Portugaliae
Electrochimica Acta

Lignin generated from biomass is the most promising fuel for industrial civilizations. It is the most common aromatic polymer on the planet and one of the most challenging substances to commercialise. Among the various compounds released by LcB during pretreatment are reducing sugars, which may be utilised to generate biofuels and other merchandises. LcB are readily available, renewable, recyclable and abundant. As a result of climate change and environmental damage, sustainability has gained popularity. Many researchers are focusing on renewable biofuel derived from sustainable sources, due to the need for a flexible approach to address expanding global energy demands. Industrial biorefineries that use LcB as feedstock for biofuel and other bioproducts have been created. Biochemical conversion of LcB into fuels and chemicals is dependent on cellulose and hemicellulose extraction. To generate sustainable energy, LcB must be pretreated to increase fragmentation and decrease lignin concentration. T, duration, particle size and solid loading are all controlling factors in lignin extraction. Effective lignin recovery and valorisation solutions have been identified by sustainable lignocellulose biorefineries. Keywords: AC; biofuels; delignification; LcB; pretreatment; sustainable.

Accelerated corrosion is closely associated with the inclusion of secondary reinforcement particulates in metal matrices, where they are usually present as cathodic sites. This hinders full utilization of composite products for engineering applications. In this study, chemical CC were used to improve MMC corrosion in atmospheric and simulated seawater environments. Comparison between CCC and PPCC performance was done to find a substitute for the former, which contains carcinogenic Cr VI ions. Japanese industrial testing method was used to determine the composite LC/CC samples adhesion characteristics, after a series of exposure regimens. CCC specimens displayed marginal corrosion resistance superiority over their PPCC counterparts. There was little to no pits on the CC substrate compared to the non-coated samples. The CC applied on the substrates prevented the coating delamination. The lacquer remained unpeeled on the substrate, during Japanese industrial testing. This indicates reduced corrosion activities on the substrates. Keywords: adhesion; AMC; CCC; corrosion; LC; PKSA; PPCC.

The present work studied SR of electroless Ni-W-P ternary alloy coatings on a Cu substrate. There is very little specific research conducted on the importance of reducing materials SR through Ni-W-P electroless coating, which further improves their mechanical properties. In this study, it was attempted to reduce the as-coated Ni-W-P Cu substrate surface SR by adopting DoE and optimizing the process parameters using CCD. The aim was to optimize the desired response controlled by multiple input parameters. ANOVA and regression analysis were implemented to indicate the significance of as-coated substrates parameters and their impact on the measured SR responses. From CCD optimization, optimal SR parameters were found to occur at low values. Furthermore, FL approach was employed to predict Ni-W-P electroless coating SR, as compared to experimental and CCD approaches. It was found that fuzzy measured values were in good agreement with experimental and CCD values. There was a small difference among all values, and response optimization predicted optimal conditions comparatively well. Therefore, the developed models can be effectively used to predict SR. Moreover, confirmation tests were performed to validate that CCD optimized levels and developed fuzzy models effectively represented SR. Optimized parameters characterization was done with the help of SEM and EDX. It was seen that globular shaped atoms were scattered all over the sample, while granular grains were more clear. From EDX, appropriate deposition of Ni-W-P substrate in Cu was found. Thus, it was concluded that Ni-W-P incorporation in the Cu substrate made a major contribution to the film morphology, enhancing the metal properties and reducing SR. Keywords: CCD; contour plot; Cu substrate; EDX; electroless coating; FL; MF; microstructure; Ni-W-P coatings; SEM; SR.

