Mild steel (MS) is a cost-effective engineering material known for its versatility and strength. The mild steel has good ductility and weldability, making it suitable for various applications like automobile, and aerospace industries. We investigated the inhibition performance of 5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol (PyTT) as an inhibitor for mild steel in 1 M hydrochloric acid at varying temperatures. The study employed conventional weight-loss along with potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). As the concentration of PyTT increased, the inhibition efficiency increased; however, it declined with higher temperatures. PyTT confirmed mixed inhibition behavior and adhered to the Langmuir isotherm. The highest inhibitory efficiency observed was 85.50% at 100 ppm and 303 K. Notably, there was strong correlation between the results obtained from PP and EIS. A probable mechanism for preventing the MS corrosion was suggested. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) were used to examine the morphological and roughness investigations of MS with, and without inhibitor (PyTT). The SEM results showed a significant adsorption between MS-PyTT inhibitor. The structure of PyTT was correlated with its ability to suppress the corrosion using Monte Carlo simulation (MCS) and density function theory (DFT) techniques. The results of this investigation showed good agreement between experimental and theoretical data. The activation energy and thermodynamic parameters were calculated, and the findings were evaluated.

This study investigates the corrosion inhibition efficiency of prickly pear peel extract (PPPE), an agro-industrial residue rich in polyphenolic compounds, on API 5L X70 pipeline steel exposed to 1 M hydrochloric acid. Electrochemical techniques, including electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), were employed alongside surface characterization (SEM–EDX) and FTIR analysis. Results demonstrate that PPPE acts as a mixed-type inhibitor, significantly reducing both anodic dissolution and cathodic hydrogen evolution. Inhibition efficiency increased with PPPE concentration, reaching 77% at 1 g/L, beyond which saturation effects were observed. Adsorption followed the Langmuir isotherm model with a high adsorption constant (Kads = 28.25 L/g) and a standard free energy of adsorption ( $$\Delta G_{{{\text{ads}}}}^{^\circ }$$ = –18.2 kJ mol–1), indicative of spontaneous physisorption. SEM–EDX analysis confirmed the formation of an organic protective film that suppressed chloride adsorption and oxide formation on the steel surface. The findings highlight PPPE as a promising, low-cost, and environmentally benign corrosion inhibitor for pipeline steel in acidic environments, offering both technical effectiveness and sustainability advantages for industrial applications.

This brief review considers the main approaches to the processing of used lithium-ion batteries. A description of the initial raw materials depending on the elemental composition of the cathode material is presented. The main currently developed methods of processing of batteries—namely, pyrometallurgical, hydrometallurgical, and direct processing—are briefly described. A hydrometallurgical method is recognized as the most optimum one. A description of the main process stages, namely, stages of preliminary treatment of batteries, alkaline treatment of the fine fraction that is a mixture of the anode and cathode materials, acidic leaching of the cathode material, and subsequent processing of the leaching product to isolate individual valuable components from it is presented for the said process.

The PCDTBT ((Poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)) is a familiar conjugated polymer utilized for optoelectronic and solar cell applications due to its significant functional characteristics, including wide absorption, improved open-circuit voltage, and suitability for solution processing. However, it found reduced variation in electron mobility, which affected the short-circuit current density and, consequently, the power conversion efficiency properties. This research overcomes the consequence and enriches the overall optoelectronic behaviour of PCDTBT-based organic photovoltaic (OPV) with an adaptation of zinc oxide (ZnO) electron transport layer (ETL) as 0, 10, 20, 30, and 40 nm thicknesses via radio frequency (RF) magnetron spattering technique and influences of ZnO ETL layer thickness on optical, electron mobility, charge transport, X-ray diffraction and PL (Photoluminescence) efficiency of PCDTBT is investigated. The optimized OPV structure features 40 nm ZnO nanoparticles incorporated into the PCDTBT active layer. The optimized structure achieves an open-circuit voltage (VOC) of 0.91 V, a short-circuit current density (JSC) of 15.09 mA/cm2, and a power conversion efficiency (PCE) of 8.5%. The photoluminescence efficiency was limited by 35%, and the charge mobility was significantly enhanced with electron and hole mobility of 1.2 × 10–3 and 1.9 × 10–4 cm2/V s. The crystallinity of PCDTBT was improved due to the wurtzite structure of ZnO achieving a maximum crystalline size of 26 nm. The results highlight the crucial role of optimizing the ZnO layer in achieving high-performance PCDTBT: ZnO OPV devices.

By reacting the free base of mesoporphyrin methyl ester with an excess of vanadyl sulfate, the corresponding vanadyl mesoporphyrinate was obtained with high yield. The resulting compound’s structure was established using EAS and mass spectrometry. Photoluminescence and electroluminescence spectra of vanadyl mesoporphyrinate in a PVK:PBD composite at the temperature of 25°C were analyzed. Based on the luminescence decay kinetic curves, it was established that the complex exhibits only phosphorescent emission. The vanadyl mesoporphyrinate photoluminescence and electroluminescence spectra shape are identical, indicating an identical ratio of intensities of 4T1–2S0 and 2T1–2S0 emission transitions during both photoexcitation and electroexcitation of vanadyl mesoporphyrinate molecules. It was found that at 1 and 5 wt % of vanadyl mesoporphyrinate in the PVK:PBD composite, no aggregation of vanadyl mesoporphyrinate occurs. This indicates that the resulting complex may have use as a dopant in the light-emitting layer of red and near-IR OLEDs.

