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EN
Microporous membranes were obtained by dry-wet phase inversion from a solution of cellulose acetate (CA) in acetone (13, 14 and 15 wt%). Polyethylene glycol was used as a blowing agent. The structure and mechanical properties were examined. FT-IR spectra show that the addition of polyethylene glycol improves the thermodynamics of the solution and increases the hydrophilicity of the membrane. The SEM method confirmed the microporous structure of membranes with an asymmetric structure and various pore sizes and porosities. Higher CA concentration resulted in better tensile properties.
PL
Mikroporowate membrany otrzymano metodą inwersji fazy sucho-mokrej z roztworu octanu celulozy (CA) w acetonie (13, 14 i 15% mas.). Jako środek porotwórczy zastosowano glikol polietylenowy. Zbadano strukturę i właściwości mechaniczne. Widma FT-IR pokazują, że dodatek glikolu polietylenowego poprawia termodynamikę roztworu i zwiększa hydrofilowość membrany. Metodą SEM potwierdzono m ikroporowatą strukturę membran o asymetrycznej budowie i różnej wielkości porów oraz porowatości. Większe stężenie CA skutkowało lepszymi właściwościami mechanicznymi przy rozciąganiu.
EN
Membrane stress under load depends on several factors in tensile membrane structures. This research aims to find out how geometry of the supports affects the membrane stress in barrel-vault shaped membranes. A numerical experiment is conducted and the parameters of the support geometry are varied in order to understand their influence on the maximal membrane stress under load. Three load types are applied to numerical models and maximal stresses are monitored. The results show how change of the size of the base of the structure and the change of the height of the supporting arches influence the stress. The results can be used in design of tensile membrane structures, but also in assessing the possibilities for integration with other systems, such as photovoltaics.
PL
Naprężenia membranowe w rozciągliwych konstrukcjach membranowych powstające pod wpływem obciążenia zależą od kilku czynników. Celem badań jest sprawdzenie, jak geometria podpór wpływa na naprężenia membranowe w membranach kolebkowych. Aby poznać wpływ obciążeń na maksymalne naprężenie membrany, przeprowadzono eksperyment numeryczny, zmieniając parametry geometrii podpory. Do modeli numerycznych stosowane są trzy typy obciążeń i monitorowane są maksymalne naprężenia. Wyniki pokazują, jak zmiana wielkości podstawy konstrukcji i zmiana wysokości łuków nośnych wpływają na naprężenia. Wyniki można wykorzystać przy projektowaniu rozciągliwych konstrukcji membranowych, ale także przy ocenie możliwości integracji z innymi systemami, takimi jak fotowoltaika.
PL
Technologia membranowa w oczyszczaniu ścieków jest uważana za najlepszą dostępną metodę. Jednak wysoka wydajność oczyszczania ścieków powoduje wzrost zanieczyszczeń w osadach ściekowych, będących produktem ubocznym procesów oczyszczania ścieków. Osady ściekowe mają właściwości glebotwórcze i nawozowe. Najlepszą metodą zagospodarowania osadów ściekowych jest wykorzystanie ich jako nawozu. Jednak głównym kryterium możliwości ich wykorzystania jako nawozów jest zawartość metali ciężkich i jaj pasożytów. W niniejszym badaniu porównano zawartość metali ciężkich w osadach ściekowych z trzech różnych oczyszczalni ścieków przed i po modernizacji do technologii MBR. Przeprowadzono analizę specjacyjną metali i obliczono wskaźniki ryzyka, w celu oszacowania rzeczywistego ryzyka zanieczyszczenia, związanego z wykorzystaniem osadów ściekowych jako nawozów. Głównym problemem badawczym artykułu jest odpowiedź na pytanie: czy podwyższona zawartość metali ciężkich w osadach ściekowych z oczyszczalni MBR może rzeczywiście powodować ryzyko skażenia środowiska?
EN
Membrane technology in wastewater treatment is considered the best method available. However, the high efficiency of wastewater treatment results in increased contaminants in sewage sludge, a byproduct of wastewater treatment processes. Sewage sludge with have soil-forming and fertilizing properties. The best method of managing sludge is to use it as fertilizer. However, the main criterion for the possibility of using them as fertilizers is determined by the content of heavy metals and parasite eggs. This study compared the heavy metal content of sludge from three different wastewater treatment plants before and after upgrading to MBR technology. A speciation analysis of the metals was performed, and risk indicators were calculated to estimate the actual risk of contamination from the use of sewage sludge as fertilizers. The main research problem of the paper is to answer the question: whether the elevated heavy metal content of sludge from MBR treatment plants can indeed cause a risk of environmental contamination.
