Green synthesis and anticorrosion effect of Allium cepa peels extract-silver nanoparticles composite in simulated oilfield pickling solution

Unveiling the corrosion inhibition efficacy and stability of silver nanoparticles synthesized using Anacardium occidentale leaf extract for mild steel in a simulated seawater solution

Plant extracts used as corrosion inhibitor for mild steel usually degrade as the temperature increases above room temperature. In this study, we used Anacardium occidentale (cashew leaf) extract to synthesize silver nanoparticles for improving mild steel's inhibition stability under salinized conditions. Cashew leaves were used as a reducing agent to synthesise silver nanoparticles. The functional group of the silver nanoparticles was determined using Fourier transform infrared spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarisation were used to study the corrosion behaviour under simulated seawater by varying the silver nanoparticle concentration between 0.1 and 0.3 g L-1. Scanning electron microscopy and atomic force microscopy were used to obtain information about the surface of the corroded sample. The green silver nanoparticles reduced the corrosion of mild steel up to 90.5% at 40 °C and 90% at 80 °C. At 80 °C, the AgNPs are biochemically and thermally stable, exhibiting a 90% inhibition efficiency. It was established that silver nanoparticles from cashew leaves can be used to improve the stability of mild steel in simulated seawater.

Metals and metal oxides polymer frameworks as advanced anticorrosive materials: design, performance, and future direction

Metals (Ms) and metal oxides (MOs) possess a strong tendency to coordinate and combine with organic polymers to form respective metal–polymer frameworks (MPFs) and metal oxide polymer frameworks (MOPFs). MPFs and MOPFs can be regarded as composites of organic polymers. MPFs and MOPFs are widely used for industrial and biological applications including as anticorrosive materials in the aqueous phase as well as in the coating conditions. The presence of the Ms and MOs in the polymer coatings improves the corrosion inhibition potential of MPFs and MOPFs by improving their self-healing properties. The Ms and MOs fill the micropores and cracks through which corrosive species such as water, oxygen, and corrosive ions and salts can diffuse and destroy the coating structures. Therefore, the Ms and MOs enhance the durability as well as the effectiveness of the polymer coatings. The present review article is intended to describe the corrosion inhibition potential of some MPFs and MOPFs of some most frequently utilized transition metal elements such as Ti, Si, Zn, Ce, Ag, and Au. The mechanism of corrosion inhibition of MPFs and MOPFs is also described in the presence and absence of metal and metal oxides.

The Use of Synthesized CoO/Co3O4 Nanoparticles as A Corrosion Inhibitor of Low-Carbon Steel in 1 M HCl

CoO/Co₃O₄ nanoparticles (CoO/Co₃O₄ NPs) were synthesized with egg white. The effectiveness of CoO/Co₃O₄ NPs to inhibit the corrosion of carbon steel has verified in acidic medium (1 M HCl). It has been found that Langmuir adsorption isotherm is the dominant adsorption process of CoO/Co₃O₄ NPs on the surface of low-carbon steel. The thermodynamic parameters also demonstrated that the adsorption process of CoO/Co₃O₄ NPs was a physicochemical, spontaneous, and exothermic process. The electrochemical impedance spectroscopy technique and potentiodynamic polarization were applied. The results obtained in this study showed that CoO/Co₃O₄ NPs acted as a mixed inhibitor for the anodic reaction and the cathodic reaction, and the efficiency to inhibit the corrosion was 93% at 80 ppm of the inhibitor. The results of scanning electron microscopy (SEM) technique, energy-dispersive X-ray spectroscopy (EDS), and X-ray electron spectroscopy (XPS) confirmed the effectiveness that was obtained using the inhibitor to protect the surface of low carbon steel. Thus, low-carbon steel can be protected against corrosion in acidic medium using CoO/Co₃O₄ NPs as inhibitors.

Biomedical Applications of Chinese Herb-Synthesized Silver Nanoparticles by Phytonanotechnology

Recent advances in nanotechnology have opened up new avenues for the controlled synthesis of nanoparticles for biomedical and pharmaceutical applications. Chinese herbal medicine is a natural gift to humanity, and it has long been used as an antibacterial and anticancer agent. This study will highlight recent developments in the phytonanotechnological synthesis of Chinese herbal medicines to utilize their bioactive components in biomedical and therapeutic applications. Biologically synthesized silver nanoparticles (AgNPs) have emerged as a promising alternative to chemical and physical approaches for various biomedical applications. The comprehensive rationale of combinational or synergistic effects of Chinese herb-based AgNPs synthesis was investigated with superior physicochemical and biological properties, and their biomedical applications, including antimicrobial and anticancer activity and wound healing properties. AgNPs can damage the cell ultrastructure by triggering apoptosis, which includes the formation of reactive oxygen species (ROS), DNA disintegration, protein inactivation, and the regulation of various signaling pathways. However, the anticancer mechanism of Chinese herbal medicine-based AgNPs is more complicated due to the potential toxicity of AgNPs. Further in-depth studies are required to address Chinese herbs' various bioactive components and AgNPs as a synergistic approach to combat antimicrobial resistance, therapeutic efficiency of drug delivery, and control and prevention of newly emerged diseases.

Mechanical and tribological behavior of Al composites containing varying beryllium aluminum silicate and constant CeO2

Abstract

The main aim of the present work is to see the performance of “Al–Beryl” composites processed via stir casting route with or without CeO2 on their mechanical, wear and corrosive properties for structural applications in heavy machinery and watercrafts. Hardness and ultimate tensile strength increased with 36% and 43%, respectively, with 9% Beryl addition. Further, effect of addition of constant 0.5 wt.% CeO2 in “Al–Beryl” composite was evaluated and remarkably improvement in corrosion resistance was observed. Tribological performance of the composites was investigated by conducting sliding wear tests against steel at different loads in dry and wet conditions. Characteristic features of adhesion, fracture and delamination were observed in SEM micrograph of the worn composite having low beryl content slid in air whereas abrasive wear predominates in water or oil. Addition of increased wt.% of beryl particles led in reduced wear of the composite at all loads. Increase in corrosion resistance by 45% decrease in weight loss with 0.5% CeO2 addition was observed. “Al6061–9% Beryl–0.5% CeO2” composite with high hardness, wear and corrosion resistance is found most promising for structural applications.

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