scholarly journals Molecular Imaging in Therapeutic Efficacy Assessment of Targeted Therapy for Nonsmall Cell Lung Cancer

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yanni Hu ◽  
Mei Tian ◽  
Hong Zhang
Keyword(s):  
Water Vapor ◽  
Cold Water ◽  
Nonsmall Cell Lung Cancer ◽  
Porous Membrane ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Heat Transfer Analysis ◽  
Operating Parameters ◽  
Permeate Flux ◽  
Pass Through

Membrane distillation is a thermally driven membrane process for seawater desalination and purification at moderate temperatures and pressures. A hydrophobic micro-porous membrane is used in this process, which separates hot and cold water, allowing water vapor to pass through; while restricting the movement of liquid water, due to its hydrophobic nature. This paper provides an experimental investigation of heat and mass transfer in tubular membrane module for water desalination. Different operating parameters have been examined to determine the mass transport mechanism of water vapor. Based on the experimental results, the effects of operating parameters on permeate flux and the heat transfer analysis have been presented and discussed in details.

scholarly journals Experimental Investigation of Heat and Mass Transfer in Tubular Membrane Distillation Module for Desalination

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Adnan Al-Hathal Al-Anezi ◽  
Adel O. Sharif ◽  
M. I. Sanduk ◽  
A. R. Khan
Keyword(s):  
Mass Transfer ◽  
Experimental Investigation ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Heat Transfer Analysis ◽  
Operating Parameters ◽  
Permeate Flux ◽  
Tubular Membrane

Membrane distillation is a thermally driven membrane process for seawater desalination and purification at moderate temperatures and pressures. A hydrophobic micro-porous membrane is used in this process, which separates hot and cold water, allowing water vapor to pass through; while restricting the movement of liquid water, due to its hydrophobic nature. This paper provides an experimental investigation of heat and mass transfer in tubular membrane module for water desalination. Different operating parameters have been examined to determine the mass transport mechanism of water vapor. Based on the experimental results, the effects of operating parameters on permeate flux and the heat transfer analysis have been presented and discussed in details.

scholarly journals Capillary Polypropylene Membranes for Membrane Distillation

Fibers ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Continuous Process ◽  
Negative Influence ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Porous Membranes ◽  
Surface Porosity ◽  
Permeate Flux ◽  
Thermally Induced

Only nonwetted porous membranes can be used in membrane distillation. The possibility of application in this process the capillary polypropylene membranes manufactured by thermally-induced phase separation was studied. The performance of a few types of membranes available commercially was presented. The resistance of the membranes to wetting was tested in the continuous process of water desalination. These studies were carried out for 1000 h without module cleaning. The presence of scaling layer on the membranes surface was confirmed by Scanning Electron Microscope observations. Both the permeate flux and distillate conductivity were almost not varied after the studied period of time, what indicates that the used membranes maintained their nonwettability, and the negative influence of scaling was limited. The role of surface porosity on the pore wetting and influence of membrane wettability on the quality of the distillate obtained were discussed.

scholarly journals Performance Investigation of O-Ring Vacuum Membrane Distillation Module for Water Desalination

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Adnan Alhathal Alanezi ◽  
H. Abdallah ◽  
E. El-Zanati ◽  
Adnan Ahmad ◽  
Adel O. Sharif
Keyword(s):  
Flow Rate ◽  
Membrane Distillation ◽  
Membrane Module ◽  
Water Desalination ◽  
Feed Flow Rate ◽  
Permeate Flux ◽  
Vacuum Degree ◽  
Flat Sheet ◽  
Vacuum Membrane Distillation ◽  
Feed Temperature

A new O-ring flat sheet membrane module design was used to investigate the performance of Vacuum Membrane Distillation (VMD) for water desalination using two commercial polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes. The design of the membrane module proved its applicability for achieving a high heat transfer coefficient of the order of 103 (W/m2 K) and a high Reynolds number (Re). VMD experiments were conducted to measure the heat and mass transfer coefficients within the membrane module. The effects of the process parameters, such as the feed temperature, feed flow rate, vacuum degree, and feed concentration, on the permeate flux have been investigated. The feed temperature, feed flow rate, and vacuum degree play an important role in enhancing the performance of the VMD process; therefore, optimizing all of these parameters is the best way to achieve a high permeate flux. The PTFE membrane showed better performance than the PVDF membrane in VMD desalination. The obtained water flux is relatively high compared to that reported in the literature, reaching 43.8 and 52.6 (kg/m2 h) for PVDF and PTFE, respectively. The salt rejection of NaCl was higher than 99% for both membranes.

scholarly journals Resistance of Polypropylene Membrane to Oil Fouling during Membrane Distillation

