Hydrazides in the Processes of Extraction of Non-ferrous Metals from Ammonia Solutions

The extraction of copper and other non-ferrous metals from ammonia solutions with hydrazides оf Versatic acids (C15–C19 fraction) is discussed in this article. Hydrazide group has been known to be a selective extractant for non-ferrous metals. Introducing the alkyl radical of -branched tert-carboxylic acids into the reagent structure may lead to new properties important for an extractant, such as chemical stability and good compatibility with solvents properties. The optimal extraction conditions, the effect of ammonium salts and the regularities of re-extraction are assessed. Keywords: extraction, hydrazides,  -branched tert-carboxylic acids, non-ferrous metal

Synthesis of Prussian Blue nanoparticles in water/alcohol mixtures

Prussian Blue, a blue coordination polymer, emerges as a promising candidate in the realm of biomedicine. Its nanoparticles, known as catalytic labels or nanozymes, exhibit remarkable peroxidase-like properties and serve as effective antioxidants. Unsurprisingly, the demand for synthesizing Prussian Blue nanoparticles with customizable sizes is on the rise. In this study, we unveil a novel approach to synthesizing Prussian Blue nanoparticles. In this work, the synthesis of Prussian Blue nanoparticles by reducing an equimolar mixture of FeCl3 and K3[Fe(CN)6] with hydrogen peroxide in different water-alcohol mixtures was demonstrated for the first time. Alcohols with a lower dielectric constant (propanol-1, isopropyl alcohol, and tert-butanol) contribute to an increase in nanoparticle size, particularly at mole fractions of 0.02-0.05 and beyond. Conversely, alcohols with a higher dielectric constant (ethanol, methanol, ethylene glycol, and propylene glycol, excluding glycerol) demonstrate the ability to decrease nanoparticle size at mole fractions of 0.2-0.26 and higher. Building upon these findings, we present a scalable and reproducible method for preparing small Prussian Blue nanoparticles, measuring 30-40 nm, with enhanced peroxidase-like activity using 79.2% ethylene glycol as a solvent. The proposed mechanism behind the effect of ethylene glycol involves the limitation of both growth and secondary aggregation of Prussian Blue nanoparticles. These synthesized nanoparticles prove their efficiency as catalytic labels in a model vertical flow immunoassay designed to detect antibodies against SARS-CoV-2