Lignin (Ln) is an intricate byproduct that is present in all vascular plants. It is essential in the formation of cell walls, particularly in wood and bark, and the development of connective tissues, since it gives stiffness, strength and resistance against external stimuli like infections. Ln has a variety of economic uses, and its extraction might lead to the development of several novel applications. This study examined several ways of extracting Ln from Bm of RH and WH. TGA, SEM, PA, UA and other detailed characterization methods gave unexpected insights. Notably, WH yield 16% Ln, after 5 h, but RH yielded 13% after 4 h. Similarly, RH and WH yielded 10% and 12% Ln, after 3 h, respectively. WH had higher Ln yield than other Bm. These findings illustrate variability in Ln concentrations among Bm, when the alkaline method was used for giving more yield. Keywords: biofuel production; Bm; Ln extraction; pretreatment; RH; SEM; TGA; WH.

This report focused on understanding the effect of various SS and pH on MS in a mine water, using a RCE. The use of this type of apparatus in lab testing provides accurate SS, and generates electrochemical signatures that deliver repeatable and accurate data. The data obtained from the RCE were correlated with a modified model predictor with comparable CR monitoring, in order to provide more insight into MS corrosion mechanism in a simulated mine water. Keywords: CR; MS; RCE; simulated mine water; solution pH.

In this study, employing an accurate and simple method of CvV and DV, combined with numerical simulation, FeCl3 was electrochemically examined in a 1 M HCl aqueous solution using Au working electrode. It was discovered that electrons exchange between Fe (III) and Fe (II) was a quasi-reversible process. CV was used to determine the electrochemical parameters of Fe (III)/Fe (II), such as D, Eo, ks and α values, which were then confirmed using a numerical simulation method. The nature of K3[Fe(CN)6] electrode reaction, in selected media at Au electrodes, was studied. It was determined that its mechanism occurred through moderately fast electrons transfer. Keywords: DV; CvV; CV; FeCl3; numerical simulation.

Herein, electrodeposition of Zn-Ni alloy thin films on CS substrates under various conditions, from sulfate baths containing Na3C6H5O7, C7H5NO3S, and 2-butyne-1,4diol, was studied. So as to have the best bath composition, a mixture design application was examined. The best obtained composition was: 0.3 M Na3C6H5O7-, 0.1 g/L C7H5NO3S and 0.1 g/L 2-butyne-1,4-diol, for theoretical and experimental responses of 215.22 and 221.60 HV, respectively. Zn-Ni coating morphological properties and composition were examined by SEM and EDS. It was found that, on optimal conditions, a significant decrease in the grain size occurred. The deposits were homogeneous, uniform, compact and fine-grained, without any pores at the surface. Keywords: 2-butyne-1,4-diol; C7H5NO3S; mixture design; Na3C6H5O7-; sulfate acid bath; Zn-Ni electrocoatings.

In 2007, a study was done using color corona spectral analysis [39]. The method was applied in laboratory conditions with the coronal glow of biological objects and liquids. A high voltage of 12 kV and a frequency of 15 kHz have been applied during the research. In 1995, Antonov created the apparatus for the study, with registration in black and white photographic films. The scientist called the method selective high-frequency discharge. It has been categorized as silverless photography. In the presence of electrical conditions, electrography is at the heart of the photocopier invention. Herein, CaCO3 in a distilled H2O solution was tested. Comparative analysis was performed with distilled H2O. Physical and chemical processes under high-frequency corona gas discharge conditions were analyzed. CaCO3 was in dynamic interaction with CO₂ and H2O at the boundary of different environments. Keywords: CaCO3; color coronal discharge; FTIR; H2O.

In order to improve the corrosion resistance of Pb anodes in 4 M Pb-H2SO4 batteries, the electrochemical and metallurgical effect of Ag addition in small quantities on Pb corrosion in 4 M H2SO4, as well as its microcrystalline morphology, were herein studied. Different techniques, such as PDP, EIS and OM, were employed. The results showed that Ag addition up to 1 wt% led to a significant decrease in Icorr and Ipass rates, and also to a reduction in sulfation phenomena, by facilitating PbSO4 and PbO conversion into PbO2. All of these improvements led to an increase in the lifetime of the conventional Pb-acid battery up to 87.24%. Therefore, the new improved battery is more resistant, durable and environment friendly. T effect on the new casting alloys CR was also studied, and found to be inexistent. Keywords: battery; CR; EIS; electrochemistry; metallurgy; OM; Pb-Ag alloy; PDP.

