝电极反应器中对OMW进行电化学处理，使有机物氧化，边缘变色，中和pH值，从而减少污染物。各种低成本吸附剂已被研究用于处理不同类型的废水。在本研究中，研究了橄榄石(OS)活性炭(C)去除OMW的潜力。研究了h3po4(磷酸)处理的OS (AOS)作为一种低成本、天然、环保的生物吸附剂对水溶液中OMW的去除效果。这项工作发现，电解时间和电流强度的增加显著改善了处理，同时观察到能量消耗和电极。结果表明，当酸性pH为5.02，电导率为14.89时，液缘被稀释了30倍。电凝(EC)处理过程中理化参数的变化表明，在电解时间为3 h、电流强度为3 a (= 416 a /m -2)的条件下，边缘变色被稀释了10倍(91%)，电极的质量损失为0.55 kg。m -3，化学需氧量(COD)降低50%。这些最佳的操作水平允许利润率的良好下降。生物吸附动力学数据符合拟二级动力学模型。采用Langmuir等温线方程和Freundlich等温线方程对实验等温线数据进行了分析。Langmuir模型拟合最佳，OWM单层生物吸附量最大可达189.83 mg/g。生物吸附本质上是放热的(物理变化:H°= -13.11 kJ/mol)。反应伴随着熵的降低(S°= -72.91 kJ/mol)。当温度从303 K升高到318 K时，吉布斯能(G°)增大，表明温度越高，吸附效果越差。结果表明，EC和ALS具有良好的去除率。
{"title":"Olive Mill Wastewater Removal by H3PO4 Treated Olive Stones as an Efficient Adsorbent and Electrocoagulation Process","authors":"W. Yassine, S. Akazdam, I. Mechnou, Y. Raji, S. Zyade","doi":"10.4152/pea.2022400601","DOIUrl":"https://doi.org/10.4152/pea.2022400601","url":null,"abstract":"Olive mill wastewater (OMW) is the major problem from olive oil extraction, due to its polluting organic and mineral matter and acid pH. This study aims to electrochemically treat OMW in an Al electrode reactor, to oxidize the organic matter, discolor the margins and neutralize the pH, thus reducing the pollutants. Various low cost adsorbents have been studied for the treatment of different types of effluents. In this study, the potential of activated carbon (C) derived from olive stones (OS) was studied for OMW removal. H 3 PO 4 (phosphoric acid) treated OS (AOS), as a low-cost, natural and eco-friendly biosorbent, was investigated for OMW removal from aqueous solutions. This work found that the increase in electrolysis time and current intensity significantly improved the treatment, while energy consumption and electrodes were observed. The results showed thirty-fold diluted margins for effluents with an acid pH of 5.02 and a conductivity of 14.89. The physicochemical parameters evolution during the electrocoagulation (EC) treatment showed that, under the conditions of an electrolysis time of 3 h and a current intensity of 3 A (= 416 A/m -2 ), the margins discoloration diluted ten times (91%), the mass loss of the electrodes was 0.55 kg.m -3 and the chemical oxygen demand (COD) reduction was 50%. These optimal operational levels allowed a good degradation of the margins. Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir’s and Freundlich’s isotherms equations. The best fit was obtained by the Langmuir’s model, with maximum OWM monolayer biosorption capacity of 189.83 mg/g. The biosorption was exothermic in nature (entalphy change: H° = -13.11 kJ/mol). The reaction was accompanied by a decrease in entropy ( S° = -72.91 kJ/mol). The Gibbs energy ( G°) was higher when the temperature was increased from 303 to 318 K, indicating a decrease in the biosorption feasibility at higher temperatures. The results have established good potentiality for EC and ALS to be used for OMW removal.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70921430","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}
Green corrosion inhibitors find various applications in the field of corrosion engineering and technology. In the present work, powder forms of Pimenta Dioica leaves were added into corrosion media to study their effect. Mild steel coupons corrosion studies showed an increase in the inhibitor efficiency, at higher concentrations, in corrosive media. The coupons electrochemical behavior was studied by OCP measurements. P. Dioica inhibition efficiency, adsorbed layers mechanism and mild steel corrosion rate were analyzed using weight loss measurements.