EN
The processes of water purification with increasing selection of permeate were studied, considering selectivity and productivity of membranes, dynamics of changes of contents of components in the concentrate. It is shown that when chlorides and sulfates are removed from water, the increase in their content in the concentrate does not differ practically from the measured and calculated values. At the same time, the nature of dependences on the change in hardness, concentration of calcium and magnesium ions, alkalinity obtained experimentally differ significantly from the dependences obtained by theoretical calculations at permeate selection levels of > 70%. А significant difference in the determined and calculated concentrations of hardness ions in the concentrates was observed after hardness values greater than 30–40 mg-eq/dm3. This indicates the partial removal of hardness ions and carbonates from the concentrates, which may be the reason for the formation of deposits on the membrane. Permissible values of the degree of permeate selection were determined, at which there is no intense deposition of carbonates and hydroxides of hardness ions on the membrane. With the initial water hardness > 8 mg-eq/dm3, the degree of permeate selection could reach 60–70% without the risk of sedimentation on the membrane. Effectiveness of the low-pressure reverse osmosis membrane in the purification of mine water with an increased level of mineralization and hardness was determined. A significant difference between the determined and calculated hardness in concentration was observed already at the degree of permeate selection of 22–33%.
EN
Forward osmosis (FO) is an emerging technology that has been extensively studied in the last decade as an efficient method for desalination and water treatment. FO presents many benefits over traditional desalination technologies such as reverse osmosis and distillation. Nevertheless, there are many decisive challenges; the great significance one is the new modification and advances in the preparation of the TFC membranes that must be achieved to enhance the FO performance. Therefore, preparing a suitable TFC membrane with a low structural parameter, low tortuosity, and high porosity are preferred in preparing the TFC membranes to get higher water flux and lower salt flux. This paper reviewed the recent development and advances in using TFC hollow fiber membranes in FO applications. Within that, the most widely applied monomers to prepare the thin polyamide layer (PA) in TFC membranes and the additives that are added during the preparation of the PA layer and their effect on the performance of the TFC membranes have been discussed. Moreover, an effort is made to generate a TFC membrane properties and performance trend according to the results of the water permeate flux and reverse salt flux of the modified TFC FO membranes and the future perspectives and concluding remarks on the FO membrane are evaluated.
EN
Impacts of precursor solution recipe, processing parameters, and pellet thickness on the lithium ionic conductivity of the ceramic materials with perovskite structure of Li0.3La0.57TiO3 were investigated and new method was proposed to synthesize Li0.3La0.57TiO3 solid state electrolyte. The results showed that ionic conductivity of Li0.3La0.57TiO3 membrane which was synthesized by firstly forming colloidal TiO2 (i.e., TiO2 sol) and then Li+ and La+ were added to the colloidal TiO2 was on the order of 10-5 S/cm. It also showed that the temperatures corresponding to a full decomposition for L0.3La0.57TiO3 is about 750°C and materials start forming perovskite structure when temperature reaches about 900°C and the lithium ionic conductivity gains about 21% increase when the pellet thickness is reduced to about ¼
EN
This research aimed to find the best-operating conditions for incorporating the GO material into PES/GO membranes for the NF applications. Organic dye molecules may foul GO-NP/PES membranes. The improved model aimed to reduce the energy lost while maintaining a high system discharge throughout the treatment process in order to face the technical problems that the membranes are exposed to. To create a particular amount of flux above the intended values, an optimization approach was used to find the optimal values for several important parameters in the process. To enhance the process effectiveness on a broader scale, mathematical and statistical studies, such as response surface methodology and statistical analysis of the parameters (ANOVA), were applied. The impact of operational factors, like the pH values of the dye feeding (3–11), GO weight content (0–2 wt.%), dye concentration (10–100 ppm) of AB-210, and the interfaces for these factors with the PES/GO membrane permeability was examined. The PES membrane had the best performance, with a result of 131.2338 L·m-2·h-1·bar-1. The pH did not influence the AB-210 dye reaction, and the Pareto chart of the standardized effects on dye permeation flux using statistical comparison at the 5% significance level supports these findings.
