Electromembrane Processes: Experiments and Modelling

The increasing demand for water and energy poses technological challenges to the implementation of efficient concepts for a sustainable development. In this perspective, electromembrane processes (EMPs) can play a crucial role in green chemistry schemes oriented towards circular economy approaches and renewable energy systems. EMPs are based on the use of ion-exchange membranes under the action of an electric field. Versatility, selectivity, high recovery, and chemical-free operations are their main strengths. Experimental campaigns and modelling tools are prompting the improvement of consolidated processes and the development of novel concepts. Several application fields have been proposed (in chemical, food, pharmaceutical industries, and others) including desalination, water and wastewater treatment, recovery of valuable products, concentration and purification operations, chemical production, and energy production and storage. This book is a collection of the scientific contributions in the Special Issue Processes: Experiments and Modelling from the journal Membranes. It is focused on recent advancements in EMPs and their applications based on the development of cutting-edge engineered systems via experiments and/or models

Fyzioterapeutická rehabilitace po endoprotéze kyčelního kloubu

Title: Case Study of Physiotherapy Treatment of a Patient with Diagnosis of Coxartrosis after Hip Endoprosthesis Thesis aim: Theoretical description of the hip joint, coxarthrosis diagnosis, endoprosthesis, and practical description of therapy for the acute phase following hip endoprosthesis. Clinical findings: The patient is 62 years old due to coxarthrosis, she underwent endoprosthesis surgery on her right lower extremity, she has a reduction in ROM at the level of the hip in flexion, extension and abduction, she is unable to fully extend her right knee. Swallen anterior and posterior lateral aspect of the tight, muscle weakness in the right lower limb. Summary: The thesis is divided into two parts. The initial section is theoretical, with a brief summary of hip joint anatomy, biomechanics, and kinesiology, as well as coxarthrosis as a disease and its prevention, hip endoprosthesis surgery clinical views and approaches, and hip endoprosthesis rehabilitation protocol. The second component is a description of the patient case study, which includes a comprehensive initial kinesiological examination, treatments used, a final kinesiological assessment, and the result of the therapies utilized. Keywords: Coxarthrosis, Osteoarthritis, Endoprosthesis, Physiotherapy, Rehabilitation.Název: Fyzioterapeutická rehabilitace po endoprotéze kyčelního kloubu Cíl disertační práce: Teoretický popis kyčelního kloubu, diagnostika koxartrosy, endoprotézy a praktický popis terapie v akutní fázi po endoprotéze kyčelního kloubu. Klinické nálezy: Pacientce je 62 let z důvodu koxartrózy, podstoupila operaci endoprotézy pravé dolní končetiny, má sníženou ROM na úrovni kyčelního kloubu ve flexi, extenzi a abdukci, není schopna plně extendovat pravé koleno. Oteklý přední a zadní laterální aspekt těsný, svalová slabost v pravé dolní končetině. Shrnutí: Práce je rozdělena do dvou částí. Úvodní část je teoretická, obsahuje stručný přehled anatomie kyčelního kloubu, biomechaniky a kineziologie, dále koxartrózu jako onemocnění a její prevenci, klinické pohledy a přístupy k operaci endoprotézy kyčelního kloubu a rehabilitační protokol endoprotézy kyčelního kloubu. Druhou částí je popis kazuistiky pacienta, která zahrnuje komplexní vstupní kineziologické vyšetření, použité léčebné postupy, závěrečné kineziologické hodnocení a výsledek použitých terapií. Klíčová slova: Fyzioterapie, rehabilitace, koxartróza, osteoartróza, endoprotéza.Katedra fyzioterapieDepartment of PhysiotherapyFaculty of Physical Education and SportFakulta tělesné výchovy a sport

Bipolar membrane reverse electrodialysis for the sustainable recovery of energy from pH gradients of industrial wastewater: Performance prediction by a validated process model