There is a growing trend in utilizing pharmaceutical compounds and plant extracts as CI. Therefore, in this study, the inhibitive performance of Citrus x aurantiifolia extract (CAE) and expired CPM on MS corrosion in 0.5 M HCl solutions was studied using Ec measurements. Furthermore, MS samples without and with inhibitors were characterized by SEM/EDX spectroscopy. Results confirmed that CAE and CPM effectively acted as CI in HCl. IE(%) increased with inhibitors higher Ct. PDP studies confirmed that the system followed a mixed mode of inhibition. Investigations by SEM/EDX established the formation of a protective film on the MS surface. CAE adsorption performance was also studied, which suggested Langmuir’s isotherm was the most suitable model. Keywords: adsorption; CAE; CI; CPM; Ec measurements; EDX; MS; PDP; SEM.

This study focuses on evaluating the analytical performance and chelation capabilities of SV, using specialized NPM-CPE sensors designed for Ca2+ ion detection. The research context centres on addressing analytical and therapeutic challenges in conditions like gout, where CaC2O4 dissolution plays a critical role. The findings demonstrate that SV exhibits a remarkable ability to chelate Ca2+ ions in a solution, resulting in the formation of stable complexes. A combination of electrochemical techniques, including SWV, CV and EIS, to characterize SV's chelation capacity, and the presence of Ca2+ metals, was employed. Through these electrochemical methods, valuable insights on the efficacy of SV in chelating Ca2+ ions were gained, which offered significant implications for conditions associated with CaC2O4 deposition, such as gout. This study addresses the need to tackle analytical and therapeutic challenges posed by gout and related disorders, and proves a novel approach to understanding and potentially treating these conditions. Detailed results of the research, which include the successful chelation of Ca2+ ions by SV, can be found in the main body of the paper, offering a comprehensive account of the findings. Keywords: chelation; electrochemical methods; gout; SV.

This paper investigated Corchorus olitorius leaves extract efficiency in preventing MS corrosion, when immersed in a KOH solution. This will be the first report on the application of this plant extract in an alkaline medium of any kind, for mitigating metals corrosion. Pc analysis was employed along with PDP and FITR spectroscopy. Pc compounds, such as steroids, saponins, flavonoids, tannins, alkaloids and phenols, were found in the extract, which produced maximum IE(%) of 99.93%. Highest CR of 5.644e+003 mm/year was obtained, while theoretical fittings of various adsorption models for the extract found that it obeyed Langmuir’s isotherm. Kads was 0.9729 g/L, with R2 of 0.9616. 〖∆G〗_ads^° calculated at room temperature was -9.882 kJ/mol. As a result, COLE adsorption onto the MS surface was found to follow physical adsorption mechanism. Keywords: COLE; inhibition; isotherm model; MS; Pcs; PDP.

SAA as novel green inhibitor of MFe corrosion studied by EIS, DFT, PDP and SEM was investigated. It was observed that the increase in SAA various Ct triggered the rise in corrosion IE(%) up to 90.6, 97.6, 98.3 and 98.7%, as shown by EIS, PDP, WL and geometric techniques, respectively. This was due to high Rct during electrochemical processes, which reduced Icorr, and to SAA molecules strong adsorption onto the MFe surface. DFT results revealed short ∆E between SAA and MFe bands, which gave rise to faster inhibitor molecular transfer, stronger adsorption and increased inhibition. Thermodynamic assessment showed that SAA caused an exothermic reaction, creating a stable and spontaneous adsorption reaction. A physical adsorption mechanism was proposed from Langmuir’s isotherm results. Keywords: alkaloids; corrosion; electrochemistry studies; inhibition; quantum chemical calculations; SAA.