{"title":"Prevention of Mild Steel Corrosion in Potable Water by an Environmentally Friendly Inhibitor","authors":"N. Suma","doi":"10.4152/pea.2022400204","DOIUrl":"https://doi.org/10.4152/pea.2022400204","url":null,"abstract":"Green corrosion inhibitors find various applications in the field of corrosion engineering and technology. In the present work, powder forms of Pimenta Dioica leaves were added into corrosion media to study their effect. Mild steel coupons corrosion studies showed an increase in the inhibitor efficiency, at higher concentrations, in corrosive media. The coupons electrochemical behavior was studied by OCP measurements. P. Dioica inhibition efficiency, adsorbed layers mechanism and mild steel corrosion rate were analyzed using weight loss measurements.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"13 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920044","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 inhibition effect of Thymus willdenowii Boiss & Reut essential oil (TW) on the mild steel corrosion in 1 M HCl has been investigated using weight loss measurements, surface analysis (SEM-EDX, three-dimensional profilometry and FT-IR), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The TW oil anticorrosion effect was evaluated using polarization potentiodynamic curves obtained after 30, 60 and 90 min of immersion in a 1 M HCl medium. Gravimetric results have shown that TW oil has a significant inhibition efficiency value of 81.42%, which was attained at 3 g/L. The polarization measurements have shown that TW is a mixed type inhibitor, with a significant reduction in cathodic and anodic current densities. Measurements by electrochemical impedance spectroscopy revealed that resistance to the charge transfer has increased with higher TW oil concentrations. From the use of SEM-EDX and three-dimensional profilometry, it is clear that the metal surface has remarkably improved in the TW oil presence, compared to the one exposed to the acid medium without essential oil. From the TW proprieties and the obtained results, it can be concluded that this oil is a new natural substance that can be used against material corrosion in aggressive solutions.
采用失重测量、表面分析(SEM-EDX、三维轮廓仪和FT-IR)、动电位极化和电化学阻抗谱(EIS)等方法研究了麝香精油(TW)对1 M HCl中低碳钢的缓蚀作用。在1 M HCl介质中浸泡30min、60min和90min，用极化电位曲线评价TW油的防腐效果。重量分析结果表明，在3 g/L时，TW油的缓蚀效率为81.42%。极化测量表明，TW是一种混合型缓蚀剂，其阴极和阳极电流密度显著降低。电化学阻抗谱测试表明，随着TW油浓度的增加，电荷转移阻力增大。通过SEM-EDX和三维轮廓测量，可以清楚地看到，与暴露在没有精油的酸性介质中的金属相比，在TW油的存在下，金属表面有了显著改善。从TW的性质和得到的结果可以看出，该油是一种新的天然物质，可以用于抗腐蚀性溶液中的材料腐蚀。
{"title":"Adsorption Properties and Electrochemical Behavior of Thymus Willdenowii Boiss and Reut Essential Oil as a Green Inhibitor for Mild Steel Corrosion in 1 M HCl","authors":"M. Ouknin, P. Ponthiaux, J. Costa, L. Majidi","doi":"10.4152/pea.2022400101","DOIUrl":"https://doi.org/10.4152/pea.2022400101","url":null,"abstract":"The inhibition effect of Thymus willdenowii Boiss & Reut essential oil (TW) on the mild steel corrosion in 1 M HCl has been investigated using weight loss measurements, surface analysis (SEM-EDX, three-dimensional profilometry and FT-IR), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The TW oil anticorrosion effect was evaluated using polarization potentiodynamic curves obtained after 30, 60 and 90 min of immersion in a 1 M HCl medium. Gravimetric results have shown that TW oil has a significant inhibition efficiency value of 81.42%, which was attained at 3 g/L. The polarization measurements have shown that TW is a mixed type inhibitor, with a significant reduction in cathodic and anodic current densities. Measurements by electrochemical impedance spectroscopy revealed that resistance to the charge transfer has increased with higher TW oil concentrations. From the use of SEM-EDX and three-dimensional profilometry, it is clear that the metal surface has remarkably improved in the TW oil presence, compared to the one exposed to the acid medium without essential oil. From the TW proprieties and the obtained results, it can be concluded that this oil is a new natural substance that can be used against material corrosion in aggressive solutions.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70919307","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}