The theoretical energy density extractable from acidic and alkaline solutions is higher than 20 kWh m-3 of single solution when mixing 1 M concentrated streams. Therefore, acidic and alkaline industrial wastewater have a huge potential for the recovery of energy. To this purpose, bipolar membrane reverse electrodialysis (BMRED) is an interesting, yet poorly studied technology for the conversion of the mixing entropy of solutions at different pH into electricity. Although it shows promising performance, only few works have been presented in the literature so far, and no comprehensive models have been developed yet. This work presents a mathematical multi-scale model based on a semi-empirical approach. The model was validated against experimental data and was applied over a variety of operating conditions, showing that it may represent an effective tool for the prediction of the BMRED performance. A sensitivity analysis was performed in two different scenarios, i.e. (i) a reference case and (ii) an improved case with high-performance membrane properties. A Net Power Density of ~15 W m-2 was predicted in the reference scenario with 1 M HCl and NaOH solutions, but it increased significantly by simulating high-performance membranes. A simulated scheme for an industrial application yielded an energy density of ~50 kWh m-3 (of acid solution) with an energy efficiency of ~80-90% in the improved scenario

Towards 1 kW power production in a reverse electrodialysis pilot plant with saline waters and concentrated brines

Reverse electrodialysis (RED) is a promising technology to extract energy from salinity gradients, especially in the areas where concentrated brine and saline waters are available as feed streams. A first pilot-scale plant was recently built in Trapani (Italy), and tested with real brackish water and brine from saltworks. The present work focuses on the scale-up of the pilot plant, reaching more than 400 m2 of total membrane area installed and representing the largest operating RED plant so far reported in the literature. With a nominal power capacity of 1 kW, the pilot plant reached almost 700 W of power capacity using artificial brine and brackish water, while a 50% decrease in power output was observed when using real solutions. This reduction was likely due to the presence of non-NaCl ions in relatively large concentration, which negatively affected both the electromotive force and stack resistance. These results provide relevant and unique information for the RED process scale-up, representing the first step for the feasibility assessment of RED technology on large scale

Experimental Analysis via Thermochromic Liquid Crystals of the Temperature Local Distribution in Membrane Distillation Modules

A reliable and optimized design of channels for Membrane Distillation (MD) requires knowledge of local temperature distributions within the module. This information is essential to measure the temperature polarization, choice the module configuration (net spacer features, channel size, etc) providing the best process performance. Notwithstanding such crucial aspects, only few studies have been devoted to the experimental characterization of MD channels and none of them includes data on the local temperature distribution. In the present work, an experimental technique based on the use of Thermochromic Liquid Crystals (TLCs) and digital image processing, previously proposed by the authors (Pitò et al., 2011), was further developed and employed in order to measure the temperature and local heat transfer coefficient distribution on the membrane surface in a MD spacer-filled channel. The performance of different types of commercial net spacers were tested. The channel provided with the symmetric net spacer was found to be the configuration leading to the best heat transfer and to the lowest temperature polarization