1-Methyl-N-((1R,3r,5S)-9-methyl-9-azabicyclo[3.3.1]nonan-3-yl)-1H-indazole-3-carboxamide (C18H24N4O: EGS) is used to prevent nausea and vomiting caused by cancer chemotherapy and radiation therapy. It works by blocking serotonin, a natural substance in the body that causes nausea and vomiting. After expiry, it can be used as additive or CI. IE% of EGS on MS corrosion in a 1 M HCl medium was herein evaluated by WL method. WL measurements showed that corrosion IE% increased with higher Ct of EGS, and its maximum value was obtained with 0.001 M. T affects CR. At high T, corrosion IE% decreased, and CR increased. The mechanistic aspects of corrosion resistance have been studied by PDP and EIS. PDP technique revealed that EGS system functioned as an inhibitor of cathodic type, controlling cathodic reactions. It was noted that, with EGS, icorr decreased and LPR increased. EIS studies revealed that a protective film (blanket effect) was formed on the MS surface, since, with EGS, Rct increased and Cdl decreased. MS surface morphology with EGS was analyzed by SEM. The constituent elements on the MS surface were characterized by EDX. Ra of MS polished, without and with EGS, was characterized by AFM. The results clearly showed that EGS has high IE% for MS corrosion in HCl. Keywords: acidic solutions; AFM; CI; EDX, EIS; EGS; IE(%); MS; PDP; SEM.

Along its 4 decades, the Portuguese Electrochemical Society (Sociedade Portuguesa de Eletroquímica, SPE) has been fostering the Electrochemical Sciences through a diversity of perspectives and pathways, which are illustrated in this talk, within the celebrations of the 40th anniversary of this Society. They include: (i) the publication of Portugaliae Electrochimica Acta (PEA), the only journal on original research in chemical sciences currently being published in Portugal; (ii) the organization of conferences of the SPE and of the Iberic Meetings of Electrochemistry (IME), the latter jointly with the Specialized Group of Electrochemistry of the Royal Spanish Chemical Society (Grupo Especializado de Electroquímica de la Real Sociedad Española de Química, GEE-RSEQ), apart from sponsoring other international conferences; (iii) the award of prizes for senior scientists and for young researchers; (iv) the coinage of celebratory medals; (v) the surveys of the Research on Electrochemistry in Portugal; (vi) the establishment of a Library; (vii) the cooperation with other scientific societies; (viii) other initiatives; and (ix) prospects. All the above-mentioned topics should contribute to the assignment of the role of the SPE within the national panorama of science and education in Portugal. Keywords: IME; PEA; RSEQ; GEE-RSEQ; SPE; SPQ; meetings; medals; prizes; research survey.

One of the most frequently produced agricultural wastes is biomass from which Lc is obtained. It contains a high concentration of Ln, Cs and Hcs. It is one of the main sources of energy in the globe, but is underutilized. To extract Ln from plants using acid pretreatment and alkali, the current research employed a Bm resource that is easily accessible. Ln was extracted from four different Bm: AS, BTB, NTB and WS. The proximate and final analyses were utilized to describe Ln after the pretreatment procedure. NTB had the lowest S content. Analysis of TGA test for Bm from Lc was performed. BTB had the highest projected Ct of Ln recovery, at 100 ºC. NTB produced a minimum Ln amount of 6%, compared to 8% yield from BTB, after 5 h. Ln yield at 160 ºC was lower. WS and AS had the same Ln yield (7%), after 5 h. The extracted Ln, which has a higher phenolic content than that from the commercial one, can be used in future applications. Keywords: Bm from Lcs; Cs; environmentally friendly; green biotechnology; renewable resource; TGA.

