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Marek Gryta
The effect of talc addition on the morphology of capillary membranes formed by a thermally induced phase separation (TIPS) method was investigated in the presented work. The usability of such formed membranes for membrane distillation was evaluated. Two types of commercial capillary polypropylene membranes, fabricated for microfiltration process, were applied in the studies. A linear arrangement of polymer chains was obtained in the walls of membranes formed without a talc addition. In the case of membranes blended with talc, the linear structure was disordered, and a more porous structure was obtained...
May 14, 2019: Membranes
Patrick Heimerdinger, Andreas Rosin, Michael A Danzer, Thorsten Gerdes
In this study, we introduce a through-plane electrochemical measurement cell for proton conducting polymer membranes (PEM) with the ability to vary temperature and humidity. Model Nafion and 3M membranes, as well as anisotropic composite membranes, were used to compare through plane and in plane conductivity. Electrochemical impedance spectroscopy (EIS) was applied to evaluate the proton conductivity of bare proton exchange membranes. In the Nyquist plots, all membranes showed a straight line with an angle of 60-70 degrees to the Z '-axis...
May 7, 2019: Membranes
Mattia Giagnorio, Francesco Ricceri, Marco Tagliabue, Luciano Zaninetta, Alberto Tiraferri
The design of a hybrid forward osmosis-nanofiltration (FO-NF) system for the extraction of high-quality water from wastewater is presented here. Simulations were performed based on experimental results obtained in a previous study using real wastewater as the feed solution. A sensitivity analysis, conducted to evaluate the influence of different process parameters, showed that an optimum configuration can be designed with (i) an influent draw solution osmotic pressure equal to 15 bar and (ii) a ratio of influent draw solution to feed solution flow rate equal to 1...
May 6, 2019: Membranes
Mustafa Al-Furaiji, Jason T Arena, Jian Ren, Nieck Benes, Arian Nijmeijer, Jeffrey R McCutcheon
A composite, three-layered membrane for membrane distillation was prepared from electrospun polyvinylidene fluoride (PVDF) nanofibers supported by commercial polyethersulfone (PES) nanofiber based nonwoven from E.I. duPont de Nemours company (DuPont). The membranes were tested in direct contact membrane distillation (DCMD) using a 5.0 M sodium chloride brine as a feed solution. The triple layer membrane combines the hydrophobicity of PVDF and the robustness of the PES. The triple layer membrane demonstrated excellent performance in DCMD (i...
May 6, 2019: Membranes
Mohammad Mahdi A Shirazi, Ali Kargari
Membrane distillation (MD) is a relatively new and underdeveloped separation process which can be classified as a green technology. However, in order to investigate its dark points, sensitivity analysis and optimization studies are critical. In this work, a number of MD experiments were performed for concentrating glucose syrup using a sweeping gas membrane distillation (SGMD) process as a critical step in bioethanol production. The experimental design method was the Taguchi orthogonal array (an L 9 orthogonal one) methodology...
May 1, 2019: Membranes
Nayan Ranjan Singha, Mrinmoy Karmakar, Pijush Kanti Chattopadhyay, Sagar Roy, Mousumi Deb, Himarati Mondal, Manas Mahapatra, Arnab Dutta, Madhushree Mitra, Joy Sankar Deb Roy
For the fulfilment of increasing global demand and associated challenges related to the supply of clean-and-safe water, PV has been considered as one of the most attractive and promising areas in desalinating salty-water of varied salinities. In pervaporative desalination, the sustainability, endurance, and structural features of membrane, along with operating parameters, play the dominant roles and impart paramount impact in governing the overall PV efficiency. Indeed, polymeric- and organic-membranes suffer from several drawbacks, including inferior structural stability and durability, whereas the fabrication of purely inorganic membranes is complicated and costly...
May 1, 2019: Membranes
Riccardo Narducci, Gianfranco Ercolani, Raul Andres Becerra-Arciniegas, Luca Pasquini, Philippe Knauth, Maria Luisa Di Vona
We synthesized anion exchange polymers by a reaction of chloromethylated poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) with strongly basic 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). TBD contains secondary and tertiary amine groups in the guanidine portion. To favor the functionalization with the secondary amine, TBD was activated with butyl lithium. The yield of amine formation via the reaction of the benzyl chloride moiety with TBD was 85%. Furthermore, we prepared polymers with quaternary ammonium groups by the reaction of PPO-TBD with CH3 I...
