卷 1, 编号 4 (2019)

The development and implementation of the extracorporeal membrane oxygenation (ECMO) technique for the treatment of patients in critical conditions make it possible to effectively and safely support gas exchange processes in the blood for a long time. One of the main components of the ECMO unit is a gas permeable membrane which is a barrier separating the blood from the gas phase. Since the 1950s, the development of this technology has been aimed at improving the safety and duration of use of membranes, which led to the creation of oxygenators that provide life support for several weeks. This review is devoted to the development of the extracorporeal membrane oxygenation technology including the choice of materials, methods to improve their hemocompatibility, and approaches to the design of the membrane contactor.

Perfluorinated sulfonated cation-exchange membranes MF-4SC containing 0.5–3.0% of carbon nanotubes (CNTs) have been synthesized. A correlation between the water uptake and transport properties of the membranes in the K⁺-form and the sensitivity of DP-sensors (with the analytical signal in the form of a Donnan potential) to the analyte and interfering ions in solutions of hydrophobic amino acids (alanine, valine, and phenylalanine) has been found. Hybrid membrane samples that provide the highest sensitivity of DP-sensors to amino acid cations and zwitterions and the lowest sensitivity to hydroxonium ions at pH < 7 in a concentration range of 1.0 × 10^–4–1.0 × 10^–1 M have been selected. Membrane modification has led to a decrease in the relative error and the relative standard deviation in the determination of amino acid ions by a factor of 3 and 1.5, respectively.

The presence of sulfur-containing impurities in petroleum naphtha causes a decrease in the cost and quality of fuels, a reduction in the service life of car engines, and an increase in the amount of harmful emissions into the atmosphere. Pervaporation is an alternative cost-effective fuel desulfurization method. In this study, hybrid membranes based on poly(2,6-dimethyl-1,4-phenylene oxide) and a star-shaped modifier for the pervaporation separation of a thiophene/n-octane model mixture is developed. Hybrid star-shaped macromolecules comprising six polystyrene arms and six poly(2-vinylpyridine)-block-poly(tert-butyl methacrylate) diblock copolymer arms grafted onto a common fullerene C₆₀ central core are used as the modifier. Membrane structure is analyzed by scanning electron microscopy and atomic force microscopy. Thermal properties are studied by differential scanning calorimetry. The separation properties of the membranes are determined at low thiophene concentrations (up to 0.08 wt %). It is shown that the introduction of a star-shaped modifier leads to an increase in the extraction efficiency of sulfur-containing impurities from octane, which is the main fuel component.

Knowledge of the scaling mechanism makes it possible to develop effective means to control scaling and improve the membrane performance, increasing the recovery. This paper presents new approaches to the study of the mechanism of scaling in the presence of polymeric inhibitors (antiscalants); the adsorption of antiscalant molecules on the crystal and membrane surfaces has been investigated. The relations of the antiscalant adsorption rates to the antiscalant dose and the calcium carbonate scaling rate have been revealed. For the first time, the inhibition process was “visualized” by using a fluorescent antiscalant containing a fluorescent moiety—a copolymer of N-allyl-4-methoxy-1,8-naphthalamide and acrylic acid (PAA-F1). The examination of the surfaces of crystals and membranes by scanning electron and fluorescence microscopy showed new unexpected results: the antiscalant is adsorbed on the membrane surface and on the surface of calcite crystals formed. Fluorescence turned out to be more intense and noticeable on the surface of crystal faces than inside the crystal. During the nucleation phase, the “dark” part of the crystal lattice is formed and then begins to be covered with a “luminous” layer of the fluorescent antiscalant, which blocks further crystal growth. During experiments with antiscalant solutions in distilled water, the antiscalant was found to be adsorbed on the membrane surface in the absence of calcium ions. In experiments in which the antiscalant was added into the original tap water, it was adsorbed on the surface of the resulting crystals, not on the membrane. The visualization of the crystal growth inhibition process opens up new possibilities for studying the mechanism of scaling and developing of new technologies to control scaling.