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reverse osmosis

Saeid Nazemi, Mehdi Mirzaii, Somayeh Yaslianifard, Davood Darban-Sarokhalil, Seyyed Sajjad Khoramrooz, Pirasteh Norozi, Fatemeh Davardoost
BACKGROUND AND OBJECTIVES: The microbiological monitoring of the water used for haemodialysis is important especially for Legionella and non-fermentative bacteria since patients with end stage renal disease (ESRD) are suffering from deteriorated function of immune system. MATERIALS AND METHODS: A total 50 water and dialysate samples were weekly collected over a period of 10 weeks from 5 sites. Total and faecal coliforms were determined by utilizing the most probable number (MPN) method...
August 2016: Iranian Journal of Microbiology
K Ambiado, C Bustos, A Schwarz, R Bórquez
The objective of this study is to evaluate the treatment of high-strength acid mine drainage (AMD) from copper mining by nanofiltration (NF) and reverse osmosis (RO) at pilot scale. The performances of two commercial spiral-wound membranes - NF99 and RO98pHt, both from Alfa Laval - were compared. The effects of pressure and feed flow on ion rejection and permeate flux were evaluated. The results showed high ion removal under optimum pressure conditions, which reached 92% for the NF99 membrane and 98% for the RO98pHt membrane...
February 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Amir Ahmad Nassiri, Monir Sadat Hakemi, Reza Safar-Pour, Ali Ahmadi, Maryam Tohidi, Babak Sharif Kashani, Fatemeh Esfehani, Soudabeh Alatab
OBJECTIVES: To determine the association of fibroblast growth factor 23 (FGF23) with left ventricular hypertrophy (LVH) through the assessment of left ventricular (LV) mass and left ventricular mass index (LVMI) in patients on hemodialysis, this study was done. METHODS: All patients on hemodialysis who are older than 18 years and in whom hemodialysis vintage was at least 6 months were enrolled. All patients were on hemodialysis thrice a week for 4 h using low-flux dialysis filters, polysulfone membranes, reverse osmosis purified water, and bicarbonate-base hemodialysis solution...
September 1, 2016: Journal of Translational Internal Medicine
Dangchen Ma, Shing Bo Peh, Gang Han, Shing Bor Chen
Zirconiumv (IV)-carboxylate metal-organic framework (MOF) UiO-66 nanoparticles were successfully synthesized and incorporated in the polyamide (PA) selective layer to fabricate novel thin-film nanocomposite (TFN) membranes. Compared to unmodified pure polyamide thin-film composite (TFC) membranes, the incorporation of UiO-66 nanoparticles significantly changes the membrane morphology and chemistry, leading to an improvement of intrinsic separation properties due to the molecular sieving and superhydrophilic nature of UiO-66 particles...
February 17, 2017: ACS Applied Materials & Interfaces
Tong Yu, Lu Meng, Qing-Bo Zhao, Ye Shi, Hong-Ying Hu, Yun Lu
Of all of the strategies for controlling reverse osmosis (RO) membrane fouling, chemical cleaning is indispensable. To study the effects of chemical cleaning on membrane foulant removal, a comparative analysis of RO membranes before and after common alkaline and acid cleaning was conducted by dissecting lead and terminal RO membranes in a full-scale municipal wastewater reclamation plant. Most foulants on the membranes were removed by chemical cleaning processes. Calcium was the major inorganic component of the foulants because of its highest concentration in the feed water...
February 2, 2017: Water Research
Aziz Ghoufi, Emil Dražević, Anthony Szymczyk
In this work we have examined a computational approach in predicting the interactions between uncharged organic solutes and polyamide membranes. We used three model organic molecules with identical molecular weights (100.1 g/mol), 4-aminopiperidine, 3,3-dimethyl-2-butanone (pinacolone) and methylisobutyl ketone for which we obtained experimental data on partitioning, diffusion and separation on a typical seawater reverse osmosis (RO) membrane. The interaction energy between the solutes and the membrane phase (fully aromatic polyamide) was computed from molecular dynamics (MD) simulations and the resulting sequence was found to correlate well with the experimental rejections and sorption data...