A graphene oxide-triazole hybrid anti-corrosive coating was done by fabricating a triazole derivative – 2-(5-mercapto-4-((3-nitrophenyl)amino)-4H-1,2,4-triazol-3-yl)isoindoline-1,3-dione (4-NBT) on a graphene oxide (GO) coated Cu electrode. The GO-4-NBT hybrid coating effect on the Cu surface corrosion behavior was electrochemically monitored through cyclic voltammetry (CV), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The fabrication of a protective coating was done in two steps. Firstly, GO was electrochemically deposited on the Cu electrode in two different aggressive media (1 M HCl and 0.1 M Na 2 SO 4 ), separately. Secondly, different 4-NBT concentrations were employed to reinforce GO corrosion resistant properties. CV studies revealed that GO-4-NBT effectively suppressed the metal oxidation and oxygen reduction. EIS studies suggested that the electrochemical process on the Cu surface with GO and GO-4-NBT was charge transfer controlled. The corrosion inhibition efficiency (IE) measured by PDP and EIS was enhanced with a related raise in 4-NBT concentration. Electrochemical studies revealed that the GO-4-NBT was a mixed type of inhibitor that predominantly inhibited the anodic reaction, especially in the case of 0.1 M Na 2 SO 4 . Adsorption studies further indicated the involvement of a stable and spontaneous adsorption mechanism, most probably by chemisorption. GO-4-NBT has shown significant corrosion protection activity in 0.1 M Na 2 SO 4. and EIS, and adsorption studies.
通过在氧化石墨烯(GO)包覆的Cu电极上制备三唑衍生物- 2-(5-巯基-4-(3-硝基苯基)氨基)- 4h -1,2,4-三唑-3-基)异吲哚-1,3-二酮(4-NBT)，制备了氧化石墨烯-三唑杂化防腐涂层。采用循环伏安法(CV)、动电位极化法(PDP)和电化学阻抗谱法(EIS)监测GO-4-NBT杂化涂层对Cu表面腐蚀行为的影响。保护涂层的制备分两步完成。首先，在两种不同的侵蚀介质(1 M HCl和0.1 M na2so4)中，将氧化石墨烯分别电化学沉积在Cu电极上。其次，采用不同浓度的4-NBT来增强氧化石墨烯的耐腐蚀性能。CV研究表明，GO-4-NBT能有效抑制金属氧化和氧还原。EIS研究表明，氧化石墨烯和氧化石墨烯-4- nbt在Cu表面的电化学过程是受电荷转移控制的。PDP和EIS测定的缓蚀效率(IE)随着4-NBT浓度的增加而提高。电化学研究表明，GO-4-NBT是一种混合型缓蚀剂，主要抑制阳极反应，特别是在0.1 M na2so4的情况下。吸附研究进一步表明了一种稳定的自发吸附机制，最有可能是化学吸附。GO-4-NBT在0.1 M na2so4中表现出明显的防腐活性。EIS和吸附研究。
{"title":"Graphene Oxide-Aryl Substituted Triazole Thin Hybrid Corrosion Resistant Coating for Copper","authors":"N. Arshad, M. Imran, M. Akram, F. Altaf","doi":"10.4152/pea.2022400304","DOIUrl":"https://doi.org/10.4152/pea.2022400304","url":null,"abstract":"A graphene oxide-triazole hybrid anti-corrosive coating was done by fabricating a triazole derivative – 2-(5-mercapto-4-((3-nitrophenyl)amino)-4H-1,2,4-triazol-3-yl)isoindoline-1,3-dione (4-NBT) on a graphene oxide (GO) coated Cu electrode. The GO-4-NBT hybrid coating effect on the Cu surface corrosion behavior was electrochemically monitored through cyclic voltammetry (CV), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The fabrication of a protective coating was done in two steps. Firstly, GO was electrochemically deposited on the Cu electrode in two different aggressive media (1 M HCl and 0.1 M Na 2 SO 4 ), separately. Secondly, different 4-NBT concentrations were employed to reinforce GO corrosion resistant properties. CV studies revealed that GO-4-NBT effectively suppressed the metal oxidation and oxygen reduction. EIS studies suggested that the electrochemical process on the Cu surface with GO and GO-4-NBT was charge transfer controlled. The corrosion inhibition efficiency (IE) measured by PDP and EIS was enhanced with a related raise in 4-NBT concentration. Electrochemical studies revealed that the GO-4-NBT was a mixed type of inhibitor that predominantly inhibited the anodic reaction, especially in the case of 0.1 M Na 2 SO 4 . Adsorption studies further indicated the involvement of a stable and spontaneous adsorption mechanism, most probably by chemisorption. GO-4-NBT has shown significant corrosion protection activity in 0.1 M Na 2 SO 4. and EIS, and adsorption studies.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920502","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}
