Portugaliae Electrochimica Acta is a bi-monthly Journal published by the Portuguese Electrochemical Society since 1983.
Portugaliae Electrochimica Acta publishes original papers, brief communications, reviews and letters concerned with every aspect of theory and practice of electrochemistry, as well as articles in which topics on history, science policy, education, etc. in the electrochemical field (teaching or research) may be discussed.
Volume 42, Issue 2, 2024
24th May, 2023
Adsorption of Calcium Particles on A36 Mild Steel and its Thermodynamic Parameters
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by Ezekiel Neza1 ,Ayodeji Ayoola1, Rasheed Babalola et al.
93-100
DOI: https://doi.org/10.4152/pea.2023420201
Abstract
Adsorption behavior of Ca particles obtained from SS, PS and ES calcination, as well as its Td parameters, during A36 MS coating via phosphating process, was investigated. A36 MS coupons surfaces were coated with phosphates and varied C of Ca particles (from 1 to 2.5 g/dm3), at a T of 60 and 80 ºC. Ca particles (as inhibitor) adsorption onto the MS surface obeyed Freundlich’s isotherm, with R2 values around 1. Kads and Td parameters, such as ∆G, ΔH and ΔS, were also determined. A36 MS coated with Ca particles obtained from calcined SS gave the best A capacity, as revealed in terms of Kads, ∆G and ∆S values. Higher Kads was obtained when T increased from 60 to 80 ºC. Also, Td parameters results revealed that Ca particles adsorption mechanism on MS was a more spontaneous process, at an increased T of 80 ºC.
Keywords: adsorption; Ca particles; corrosion; MS; Td.
S275JR Mild Steel Corrosion Sites Deactivation in Sodium Sesquicarbonate Heavy Deposits Using Piperaquine as Alternative Inhibitor
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by B. U. Ugi1, V. M. Bassey, P. B. Ashishie et al.
101-114
DOI: https://doi.org/10.4152/pea.2023420202
Abstract
This study researched S275JR MS corrosion sites deactivation in [Na3H(CO3)2] heavy deposits (Gamboru, Borno State, Nigeria), using PPQ as alternative inhibitor, and employed WL, HER, EIS, PDP, SEM and computational techniques. PPQ showed effective MS corrosion mitigation in [Na3H(CO3)2] heavy deposits. IE(%) of 98.8, 99.5, 82.9 and 95.9 %, for gravimetric, HER, EIS and PDP, respectively, at 208 K, were obtained. PPQ had a shortest E of 0.1 eV, with a higher absolute molecular σ of 2.4, compared to molecular η of 0.4, which makes it a better inhibitor of MS corrosion in [Na3H(CO3)2] heavy deposits. With higher inhibitor Ct, its IE(%) increase and CR of MS decreased. This was due to PPQ molecules strong adsorption onto the MS surface. PPQ was also thermodynamically stable, showed less disorderliness, and its absorption was spontaneous and physical.
Keywords: adsorption; corrosion; EIS; HOMO; LUMO; [Na3H(CO3)2]; physisorption PDP; PPQ; SEM.
Citrus Paradisi Organic Inhibitor Effect on Ti Steel Corrosion in Acidic Solutions
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by Olayemi Odunlami, Muyiwa Fajobi, Toluwalase Fernandez et al.
115-122
DOI: https://doi.org/10.4152/pea.2023420203
Abstract
The word corrosion has been a major issue in the industry, especially in industrial infrastructures, such as steel materials, causing great losses in revenues and environmental pollution. This research goal was to contribute to solving the aforementioned issues. CP as CI, on TS samples in 0.5 M HCl and 0.25 M H2SO4 media, was studied via electrochemical, FTIR and OM techniques. All the results proved the presence of active components in CP, which mitigated TS samples corrosion in the corrosive media. CR reduced greatly for all the TS samples, as CP IE(%) increased. Also, OCP showed that CP operated with mixed adsorption mechanisms. FTIR analysis revealed the numerous functional groups that enabled CP IE(%), by retarding TS samples corrosion. OM images showed the corrosion damage on TS samples without CP, and the film coverage on the alloy, after the inhibitor addition. This confirms CP excellent adsorption onto TS samples.
Keywords: active components; CI; CR, functional groups; FTIR; OM.
Optimization Study of Eggshell Extract as Inhibitor of Mild Steel Corrosion in a 30 wt% NaCl Solution
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by O. Oyewole1, J. B. Adeoye, M. Lucas et al.
123-136
DOI: https://doi.org/10.4152/pea.2023420204
Abstract
Corrosion is a major challenge faced in industries, which has to be addressed by using inhibitors. The aim of this study was to investigate ESE as CI of MS in a 30 wt% NaCl solution. ESE was subjected to Pc analysis, to identify the presence of active ingredients that would create a good CI. CI of ESE at different C was investigated using WL, PDP, SEM, FTIR and EDXS techniques, to characterize MS samples. The best process level from the experimental design was observed at T of 24.4 ºC, IT of 6 days and ESE C of 0.4 g/L, with IE(%) of 95.5%. The presence of metabolites in ESE was confirmed by Pc analysis, which suggested the extract was a good CI. Results from PDP and WL techniques were in good agreement. SEM, FTIR and EDS data revealed that the optimal procedure level produced a stronger protective film on the MS surface. It was concluded that ESE acted as a good and environmentally friendly CI.
Keywords: CR; EDXS; FTIR; IE(%); optimization; PDP; SEM; WL.
Inhibition of Copper Corrosion in Sulfuric Acid by Mentha Pulegium L.
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by S. Rached, K. Mzioud, A. Habsaoui et al.
137-153
DOI: https://doi.org/10.4152/pea.2023420205
Abstract
The application of inhibitors against metals and alloys corrosion in various aggressive environments is an excellent solution. The present study explored Cu corrosion inhibition in a 0.5 M H2SO4 solution by MP EO, from Western Morocco, using EIS and PDP analyses. GC coupled with MS revealed that MP EO is mainly composed of pulegone (23.38%), isomenthone (20.54%) and l-menthone (9.56%). MP inhibitory behavior was of mixed type. MO EO prevented Cu corrosion in H2SO4, with an IE(%) that increased with its Ct, at a maximum of 91.0%, with 1 g/L. The Cu surface was studied by SEM coupled with EDS.
Keywords: Cu, EDS, EIS, EO, GC, H2SO4, IE(%), MP, MS and SEM.