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 552
Author(s):  
Marek Gryta
Keyword(s):  
Membrane Distillation ◽  
Water Desalination ◽  
Feed Water ◽  
Permeate Flux ◽  
Feed Composition ◽  
Oil Emulsion ◽  
Thermally Induced ◽  
Polypropylene Membrane ◽  
Capillary Membranes ◽  
The Impact

The influence of oil emulsion presence in the water on the course of water desalination by membrane distillation was studied. The feed water was contaminated by oil collected from the bilge water. The impact of feed composition on the wetting resistance of hydrophobic polypropylene membranes was evaluated during long-term studies. Two types of the capillary membranes fabricated by thermally induced phase separation method were tested. It has been found that these membranes were non-wetted during the separation of NaCl solutions over a period of 500 h of modules exploitation. The addition of oil (5–100 mg/L) to the feed caused a progressive decline of the permeate flux up to 30%; however, the applied hydrophobic membranes retained their non-wettability for the consecutive 2400 h of the process operation. It was indicated that several compounds containing the carbonyl group were formed on the membranes surface during the process. These hydrophilic compounds facilitated the water adsorption on the surface of polypropylene which restricted the oil deposition on the membranes used.

scholarly journals Produced Water Desalination via Pervaporative Distillation

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3560
Author(s):  
Jingbo Wang ◽  
Dian Tanuwidjaja ◽  
Subir Bhattacharjee ◽  
Arian Edalat ◽  
David Jassby ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Produced Water ◽  
Operating Mode ◽  
Porous Membrane ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Water Desalination ◽  
Feed Water ◽  
Water Composition ◽  
Salt Passage

Herein, we report on the performance of a hybrid organic-ceramic hydrophilic pervaporation membrane applied in a vacuum membrane distillation operating mode to desalinate laboratory prepared saline waters and a hypersaline water modeled after a real oil and gas produced water. The rational for performing “pervaporative distillation” is that highly contaminated waters like produced water, reverse osmosis concentrates and industrial have high potential to foul and scale membranes, and for traditional porous membrane distillation membranes they can suffer pore-wetting and complete salt passage. In most of these processes, the hard to treat feed water is commonly softened and filtered prior to a desalination process. This study evaluates pervaporative distillation performance treating: (1) NaCl solutions from 10 to 240 g/L at crossflow Reynolds numbers from 300 to 4800 and feed-temperatures from 60 to 85 °C and (2) a real produced water composition chemically softened to reduce its high-scale forming mineral content. The pervaporative distillation process proved highly-effective at desalting all feed streams, consistently delivering <10 mg/L of dissolved solids in product water under all operating condition tested with reasonably high permeate fluxes (up to 23 LMH) at optimized operating conditions.

scholarly journals Evaluating Critical Influencing Factors of Desalination by Membrane Distillation Process—Using Multi-Criteria Decision-Making

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 164
Author(s):  
Ali E. Anqi ◽  
Azam A. Mohammed
Keyword(s):  
Influencing Factors ◽  
Fuzzy Ahp ◽  
Thermal Power ◽  
Feed Solution ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Membrane Thickness ◽  
Permeate Flux ◽  
Wide Range ◽  
Feed Channel

Water desalination by membrane distillation (MD) can be affected by a wide range of operating parameters. The present work uses combinational approach of Analytical Hierarch process (AHP) and Fuzzy Analytical Hierarchy process (Fuzzy-AHP) to identify the most important parameters in the MD desalination. Five process parameters and key-performance indicators, named derivable outputs (DOs), are considered, along with the critical factors affecting these DOs in the current study. The DOs and the critical influencing factors (CIFs) are selected based on their experimental feasibility. The investigation involves five DOs, which are liquid entry pressure, thermal power consumption, permeate quality, permeate flux, and pumping (feed circulation) power. A total of twenty-five critical influencing factor were associated with the DOs. The identification of the DOs and CIFs was based on the literature review, and further analyses were performed. Both methods, AHP and Fuzzy-AHP, determined six extremely important CIFs in the desalination MD, which are feed temperature, feed concentration, or feed salinity; feed flow rate; membrane hydrophobicity; pore size; and membrane material. Moderately important CIFs are found to be four by both methods. These common CIFs are feed solution properties, membrane thickness, feed channel geometry, and pressure difference along the feed channel. Finally, the least preferred CIFs are four common in both methods that are MD configuration, duration of test, specific heat of feed solution, and viscosity.