A membrane sensor using an ion association complex of hydroxyzine hydrochloride (HDH) with Orange II (ORG-II) dye, in a polyvinyl chloride (PVC) matrix, has been developed and used as a selective electrode for HDH quantification in pharmaceuticals. The sensor is suitable to determine 2.2 × 10 -5 - 1.1 × 10 -3 mol L -1 HDH, in the pH range from 2.5 to 5.21, with the Nernstian slope of 57.41±1.04 mV/decade, under optimum conditions. The regression coefficient (RC) value of 0.999 shows a good correlation between HDH concentration and the potential measured using the proposed sensor. The sensor limit of detection (LOD) was 4.5 × 10 -6 M. A standard-addition procedure was followed to study the effect of various interferents. The results revealed no variations caused by foreign ions or species. The regression equation (RE) and relative standard deviation (RSD) values, from 1.67 to 5, and from 1.86 to 4.81%, respectively, indicated the HDH-ORG sensor acceptable accuracy and precision. The RSD values of ≤5.67 and <5% indicated the sensor acceptable robustness and ruggedness, respectively. It has been successfully used to determine HDH in tablets, and excellent results were obtained.
{"title":"A Selective PVC Matrix Assisted Potentiometric Sensor for the Determination of Hydroxyzine Hydrochloride (HDH)","authors":"R. N. Prasad, C. Siddaraju","doi":"10.4152/pea.2022400503","DOIUrl":"https://doi.org/10.4152/pea.2022400503","url":null,"abstract":"A membrane sensor using an ion association complex of hydroxyzine hydrochloride (HDH) with Orange II (ORG-II) dye, in a polyvinyl chloride (PVC) matrix, has been developed and used as a selective electrode for HDH quantification in pharmaceuticals. The sensor is suitable to determine 2.2 × 10 -5 - 1.1 × 10 -3 mol L -1 HDH, in the pH range from 2.5 to 5.21, with the Nernstian slope of 57.41±1.04 mV/decade, under optimum conditions. The regression coefficient (RC) value of 0.999 shows a good correlation between HDH concentration and the potential measured using the proposed sensor. The sensor limit of detection (LOD) was 4.5 × 10 -6 M. A standard-addition procedure was followed to study the effect of various interferents. The results revealed no variations caused by foreign ions or species. The regression equation (RE) and relative standard deviation (RSD) values, from 1.67 to 5, and from 1.86 to 4.81%, respectively, indicated the HDH-ORG sensor acceptable accuracy and precision. The RSD values of ≤5.67 and <5% indicated the sensor acceptable robustness and ruggedness, respectively. It has been successfully used to determine HDH in tablets, and excellent results were obtained.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"30 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920711","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}
Molecularly imprinted polymers (MIPs) are an important class of compounds with wider sensing applications for the determination of substances ranging from small molecular masses to macro size. The hyphenation of MIP principle with other likewise conducting polymers yields the devices for sensing purposes. MIPs are robust against environmental conditions, more economical than natural receptors, and their preparation is also adequate for substances without natural receptors. Organic mediated MIPs compounds are of current interest, due to their applicability as quantification tools to determine electroactive substances in a variety of real samples. MIPs are highly selective for target molecules, mechanically strong, resistant to temperature and pressure, inert towards acids, bases, metal ions and organic solvents, highly stable for longer periods, and operative at room-temperature. Therefore, during past years, MIPs have been used as electrochemical and optical sensors, sorbents, solid phase media, and so on. Herein, there is a focus on the use of Pyrrole (Py) as a monomeric molecule to fabricate MIPs. Py or poly-Py (p-Py) based MIPs are synthesized and used in various capacities as chemo electrochemical sensors. A detailed discussion on the application of Py-mediated MIPs for the electrochemical determination of some organic compounds of therapeutic and environmental interest is herein presented as a review.
