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Extraction of trace pertechnetate ( 99m TcO 4 − ) from aqueous media using hydrophobic deep eutectic solvents (DESs) is reported for the first time. The hydrophobic DESs studied comprise a 1:2 molar ratio of a tetraalkylammonium or tetraalkylphosphonium halide mixed with a monocarboxylic acid (i.e., saturated fatty acid). Quantitative (>99%) removal of tracer levels of 99m TcO 4− from an aqueous phase in the presence of a large excess of competing anions (e.g., Cl − , NO 3 − , HCO 3 − , H 2 PO 4 − , SO 4 2− ) within 5−60 min at 25 °C without the aid of a formal extracting agent (e.g., ionophore) demonstrates an efficient and selective extraction. At infinite dilution of pertechnetate, very high distribution ratios in excess of 10 3 are observed. Attempts to strip technetium from the DES extractant phase by reduction with SnCl 2 are also reported. Overall, these outcomes provide the basis for considering hydrophobic DESs as an alternative platform for 99 TcO 4 − waste management.

Organosoluble silver nanoparticles (AgNPs) have been synthesized for the first time in a task-specific, halide-free, deep eutectic solvent (DES) using a simple and convenient wet chemical reduction route involving microwave (MW) heating with oleylamine (OAm) acting as a surfactant and reducing agent. Nanoparticle formation is extremely rapid and occurs within 30 s of microwave heating at 100 °C. The effects of various reaction parameters (e.g., synthesis temperature, MW irradiation time, maximal MW power, water content of the medium) on the size and uniformity of the prepared AgNPs have been elucidated in this study. The produced colloidal AgNPs were characterized using UV–vis spectroscopy and transmission electron microscopy (TEM), with the aim of identifying reaction parameters simultaneously achieving optimal particle yield and colloid uniformity. This work illustrates how the versatile nature of DESs can be exploited to create unconventional DESs designed for nanoscale tasks for which conventional (e.g., halide-containing) DESs may be poorly suited, further expanding the repertoire of these solvents as sustainable media for various nanoapplications.

We report on a simple, rapid, and room-temperature undergraduate-level experiment for gold nanoparticle synthesis, analysis, and utilization as a catalyst for the sodium-borohydride-assisted reduction of methylene blue and Congo red dyes. Typical procedures toward gold nanoparticle formation require an elaborate, lengthy synthesis (some requiring 1 h for completion of nanoparticle formation and ripening), whereas faster methods frequently yield inhomogeneous or catalytically inferior gold nanoparticles. This situation limits the usefulness of gold nanoparticles as rudimentary nanochemistry teaching tools in time-restricted undergraduate laboratories. The rapid gold nanoparticle synthesis presented herein utilizes ascorbic acid or sodium borohydride as dual reducing/capping agents to produce catalytically active gold nanoparticles at the “speed of mixing” under ambient conditions, allowing preparation and characterization to be performed within a single laboratory period. Furthermore, whereas most gold nanoparticle syntheses require rigorously cleaned glassware to avoid contamination and irreproducibility, the devised undergraduate experiment reported here alleviates this burden by employing disposable reaction vessels. Thus, this undergraduate-level laboratory experiment is designed to provide a meaningful introduction to metal nanoparticle synthesis and application while simultaneously being accommodated by a typical 2–4 h laboratory period, providing much-needed teaching assistance in the growing field of nanomaterials education.

Absent explicit knowledge of catalyst loading, the apparent rate (kapp) is a totally meaningless measure of catalytic activity.