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reverse osmosis

Fengjing Wu, Xiaojuan Liu, Chaktong Au
The polyamide reverse osmosis (RO) membranes were prepared through interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). The use of dimethyl sulfoxide (DMSO) and glycerol as additives for the formation of thin-film composite (TFC) was investigated. We studied the effect of DMSO and glycerol addition on membrane property and RO performance. Microscopic morphology was examined by atomic force microscopy and scanning electron microscopy. The surface hydrophilicity was characterized on the basis of water contact angle and surface solid-liquid interfacial free energy (-ΔGSL)...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Abdullah H A Dehwah, Samir Al-Mashharawi, Kim Choon Ng, Thomas M Missimer
An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed...
October 17, 2016: Ground Water
Channa Jayasumana, Omesh Ranasinghe, Sachini Ranasinghe, Imalka Siriwardhana, Sarath Gunatilake, Sisira Siribaddana
OBJECTIVE: Chronic Interstitial Nephritis in Agricultural Communities (CINAC) causes major morbidity and mortality for farmers in North-Central province (NCP) of Sri Lanka. To prevent the CINAC, reverse osmosis (RO) plants are established to purify the water and reduce the exposure to possible nephrotoxins through drinking water. We assessed RO plant maintenance and efficacy in NCP. METHODS: We have interviewed 10 RO plant operators on plant establishment, maintenance, usage and funding...
October 15, 2016: Environmental Health and Preventive Medicine
Yufeng Gong, Hua Tian, Xiaona Zhang, Yifei Dong, Wei Wang, Shaoguo Ru
To elucidate the potential thyroid disrupting effects of refuse leachate on females, female goldfish (Carassius auratus) were exposed to 0.5% diluted leachates from each step of a leachate treatment process (i.e. raw leachate before treatment, after membrane bioreactor treatment, and the final treated leachate) for 21days. Raw leachate exposure caused disturbances in the thyroid cascade of female fish, as evidenced by the elevated plasma 3,3',5-triiodo-l-thyronine (p<0.05) and thyroid-stimulating hormone (p<0...
October 5, 2016: Environmental Toxicology and Pharmacology
David M Warsinger, Emily W Tow, Kishor G Nayar, Laith A Maswadeh, John H Lienhard V
As reverse osmosis (RO) desalination capacity increases worldwide, the need to reduce its specific energy consumption becomes more urgent. In addition to the incremental changes attainable with improved components such as membranes and pumps, more significant reduction of energy consumption can be achieved through time-varying RO processes including semi-batch processes such as closed-circuit reverse osmosis (CCRO) and fully-batch processes that have not yet been commercialized or modelled in detail. In this study, numerical models of the energy consumption of batch RO (BRO), CCRO, and the standard continuous RO process are detailed...
September 25, 2016: Water Research
A H Haidari, S G J Heijman, W G J van der Meer
It is widely accepted that our understanding about the membrane process increases by investigation of the hydraulic conditions of membranes. While numerical studies have been broadly used for this purpose, the experimental studies of a comparable resolution are scarce. In this study, we compared the pressure drop, the temporal and the spatial velocity maps of a spacer-filled channel and an empty channel of the same size to determine the effect of presence of the feeds spacer on hydraulic conditions. The velocity maps are obtained experimentally by using of the Particle Image Velocimetry (PIV) technique...
October 5, 2016: Water Research
Ngai Yin Yip, Doriano Brogioli, Hubertus V M Hamelers, Kitty Nijmeijer
Combining two solutions of different composition releases the Gibbs free energy of mixing. By using engineered processes to control the mixing, chemical energy stored in salinity gradients can be harnessed for useful work. In this critical review, we present an overview of the current progress in salinity gradient power generation, discuss the prospects and challenges of the foremost technologies - pressure retarded osmosis (PRO), reverse electrodialysis (RED), and capacitive mixing (CapMix) and provide perspectives on the outlook of salinity gradient power generation...