{"title":"Applications of Pyrrole Based Molecularly Imprinted Polymers as Analytical Sensors: a Review","authors":"N. Rajendraprasad","doi":"10.4152/pea.2022400404","DOIUrl":"https://doi.org/10.4152/pea.2022400404","url":null,"abstract":"Molecularly imprinted polymers (MIPs) are an important class of compounds with wider sensing applications for the determination of substances ranging from small molecular masses to macro size. The hyphenation of MIP principle with other likewise conducting polymers yields the devices for sensing purposes. MIPs are robust against environmental conditions, more economical than natural receptors, and their preparation is also adequate for substances without natural receptors. Organic mediated MIPs compounds are of current interest, due to their applicability as quantification tools to determine electroactive substances in a variety of real samples. MIPs are highly selective for target molecules, mechanically strong, resistant to temperature and pressure, inert towards acids, bases, metal ions and organic solvents, highly stable for longer periods, and operative at room-temperature. Therefore, during past years, MIPs have been used as electrochemical and optical sensors, sorbents, solid phase media, and so on. Herein, there is a focus on the use of Pyrrole (Py) as a monomeric molecule to fabricate MIPs. Py or poly-Py (p-Py) based MIPs are synthesized and used in various capacities as chemo electrochemical sensors. A detailed discussion on the application of Py-mediated MIPs for the electrochemical determination of some organic compounds of therapeutic and environmental interest is herein presented as a review.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70920782","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}
Pinus oocarpa seed extract corrosion inhibition effect on galvanized steel has been studied in 2 M hydrochloric acid, at 303 K and 333 K, by gravimetric methods. The inhibitor efficiency decreased with higher temperatures, which suggests physisorption. Potassium iodide (KI) synergistic action produced an increase in the extract inhibition efficiency, but its parameter decreased with higher inhibitor concentrations. The galvanized steel optical microscopy shows that the metal surface was coated with P. oocarpa seed extract, and that the cracks observed in the inhibitor absence were filled. This observation suggests that the extract can be used as a coating to prevent galvanized steel corrosion.
{"title":"Evaluating the Deterioration of Galvanized Steel in an Acidic Medium using Pinus Oocarpa Seed Extract as Inhibitor","authors":"M. O. Nkiko","doi":"10.4152/pea.2022400202","DOIUrl":"https://doi.org/10.4152/pea.2022400202","url":null,"abstract":"Pinus oocarpa seed extract corrosion inhibition effect on galvanized steel has been studied in 2 M hydrochloric acid, at 303 K and 333 K, by gravimetric methods. The inhibitor efficiency decreased with higher temperatures, which suggests physisorption. Potassium iodide (KI) synergistic action produced an increase in the extract inhibition efficiency, but its parameter decreased with higher inhibitor concentrations. The galvanized steel optical microscopy shows that the metal surface was coated with P. oocarpa seed extract, and that the cracks observed in the inhibitor absence were filled. This observation suggests that the extract can be used as a coating to prevent galvanized steel corrosion.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70919797","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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