Effect of Membrane Material Properties on Efficiency of Membrane Distillation

2011 ◽  
Vol 695 ◽  
pp. 85-88 ◽  
Author(s):  
Hwan Kim ◽  
June Seok Choi ◽  
Sang Ho Lee
Keyword(s):  
Membrane Distillation ◽  
Contaminated Water ◽  
Initial Screening ◽  
Membrane Material ◽  
Membrane Materials ◽  
Flat Sheet ◽  
Hydrophobic Membranes ◽  
The Stability ◽  
Physical And Chemical

Membrane distillation (MD) integrates membrane technology with evaporation process to produce fresh water from seawater or contaminated water. In this study, we investigated the effect of membrane materials on the efficiency of membrane distillation process. Flat sheet hydrophobic membranes (PVDF, PTFE) with different characterizes were chosen as well as hollow fiber membranes (PE). Laboratory-scale systems were developed for initial screening of various membranes. The performance of the membrane was analyzed in terms of water permeability and salt rejection. Synthetic seawater (TDS = 35,000 mg/L) was used for the lab-scale tests. A simple model to analyze the transport of water through MD membranes was developed to interpret experimental results. In addition, long-term performances of the membranes were compared to examine the stability of membrane materials and fouling tendency using real seawater. Based on the lab-scale experiments, techniques to improve the performance of the membranes were examined by applying physical and chemical modification.

scholarly journals A contact angle study of different greywater sources with hydrophobic membranes

2020 ◽  
Vol 55 (3) ◽  
pp. 310-326
Author(s):  
Mohammad Ramezanianpour ◽  
Muttucumaru Sivakumar ◽  
Natalie Osborn ◽  
Ying Zhang ◽  
Hakim Kawa
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Pure Water ◽  
Membrane Distillation ◽  
Hydrophobic Membrane ◽  
Flat Sheet ◽  
Hydrophobic Membranes ◽  
Different Types ◽  
The Impact ◽  
Surface Tension Forces

Abstract The wetting phenomenon is a major problem in the membrane distillation (MD) process, and it is the main reason that limits MD being used in wastewater reclamation. Active surfactant in the detergents reduces the contact angle between the liquid and the hydrophobic membrane surface, which could result in wetting. Extensive laboratory research was conducted using commercial hydrophobic flat-sheet membranes to identify the impact of anionic surfactants and surface tension forces on these membranes. The aim of this paper is to find a suitable membrane for pure water production from greywater using MD, as well as to provide a relationship between surfactant concentration and the contact angle for different types of membrane. The absorbance of each sample was measured by a spectrophotometer prior to the contact angle test on four different types of hydrophobic membranes. It was concluded that the polypropylene membrane would be unsuitable for the treatment of greywater directly due to the loss of surface tension forces upon the addition of an anionic surfactant. However, the polytetrafluoroethylene membrane could be effective in this process while the concentration of surfactant in the feed source is kept constant. The results from the experimental tests proposed a relationship between the contact angle of a water droplet on the surface of a flat-sheet membrane and the concentration of surfactant in the solution.

Minerals control phosphorus solubility in long-term-cultivated calcareous soils

Soil Research ◽  
2017 ◽  
Vol 55 (2) ◽  
pp. 182 ◽  
Author(s):  
Mohsen Jalali ◽  
Mahdi Jalali
Keyword(s):  
Crop Production ◽  
Calcareous Soils ◽  
Chemical Properties ◽  
Dicalcium Phosphate ◽  
Equilibration Time ◽  
Soil P ◽  
Wide Range ◽  
The Stability ◽  
Physical And Chemical

Little information is available on phosphorus (P) solubility in long-term cultivated calcareous soils. Improved characterisation of P-containing minerals and soil P species in calcareous soils leads to better management of crop production, water quality and soil quality. In this study, we investigated the solubility relationships of P for 20 surface-soil samples from Hamedan, western Iran, with a wide range of physical and chemical properties. Two equilibration times (0.5 and 168h) were used to evaluate the effect of equilibration times on P activities. We observed up to 67% decrease in mean P concentration when equilibration time was increased from 0.5 to 168h. Solubility diagrams support the stability of hydroxyapatite with 0.5h equilibration and hydroxyapatite and β-tricalcium phosphate with 168h equilibration. Geochemical modelling predicted that dicalcium phosphate, dicalcium phosphate dihydrate and magnesium-P minerals would be unstable and thus would gradually dissolve and supply P in solution in these calcareous soils. The information obtained can be used to predict the behaviour of P and its availability for agricultural crops in calcareous soils.

scholarly journals SHELF LIFE PREDICTION OF DIAGNOSTIC FLUORESCENT TULAREMIA DRY IMMUNOGLOBULINS

2019 ◽  
pp. 56-60
Author(s):  
O.L. Startseva ◽  
S.A. Kurcheva
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Chemical Properties ◽  
Storage Conditions ◽  
Medical Product ◽  
Shelf Life Prediction ◽  
The Stability ◽  
Physical And Chemical

We described the results of studying the stability of the main indicators of medical product quality for in vitro diagnostics - diagnostic fluorescent tularemia dry immunoglobulins RIF-Tul-StavNIPCHI, developed on the basis of Stavropol Anti-Plague Institute of Rospotrebnadzor to justify the shelf life and recommended storage conditions when used on a real scale time and accelerated research methods. At the same time, one of the main criteria for the study of stability is its study during sample storage not only in the primary packaging of an industrial output, but also after the first opening of the package, during the use period of the reconstituted preparation. On the basis of data obtained in both long-term and accelerated trials, a shelf life of three years is recommended. It was experimentally proved that during this period of time, the quality indicators of the drug remain at a level one that complies with the requirements of technical and operational documentation. In the course of application the recovered product demonstrates stability of its biological and physical-and-chemical properties within 5 days at a storage temperature of 2 to 8°С.