February 14, 2017: Environmental Science & Technology
M Vera, S Cruz, M R Boleda, J Mesa, J Martín-Alonso, S Casas, O Gibert, J L Cortina
Fluorescence excitation emission matrix (FEEM) spectroscopy was used to evaluate its applicability as a tool to track dissolved organic matter (DOM) in a drinking water treatment plant (DWTP) that incorporates a conventional line (consisting in ozonation and GAC filtration) and a membrane-based line (consisting in ultrafiltration, reverse osmosis and mineralization) working in parallel. Seven sampling points within the different process stages were characterized monthly during 2014. A global Parallel Factor Analysis (PARAFAC) was used to pull out underlying organic fractions from the fluorescence spectra...
February 3, 2017: Science of the Total Environment
Jessica R Ray, Whitney Wong, Young-Shin Jun
Mineral scaling persists in many water treatment processes. More specifically, it can significantly reduce the efficacy of aromatic polyamide (PA) membranes during reverse osmosis (RO) water treatment. Previous studies have integrated hydrophilic materials, such as polyethylene glycol (PEG), onto RO membranes to combat scaling from generally hydrophobic feed water constituents; however, there are still outstanding knowledge gaps regarding the interplay of the modified membrane surface chemistry and the water chemistry in complex RO feed waters...
February 7, 2017: Physical Chemistry Chemical Physics: PCCP
Scott A Sarver, Nicole M Schiavone, Jennifer Arceo, Elizabeth H Peuchen, Zhenbin Zhang, Liangliang Sun, Norman J Dovichi
We demonstrate an electrokinetically pumped sheath flow nanospray interface for capillary electrophoresis coupled to negative mode electrospray mass spectrometry. In this interface, application of an electric field generates electro-osmotic flow at the interior of a glass emitter that is pulled to a 10-20µm inner diameter orifice. Electro-osmotic flow pumps liquid around the distal tip of the separation capillary, ensheathing analyte into the electrospray electrolyte. In negative ion mode, negative potential applied to an untreated glass emitter drives sheath flow away from the emitter orifice, decreasing the stability and efficiency of the spray...
April 1, 2017: Talanta
Yang Song, Fang Xu, Mingjie Wei, Yong Wang
Water flow inside polyamide (PA) reverse osmosis (RO) membranes is studied by steady state nonequilibrium molecular dynamics (NEMD) simulations in this work. The PA RO membrane is constructed with the all-atom model, and the density and average pore size obtained thereby are consistent with the latest experimental results. To obtain the time-independent water flux, a steady state NEMD method is used under various pressure drops. The water flux in our simulations, which is calculated under higher pressure drops, is in a linear relation with the pressure drops...
February 10, 2017: Journal of Physical Chemistry. B
Hyun-Suk Oh, Chuan Hao Tan, Jiun Hui Low, Miles Rzechowicz, Muhammad Faisal Siddiqui, Harvey Winters, Staffan Kjelleberg, Anthony G Fane, Scott A Rice
Over the last few decades, significant efforts have concentrated on mitigating biofouling in reverse osmosis (RO) systems, with a focus on non-toxic and sustainable strategies. Here, we explored the potential of applying quorum quenching (QQ) bacteria to control biofouling in a laboratory-scale RO system. For these experiments, Pantoea stewartii was used as a model biofilm forming organism because it was previously shown to be a relevant wastewater isolate that also forms biofilms in a quorum sensing (QS) dependent fashion...
January 18, 2017: Water Research
Katie Baransi Karkaby, Maria Bass, Stanislav Levchenko, Shahar Eitan, Viatcheslav Freger
The top polyamide layer of composite reverse osmosis (RO) membranes has a fascinatingly complex structure, yet nanoscale non-uniformities inherently present in polyamide layer may reduce selectivity, e.g., for boron rejection. This study examines improving selectivity by in situ "caulking" such non-uniformities using concentration polarization-enhanced graft-polymerization with a surfactant added to the reactive solution. The surfactant appears to enhance both polarization (via monomer solubilisation in surfactant micelles) and adherence of graft-polymer to the membrane surface, which facilitates grafting and reduces monomer consumption...
January 26, 2017: Environmental Science & Technology
A Karthikeyan, S Coulombe, A M Kietzig
Nanofluids-engineered colloidal suspensions in base liquids-have captivated the interest of researchers over the last two decades for various existing as well as emerging technological applications. The main impetus for the synthesis of such novel nanocomposite liquids is the potential to alter properties of the base liquid, such as its viscosity, thermal conductivity, and surface tension, and to introduce specific optical and magnetic properties. Numerous studies suggest trends and explanations for the effects associated with the addition of nanoparticles, and that deviation from the base liquid properties are dependent on nanoparticle concentration...