EN
The process of extracting nitrates from water by the methods of reverse osmosis and ion exchange was investigated in the paper. In the formation of reverse osmosis, low-pressure membranes were used, and in ion-exchange processes, highly alkaline anionite AB–17–8 was applied in salt form. The dynamics of changes in the concentration of nitrates in the permeate and the concentration with an increase in the degree of permeate selection from 9 to 90% at initial nitrate concentrations of 18, 50 and 100 mg/dm3 were determined. The indicators of selectivity and productivity of membranes were calculated depending on the degree of permeate selection. It was shown that the low-pressure reverse osmosis membrane is characterized by low selectivity values at high productivity values in the selected part of the nitrate concentration. It was established that the ion exchange method is significantly more effective than reverse osmosis in removing nitrates from water. It ensures the reduction of nitrate content in purified water to a value of less than 1 mg/dm3 when the degree of their extraction is reached at the level of 99%. As the ionite is saturated with nitrates, the efficiency of their extraction decreases. Anionite sorbs nitrates effectively enough, being both in the chloride mixture and in the sulfate form. Nitrates are effectively desorbed by 2H solutions of sodium chloride and sodium or ammonium sulfate.
EN
The processes of desalination of weakly mineralized waters using a reverse osmosis membrane were studied. The operational efficiency of membranes is limited mainly by membrane contamination. It was shown that the preliminary mechanical water purification helps to increase the productivity and selectivity of the membrane. One of the main causes of membrane contamination is the formation of carbonate deposits on their surface. One way to prevent membrane contamination is to dose antiscalants. It was established that the use of hydrolyzed polyacrylonitrile (HPAN) and hydrolyzed polyacrylamide (HPAA) as a stabilizer of scale formation is effective for concentrates of reverse osmosis desalination of water.
PL
Przedmiotem artykułu są materiały stosowane do wtórnej hydroizolacji budynków – membrany z tworzyw sztucznych i kauczuku. Autor analizuje zagadnienia związane ze stosowaniem folii i membran, zajmuje się hydroizolacją przyziemi budynków, po czym przechodzi do omówienia norm krajowych i międzynarodowych. Uwagę poświęca także mocowaniu membran do podłoża oraz wrażliwości membran na uszkodzenia mechaniczne.
EN
The article focuses on materials used for secondary waterproofing of buildings - plastic and rubber membranes. The author analyzes the issues related to the use of films and membranes, deals with waterproofing the basement of buildings, and then discusses national and international standards. He also pays attention to fixing the membranes to the substrate and the sensitivity of the membranes to mechanical damage.
EN
The cotton-based composite is equipped with a single/double semipermeable membrane made of polyurethane (PU) (100%), which blocks liquid transport to the surrounding environment. The complex problem analyzed involves the coupled transport of water vapor within the textile material, transport of liquid water in capillaries, as well as heat transport with vapor and liquid water. The problem can be described using the mass transport equation for water vapor, heat transport equation, and mass transport equation for liquid moisture, accompanied by the set of corresponding boundary and initial conditions. State variables are determined using a complex multistage solution procedure within the selected points for each layer. The distributions of state variables are determined for different configurations of membranes.
12
Content available remote Wprowadzenie MWK do obrotu a UV
PL
Wysokoparoprzepuszczalne membrany wstępnego krycia (oznaczane w [1] jako MWK) są sprzedawane w Polsce od 30 lat. W tym czasie zmieniły się normatywne zasady wprowadzania ich do sprzedaży.
EN
This article is inspired by the research on membrane training platforms, which has been conducted by the author for over two years. Currently, they are at the stage of building an experimental prototype in a real scale. These studies are the result of cooperation between the Wrocław University of Technology and the Center "Lunares Space - simulated space base" in Piła and the cooperation with the Academy of Physical Education in Wrocław regarding training devices. The membrane training platform is a spatial membrane, mesh, rope or belt installation, stretched elastically on a light and economical, spatial rod structure. A membrane is understood as a bi-curved surface, which is an unstable substrate, generating significant deformations under a load from a human walking on it - simulating walking "in deep snow" or in conditions of reduced gravity. The author's experience, gained in the course of this scientific work, gave him the idea of applying a similar idea to health-promoting urban installations intended for children and adolescents. The author presents this concept against the background of currently known devices with a similar function and character. At the same time, he shows arguments in favor of the implementation of this unconventional proposal, justifying in detail the need to develop this type of activity for children and adolescents, and even for the elderly. The presented proposals for new functional and spatial forms, intended for location in open space, are based on the use of low-cost, single-layer, octagonal and hexagonal bar systems, designed in such a way as to form closed systems, well absorbing forces from polypropylene nets, tapes or membranes stretched inside. According to the author, apart from their functional tasks, these objects could create intriguing, attractive architectural forms, enriching the city space.
