Design of New Ecofriendly Schiff Base Inhibitors for Carbon Steel Corrosion Protection in Acidic Solutions: Electrochemical, Surface, and Theoretical Studies

Corrosion poses a significant problem for several industrial sectors, inducing continuous research and development of corrosion inhibitors for use across a wide range of industrial applications. Here, we report the effectiveness of three newly developed Schiff bases derived from amino acids and 4-aminoacetophenone, namely, AIP, AMB, and AImP, as environmentally friendly corrosion inhibitors for Q235 steel in hydrochloric acid using electrochemical and surface analyses, in addition to theoretical techniques. The electrochemical findings of potentiodynamic polarization (PDP) demonstrated that the explored compounds serve as mixed-type inhibitors and can effectively suppress steel corrosion, with maximal protection efficiencies of 93.15, 96.01, and 77.03% in the presence of AIP, AMB, and AImP, respectively, at a concentration of 10 mM. The electrochemical impedance spectroscopy (EIS) and polarization results confirmed the growth of a durable protective barrier on the steel surface in the existence of the inhibitors, which is responsible for decreasing the metallic dissolution. Results were further supported by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), UV-vis, and Fourier transform infrared (FTIR), which ascribed the development of inhibitor-adsorption films on the steel surface. The results of EDS and XPS analyses demonstrated the existence of the distinctive elements of the inhibitors on the metallic surface. Furthermore, density functional theory (DFT) calculations and Monte Carlo (MC) simulations showed the electronic structure of the examined inhibitors and their optimized adsorption configurations on the steel surface, which helped in explaining the anticorrosion mechanism. Finally, the theoretical and experimental findings exhibit a high degree of consistency.

Covalently linked pyrene antennas for optically dense yet aggregation-resistant light-harvesting systems

In this study we present a novel energy transfer material inspired by natural light-harvesting antenna arrays, zinc(II) phthalocyanine-pyrene (ZnPcPy). The ZnPcPy system facilitates energy transfer from 16 covalently linked pyrene (Py) donor chromophores to the emissive central zinc(II) phthalocyanine (ZnPc) core. Nearly 98% energy transfer efficiency is determined from the changes in emission decay rates between free MePy to covalently linked Py, supported by comparisons of photoluminescence quantum yields using different excitation wavelengths. A comparative analysis of ZnPcPy and an equivalent mixture of ZnPc and MePy demonstrates the superior light-harvesting performance of the covalently linked system, with energy transfer rates 9705 times higher in the covalently bound system. This covalent strategy allows for very high loadings of absorbing Py chromophores to be achieved while also avoiding exciton quenching that would otherwise arise, with the same strategy widely applicable to other pairs of Főrster resonance energy transfer (FRET) chromophores.

Enhancement of Supercapacitor Performance of Electrochemically Grown Nickel Oxide by Graphene Oxide

β-Ni(OH)₂ and β-Ni(OH)₂/graphene oxide (GO) were prepared on an Ni foil electrode using the electrochemical cyclic voltammetry formed in 0.5 M KOH solution. Several surface analyses such as XPS, XRD, and Raman spectroscopies were used to confirm the chemical structure of the prepared materials. The morphologies were determined using SEM and AFM. The addition of the graphene oxide layer showed a remarkable increase in the specific capacitance of the hybrid. Through the measurements, the specific capacitance values were 280 F g^-1 and 110 F g^-1 after and before adding 4 layers of GO, respectively. The supercapacitor displays high stability until 500 cycles are charged and discharged almost without a loss in its capacitance values.

CuO/Cu/rGO nanocomposite anodic titania nanotubes for boosted non-enzymatic glucose biosensors

Highly arranged porous anodic titania (TiO2) nanotube arrays (ATNT) were fruitfully fabricated by the anodization of Ti foil in an ammonium fluoride electrolyte.

Development of Uniform Porous Carbons From Polycarbazole Phthalonitriles as Durable CO2 Adsorbent and Supercapacitor Electrodes

Advances in new porous materials have recognized great consideration in CO₂ capture and electrochemical energy storage (EES) applications. In this study, we reported a synthesis of two nitrogen-enriched KOH-activated porous carbons prepared from polycarbazole phthalonitrile networks through direct pyrolysis protocol. The highest specific surface area of the carbon material prepared by pyrolysis of p-4CzPN polymer reaches 1,279 m² g⁻¹. Due to the highly rigid and reticular structure of the precursor, the obtained c-4CzPN–KOH carbon material exhibits high surface area, uniform porosity, and shows excellent CO₂ capture performance of 19.5 wt% at 0°C. Moreover, the attained porous carbon c-4CzPN–KOH showed high energy storage capacities of up to 451 F g⁻¹ in aqueous electrolytes containing 6.0 M KOH at a current density of 1 A g^-1. The prepared carbon material also exhibits excellent charge/discharge cycle stability and retains 95.9% capacity after 2000 cycles, indicating promising electrode materials for supercapacitors.

Electrochemical capacitive performance of thermally evaporated Al-doped CuI thin films

Schematic diagram showing the preparation of the bare and Al-doped CuI thin films for supercapacitor applications.

