Development and anti-corrosion performance of hyperbranched polyglycerol-decorated Fe3O4@SiO2 on mild steel in 1.0 M HCl

Facile Strategy for Fabricating an Organosilica-Modified Fe3O4 (OS/Fe3O4) Hetero-nanocore and OS/Fe3O4@SiO2 Core-Shell Structure for Wastewater Treatment with Promising Recyclable Efficiency

The development of a sustainable process for heavy metal ion remediation has become a point of interest in various fields of research, including wastewater treatment, industrial development, and health and environmental safety. In the present study, a promising sustainable adsorbent was fabricated through continuous controlled adsorption/desorption processes for heavy metal uptake. The fabrication strategy is based on a simple modification of Fe₃O₄ magnetic nanoparticles with organosilica in a one-pot solvothermal process, carried out in order to insert the organosilica moieties into the Fe₃O₄ nanocore during their formation. The developed organosilica-modified Fe₃O₄ hetero-nanocores had hydrophilic citrate moieties, together with hydrophobic organosilica ones, on their surfaces, which facilitated the further surface coating procedures. To prevent the formed nanoparticles from leaching into the acidic medium, a dense silica layer was coated on the fabricated organosilica/Fe₃O₄ (OS/Fe₃O₄). In addition, the prepared OS/Fe₃O₄@SiO₂ was utilized for the adsorption of cobalt(II), lead(II), and manganese(II) from the solutions. The data for the adsorption processes of cobalt(II), lead(II), and manganese(II) on OS/(Fe₃O₄)@SiO₂ were found to follow the pseudo-second-order kinetic model, indicating the fast uptake of heavy metals. The Freundlich isotherm was found to be more suitable for describing the uptake of heavy metals by OS/Fe₃O₄@SiO₂ nanoparticles. The negative values of the ΔG° showed a spontaneous adsorption process of a physical nature. The super-regeneration and recycling capacities of the OS/Fe₃O₄@SiO₂ were achieved, comparing the results to those of previous adsorbents, with a recyclable efficiency of 91% up to the seventh cycle, which is promising for environmental sustainability.

Assessment of Corrosion Protection Performance of FeOOH/Fe3O4/C Composite Coatings Formed In Situ on the Surface of Fe Metal in Air-Saturated 3.5 wt.% NaCl Solution

The purpose of this work is to evaluate the corrosion-inhibition behavior of deposited carbon and some iron-oxide hybrid coatings which derived from the in situ deposition method on the surface of Fe foil. Various contents of precursor methane gas were deposited over a mild iron foil substrate and formed different composites. It was found that the incorporation of C into the Fe matrix led to a thin film on the surface of the matrix and produced an anti-corrosion effect. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and potentiometric tests were used to compare the corrosion behaviors of the films in air-saturated 3.5 wt.% NaCl solution. According to the results, Fe-oxide- and C-composite-coated iron foil has a much higher corrosion resistance than the raw blank sample without the addition of C. Generally, the corrosion charge transfer resistance of one kind of iron oxide coated with carbon layers of several nanometers was enhanced up to 28,379 times (R_ct changes from 1487 Ω cm² to 4.22 × 10⁷ Ω cm²), which is the biggest improvement so far. The maximum protection efficiency was obtained for the in situ grown coating prepared by 10 and 15 sccm CH₄ precursor gas (eta = 100%). In conclusion, an iron oxide and carbon composite was found to be a great candidate for applications in the corrosion-resistance area.

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.

Organic Compounds as Corrosion Inhibitors for Carbon Steel in HCl Solution: A Comprehensive Review

Most studies on the corrosion inhibition performance of organic molecules and (nano)materials were conducted within “carbon steel/1.0 M HCl” solution system using similar experimental and theoretical methods. As such, the numerous research findings in this system are sufficient to conduct comparative studies to select the best-suited inhibitor type that generally refers to a type of inhibitor with low concentration/high inhibition efficiency, nontoxic properties, and a simple and cost-economic synthesis process. Before data collection, to help readers have a clear understanding of some crucial elements for the evaluation of corrosion inhibition performance, we introduced the mainstay of corrosion inhibitors studies involved, including the corrosion and inhibition mechanism of carbon steel/HCl solution systems, evaluation methods of corrosion inhibition efficiency, adsorption isotherm models, adsorption thermodynamic parameters QC calculations, MD/MC simulations, and the main characterization techniques used. In the classification and statistical analysis section, organic compounds or (nano)materials as corrosion inhibitors were classified into six types according to their molecular structural characteristics, molecular size, and compound source, including drug molecules, ionic liquids, surfactants, plant extracts, polymers, and polymeric nanoparticles. We outlined the important conclusions obtained from recent literature and listed the evaluation methods, characterization techniques, and contrastable experimental data of these types of inhibitors when used for carbon steel corrosion in 1.0 M HCl solution. Finally, statistical analysis was only performed based on these data from carbon steel/1.0 M HCl solution system, from which some conclusions can contribute to reducing the workload of the acquisition of useful information and provide some reference directions for the development of new corrosion inhibitors.

Hyperbranched molecules having multiple functional groups as effective corrosion inhibitors for Al alloys in aqueous NaCl

Hyperbranched molecules are a kind of promising materials due to their unique structures. In this work, two hyperbranched molecules (GON and GOH) are used as effective inhibitors for Al alloys in NaCl solution. Their inhibitive performances are evaluated by electrochemical measurements and surface characterization. The results indicate that inhibition performances of GON and GOH are closely related to the concentrations, influenced by the combination of steric hindrance and bonding effects. At relatively low concentrations (0.03-0.10 mM), GON displays a more pronounced ability to inhibit corrosion than GOH, owing to more anchoring functional groups. Oppositely, GOH has good inhibition performance at higher concentrations (0.50-1.00 mM). The interaction between the Al electrode and GOH results in the formation of a more condenser protective film than GON at high concentrations. In addition, the adsorption mechanism of two hyperbranched molecules is revealed by theoretical calculations.