Virus removal can be successfully achieved based on an electrostatic adsorption mechanism. The key requirement for this process is to develop filter materials that can be produced by low-cost technologies and are suitable in large-scale production for real applications. In this study, we report development of spray-dried alumina granules modified with copper (oxide) nanoparticles and critically assess the effect of copper oxidation state on virus removal capacity. Using plate-shaped alumina as a support material resulted in porous structure, which in turn ensured prolonged contact time of contaminated water with the material. Subsequently, copper (oxide) nanoparticles provided a large number of adsorption sites. Flow experiments revealed that copper­(I) oxide and metallic copper were the active phases in virus removal and 99.9% of MS2 bacteriophages could be removed. However, almost no virus removal was observed in the presence of copper­(II) oxide. Contrasting virus removal characteristics are associated with the different surface charge of copper species, as determined by zeta potential measurements.

The constant progress in novel nanomaterials synthesis has contributed to the rapid development of nonenzymatic glucose sensors. For working electrodes preparation, drop casting proved to be the most convenient and thus most widely applied method. However, appropriate interpretation of obtained electrochemical signal requires in-depth knowledge of limitations related to this technique. In this study, we prepared solutions based on commonly reported polymers for nanostructures immobilization and investigated their influence on copper sulfides distribution on the electrode. Characterization of suspensions properties and behavior of particles during droplet drying revealed that nonionic polyvinylpyrrolidone (PVP) was favorable for electrodes modification with copper sulfides in comparison with Nafion and chitosan. It ensured homogeneity of the suspension as well as the uniform coverage of the electrode surface with particles, what resulted in increased active surface area and, therefore, higher signal from glucose addition. On the other hand, when cationic chitosan was used as a binder, suspensions were agglomerated and, within dry deposits, a coffee-ring effect was observed. Appropriate adjustment of material and polymer interactions led to enhanced electrode electrochemical performance.

The multi-component approach to materials design, together with the adaptation of the processing conditions, is gaining increasing popularity in energy-conversion-oriented applications allowing highly effective catalysts to be obtained.

Flower-like copper sulfides nanostructures were synthesized via the solvothermal route. The structural, optical and electrochemical properties of the synthesized materials were characterized by means of X-ray diffraction (XRD), scanning electron microscopy, ultraviolet-visible spectrometry and Fourier transform infrared spectroscopy (FTIR). Thermal behavior of the obtained flower-like materials was analyzed by TG, XRD and FTIR in situ measurements, over the temperature range of 25-800°C. It was found that both shape and phase composition remain stable until the temperature reaches 200°C. Phase transformation mechanism was discussed. During annealing, mixture of CuS and Cu 1.8 S is converted to copper sulfide hydroxides (200-500°C) and further to CuO (700°C and higher). Nevertheless, hierarchically porous structure is stable only to 200°C. Applying higher temperatures affects the solubility of the material and inflicts structural damage, resulting in the formation of dense oval particles with size of 20 to 200 nm.