PL
Inspiracją niniejszego artykułu są prowadzone przez autora od ponad dwóch lat badania nad membranowymi platformami treningowymi. Aktualnie znajdują się one w stadium budowy doświadczalnego prototypu w skali rzeczywistej. Badania te są rezultatem współpracy Politechniki Wrocławskiej z Centrum „Lunares Space - symulowana baza kosmiczna” w Pile oraz współpracy z Akademią Wychowania Fizycznego we Wrocławiu w zakresie urządzeń treningowych. Membranowa platforma treningowa jest przestrzenną instalacją membranową, siatkową, linową lub taśmową, rozpiętą sprężyście na ekonomicznym, przestrzennym stelażu prętowym. Pod pojęciem membrany rozumie się powierzchnię dwukrzywiznową, która stanowi niestabilne podłoże generujące znaczne deformacje pod obciążeniem od chodzącego po niej człowieka – symulujące chodzenie „w głębokim śniegu” czy w warunkach zmniejszonej grawitacji. Doświadczenia autora, zdobyte w trakcie tej pracy naukowej, nasunęły mu koncepcję zastosowania podobnej idei dla prozdrowotnych instalacji miejskich przeznaczonych dla dzieci i młodzieży. Autor przedstawia tę koncepcję na tle znanych obecnie urządzeń, o podobnej funkcji oraz charakterze. Wykazuje równocześnie argumenty przemawiające za sensem realizacji tej niekonwencjonalnej propozycji, szczegółowo uzasadniając potrzeby rozwijania tego typu aktywności u dzieci i młodzieży, a nawet u osób starszych. Prezentowane propozycje nowych form funkcjonalno-przestrzennych przeznaczonych do lokalizacji w otwartej przestrzeni oparte są o wykorzystanie niskobudżetowych, jednopowłokowych systemów prętowych – oktagonalnych i heksagonalnych - projektowanych w taki sposób, by tworzyły systemy zamknięte dobrze przejmujące siły z rozpiętych wewnątrz siatek, taśm lub membran polipropylenowych. Zdaniem autora oprócz swych zadań użytkowych obiekty te mogłyby tworzyć intrygujące, atrakcyjne formy architektoniczne wzbogacające przestrzeń miasta.
EN
Power generation units, suitable for individual users and small scale applications, are mainly based on spark ignition engines. In recently performed research, reductions of emissions coming from such units, especially considering carbon dioxide emissions, are deemed as the issue of particular importance. One of solutions, postponed to reduce impact of spark ignition engine-based units on the natural environment, is transition from fossil fuels into renewable gaseous fuels, as products of organic digestion. Nonetheless, development of new solutions is required to prevent further carbon dioxide emissions. The paper presents a novel dual approach developed to reduce carbon dioxide emissions from stationary power units, basing on spark ignition engine. The discussed approach includes both reduction in carbon content in the fuel, which is realized by its enrichment with hydrogen produced using the solar energy-supported electrolysis process, as well as application of post-combustion carbon dioxide separation. Results of the performed analysis suggest profitability of transition from fossil into the hydrogen-enriched fuel mixture, with significant rise in operational parameters of the system following increase in the hydrogen content. Nevertheless, utilization of the carbon dioxide separation leads to vital soar in internal energy demand, causing vital loss in operational and economical parameters of the analyzed system.
15
Content available Ponding on an inflated tube and the membrane trough
EN
The ponding on an inflated membrane tube is studied. Membrane tubes have the advantage of zero leakage and ease of transportation and set-up. A novel related problem is the membrane trough which can be used to contain water and does not need anchoring. These problems depend on two non-dimensional parameters which characterize membrane tension and pressure. Perturbation solutions to second order are found for shallow ponding, and compare well with those of exact numerical integration. Tables for the pertinent parameters are constructed and cross section geometries are found. This research illustrates the interaction of membrane structure, pressure load, and hydrostatics.
EN
To collect permeability data and establish its database of fertilizer nutrients and water vapor through different polymer membranes for the development of polymer-coated fertilizer, the permeabilities of N-, P-, and K-nutrient from saturated aqueous of urea, NaH2PO4 and KCl solution and the permeability of water vapor through the membranes of poly lactic acid (PLA), its blends with polystyrene (PS), and its composites with humic acid (HA) particles were determined experimentally at the temperatures of 288, 298, and 308 K, respectively. The effects of the addition of PS and HA particles, temperature, and coating thickness on the permeability of fertilizer nutrient and water vapor were investigated. It was found that the addition of PS and HA increased the permeability for both the fertilizer nutrients and water vapor. The increase in temperature raised the permeability of N-, P-, and K-nutrient while decrease the permeability of water vapor in the range studied.
