Flow-mode water treatment under simultaneous hydrodynamic cavitation and plasma.

Over the last two decades, the scientific community and industry have made huge efforts to develop environmental protection technologies. In particular, the scarcity of drinking water has prompted the investigation of several physico-chemical treatments, and synergistic effects have been observed in hyphenated techniques. Herein, we report the first example of water treatment under simultaneous hydrodynamic cavitation and plasma discharge with the intense generation of radicals, UV light, shock waves and charged particles. This highly reactive environment is well suited to the bulk treatment of polluted water (i.e. E. coli disinfection and organic pollutant degradation). We have developed a new prototype and have efficiently applied this hybrid technology to water disinfection and the complete degradation of methanol in water with the aim of demonstrating its scalability. We have analyzed the mechanisms of water disinfection under the abovementioned conditions and verified them by measuring cavitation noise spectra and plasma emission spectra. We have also used the degradation of textile dyes and methanol solutions as an indicator for the formation of radicals.

Strong Antibacterial Properties of Cotton Fabrics Coated with Ceria Nanoparticles under High-Power Ultrasound.

Flexible materials, such as fabric, paper and plastic, with nanoscale particles that possess antimicrobial properties have a significant potential for the use in the healthcare sector and many other areas. The development of new antimicrobial coating formulations is an urgent topic, as such materials could reduce the risk of infection in hospitals and everyday life. To select the optimal composition, a comprehensive analysis that takes into account all the advantages and disadvantages in each specific case must be performed. In this study, we obtained an antimicrobial textile with a 100% suppression of E. coli on its surface. These CeO2 nanocoatings exhibit low toxicity, are easy to manufacture and have a high level of antimicrobial properties even at very low CeO2 concentrations. High-power ultrasonic treatment was used to coat the surface of cotton fabric with CeO2 nanoparticles.

The pecularities of ultrasonic equipment design for stabilization of dispersed structures of alumosilicic reagents for wastewater treatment.

Acoustic fields formed during operation of ultrasonic reactors with waveguides of following types: rod-type, cylindrical with rectangular protrusions and tubular were calculated and measured. The influence of distribution of acoustic fields arising from the operation of waveguide systems of three different types on the efficiency of ultrasonic activation of alumosilicic flocculant-coagulant and magnetite intended for water purification was investigated. It was shown that regardless of the equipment used on an industrial scale it is possible to reactivate the alumosilicic flocculant-coagulant even after the shelf life period of it passed, however in case of activation of magnetite the use of a bigger reactor in inefficient. In case of industrial scale processes, the choice of the correct reactor design is of significant importance, since it allows to reduce the required processing time, and, as a result, the energy consumption of the processes. The advantages of tubular waveguide systems include the possibility of processing large volumes of liquid. The high efficiency and uniformity of the excited ultrasonic fields can lead to reduction of operating costs. In case of smaller flows, the waveguide system with rectangular protrusions allowed to obtain better results. Our work illustrates the dependence of the success of a specific method on the choice of the waveguide and the size of the reactor during upscale.