Copernican Letters https://apcz.umk.pl/CL <strong>Copernican Letters</strong> (CL) is an international journal covering general fields of chemistry, material chemistry, life sciences, technology and biotechnology. en-US eszlyk@chem.umk.pl (Edward Szłyk) greg@umk.pl (Grzegorz Kopcewicz) Fri, 24 Feb 2017 18:08:49 +0100 OJS 3.3.0.8 http://blogs.law.harvard.edu/tech/rss 60 - https://apcz.umk.pl/CL/article/view/8613 - - Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/8613 Tue, 01 Dec 2015 00:00:00 +0100 Stimuli responsive membranes in separation processes- short review https://apcz.umk.pl/CL/article/view/CL.2015.001 <p>The paper discusses some basic issues related to synthesis and properties of stimuli responsive membranes. Two commonly studied forms of these membranes are presented, namely pore surface grafted and pore volume functionalized membranes. The critical feature allowing to classify membrane to one of the above category is their grafting yield. The first kind of membranes, known under the name of ‘membrane valves’, can be used in stimuli controlled filtration when membrane cut-off is controlled by means of external stimuli. The second category, called sometimes ‘gating membranes’, can be used for transport facilitation of some species. The paper is illustrated by description of our attempts in syntheses of both membrane forms and evaluation of their separation properties. </p> Marek Bryjak, Joanna Wolska, Anna Siekierka, Jan Kujawski Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/CL.2015.001 Tue, 01 Dec 2015 00:00:00 +0100 High performance membrane materials for gas separation https://apcz.umk.pl/CL/article/view/CL.2015.002 <p>The use of membranes in various gas separations has increased significantly in recent times. This review presents some of the recent noteworthy advances in the field of membranes materials for these applications. A description of the most promising groups of high free volume polymers, including polyimides, thermally rearranged (TR) polymers, substituted polyacetylenes, perfluoropolymers, and polymers with intrinsic microporosity (PIM) is provided. High performance, rubbery, polyethers and polyether based copolymers are shown as another important class of polymer membrane materials. The development of inorganic membranes, which are not bound to the trade-off limitations between permeability and selectivity exhibited by polymers is also presented. The attention is focused on zeolitic materials, metal organic frameworks (MOF), and carbon molecular sieves (CMS). The field of mixed matrix membranes composed of inorganic particles embedded in a polymer matrix is also briefly outlined.</p> Aleksandra Wolińska-Grabczyk, Andrzej Jankowski Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/CL.2015.002 Tue, 01 Dec 2015 00:00:00 +0100 On photocatalytic membrane reactors in water and wastewater treatment and organic synthesis https://apcz.umk.pl/CL/article/view/CL.2015.003 <p>A brief overview of hybrid photocatalysis-membrane processes and their possible applications in water/wastewater treatment and organic synthesis is presented. Moreover, a short introduction to photocatalysis is shown. The paper summarizes the main advantages and disadvantages of photocatalytic membrane reactors (PMRs) with photocatalytic membranes or a photocatalyst in suspension. Furthermore, the influence of photocatalysis on membranes performance in terms of fouling and efficiency of removal of organic contaminants during treatment of water and wastewater is discussed. In the second part of the review the examples showing the possibilities of application of PMRs in recovery of valuable compounds (benzaldehyde, vanillin) or photocatalytic partial oxidation of benzene to phenol are presented. It was concluded that PMRs exhibit numerous advantages over the conventional photoreactors, however, further investigations are still needed in order to improve the hybrid processes performance.</p> Sylwia Mozia Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/CL.2015.003 Tue, 01 Dec 2015 00:00:00 +0100 Application of membrane techniques for the removal of micropollutants from water and wastewater https://apcz.umk.pl/CL/article/view/CL.2015.004 <p>A number of inorganic anions and heavy metals, microorganisms, natural organic matter, and organic micro-pollutants, among them disinfection by-products, pharmaceutical active compounds and endocrine disrupting compounds, have been found in potentially harmful concentrations in numerous water sources. The maximum permissible levels of these compounds, in drinking water and wastewaters discharged to environment, set by the WHO and a number of countries are very low (from µg/L to a few mg/L).</p><p>Several common treatment technologies, which are nowadays used for removal of inorganic and organic contaminants from natural water supplies, represent serious exploitation problems. Membrane processes such as RO and NF, UF and MF in integrated systems, Donnan dialysis and electrodialysis as well as MBR and liquid membranes, if properly selected, offer the advantage of producing high quality drinking water as well as purified wastewater which can be drained off to natural water sources.