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The bubble breakup after collision with a vortex ring was validated as source of breakup parameters for population balance modeling. This system was chosen as a deterministic alternative to the stochastic nature of bubble breakup studies under turbulent flow. The vortex ring was characterized by combining experimental visualization and numerical simulations. Breakup frequency, mean number of daughter bubbles, and its size distribution were obtained by high‐speed camera recording of the collision process. The dependence of breakup parameters on the size of the mother bubble and Weber number was determined.

The mixing of powders and granular materials is decisive for the quality of a final product. Simulations of granular mixing via discrete element method are performed. Mixing was done in a vertical cylindrical mixer with two opposed flat blades with 90°rake angle. The effects of packed-bed depth and blade rotational speed on the process of homogenization and on the development of flow patterns were evaluated. The process of homogenization was analyzed at macroscopic scale by global mixing indexes and at microscopic scale by the complex flow patterns with different nature. Macroscopic and microscopic approaches were connected and from flow pattern observation optimal conditions for the best homogenization were predicted.

The hydrophilic and hydrophobic single-walled carbon nanotube membranes were prepared and progressively applied in sorption, filtration, and pertraction experiments with the aim of eliminating three antibiotics—tetracycline, sulfamethoxazole, and trimethoprim—as a single pollutant or as a mixture. The addition of SiO2 to the single-walled carbon nanotubes allowed a transparent study of the influence of porosity on the separation processes. The mild oxidation, increasing hydrophilicity, and reactivity of the single-walled carbon nanotube membranes with the pollutants were suitable for the filtration and sorption process, while non-oxidized materials with a hydrophobic layer were more appropriate for pertraction. The total pore volume increased with an increasing amount of SiO2 (from 743 to 1218 mm3/g) in the hydrophilic membranes. The hydrophobic layer completely covered the carbon nanotubes and SiO2 nanoparticles and provided significantly different membrane surface interactions with the antibiotics. Single-walled carbon nanotubes adsorbed the initial amount of antibiotics in less than 5 h. A time of 2.3 s was sufficient for the filtration of 98.8% of sulfamethoxazole, 95.5% of trimethoprim, and 87.0% of tetracycline. The thicker membranes demonstrate a higher adsorption capacity. However, the pertraction was slower than filtration, leading to total elimination of antibiotics (e.g., 3 days for tetracycline). The diffusion coefficient of the antibiotics varies between 0.7–2.7 × 10−10, depending on the addition of SiO2 in perfect agreement with the findings of the textural analysis and scanning electron microscopy observations. Similar to filtration, tetracycline is retained by the membranes more than sulfamethoxazole and trimethoprim.

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