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Aiming at the development of a low-cost technology for multipurpose water and surface treatment in the chemical industry and beyond, using microbubbles, a novel scheme of liquid-gas interaction within a specially designed bubble generator was tested. Its efficiency for the production of microbubbles with a size distribution in the micron range is confirmed. The basic element of the device is a vortex chamber with water supply through tangential ducts, while the gas (air) is introduced in a highly turbulent swirling flow of water in radial direction through the orifice in the gas supply duct, located on the chamber axis. Bubble diameters, bubble velocities in the pipe flow and effect of the output pressure on the bubble size distribution were studied.

Studies of electrostatic repulsion in ultrafiltration membranes are limited to applications of different organic compounds carrying a set of unique characteristics, or to changes of general water parameters such as ionic strength and pH. The proposed method of deliberate alteration of surface charge of organic molecule by succinylation or by guanidination provides an opportunity to selectively investigate the electrostatic mechanism without changing size or hydrophobic properties of investigated molecule. The approach was successfully implemented on BSA protein, and new inside into the mechanism of electrostatic mechanism was obtained. The electrostatic repulsion becomes important when zeta potential of the protein exceeded 20 mV, when before the threshold the interactions were mainly governed by size exclusion.