March 10, 2017: Nanotechnology
Eduardo Coutinho de Paula, Míriam Cristina Santos Amaral
The reverse osmosis (RO) technology for desalination and demineralization serves the global water crisis context, both technically and economically, and its market is growing. However, RO membranes have a limited life-cycle and are often disposed of in landfills. The impacts caused by the disposal of thousands of tonnes per annum of RO membranes have grown dramatically around the world. Waste prevention should have a high priority and take effect before the end-of-life phase of a product is reached. In this review, a summary is presented of the main advances in the performance of the RO technology and the membrane lifespan...
January 1, 2017: Waste Management & Research
Yi-Hsueh Chuang, William A Mitch
Ozonation followed by biological activated carbon (O3/BAC) is being considered as a key component of reverse osmosis-free advanced treatment trains for potable wastewater reuse. Using a laboratory-scale O3/BAC system treating two nitrified wastewater effluents, this study characterized the effect of different ozone dosages (0-1.0 mg O3/mg dissolved organic carbon) and BAC empty bed contact times (EBCT; 15-60 minutes) on the formation after chlorination or chloramination of 35 regulated and unregulated halogenated disinfection byproducts (DBPs), 8 N-nitrosamines, and bromate...
January 17, 2017: Environmental Science & Technology
Ioannis A Katsoyiannis, Petros Gkotsis, Massimo Castellana, Fabricio Cartechini, Anastasios I Zouboulis
The operation and efficiency of a modern, high-tech industrial full-scale water treatment plant was investigated in the present study. The treated water was used for the supply of the boilers, producing steam to feed the steam turbine of the power station. The inlet water was the effluent of municipal wastewater treatment plant of the city of Bari (Italy). The treatment stages comprised (1) coagulation, using ferric chloride, (2) lime softening, (3) powdered activated carbon, all dosed in a sedimentation tank...
April 1, 2017: Journal of Environmental Management
Shu Zhu, Mingyu Li, Mohamed Gamal El-Din
As the volume of oil sands process-affected water (OSPW) stored in tailings ponds increases, it is urgent to seek for water management approaches to alleviate the environmental impact caused by large quantity of toxic water. Forward osmosis (FO) utilizes osmotic pressure difference between two solutions, thereby giving a potential to manage two wastewaters. In this study, FO was proposed to manage OSPW, using on-site waste basal depressurization water (BDW) as draw solution. To investigate its feasibility, both short and long-term OSPW desalination experiments were carried out...
December 21, 2016: Journal of Hazardous Materials
Mirley Alves Vasconcelos, Priscila Capelari Orsolin, Rosiane Gomes Silva-Oliveira, Júlio César Nepomuceno, Mário Antônio Spanó
High intensity-sweeteners (HIS) are natural or synthetic substances, sweeter than sugar, providing sweetness without calories. Sweeteners are mainly used as an aid in losing weight, preventing obesity and controlling blood sugar levels for diabetics. The objective of this study was to evaluate the carcinogenic potential of the sweeteners aspartame, sucralose, sodium saccharin and steviol glycoside, using the test for detection of epithelial tumor clones in Drosophila melanogaster. Larvae of 72 ± 4h, obtained from wts/TM3 female mated with mwh/mwh males, were treated for approximately 48h with different concentrations of aspartame (0...
December 24, 2016: Food and Chemical Toxicology
A Siddiqui, S Lehmann, Sz S Bucs, M Fresquet, L Fel, E I E C Prest, J Ogier, C Schellenberg, M C M van Loosdrecht, J C Kruithof, J S Vrouwenvelder
Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems. The objective of this study was to evaluate the biofouling potential of two commercially available reference feed spacers and four modified feed spacers. The spacers were compared on hydraulic characterization and in biofouling studies with membrane fouling simulators (MFSs)...
December 21, 2016: Water Research
Ryan S Kingsbury, Orlando Coronell
Aqueous processes for energy storage and conversion based on reverse electrodialysis (RED) require a significant concentration difference across ion exchange membranes, creating both an electrochemical potential and an osmotic pressure difference. In closed-loop RED, which we recently demonstrated as a new means of energy storage, the transport of water by osmosis has a very significant negative impact on the faradaic efficiency of the system. In this work, we use neutral, nonpermeating solutes as "osmotic ballasts" in a closed-loop concentration battery based on RED...
January 11, 2017: Environmental Science & Technology
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