April 29, 2019: Membranes
Mohammadamin Esmaeili, Tiina Virtanen, Jussi Lahti, Mika Mänttäri, Mari Kallioinen
Fouling as an intricate process is considered as the main obstacle in membrane technologies, and its control is one of the main areas of attention in membrane processes. In this study, a commercial polyethersulfone ultrafiltration membrane (MWCO: 4000 g/mol) was surface modified with different concentrations of vanillin as an antifouling and hydrophilicity promoter to improve its performance. The presence of vanillin and its increasing adsorption potential trends in higher vanillin concentrations were clearly confirmed by observable changes in FTIR (Fourier transform infrared) spectra after modification...
April 24, 2019: Membranes
Thet Lei Yee, Thusitha Rathnayake, Chettiyappan Visvanathan
Anaerobic treatment processes have achieved popularity in treating palm oil mill effluent due to its high treatability and biogas generation. The use of externally submerged membranes with anaerobic reactors promotes the retention of the biomass in the reactor. This study was conducted in thermophilic conditions with the Polytetrafluoroethylene hollow fiber (PTFE-HF) membrane which was operated at 55 °C. The reactor was operated at Organic Loading Rates (OLR) of 2, 3, 4, 6, 8, and 10 kg Chemical Oxygen Demand (COD)/m3 ·d to investigate the treatment performance and the membrane operation...
April 18, 2019: Membranes
Roman Selyanchyn, Shigenori Fujikawa, Naohiro Katsuta, Kazuya Suwa, Masashi Kunitake
The transport of small gases (H2 , CO2 , N2 , O2 ) through a series of novel membranes based on necklace-shaped inorganic polymers (DMS@POSS), in which a polyhedral oligomeric silsesquioxane (POSS) cage unit and soft chains of oligo-dimethyl siloxane (DMS) were alternately connected, was investigated. The influence of the DMS chain length and crosslinking density of the DMS@POSS on membrane properties were studied. The membranes revealed characteristic structure-property relation towards both glass transition and gases transport...
April 16, 2019: Membranes
Anatoly Reshetilov, Yulia Plekhanova, Sergei Tarasov, Sergei Tikhonenko, Alexey Dubrovsky, Alexander Kim, Vadim Kashin, Andrey Machulin, Gou-Jen Wang, Vladimir Kolesov, Iren Kuznetsova
This work investigated changes in the biochemical parameters of multilayer membrane structures, emerging at their modification with multiwalled carbon nanotubes (MWCNTs). The structures were represented by polyelectrolyte microcapsules (PMCs) containing glucose oxidase (GOx). PMCs were made using sodium polystyrene sulfonate (polyanion) and poly(allylamine hydrochloride) (polycation). Three compositions were considered: with MWCNTs incorporated between polyelectrolyte layers; with MWCNTs inserted into the hollow of the microcapsule; and with MWCNTs incorporated simultaneously into the hollow and between polyelectrolyte layers...
April 12, 2019: Membranes
Frank Y C Huang, Allie Arning
Increasing water demand coupled with projected climate change puts the Southwestern United States at the highest risk of water sustainability by 2050. Membrane distillation offers a unique opportunity to utilize the substantial, but largely untapped geothermal brackish groundwater for desalination to lessen the stress. Two types of hydrophobic, microporous hollow fiber membranes (HFMs), including polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), were evaluated for their effectiveness in direct contact membrane distillation (DCMD)...
April 11, 2019: Membranes
Fynn Weigelt, Sara Escorihuela, Alberto Descalzo, Alberto Tena, Sonia Escolástico, Sergey Shishatskiy, Jose Manuel Serra, Torsten Brinkmann
Novel selective polymeric thin-film composite membranes (TFCMs) for applications at elevated temperatures were developed. Thin selective layers of the polyimides Matrimid 5218® and 6FDA-6FpDA were cast on a developed polybenzimidazole (PBI) porous support prepared by a phase inversion process. The TFCM properties were investigated with different gases in a wide temperature range, including temperatures up to 270 °C. The membranes showed very high thermal stability and performed well at the elevated temperatures...