CFD analysis of the fluid flow behavior in a reverse electrodialysis stack

Salinity Gradient Power by Reverse Electrodialysis (SGP-RE) technology allows the production of electricity from the different chemical potentials of two differently concentrated salty solutions flowing in alternate channels suitably separated by selective ion exchange membranes. In SGP-RE, as well as in conventional ElectroDialysis (ED) technology, the process performance dramatically depends on the stack geometry and the internal fluid dynamics conditions: optimizing the system geometry in order to guarantee lower pressure drops (DP) and uniform flow rates distribution within the channels is a topic of primary importance. Although literature studies on Computational Fluid Dynamics (CFD) analysis and optimization of spacer-filled channels have been recently increasing in number and range of applications, only a few efforts have been focused on the analysis of the overall performance of the process. In particular, the proper attention should be devoted to verify whether the spacer geometry optimization really represents the main factor affecting the overall process performance. In the present work, realized within the EU-FP7 funded REAPower project, CFD simulations were carried out in order to assess the effects of different parameters on the global process efficiency, such as the choice of spacer material and morphology, and the optimization of feed and blowdown distribution systems. Spacer material and morphology can affect the fluid dynamics inside each channel. In particular, the appropriate choice of net spacer material can influence the slip/no-slip condition of the flow on the spacer wires, thus significantly affecting the channel fluid dynamics in terms of pressure drops. A Unit Cell approach was adopted to investigate the effect of the different choices on the fluid flow along the channel. Also, the possibility of choosing a porous medium to substitute the net spacer was theoretically addressed. Such investigation focused on the porosity and the fiber radius required to respect the process constrains of pressure drops and mechanical stability. On the other hand, the overall pressure drops of a SGP-RE or ED stack can be considered as resulting from different contributions: the pressure drop relevant to the feed distributor, the pressure drop inside the channel, and the pressure drop in the discharging collector. The choice of the optimal stack geometry is, therefore, strongly related to the need of both minimizing each of the above terms and obtaining the most uniform feed streams distribution among the stack channels. In order to investigate such aspects, simulations were performed on a simplified ideal planar stack with either 50 spacer-less or 50 spacer-filled channels. The effect of the distribution/collector channel thickness and geometry on single-channel flow rates and overall pressure drops in the system was analyzed and a significant influence of distributor layout and size on the overall process performance was found

Effect of Design Features and Operating Conditions on the Performance of a Bipolar Membrane-Based Acid/Base Flow Battery

In the context of renewable energy sources, storage systems have been proposed as a solution to the issues related to fluctuations in the production and consumption of electric power. The EU funded BAoBaB project is aimed at developing the Acid/Base Flow battery (AB-FB), an environment-friendly, cost-competitive, grid-scale battery storage system based on the cyclic coupling of Bipolar Membrane ElectroDialysis (BMED) and its reverse, the Bipolar Membrane Reverse ElectroDialysis (BMRED) (Pärnamäe et al., 2020). Bipolar membranes promote catalytically water dissociation, thus allowing the storage of electric power in the form of acidic and alkaline solutions (pH gradient), obtained from their corresponding salt (charging mode - BMED), which are then recombined to provide electrical power (discharging mode - BMRED). The membranes are key elements for the process performance; however, the energy conversion efficiency is also affected by the operating parameters of the process and the design features of the stack. In this work, we performed a sensitivity analysis by a mathematical multi-scale model previously developed (Culcasi et al., 2020a). The performance of AB-FB systems was predicted, focusing on the Round Trip Efficiency. Results showed that proper design features made the effect of parasitic currents negligible. Moreover, proper operating conditions maximized the RTE up to 66%

Salinity Reduction of Real Produced Waters via Assisted Reverse Electrodialysis

Produced waters (PWs) are waste streams generated during the crude oil extraction processes. The management of these wastewaters is complicated by the large volumes extracted during the oil recovery operations: these depends on the life of the oil-well: typically, 3 barrels of PWs on average are produced for each barrel of oil extracted. After oil separation, PWs are usually re-injected into the well, but this approach is not always possible without a preliminary and suitable treatment. Bioremediation techniques might be a good option, but they fail due to the PWs high salinity, which inhibit bacteria growth and metabolism. Thus, reducing their salinity upstream a bioremediation unit is a matter of crucial importance. To this aim, Assisted Reverse electrodialysis (ARED) along with the use of a dilute stream typically available on site is here proposed as a novel solution. In ARED an additional voltage is applied in the same direction of the salinity gradient through the membranes in order to enhance the passage of ions from the PW to the diluted solution, thus significantly reducing the required membrane area. An experimental campaign was carried out in order to assess the process feasibility. A fixed volume of real PWs was fed to a laboratory scale ARED unit. Each experimental test lasted for three days to reduce the salinity down to about 20 g l-1, a value compatible with the biomass metabolism for a downstream bioremediation step. Two different types of commercial membranes were tested and relevant energy consumptions were calculated. The long-runs performed did not show a significant loss of efficiency due to fouling, thus suggesting that ARED might a suitable technology for a pre-dilution of produced water