EC is an emerging technique used for various applications, due to its benefits, such as coagulation, flocculation and Ec treatment. Emerging pollutants are a real concern, and many researchers have focused on their removal, using EC, due to its several advantages, such as easiness of operation, less space requirements, versatile pollutants removal, lower sludge production, cost effectiveness, lower energy consumption and environment friendliness. Literature has also determined that EC technology is a proven efficient technology for treating various nature industrial effluents. However, those emerging pollutants, such as pesticides, Polyfluoroalkyl substances, cyproflyxin, amoxicillin and surfactants are not efficiently treated by simple EC technology, and their separation is not the solution, since they require degradation and safe disposal. Therefore, waste disposal from this process is a major concern, and the choice of advanced EC-degradation technology depends upon the nature and strength of the pollutant. To address these issues, various processes coupled with EC have been used, such as EF, PDS, EO, ozonation, photochemical degradation, PC, aeration and sonication. Thus, this paper focuses on the basics of EC technology, several degradation systems and application of combined degradation-EC technologies, for treating various WW. Keywords: di-sulfate oxidation; Fenton process; ozonation; PC; per-sulfate.

DAD was investigated as CI for SS corrosion in a 3.5% NaCl solution, using WL, thermometric and RSM techniques. The analyses results show that IE(%) of DAD was dependent on its Ct and T. The highest IE(%) values were recorded on 5.0 g/L, at 303 K, by thermometric and WL methods (90.0 and 98%, respectively). DAD adsorption onto the SS surface was found to be spontaneous, obeyed Langmuir’s isotherm, and its mechanism appeared to be partly physical, partly chemical. The results of RSM techniques supported experimental data. Finally, SEM was used to examine SS surfaces morphology without and with DAD, and its results confirmed the CI process. Keywords: adsorption; corrosion; DAD; NaCl; RSM; SEM; SS; WL.

In this study, to determine chemical elements and stable isotopes in 30 GW samples collected from SS Moroccan L-D region, various analytical techniques were used. Thus, the goal was to identify and understand different geochemical processes contributing to water mineralization in the study area. In fact, statistical results for major cations and anions indicated that they obeyed the following trend: Na+ > Ca2+ > Mg2+ > K+, and Cl- > SO42- > HCO3- > NO3-, respectively. Additionally, it was found that water EC values varied from 1290 to 6895 µs/cm. Indeed, pH values of investigated GW was from 6.88 to 7.75. Studied GW had HG facies with 86.66% Na-Cl and 13.33% Ca-SO4. This finding is explained by the dissolution of evaporative formations that characterizes Saharan sections. Additionally, ionic ratios analysis revealed that GW chemical evolution was influenced by processes such as rock weathering, mineral compounds dissolution and evaporation. Therefore, a better relationship between Ca and SO4 suggested gypsum and anhydrite leaching. It was found that stable isotopes (δ18O and δ2H) values differed from -6.96 to -8.93‰ and from -51.5 to 65.56‰, respectively. These findings strongly suggest that waters in the region undergo significant evaporation before reaching the aquifer. In addition, the aquifer's recharge height was also predicted to be no higher than 300 m, with a latitudinal gradient of δ18O, including 0.52 per 100 m. These results can serve as valuable guidance for decision makers in optimizing exploitation and assessment processes in Moroccan SS area. Keywords: AAS; GW; HG; mineralization; Moroccan SS; stable isotopic.

In this study, a composite material containing PY and CTS, as functional material, and dopamine, as template, was electrodeposited onto a GCE surface modified with NP from TiO2. The prepared MIP sensor was characterized by CV, SEM, FTIR and UV-vis techniques. The developed MIP matrix was used for dopamine detection, using DPV method. Diverse analytical parameters were optimized, such as: monomer, template, SE concentrations, electropolymerization cycles, pH medium, incubation time and scan rate. In the best conditions, the sensor response to dopamine was linear, in the concentration range from 1 x 10-6 to 1 x 10-5 mol/L-1. LOD was about 2.81.10-7 mol/L-1, and sensitivity was 3.202 μA/L/mol-1/cm-2. Furthermore, the proposed MIP sensor showed good selectivity, repeatability, reproducibility and stability. Also, it was successfully applied for dopamine determination in urine samples. Keywords: CV; dopamine; DVP; FTIR; MIP; PPY-CTS composite; SEM; TiO2; urine samples; UV-vis.