Воздействие высокой концентрации оксида азота на оксигенаторы аппаратов искусственного кровообращения (экспериментальное исследование)

The aim of the study. To study the effect of high nitric oxide concentrations on hollow polypropylene fibers of oxygenators.Materials and methods. The study was conducted in two stages. At the first stage, we evaluated the stability of oxygenator membrane made of hollow polypropylene fibers after six hours of exposure to air-oxygen mixture containing NO at 500 parts per million, or 500 pro pro mille (ppm) concentration, using mass spectrometry and infrared spectroscopy. At the second stage, an experiment with cardiopulmonary bypass (CPB) was conducted on 10 pigs. In the study group (n=5) animals sweep gas was supplied to the oxygenator as an air-oxygen mixture with NO at 100 ppm. In the control group animals (n=5) an air-oxygen mixture was used without NO. The CPB lasted for 4 hours, followed by observation for 12 hours. NO, NO2 (at the inlet and outlet of the oxygenator), and the dynamics of methemoglobin were evaluated. After weaning of animals from CPB, the oxygenators were tested for leakproofness, and scanning electron microscopy (SEM) was performed.Results. The oxygenator made of polypropylene hollow fibers retained its gas transfer parameters after six hours of exposure to air-oxygen mixture containing NO at 500 ppm. Based on IR-Fourier spectroscopy findings, NO did not affect structural integrity of polypropylene membranes. NO added to gas mixture at 100 ppm did not increase NO2 to toxic level of 2 ppm in 91% of control tests during 4 hours CPB in pigs; mean value was 1.58 ± 0.28 ppm. Methemoglobin concentration did not exceed the upper limit of permissible level (3%), and there were no statistically significant differences with the control group. All tested oxygenators have passed the leakproofness test. According to SEM findings, larger amounts of fibrin deposits were found in the control group oxygenators vs study group.Conclusion. There were no negative effects of NO at 500 ppm concentration on the oxygenator membrane made of hollow polypropylene fibers. NO at 100 ppm in a gas-mixture supplied to oxygenators did not lead to an exceedance of safe NO2 and methemoglobin concentrations in an animal model. Reduced fibrin deposits on hollow fibers of polypropylene oxygenator membranes were observed when with NO at a level of 100 ppm was added to a gas mixture.  Цель исследования. Изучить воздействие высоких концентраций оксида азота на полипропиленовые полые волокна оксигенаторов.Материалы и методы. Исследование провели в два этапа. На первом этапе с помощью масс-спектрометрии и инфракрасной спектроскопии выполнили оценку стабильности мембраны оксигенатора из полых волокон полипропилена после шестичасового воздействия воздушно-кислородной смеси, содержащей NO в концентрации 500 пропромилле, или 500 частей на миллион – parts per million (ppm). На втором этапе провели эксперимент на 10 свиньях с подключением аппарата искусственного кровообращения (ИК). Животным основной группы (n=5) в оксигенатор подавали воздушно-кислородную смесь, содержащую NO в концентрации 100 ppm. Животным контрольной группы (n=5) в оксигенатор подавали воздушно-кислородную смесь без NO. Процедура ИК длилась 4 часа, затем следовало наблюдение в течение 12 часов. Оценивали NO, NO2 (на входе и выходе из оксигенатора), динамику метгемоглобина. После отключения от ИК оксигенаторы тестировали на герметичность, а также выполняли сканирующую электронную микроскопию (СЭМ).Результаты. Оксигенатор из полипропиленовых полых волокон сохранял свои газотранспортные характеристики после шестичасового воздействия воздушно-кислородной смеси с добавлением NO в концентрации 500 ppm. По данным ИК-Фурье спектроскопии показали, что NO не влияет на структуру мембран из полипропилена. Добавление NO в дозировке 100 ppm во время 4 часов ИК у свиней не сопровождалось повышением концентрации NO2 до токсичного уровня 2 ppm в 91% измерений: среднее значение составило 1,58 ± 0,28 ppm. Концентрация метгемоглобина не превышала верхнего  предела  допустимых  значений  (3%),  не  обнаружили  каких-либо статистически значимых различий при сравнении с группой контроля. Все исследуемые оксигенаторы выдержали тестирование на герметичность. По результатам СЭМ оксигенаторы группы контроля характеризовались большим количеством отложений фибрина, чем оксигенаторы основной группы.Заключение. Негативного воздействия NO в концентрации 500 ppm на мембраны оксигенаторов из полых волокон полипропилена не обнаружили. Подача в оксигенатор NO в концентрации 100 ppm NO2 не приводила к превышению безопасного содержания NO2 и метгемоглобина в эксперименте на животных. Выявили снижение образования отложений фибрина на полых волокнах мембран оксигенаторов из полипропилена при подаче NO в концентрации 100 ppm

Absorption Behavior of Acid Gases in Protic Ionic Liquid/Alkanolamine Binary Mixtures

Herein, we studied the absorption of H₂S and CO₂ by alkanolamine–protic ionic liquids binary mixtures based on 2-hydroxyethylammonium (MEA) or triethanolammonium cations and residues of 2-hydroxy-5-sulfobenzoic acid or pyridine-3-carboxylic acid at various temperatures and partial gases pressures. It was found that absorbents based on the 2-hydroxyethylammonium cation, performed high absorption properties toward the H₂S. The solubility of hydrogen sulfide, characterized by the Henry’s Law constant, in MEA-based binary mixtures had the values comparable to the commercially available ionic liquids. The results of thermal desorption analysis demonstrated that the capture of acid gases in MEA-based absorbents occurred at two stages: through the dissolution in MEA component and in protic ionic liquid

Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2

CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS)–poly(styrene) (PS) and chitosan (CS)–poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75–104 MPa for CS-PAN and 69–75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2) = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C

Acidic Gases Solubility in Bis(2-Ethylhexyl) Sulfosuccinate Based Ionic Liquids Using the Predictive Thermodynamic Model

To properly design ionic liquids (ILs) adopted for gases separation uses, a knowledge of ILs thermodynamic properties as well their solubilities with the gases is essential. In the present article, solubilities of CO2 and H2S in bis(2-Ethylhexyl)sulfosuccinate based ILs were predicted using the conductor like screening model for real solvents COSMO-RS. According to COSMO-RS calculations, the influence of the cation change was extensively analyzed. The obtained data are used for the prediction of adequate solvent candidates. Moreover, to understand the intrinsic behavior of gases solubility the free volume of the chosen ILs and their molecular interactions with respectively CO2 and H2S were computed. The results suggest that hydrogen bonding interactions in ILs and between ILs and the gases have a pivotal influence on the solubility

Membrane gas separation module with pulsed retentate for low-permeable component recovery

The paper presents the experimentalstudy of a novel unsteady-statemembrane gas separation approachfor recovery of a slow-permeant component in the membrane module with periodical retentate with-drawals. The case study consisted in the separation of binary test mixtures based on the fast-permeantmain component (N2O, C2H2) and the slow-permeant impurity (1% vol. of N2)using a radial counter-current membrane module. The novel semi-batch withdrawal technique was shown to intensify theseparation process and provide up to 40% increase in separation efficiency compared to a steady-stateoperation of the same productivity

The Future of Chemistry is Global

International audienc

The Cation Effect on the Free Volume and the Solubility of H₂S and CO₂ in Ionic Liquids Based on Bis(2-Ethylhexyl) Sulfosuccinate Anion

Herein, we report for the first time a study dedicated to acidic gases’ solubility in ionic liquids with sterically hindered bulky anion, namely bis(2-ethylhexyl) sulfosuccinate ([doc]), experimentally evaluated at low pressures. The effect of cation change (imidazolium, pyridinium, and pyrrolidinium) on the thermophysical properties and sorption capacities was also discussed. The densities and the activation energies of the tested ILs exhibited minor differences. Furthermore, the COSMO-RS model was used to predict the free volumes of ILs aiming to investigate its influence on gas solubilities. The conducted calculations have revealed an antibate correlation between the fractional free volume (FFV) and Henry’s law constant. In particular, the lowest FFV in 1-methylimidazolium [doc] corresponded to the minimal sorption and vice versa. In addition, it was shown that the presence of protic cation results in a significant reduction in CO2 and H2S solubilities. In general, the solubility measurement results of the synthesized ILs have shown their superiority compared to fluorinated ILs based on the physical absorption mechanism

An Efficient Technique for Ammonia Capture in the Haber–Bosch Process Loop—Membrane-Assisted Gas Absorption

The present study continues the development and enhancement of a highly efficient unique hybrid technique—membrane-assisted gas absorption in designing the separation unit, which provides the improvement in mass-transfer of a target component during the ammonia capture process from a process loop of the Haber–Bosch technological route. In order to minimize the absorbent volume to membrane area ratio, the special separation cell was designed based on a combination of two types of hollow fiber membranes, dense gas separation membrane and porous pervaporation membrane. The separation performance tests were implemented under two sets of conditions, sweeping the bore (permeate) side of a cell with helium and hydrogen-nitrogen mix. For both cases, the membrane-assisted gas absorption cell demonstrated high separation efficiency, and the ammonia concentration in the permeate was never lower than 81 mol%; meanwhile, under the hydrogen-nitrogen bore sweep conditions, the ammonia concentration in the permeate reached 97.5 mol% in a single-step process. Nevertheless, there is a product purity–recovery rate trade-off, which is a typical issue for separation processes

Synthesis and Study of Gas Transport Properties of Polymers Based on Macroinitiators and 2,4-Toluene Diisocyanate

Nowadays, block copolymers hold great promise for the design of novel membranes to be applied for the membrane gas separation. In this regard, microporous block copolymers based on a macroinitiator with an anionic nature, such as potassium-substituted block copolymers of propylene oxide and ethylene oxide (PPEG) and 2,4-toluene diisocyanate (TDI), were obtained and investigated as effective gas separation membranes. The key element of the macromolecular structure that determines the supramolecular organization of the studied polymers is the coplanar blocks of polyisocyanates with an acetal nature (O-polyisocyanate). In the present research, the influence of the content of peripheral polyoxyethylene (POE) blocks in PPEG on the supramolecular structure processes and gas transport characteristics of the obtained polymers based on PPEG and TDI was investigated. According to the study of polymers if the POE block content is 15 wt %, the polyoxypropylene segments are located in the internal cavity of voids formed by O-polyisocyanate blocks. When the POE block content is 30 wt %, the flexible chain component forms its own microphase outside the segregation zone of the rigid O-polyisocyanate blocks. The permeability for polar molecules, such as ammonia or hydrogen sulfide, significantly exceeds the permeability values obtained for non-polar molecules He, N2 and CH4. A relatively high permeability is also observed for carbon dioxide. At the same time, the content of POE blocks has a small effect on the permeability for all studied gases. The diffusion coefficient increases with an increase in the POE block content in PPEG for all studied gases

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S