October 10, 2016: Environmental Science & Technology
Li Zhang, Moran Wang
Surface charge at solid-electrolyte interface is generally coupled with the local electrolyte properties (ionic concentration, pH, etc.), and therefore not as assumed homogeneous on the solid surfaces in the previous studies. The inhomogeneous charge brings huge challenges in predictions of electro-osmotic transport and has never been well studied. In this work, we first propose a classification of electro-osmosis based on a dimensionless number which is the ratio of the Debye length to the characteristic pore size...
September 29, 2016: Journal of Colloid and Interface Science
Jingcheng Xu, Gang Zhao, Xiangfeng Huang, Haobo Guo, Wei Liu
According to the characteristics of the reverse osmosis concentrate (ROC) generated from Iron and Steel Company, we used three sets of parallel horizontal subsurface flow (HSF) constructed wetlands with different plants and substrate layouts to treat the high salinty wastewater. The plant growth and removal efficiencies under saline condition were evaluated. The evaluation was based entirely on routinely-collected water quality data, physical and chemical characteristics of the plants (Phragmites australis, Typha latifolia, Iris wilsonii, and Scirpus planiculmis)...
August 11, 2016: International Journal of Phytoremediation
Wail Falath, Aneela Sabir, Karl I Jacob
A novel crosslinked Poly (vinyl alcohol) (PVA) reverse osmosis (RO) thin film membrane conjugated with Gum Arabic (GA) with superb performance and features was synthesized for water desalination. RO membrane desalination parameters, such as hydrophilicity, surface roughness, water permeability, salt rejection, Chlorine resistance and biofouling resistance were evaluated using a dead end RO filtration unit. The incorporation of Pluronic F127 and the conjugation of Gum Arabic improved the overall RO performance of the membranes...
January 2, 2017: Carbohydrate Polymers
Mohan Qin, Ibrahim M Abu-Reesh, Zhen He
Osmotic microbial fuel cells (OsMFCs) take advantages of synergy between forward osmosis (FO) and microbial fuel cells (MFCs) to accomplish wastewater treatment, current generation, and high-quality water extraction. As an FO based technology, OsMFCs also encounter reverse salt flux (RSF) that is the backward transport of salt ions across the FO membrane into the treated wastewater. This RSF can reduce water flux, contaminate the treated wastewater, and increase the operational expense, and thus must be properly addressed before any possible applications...
November 15, 2016: Water Research
Ang Li, Qian-Yuan Wu, Gui-Peng Tian, Hong-Ying Hu
Methylisothiazolone (MIT) is a common biocide that is widely used in water-desalination reverse-osmosis processes. The transformation of MIT during water treatment processes is poorly understood. The kinetics and mechanisms involved in the degradation of MIT during ozonation were investigated in this study. Ozonation was found to be a useful way of degrading MIT in water, and the degradation rate constant was 0.11 (±0.1) × 10(3) L/(mol·s). The degradation rate constant did not change when the pH was increased from 3 to 9...
December 1, 2016: Journal of Environmental Management
Rumwald Leo G Lecaros, Zih-Chi Syu, Yu-Hsuan Chiao, S Ranil Wickramasinghe, Yan-Li Ji, Quan-Fu An, Wei-Song Hung, Chien-Chieh Hu, Kueir-Rarn Lee, Juin-Yih Lai
A thermoresponsive chitosan derivative was synthesized by reacting chitosan (CS) with butyl glycidyl ether (BGE) to break the inter- and intramolecular hydrogen bonds of the polymer. An aqueous solution of the thermoresponsive CS derivative exhibits a lower critical solution temperature (LCST) than CS, and it undergoes a phase transition separation when the temperature changes. Successful incorporation of BGE into the CS was confirmed by FTIR and XPS analyses. Varying the BGE content and the concentration of the aqueous solution produced different LCST ranges, as shown by transmittance vs temperature curves...