Distillation of high concentrated salt solution by vacuum multi effect membrane distillation (VMEMD) of memsys

2015 ◽  
Vol 10 (3) ◽  
pp. 478-485 ◽  
Author(s):  
M. Wenzel ◽  
S. Büttner ◽  
W. Heinzl ◽  
S. Heinzl
Keyword(s):  
Salt Solution ◽  
Salt Water ◽  
Membrane Distillation ◽  
Separation Process ◽  
Recovery Ratio ◽  
Distillation Process ◽  
High Recovery ◽  
Distillate Output ◽  
Hydrophobic Membranes

Vacuum multi effect membrane distillation (VMEMD) is a thermal separation process with microporous hydrophobic membranes that is able to concentrate liquids with high salt concentrations close to saturation. This document describes the technology, test runs with high concentrated salt solution, observed phenomena and experiences gathered from the testing with VMEMD modules by memsys. Salt influences the distillation process in direction to lower distillate output due to boiling point elevation of the salt water. The process proofs reliability in a 365 days long-term testing with feed at conductivities between 130′000 μS/cm and 240′000 μS/cm (approximately 9.5–22wt% salt in solution) and distillate output with less than 10 μS/cm. The testing program delivers experience for the layout of modules with high recovery ratio.

scholarly journals The Influence of Talc Addition on the Performance of Polypropylene Membranes Formed by TIPS Method

Membranes ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 63 ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Linear Structure ◽  
Membrane Distillation ◽  
Polymer Chains ◽  
Thermally Induced Phase Separation ◽  
Linear Arrangement ◽  
Thermally Induced ◽  
Capillary Membranes ◽  
The Stability ◽  
Long Term Studies

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. The changes in morphology enhanced the mechanical properties of blended membranes, and their lower thermal degradation was observed during 350 h of membrane distillation studies. Long-term studies confirmed the stability of talc dispersion in the membrane matrix. A leaching of talc from polypropylene (PP) membranes was not found during the membrane distillation (MD) process.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

Influence of internal and external risks on sustainability of financial system of Аltai krai

2018 ◽  
Vol 35 (4) ◽  
pp. 133-136
Author(s):  
R. N. Ibragimov
Keyword(s):  
Sustainable Development ◽  
Financial Stability ◽  
Management Strategy ◽  
Financial System ◽  
Risk Management Strategy ◽  
The Sustainable Development ◽  
The Stability ◽  
The Impact

The article examines the impact of internal and external risks on the stability of the financial system of the Altai Territory. Classification of internal and external risks of decline, affecting the sustainable development of the financial system, is presented. A risk management strategy is proposed that will allow monitoring of risks, thereby these measures will help reduce the loss of financial stability and ensure the long-term development of the economy of the region.

scholarly journals Filter lifetimes of different hemodiafiltration membrane materials in dogs: reevaluation of the optimal anticoagulant dosage

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hiroko Yuzawa ◽  
Yousuke Hirose ◽  
Tomonori Kimura ◽  
Keisuke Shinozaki ◽  
Moe Oguchi ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Activated Partial Thromboplastin Time ◽  
Target Range ◽  
Membrane Material ◽  
Actual Clinical Practice ◽  
Membrane Materials ◽  
Filter Membrane ◽  
Hemorrhagic Complications ◽  
Materials Used ◽  
Nafamostat Mesylate

Abstract Background In continuous renal replacement therapy (CRRT), administration of anticoagulants is necessary for achieving a certain level of filter lifetime. Generally, anticoagulant doses are controlled to keep activated partial thromboplastin time and other indicators within a certain target range, regardless of the membrane materials used for the filter. However, in actual clinical practice, the filter lifetime varies significantly depending on the membrane material used. The objective of this study was to demonstrate that the minimum anticoagulant dose necessary for prolonging the filter lifetime while reducing the risk of hemorrhagic complications varies depending on the type of membrane. Methods In three beagles, hemodiafiltration was performed with hemofilters using polysulfone (PS), polymethylmethacrylate (PMMA), and AN69ST membranes separately. The minimum dose of nafamostat mesylate (NM) that would allow for 6 h of hemodiafiltration (required dose) was investigated for each membrane material. Results The NM doses required for 6 h of hemodiafiltration were 2 mg/kg/h for the PS membrane, 6 mg/kg/h for the PMMA membrane, and 6 mg/kg/h for the AN69ST membrane. Conclusion For hemodiafiltration performed in beagles, the required NM dose varied for each filter membrane material. Using the optimal anticoagulant dose for each membrane material would allow for safer CRRT performance.

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