Effect of Ligand Concentration, Dilution, and Excitation Wavelength on the Emission Properties of CdSe/CdS Core Shell Quantum Dots and Their Implication on Detection of Uranium

Novel Co3O4@TiO2@CdS@Au double-shelled nanocage for high-efficient photocatalysis removal of U(VI): Roles of spatial charges separation and photothermal effect

Effective spatial separation and utilization of photogenerated charges are critical for photocatalysis process. Herein, novel Co₃O₄ @TiO₂ @CdS@Au double-shelled nanocage (CTCA) with spatially separated redox centers was synthesized by loading Co₃O₄ and Au NP cocatalysts on the inner and outer surfaces of Z-scheme heterojunction (TiO₂ @CdS). The reduction rate constant of U(VI) by CTCA reached 0.218 min^-1 under simulated sunlight irradiation, which was 6.6, 3.2 and 36.3 times than that of monolayer CTCA (0.033 min^-1), CTC (0.068 min^-1) and CT (0.006 min^-1). The full-spectrum light-assisted photothermal catalytic performance can enable CTCA to remove 98.8% of U(VI) and degrade nearly 90% of five organic pollutants simultaneously. Detailed characterizations and theory calculations revealed that the photogenerated holes and electrons in CTCA flow inward and outward. More importantly, Co₃O₄ acts as a "nano heater" to generate the photothermal effect for further enhancing the charge transfer and accelerating the surface reaction kinetics. Meanwhile, the photogenerated electrons and superoxide radicals play a dominant role in reducing the adsorbed U(VI) to insoluble (UO₂)O₂·2H₂O(s). This work provides valuable input toward a novel double-shelled hollow nanocage reactor with excellent photothermal catalysis ability for efficient recovery U(VI) from uranium mine wastewater to address environmental contamination issues.

Efficient extraction of uranium from environmental samples using phosphoramide functionalized magnetic nanoparticles: Understanding adsorption and binding mechanisms

Phosphoramide functionalized Fe₃O₄ nanoparticles (NPs) were synthesized by a three step procedure and its application for uranium extraction from different enviornmental matrices has been demonstrated. A maximum adsorption capacity of 95.2 mg of U/g of the sorbent has been achieved which is higher as compared to many reported magnetic NPs. pH dependent adsorption studies were performed at 1 ppm uranium concentrations which suggests more than 80% adsorption in pH range of 4-8 with maximum adsorption at pH 6. Interestingly this is the pH range of most naturally occurring water bodies suggesting the potential of this material to extract uranium from real environmental samples. Adsorption studies were carried out with tap water, drinking water and sea water and more than 90% uranium extraction was observed. Desorption studies were performed with different reagents suggesting that the material can be reused again. EXAFS studies have been carried out which suggests that the uranium binds with oxygens of three PO group at the surface of phosphoramide functionalized NPs and based on this, binding mode of uranium with the synthesized sorbent is proposed.

Transforming lanthanide and actinide chemistry with nanoparticles

Lanthanides and actinides are used in a wide variety of applications, from energy production to life sciences. To address toxicity issues due to the chemical, and often radiological, properties of these elements, methods to quantify and recover them from industrial waste are necessary. When used in biomedicine, lanthanides and actinides are incorporated in compounds that show promising therapeutic and/or bioimaging properties, but lack robust strategies to target cancer and other pathologies. Furthermore, current decorporation protocols to respond to accidental actinide exposure rely on intravenous injections of soluble chelating agents, which are inefficient for treatment of inhaled radionuclides trapped in lungs. In recent years, nanoparticles have emerged as powerful tools in both industry and clinical settings. Because some inorganic nanoparticles are sensitive to external stimuli, such as light and magnetic fields, they can be used as building blocks for sensitive bioassays and separation techniques. In addition, nanoparticles can be functionalized with multiple ligands and act as carriers for selective delivery of therapeutic and contrast agents. This review summarizes and discusses recent progress on the use of nanoparticles in lanthanide and actinide chemistry. We examine different types of nanoparticles based on composition, functionalization, and properties, and we critically analyze their performance in a comparative mode. Our focus is two-pronged, including the nanoparticles free of lanthanides and actinides that are used for the detection, separation, or decorporation of f-block elements, as well as the nanoparticles that enhance the inherent properties of lanthanides and actinides for therapeutics, imaging and catalysis.