Climate change poses a threat to the water security by altering the precipitation patterns and other weather variables, which affect stream flow and freshwater availability. In this study, a soil and water assessment tool was used for the scarcity of blue and green water for future periods for sustainable management of freshwater resources away from lead pollution. Indeed, the presence of Pb2+ is an environmental problem and we have explored the use of natural phosphates (NP) as adsorbents for its elimination. The adsorbent NP was characterized by FTIR spectroscopy, scanning electron microscopy (SEM) and BET analysis. Batch adsorption experiments were performed to examine the effects of physical parameters namely the contact time, pH, stirring speed, temperature, adsorbent dose and initial Pb2+ concentration on the uptake capacity. Different models were used to fit the experimental data and to evaluate the kinetics, isotherms and thermodynamics of the Pb2+ adsorption. A high adsorption capacity of 66.66 mg/g was reached at 25°C and pH 6 and follows the Langmuir isotherm with a pseudo-second order kinetic. The adsorption is spontaneous and endothermic, indicating a structural exchange between NP and Pb2+ ions. Such results suggest that NP is a promising adsorbent for Pb2+ removal from wastewater.

Zr–Ti–B–C–N coatings were obtained by reactive pulsed magnetron sputtering at frequencies of 0, 50, and 350 kHz. The coatings contained a high total concentration of non-metallic elements in the range of 80–84 at % and had a dense, low-defect amorphous structure. The coatings were dominated by B–N, B–C, and Zr–O bonds. The hardness of the coatings was 8–9 GPa, and the modulus of elasticity and elastic recovery were within the ranges of 126–144 GPa and 36–40%, respectively. The coating deposited at a frequency of 350 Hz had the lowest coefficient of friction (~0.15). The maximum optical transmittance of ~90% was demonstrated by a coating obtained at 50 kHz characterized by minimal thickness and increased oxygen concentration. The Zr–Ti–B–C–N coatings with the optimal composition outperformed the Zr–B–N comparison samples in terms of transmittance.

The synergistic corrosion inhibition effect of lavender essential oil (LEO) and cocamidopropyl betaine (CAPB) on carbon steel in 3.5% NaCl solution was investigated. The inhibitors were characterized by GC–MS and FTIR, revealing linalyl acetate as the major LEO component and the functional groups responsible for metal interaction. Corrosion inhibition efficiency was evaluated using potentiodynamic polarization and Tafel analysis. The highest efficiency, up to 95%, was achieved by the LEO/CAPB mixture, compared to 78 and 67% for LEO and CAPB, respectively. The inhibition efficiency of LEO/CAPB remained high (87%) at 328 K, confirming its good thermal stability. Adsorption followed the Flory–Huggins isotherm (R2 = 0.999), suggesting multilayer adsorption. Thermodynamic parameters showed negative $$\Delta G_{{{\text{ads}}}}^{0}$$ values, confirming spontaneous adsorption, with magnitude indicating a mixed physisorption–chemisorption mechanism for LEO/CAPB. Surface analyses by optical microscopy and profilometry showed that the mixture forms a uniform, protective film on the steel surface, in contrast to severe corrosion in the blank solution. DFT calculations on LEO components identified linalyl acetate as the most reactive, due to its high HOMO, low LUMO, and narrow energy gap, favoring donor–acceptor interactions. A synergistic mechanism is proposed where CAPB acts as a molecular bridge, enhancing LEO adsorption and reducing corrosion. The results confirm the LEO/CAPB system as a highly efficient, eco-friendly corrosion inhibitor for carbon steel in saline environments.

A highly active microporous carbon adsorbent, KAUSORB-VA, with a micropore volume of 0.68 cm3/g and a specific BET surface of 1640 m2/g, was synthesized from nut shells for systems of adsorption storage of natural gas. Methane adsorption onto the adsorbent was measured at pressures up to 40 MPa and at temperatures of 303, 313, 323, and 333 K. The methane adsorption was found to achieve a maximum value of ~13.5 mmol/g (21.5 wt %) at a temperature of 303 K. The average differential molar isosteric heat of methane adsorption at 303 K was found to be ~16 kJ/mol.

Electrodeposition of composition modulated multilayer (CMM) coatings of Ni–Co alloy was accomplished on mild steel using single bath technique (SBT). Multilayer coatings, having layers of alternatively different compositions have been produced on the mild steel using the electrolytic bath having both Ni and Co ions by periodic pulsing of the current density between two set values, known as cyclic cathode current densities (CCCD’s). The deposition conditions, in terms of the composition and thickness of alternate layers were identified for best performance of those coatings against the corrosion. Electrochemical corrosion study of alloy coatings has been made using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. It was found that CMM(Ni–Co)1.0/3.0/60 coatings shows approximately three times better corrosion resistance than its monolayer counterpart, deposited from same bath for same duration. The experimental study demonstrated that corrosion protection efficacy of CMM Ni–Co alloy increased with number of layers up to 60 layers, and then started decreasing. The observed increase of corrosion rate at high degree of layering (after 60 layers) was attributed to the diffusion of layers, affected due to rapid change of current densities during deposition. Improved corrosion protection efficacy of multilayer coating is attributed to the alternate layers of alloys having different composition, confirmed by energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The deposited coatings were analyzed for both surface and cross-sectional features using scanning electron microscopy (SEM), and results are discussed.