Portugaliae
Electrochimica Acta

In this study, an alkaloid was extracted from LN leaves. The AE was firstly evaluated as AO, by using a DPPH solution, and comparing it with a BHT standard solution. The AE, at 200 mg/mL, showed high efficiency as AO (93%). Furthermore, it was studied as a CI for an Fe alloy in HCl, at 25 ºC, with different C (1 to 5 ppm). The AE depicted the highest IE(%) of 92.42%, at 5 ppm. T effect on IE(%), for optimal C (5 ppm), was studied at 35, 45 and 55 ºC. The results revealed that the IE(%) decreased with higher T. Additionally, kinetic parameters, such as Ea*, H* and S*, were calculated. Keywords: AE, LN, AO, corrosion inhibitors and DPPH.

MS effective corrosion inhibition by SVLE has been investigated using electrochemical methods. Tafel polarization measurements suggested that the reaction at the anode occurred with MS dissolution, due to the strong medium aggressiveness, but SVLE addition led to a corrosion IE(%) of 93.6%, at 298 K. SVLE IE(%) still was 86% at an elevated T of 328 K, which was also confirmed by SEM observations that revealed a protective adsorbed film formed by the inhibitor onto the MS surface. Keywords: SVLE, MS, corrosion, polarization curve and high T IE(%).

WO contain many elements that are toxic to the health and environment. WO discharge into the natural environment without any prior treatment can clog the filters in the water treatment stations, disrupting the biological purification processes. It is also forbidden to burn these fluids without pretreating them: their wild incineration releases dioxins and greenhouse gases. In WO recycling process, the final step is to pass it through a press filter containing BT oil treated at a ratio of 10:90. The pressed cake is then abandoned in nature, or transported to the landfill. This study focused on the reuse of BT mud cakes soiled with impurities from recycled WO. A PC study of the pulp properties, followed by a toxicological study, enabled to recommend the reuse of this slurry mud as a tight and very suitable soil covering. Thus, controlled landfills, sports fields and storage tanks for irrigation water can be coated with this compact clay, and prevent seepage into the water table. Our work is divided into two main parts: the first concerned the study of the specific characteristics of BT extracted from WO (permeability, specific surface, porosity, adhesion to the ground and durability); and the second carried out the bacteriological and eco-toxicological study of BT-WO residues, in order to prevent all negative impacts likely to reduce the quality of the soil, groundwater, human health and vegetation. Keywords: WO, surface area, permeability, porosity, waterproofing, eco-toxicity, BT and floor covering.

Issues regarding corrosion have become a substantial source of expenditure for oil and gas industries. Apart from that, oil spillages resulting from leakages in pipelines pose severe environmental challenges, such as pollution and fire outbreaks. A36 LCS is commonly used for fabricating oil and gas pipelines, due to its availability and cost. The aim of this study was to deposit Zn-MgO-xCn CC on A36 LCS substrates, to improve their CRS in acidic media, through the ED route. W corrosion determination technique was used for determining the developed coatings CR. The CC surface morphology and phase evolution were determined by OPM, SME and X-RD. The results showed that all the developed CC offered lower CR values than that of the A36 LCS substrate, which was 5.4392 mm/y. Sample D4 (20 g Zn and 20 g MgO-Cn) had the lowest CR value of 0.7199 mm/y, corresponding to a coating E of 86% on the substrate. Finally, among the developed coatings, sample E1 (Zn and 20 g MgO) gave the highest CR values of 2.1030 mm/y, with an E value of 61%. The study showed that the CC were able to form protective barriers on the substrate in the corrosive media. Keywords: CC, NP, substrates and corrosion.

The increasing challenge of components used for the development of new materials, in order to improve their mechanical performance, can never be over-emphasized. The present research of a produced P-Al2O3 coating grafted into a Zn electrolyte was done through the thin-film alloy ED on MS, in a time range from 15 to 30 min, pH 5 and T of 95±5 ºC. P-Al2O3 morphological properties were characterized by TESCAN SEM and elemental quantification with EDS. The deposited alloy strengthening and dislocation performance were studied using diamond-based Vickers  test and a reciprocated wear slider, under a 5 N load. The pitting corrosion study was made using a PGStat101 auto lab potentiostat galvanostat, by LSV and OCP methods. The results show that P-Al2O3 is an active corrosion inhibitor and adsorption composite. The ED mass was obtained at a significant value of 0.1302 and 0.1567 g, at 25 and 30 min DT. At 30 min, wear loss and CR, along with the interfacial surfaces of this CC, were lower than those of other developed alloys, at 15 min, due to the progressive particulates loading effect. The average significant HVN trend was influenced by the particulates weight fraction precipitation. MS properties enhancement by P-Al2O3 indicated that the CC can be used for advanced industrial applications, especially in corrosive environments. Keywords: adsorption, components, corrosion, MS, P-Al2O3 and protection.