Aramid-Zirconia Nanocomposite Coating With Excellent Corrosion Protection of Stainless Steel in Saline Media

Resistance to stainless steel corrosion in marine-based industries requires more research into materials with an improved surface and enhanced protection by utilizing surface coatings. Herein, a thermally stable aramid–zirconia nanocomposite has been successfully prepared using the sol–gel method to produce a zirconia network-structure bonded to the polymer chain. Using thermal gravimetric analysis (TGA), the residue mass of zirconia retained after the thermal degradation of aramid-zirconia film was determined and found to be 10% by mass. The investigated nanocomposite (using 10% zirconia) was coated on the stainless-steel surface through a facile and effective spin coating method and its protection was examined in saline solution (3.5% NaCl). The aramid–zirconia nanocomposite coating (Ar-Zr10) was found to provide an outstanding corrosion resistance to steel surfaces which led to protecting it against the corrosive marine environment. The electrochemical impedance (EIS) measurements were carried out to evaluate steel resistance against dissolution in chloride solution in the absence and presence of the investigated coatings showed a corrosion protection efficiency of 99.3% using Ar-Zr10 compared to 92.1% using pure aramid. Moreover, the potentiodynamic polarization (PDP) plots showed a pronounced decrease in the corrosion current values which confirmed the formation of a passive layer which mitigated the corrosion reaction and ions diffusion. The water contact angle of stainless-steel coated with pure aramid and the aramid–zirconia was found to be 84.2° and 125°, respectively, confirming the hydrophobic nature of the hybrid coating Ar-Zr10. On the other hand, the results achieved through the electrochemical and surface techniques were used to clarify the protection mechanism. The aramid–zirconia nanocomposite coating showed a remarkable protection performance by controlling the charge transfer at the interface between the steel alloy and the electrolyte which prevented the alloy dissolution.

CeO2-CB nanocomposite as a novel SALDI substrate for enhancing the detection sensitivity of pharmaceutical drug molecules in beverage samples

SALDI-MS analysis of pharmaceutical drug molecules (amitriptyline, imipramine and promazine) using carbon-based substrates, namely, activated charcoal (AC), carbon nanotubes (CNTs), carbon black (CB), graphene (rGO), graphene oxide (GO) and graphite, was explored and compared with the conventional organic matrix of MALDI. CB exhibited superior performance with respect to the other substrates in terms of detection sensitivity. Despite the effectiveness of CB to detect all drug molecules, it demonstrated a number of background signals, which may be an issue for the analysis of other molecules in the future. Therefore, for the first time, a CeO₂-CB nanocomposite was synthesized and applied as a novel SALDI substrate to minimize the background signals and stabilize CB when exposed to high laser power. The nanocomposite was characterized using XRD, TEM, FTIR, UV-Vis and N₂ sorpometry. The spectrum obtained using the novel nanocomposite in the absence of the drug molecules showed minimal background signals compared to CB. Additionally, the CeO₂-CB nanocomposite enhanced the detection sensitivity of the drug molecules with a limit of detection (LOD) of 100 ng/mL. This active substrate nanocomposite was further applied for the analysis of drug-spiked beverages without sample pretreatment or extraction, mimicking cases encountered by forensic toxicologists. All of the drugs and/or their adducts were detected in the drug-spiked beverage samples.

Controlled Synthesis of ZrO2 Nanoparticles with Tailored Size, Morphology and Crystal Phases via Organic/Inorganic Hybrid Films

In this investigation, well defined mesoporous zirconia nanoparticles (ZrO₂ NPs) with cubic, tetragonal or monoclinic pure phase were synthesized via thermal recovery (in air) from chitosan (CS)- or polyvinyl alcohol (PVA)-ZrO_x hybrid films, prepared using sol–gel processing. This facile preparative method was found to lead to an almost quantitative recovery of the ZrOx content of the film in the form of ZrO₂ NPs. Impacts of the thermal recovery temperature (450, 800 and 1100 °C) and polymer type (natural bio-waste CS or synthetic PVA) used in fabricating the organic/inorganic hybrid films on bulk and surface characteristics of the recovered NPs were probed by means of X-ray diffractometry and photoelectron spectroscopy, FT-IR and Laser Raman spectroscopy, transmission electron and atomic force microscopy, and N₂ sorptiometry. Results obtained showed that the method applied facilates control over the size (6–30 nm) and shape (from loose cubes to agglomerates) of the recovered NPs and, hence, the bulk crystalline phase composition and the surface area (144–52 m²/g) and mesopore size (23–10 nm) and volume (0.31–0.11 cm³/g) of the resulting zirconias.

Organic nanoparticles of acetohydrazides as novel inhibitors for mild steel corrosion

Novel organic nanoparticles were successfully prepared using the re-precipitation method and showed superior protection against mild steel corrosion in acidic media.

Impact of soil and air contaminants on the composition of rail-head surface rust

Purpose

– The purpose of this paper is to explore the environment around the rail track at different sites in Nile Delta region, Egypt, through the measurements of the air pollutants and corrosive ionic species present in surface soil and also to investigate the impact of the existing contaminants on the composition of iron rust formed on the rail head surface at these sites and then the durability of rail itself.

Design/methodology/approach

– The soil characterization was studied by means of sieve shakers, pH meter, conductivity meter and ion chromatography instrument. Scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy and X-ray diffraction were used to characterize the rust layer formed on the rail head surface.

Findings

– The results showed the relation between the contaminants and the composition of the rust layer. Magnetite and goethite were the major phases identified in the rust layers. Akaganeite was detected in the marine atmosphere. Iron sulfide and iron oxide nitrate hydroxide were detected in environments rich in H2S and NO2 gases, respectively. The appearance of phases like FeCl2 and FeOCl only at marine atmospheres reflects that the corrosive species in suspended particulate matter like chloride ion have a higher effect on the rust composition of the rail head surface than that in surface soil layer.

Originality/value

– This paper revealed the impact of air and soil contaminants on the composition of rust layer on the rail head surface and may provide guidance for the durability of rails and the necessity for their preservation.

Hydrothermally modified PVA/ZnS-NCQD nanocoating for stainless steel corrosion protection in saline water

Herein, we report a facile method for the fabrication of a hydrothermally modified well shaped nanocubed ZnS quantum dot (NCQD)/polyvinyl alcohol nanocomposite.