</p><p>High-pressure membrane techniques, i.e. RO and NF can be used for direct removal of inorganic and organic micropollutants, while low-pressure (MF and UF) in integrated systems, first of all with coagulation and adsorption and in MBR as well as after complexion with polymers or surfactants.</p><p>Processes with ion-exchange membranes are suitable for micropollutants having electrical charge. Because of that property they are used in many large scale applications including the separation of ions, desalination, removal of ionic species etc. </p> Michał Bodzek Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/CL.2015.004 Tue, 01 Dec 2015 00:00:00 +0100 Innovations in electromembrane processes https://apcz.umk.pl/CL/article/view/CL.2015.005 <p>Electromembrane processes are increasingly important group of separation methods, widely used for removal of charged components from solutions. It is a growing field of research with a plethora of both existing and still developed applications. The separation is based on ion migration across the charged membranes (a polymeric matrix with fixed charged groups, counterbalanced with mobile counter-ions), placed in the electric field. This paper presents the main electromembrane processes: electrodialysis (ED), electrodialysis reversal (EDR), electrodialysis with bipolar membrane (EDBM), electrodeionization (EDI), membrane capacitive deionization (MCDI), reverse electrodialysis (RED). We present the common applications of electromembrane processes and discuss the physical basis of the electromembrane processes. The most important parameters of the ion-exchange membranes are discussed, as well as the novel approaches towards mitigation of scaling, enhancement of mass transfer, decreasing the concentration polarization, and new hybrid electromembrane processes. Critical analysis of the possibility of energy production by reverse electrodialysis is presented.</p> Krzysztof Mitko, Marian Turek Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/CL.2015.005 Tue, 01 Dec 2015 00:00:00 +0100 Principles and applications of high temperature ion conducting ceramic in power generation - fuel cells and oxygen membranes https://apcz.umk.pl/CL/article/view/CL.2015.006 <p>High temperature membranes can be used in numerous applications including ceramic filters, selective sieves, removal of impurities, oxygen and hydrogen separation, electrochemical devices such as solid oxide fuel cells and solid oxide electrolysers. The fabrication process is oriented at achieving desired properties of the final product, including proper conductivity, size and density of pores, tortuosity, mechanical stability in high operating temperatures and others. Among the mentioned applications, solid oxide fuel cells and oxygen separation membranes represent materials with mixed ionic and electronic conductivity (MIEC) which will be further discussed in the lecture. Such material are often referred as membranes designed specifically for transport of ions and electrons.<em></em></p> Jakub Kupecki Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/CL.2015.006 Tue, 22 Mar 2016 00:00:00 +0100 Use of membranes in the implementation of the "Power to gas" concept https://apcz.umk.pl/CL/article/view/Cl.2015.007 <p>This paper presents the possibility of membrane use in the Power to Gas concept.</p><p>Power to Gas is a concept of electrical energy conversion into the gaseous methane by well known Sabatier reaction. This reaction needs pure reagents such as carbon dioxide and hydrogen. The polymeric dense membranes could be used to obtain pure carbon dioxide from the stream of biogas or flue gas. The products of this reaction are methane and water. For methane dewatering one could also use polymeric membranes. </p><p>The paper presents literature data as well as the Author’s own research results.</p> Maciej Szwast Copyright (c) 2016 Copernican Letters https://apcz.umk.pl/CL/article/view/Cl.2015.007 Tue, 22 Mar 2016 00:00:00 +0100 Surface Modification of Membranes for Fouling Reduction https://apcz.umk.pl/CL/article/view/Cl.2015.008 <p>Despite great effort that has been made to reduce and understand fouling, this phenomenon is still a major problem in membrane applications. Numerous methods, both from a chemical and engineering point of view, have been introduced to overcome this problem. In this contribution, we report on the modification of membranes with polyelectrolytes and polyelectrolyte multilayers utilizing two of the mentioned strategies. The effect of surface modification on the fouling behavior as well as on the critical flux will be discussed on two examples, microfiltration membranes and RO membranes.</p> Jochen Meier-Haack, Kornelia Schlenstedt, Christian Langner Copyright (c) 2017 Copernican Letters https://apcz.umk.pl/CL/article/view/Cl.2015.008 Mon, 30 May 2016 00:00:00 +0200