April 10, 2019: Membranes
Víctor Gregorio, Nuria García, Pilar Tiemblo
Solid electrolytes for Li transport have been prepared by melt-compounding in one single step. Electrolytes are composed of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) with PYR13TFSI on its own or with varying concentration of LiTFSI. While the extrusion of PVDF-HFP with PYR13TFSI is possible up to relatively high liquid fractions, the compatibility of PVDF-HFP with LiTFSI/PYR13TFSI solutions is much lower. An organo-modified sepiolite with D-α-tocopherol polyethylene glycol 1000 succinate (TPGS-S) can be used to enhance the compatibility of these blends and allows to prepare homogeneous PYR13TFSI/LiTFSI/PVDF-HFP electrolytes with controlled microphase separations by melt-compounding...
April 10, 2019: Membranes
Laura Navarrete, Andreu Andrio, Sonia Escolástico, Sergio Moya, Vicente Compañ, José M Serra
CsH₂PO₄ is a proton conductor pertaining to the acid salts group and shows a phase transition from monoclinic to cubic phase at 232 ± 2 °C under high-steam atmospheres (>30%). This cubic phase gives rise to the so-called superprotonic conductivity. In this work, the influence of the partial substitution of Cs by Ba and Rb, as well as the partial substitution of P by W, Mo, and S in CsH₂PO₄ on the phase transition temperature and electrochemical properties is studied. Among the tested materials, the partial substitution by Rb led to the highest conductivity at high temperature...
April 9, 2019: Membranes
Pierre Haldenwang, Braulio Bernales, Pierrette Guichardon, Nelson Ibaseta
In cross-flow membrane filtration, fouling results from material deposit which clogs the membrane inner surface. This hinders filtration, which experiences the so-called limiting flux. Among the models proposed by the literature, we retain a simple one: a steady-state reversible fouling is modelled with the use of a single additional parameter, i.e., N d , the ratio of the critical concentration for deposition to the feed concentration at inlet. To focus on fouling, viscous pressure drop and osmotic (counter-)pressure have been chosen low...
April 3, 2019: Membranes
Sowmya Surappanahalli Rajanna, Gattumane Motappa Madhu, Chengala Damodara Madhusoodana, Adithya Govindarajan
In the present study, a submerged ceramic membrane bioreactor was used to effectively treat industrial wastewater. The outcome of membrane coatings on the efficacy of the membrane was investigated using a silicon carbide (SiC) coating. The flux data obtained from the study were fitted into two mathematical models, namely, the standard pore blocking model (SPBM) and the complete pore plugging model (CPPM) in order to determine the fouling mechanism. It was observed that the SPBM fit with a minimum coefficient of regression of 0...
April 2, 2019: Membranes
Kyohei Ueno, Hideyuki Negishi, Takuya Okuno, Hiromasa Tawarayama, Shinji Ishikawa, Manabu Miyamoto, Shigeyuki Uemiya, Yasunori Oumi
Silicalite-1 membranes with high pervaporation performance were prepared successfully on a silica-particle-coated tubular silica support using a gel-free steam-assisted conversion (SAC) method. The effects of the silica-particle layer formed on the top surface of the silica support and the physical properties of the silica particles themselves on the membrane-formation process were investigated. The silica particles coated served as the additional silica source for growing the silicalite-1 seed crystal layer into the silicalite-1 membrane...
April 1, 2019: Membranes
Daniel Humpert, Mehrdad Ebrahimi, Annika Stroh, Peter Czermak
Spent sulfite liquor is an abundant but currently less used wastewater stream from the pulp and paper industry. The recovery of lignin from this resource would provide an inexpensive raw material for the manufacture of fuels and fine chemicals. Here we investigated the suitability of ceramic hollow-fiber membranes for the concentration of spent sulfite liquor as an alternative to common membrane technologies. We tested three ceramic hollow-fiber membranes (3, 8, and 30 nm) in different membrane processes (fed-batch and total recycle mode) and compared their performance with the widely-used tubular membrane geometry...
March 28, 2019: Membranes
Mariusz Dudziak, Joanna Wyczarska-Kokot, Edyta Łaskawiec, Agnieszka Stolarczyk
Swimming pool water was treated using an ultrafiltration process using ceramic and polymer membranes for comparison. It was determined that the efficiency of the process depended on the type of membrane used. The polymer membrane decreased the absorbance and concentration of combined chlorine in the pool water to a greater extent than the ceramic membrane. In the case of a ceramic membrane, the concentration of combined chlorine in the permeate exceeded the limit values. During the ultrafiltration process, the permeate flux decreased, causing the blockage of membrane pores...
March 25, 2019: Membranes
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