October 11, 2016: Environmental Science & Technology
Qingwu Long, Liang Shen, Rongbiao Chen, Jiaqi Huang, Shu Xiong, Yan Wang
The development of suitable draw solution in forward osmosis (FO) process has attracted the growing attention for water treatment purpose. In this study, a series of organic phosphonate salts (OPSs) are synthesized by one-step Mannich-like reaction, confirmed by FTIR and NMR characterizations, and applied as novel draw solutes in FO applications. Their solution properties including osmotic pressures and viscosities, as well as their FO performance as a function of the solution concentration are investigated systematically...
October 13, 2016: Environmental Science & Technology
Y Yang, M Kitajima, T P T Pham, L Yu, R Ling, K Y H Gin, M Reinhard
Hydrogen peroxide (H2 O2 ) is widely used in water treatment for biofouling control and, in conjunction with catalysts, as a powerful oxidant for contaminant destruction. H2 O2 could potentially serve as an anti-fouling agent in reverse osmosis systems in lieu of chlorine-based disinfectants. The dependence of the biocidal efficiency of H2 O2 on cell density, temperature and H2 O2 concentration by determining the growth, attachment and viability of the model bacterium P. aeruginosa PAO1 was studied. For controlling growth of planktonic PAO1 cells, the minimally required H2 O2 concentration depends on the cell density and temperature...
September 28, 2016: Letters in Applied Microbiology
Justin P Jahnke, Thomas Hoyt, Hannah M LeFors, James J Sumner, David M Mackie
Consortia of Aspergillus oryzae and Saccharomyces cerevisiae are examined for their abilities to turn complex carbohydrates into ethanol. To understand the interactions between microorganisms in consortia, Fourier-transform infrared spectroscopy is used to follow the concentrations of various metabolites such as sugars (e.g., glucose, maltose), longer chain carbohydrates, and ethanol to optimize consortia conditions for the production of ethanol. It is shown that with proper design A. oryzae can digest food waste simulants into soluble sugars that S...
February 4, 2016: Microorganisms
Antonin Azaïs, Julie Mendret, Eddy Petit, Stephan Brosillon
Global population growth induces increased threat on drinking water resources. One way to address this environmental issue is to reuse water from wastewater treatment plant. The presence of pathogenic microorganisms and potentially toxic organic micropollutants does not allow a direct reuse of urban effluents. Membrane processes such reverse osmosis (RO) or nanofiltration (NF) can be considered to effectively eliminate these pollutants. The integration of membrane processes involves the production of concentrated retentates which require being disposed...
December 2016: Chemosphere
Wisam M Khadra, Pieter J Stuyfzand, Ibrahim M Khadra
Most countermeasures to mitigate saltwater intrusion in coastal, karstic or fractured aquifers are hindered by anisotropy, high transmissivities and complex dynamics. A coupled strategy is introduced here as a localized remedy to protect shallow freshwater reserves while utilizing the deeper intercepted brackish water. It is a double sourcing application where fresh-keeper wells are installed at the bottom of a deepened borehole of selected salinized wells, and then supported by high recovery RO desalination...
September 21, 2016: Science of the Total Environment
Sylvain Merel, Shane A Snyder
The insect repellent diethyltoluamide (DEET) is among the most frequently detected organic chemical contaminants in water across a wide range of geographies from around the world. These observations are raising critical questions and increasing concerns regarding potential environmental relevance, particularly when the emergence of severe neurological conditions attributed to the Zika virus has increased the use of insect repellents. After dermal application, DEET is washed from the skin when bathing and enters the municipal sewer system before discharge into the environment...
September 15, 2016: Environment International
Yi-Hsueh Chuang, Kimberly M Parker, William A Mitch
Previous research has demonstrated that the reverse osmosis and advanced oxidation processes (AOPs) used to purify municipal wastewater to potable quality have difficulty removing low molecular weight halogenated disinfection byproducts (DBPs) and industrial chemicals. Because of the wide range of chemical characteristics of these DBPs, this study developed methods to predict their degradation within the UV/H2O2 AOP via UV direct photolysis and hydroxyl radical ((•)OH) reaction, so that DBPs most likely to pass through the AOP could be predicted...
October 18, 2016: Environmental Science & Technology
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