17
Content available remote Hydroizolacje rolowe - wybrane zagadnienia
PL
Przedmiotem artykułu jest omówienie wybranych zagadnień dotyczących hydroizolacji rolowych. Poruszane są w nim kwestie związane z błędami izolacji na poziomie projektowania i prowadzenia robót z zastosowaniem materiałów rolowych. Po nich następuje charakterystyka folii wykorzystywanych do hydroizolacji i omówienie procesu wykonywania hydroizolacji z uwzględnieniem wymagań stawianych foliom i membranom, a także podłożu. Następnie scharakteryzowane zostają rolowe materiały bitumiczne i papy termozgrzewalne.
EN
The purpose of the paper is to present selected issues concerning continuous waterproof insulation materials. It describes the problems related with insulation faults occurring at the design and execution stage when using reeled materials. A part of the paper contains the characteristics of waterproof insulation membranes and explains the installation pracess of waterproof insulation considering the requirements for foil and membranes, as well as the substrate. Reeled bituminous materials and torchon membranes are also described.
EN
This paper presents the findings of experimental research on employing ultrafiltration and microfiltration ceramic modules (150 kDa, 0.14 μm, 0.45 μm) for removal and concentration of the cationic surfactant Tequat LC90i (TEAQ) from water solutions. The filtration tests were performed at a semi-pilot installation in a crossflow regime. The feed solution parameters (surfactant concentration, pH of the treated solution, the presence of inorganic salt), and process conditions (transmembrane pressure and linear velocity) on the membrane filtration efficiency were evaluated. In all tests, very satisfactory TEAQ retention coefficients (in the range of 70–95) have been achieved. However, surfactant fouling occurred resulting in deterioration of the permeability of the modules. Modules characterized by the pore sizes greater than the size of surfactant particles (i.e., 0.45 μm modules) proved to be the most fouling resistant ones. It was also proven that process performance at high linear flow velocity can efficiently reduce the intensity of membrane pore blocking.
19
Content available remote The Hydrophobization of a Nanofiber Layer Using Low-Vacuum Plasma
EN
Nanofiber materials offer a wide range of use in various production fields, e.g., different types of filtration, or areas requiring high hydrostatic resistance. They are made from different polymers, some of which are more hydrophobic than others, for instance some types of polyurethanes and polyvinylidene fluoride. However, even these polyurethanes cannot guarantee a high hydrophobicity of the final nanofiber material. To increase this desired property, we have to use the so-called hydrophobic substances like fluorocarbon. The nanofiber layer has to be prepared so that its pores do not get blocked, which would worsen its filtration capability and air permeability. This is why a roll-to-roll low-vacuum plasma was used in our case for creating a fabric with nanofiber layer for the clothing industry. The result is a nanofiber material with a hydrostatic resistance higher than a 15,000 mm water column. Under suitable conditions, we can produce a nanofiber membrane for clothing with thermophysiological properties similar to those of membranes produced with different principles, e.g., nanoporous membranes. The nanofiber membrane provides us desirable properties such as stability during repeated washing.
EN
Biofouling is a phenomenon that adversely affects the efficiency of filtration hindering wide the application of filtration materials. One of the methods for biofouling prevention is coating of antibacterial nanoparticles on a surface of filters and membranes using ultrasound. In the paper, the possibility of using an ultrasonic method was evaluated to implement nanoparticles of titanium dioxide (TiO2 ) and zinc oxide (ZnO) on polymeric filtration materials via different types of transducers and selected parameters of the ultrasound generator. Ultrasonic methods of modification were found to be efficient in terms of imparting antibacterial properties; however, the functional additives coated on polymeric materials were characterized by poor resistance to leaching. Thus, further work needs to be performed to improve the adhesion and stability of nanoparticles onto polymeric materials to enable the generation of filtration materials characterized by high stability during real operating conditions.
PL
Biofouling materiałów filtracyjnych jest zjawiskiem niekorzystnie wpływającym na efektywność filtracji i hamującym wprowadzanie tej technologii w nowe obszary zastosowań. Jedną z metod zapobiegania biofoulingowi jest modyfikacja powierzchni membran antybakteryjnymi nanocząstkami. W artykule opisano prace studialne nad wykorzystaniem do tego celu metody nanoszenia ultradźwiękowego. Przedstawiono konstrukcje i parametry zestawionych stanowisk do generacji ultradźwięków, wyniki procesów nanoszenia nanocząstek tlenku tytanu i tlenku cynku, wpływ głównych parametrów procesu na strukturę uzyskiwanych pokryć. Oceniono ich właściwości antybakteryjne oraz odporność na wymywanie. Określono kierunki dalszych prac mających na celu wytworzenie metodą ultradźwiękową materiałów filtracyjnych charakteryzujących się stabilno- ścią podczas pracy w warunkach rzeczywistych.
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