Corrosion of α-Brass in Solutions Containing Chloride Ions and 3-Mercaptoalkyl-5-amino-1H-1,2,4-triazoles

Revealing the Correlation between Molecular Structure and Corrosion Inhibition Characteristics of N-Heterocycles in Terms of Substituent Groups

Controlling metal corrosion can directly address the waste of metal and the environmental pollution and resource depletion caused by metal recycling, very significant factors for green and sustainable development. The addition of corrosion inhibitors is a relatively cost-effective means of corrosion prevention. Among these, N-heterocycles have been widely used because heteroatoms contain lone pairs of electrons that can be strongly adsorbed onto metals, protecting them in highly corrosive environments at relatively low concentrations. However, due to the large variety of N-heterocycles, their corrosion inhibition characteristics have seldom been compared; therefore, the selection of appropriate N-heterocycles in the development of anti-corrosion products for specific applications was very difficult. This review systematically analyzed the influence of different substituents on the corrosion inhibition performance of N-heterocycles, including different alkyl chain substituents, electron-donating and electron-withdrawing substituents, and halogen atoms, respectively. The correlation between the molecular structure and corrosion inhibition characteristics of N-heterocycles was comprehensively revealed, and their action mechanism was analyzed deeply. In addition, the toxicity and biodegradability of N-heterocycles was briefly discussed. This study has provided a significant guideline for the development of green, promising corrosion inhibitors for advanced manufacturing and clean energy equipment protection.

Photocatalytic activity of micron-scale brass on emerging pollutant degradation in water: mechanism elucidation and removal efficacy assessment

Alloys or smelted metal mixtures have served as cornerstones of human civilization. The advent of smelted copper and tin, i.e., bronze, in the 4^th millennium B.C. in Mesopotamia has pioneered the preparation of other metal composites, such as brass (i.e., mixture of copper and zinc), since the bronze age. The contemporary use of these alloys has expanded beyond using their physical strength. The catalytic chemistry of micron-scale brass or copper–zinc alloy can be utilized to effectively degrade emerging contaminants (ECs) in water, which are presenting significant risks to human health and wildlife. Here, we examine the photocatalytic activity of a commercially available micro-copper–zinc alloy (KDF® 55, MicroCuZn), made with earth abundant metals, for oxidative removal of two ECs. The micron-scale brass is independently characterized for its morphology, which confirms that it has the β-brass phase and that its plasmonic response is around 475 nm. Estriol (E3), a well-known EC, is removed from water with ultraviolet (UV) radiation catalyzed by MicroCuZn and H₂O₂–MicroCuZn combinations. The synergy between H₂O₂, UV, and MicroCuZn enhances hydroxyl radical (˙OH) generation and exhibit a strong pseudo-first-order kinetic degradation of E3 with a decay constant of 1.853 × 10⁻³ min⁻¹ (r² = 0.999). Generation of ˙OH is monitored with N,N-dimethyl-4-nitrosoaniline (pNDA) and terephthalic acid (TA), which are effective ˙OH scavengers. X-ray photoelectron spectroscopy analysis has confirmed ZnO/CuO–Cu₂O film formation after UV irradiation. The second EC studied here is Δ9-tetrahydrocannabinol or THC, a psychotropic compound commonly consumed through recreational or medicinal use of marijuana. The exceptionally high solids–water partitioning propensity of THC makes adsorption the dominant removal mechanism, with photocatalysis potentially supporting the removal efficacy of this compound. These results indicate that MicroCuZn can be a promising oxidative catalyst especially for degradation of ECs, with possible reusability of this historically significant material with environmentally-friendly attributes.

Micron-scale brass is a catalyst that can be activated with ultraviolet radiation to remove emerging contaminants from water via oxidation by hydroxyl radicals.

Corrosion inhibition of brass 60Cu-40Zn in 3% NaCl solution by 3-amino-1, 2, 4-triazole-5-thiol

In this article, we tested a new organic molecule used as a corrosion inhibitor of the 60Cu–40Zn alloy in an aqueous solution similar to sea water 3% NaCl namely 3-amino-1,2,4-triazole-5-thiol (ATT) using stationary and transient electrochemical methods (polarization curves and electrochemical impedance spectroscopy (EIS)). In addition, the metal surface analysis was performed by the scanning electron microscopy (SEM) coupled with the X-ray dispersion energy (EDX) in the absence and in the presence of the inhibitor tested. Analysis of the polarization curves reveals that the ATT acts as a mixed inhibitor, while the inhibition efficiency reaches a value of 97% for a concentration of 1mM of ATT, these results are confirmed by the EIS techniques, indicating that the value of the charge transfer resistance increases with increasing of ATT concentrations, consequently the inhibitory efficiency increases and reaches a maximum value of 99% in the presence of 1mM of ATT. the influence of the immersion time shows that the corrosion inhibition of the brass 60Cu–40Zn improves with the increase of the immersion time and that the molecule adsorbs chemically and follows the Langmuir isotherm. SEM/EDS study confirms the presence of protective film on the Brass surface.