Development and Testing of a Lab-Scale Air-Gap Membrane Distillation Unit for Water Desalination

2018 ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
Keaton Cornell ◽  
Benny Ly ◽  
Aaron Chan ◽  
Sepideh Jankhah
Keyword(s):  
Elevated Temperatures ◽  
Membrane Distillation ◽  
Air Gap ◽  
Water Desalination ◽  
Coolant Temperature ◽  
Feed Water ◽  
Permeate Flux ◽  
Flow Rates ◽  
Air Gap Membrane Distillation ◽  
Membrane Porosity

As the population grows, one issue that is continually being addressed is the lack of clean water resources. In order to explore viable solutions, rapid experimentation and research has been underway to alleviate the water crisis. With the addition of new emerging technology, the development, improvement, and understanding of various techniques used to treat non-potable water has expanded. One subcategory of water filtration in particular that has seen rapid growth is Membrane Distillation (MD). MD is a filtration process that utilizes thermal energy to desalinate and decontaminate water. Compared to current industry leading techniques such as reverse osmosis, MD does not require such large operating pressures, leading to less power consumption. MD is accomplished primarily by flowing contaminated feed water at elevated temperatures across semi-permeable membranes. The membranes used are made to allow water vapors to penetrate through and separate from the contaminated liquid portion. By maintaining a temperature difference across the membrane, a pressure gradient is created, which drives the vapor of feed water through the pores in the membrane. Once the vapor passes through the membrane, it condenses through various methods and is collected. Air Gap Membrane Distillation (AGMD) has shown significant ability to desalinate water effectively in small scales. The air gap between the membrane and condensation plate minimizes heat loss through conduction, making AGMD a more attractive option for upscaling. In this project a laboratory-scale test cell was developed to test AGMD using different membranes, and operational parameters. In order to test such parameters, a unique design with baffled channels to induce turbulence was designed and manufactured. Feed water and coolant temperature differences, flow rates, membrane porosity, and air gap thickness are among the parameters that has been studied in this research. Temperatures of the hot feed were varied from 40°C to 80°C while the cold feed temperature was kept at a near constant temperature of 0°C. Flow rates of feed water and coolant water range from 1 to 3 L/Min. It was observed that the permeate flux is an increasing function of feed water temperature and membrane porosity. The air gap thickness plays a major role in permeate flux and energy consumption of the system.

scholarly journals Energy evaluation and treatment efficiency of vacuum membrane distillation for brackish water desalination

2014 ◽  
Vol 5 (2) ◽  
pp. 119-131
Author(s):  
Mohammad Ramezanianpour ◽  
Muttucumaru Sivakumar
Keyword(s):  
Brackish Water ◽  
Potable Water ◽  
Membrane Separation ◽  
Rapid Development ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Treated Wastewater ◽  
Permeate Flux ◽  
Effective Parameters ◽  
Vacuum Membrane Distillation

Strict environmental regulations have led to the rapid development of membrane separation technologies for the production of potable water, for industrial water supply, and for the reuse and discharge of treated wastewater. Promotion of water recycling and the provision of potable water from brackish water prevent significant negative effects on the environment and drinking water supplies. This study is intended to describe and compare a sustainable technology for brackish water treatment. Among the four configurations of the membrane distillation process, vacuum membrane distillation (VMD) produces higher flux and results in a low fouling rate. It comprises evaporation and condensation that mimics what occurs in nature. Mathematical models proposed for the VMD transport mechanisms are incorporated to predict the actual experimental flux. The response of the flux rate to various process operating parameters is demonstrated. Variation of effective parameters is investigated in terms of energy consumption. The data indicate that the permeate flux is highly responsive to the variation of pressure and temperature. VMD enables the removal of 99.9% of total dissolved solids from natural and contaminated water sources. The findings are that the quality of the permeate water from all sources was at acceptable standards for potable use.

scholarly journals Direct contact membrane distillation applied to saline wastewater: parameter optimization

2018 ◽  
Vol 77 (12) ◽  
pp. 2823-2833 ◽  
Author(s):  
Sana Abdelkader ◽  
Ali Boubakri ◽  
Sven Uwe Geissen ◽  
Latifa Bousselmi
Keyword(s):  
Direct Contact ◽  
Removal Rate ◽  
Statistical Significance ◽  
Oxygen Demand ◽  
Resource Depletion ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Permeate Flux ◽  
Saline Wastewater ◽  
Direct Contact Membrane Distillation

Abstract Freshwater availability is increasingly under pressure from growing demand, resource depletion and environmental pollution. Desalination of saline wastewater is an option for supplying households, industry and agriculture with water, but technologies such as reverse osmosis, evaporation or electrodialysis are energy intensive. By contrast, membrane distillation (MD) is a competitive technology for water desalination. In our study, response surface methodology was applied to optimize the direct contact membrane distillation (DCMD) treatment of synthetic saline wastewater. The aim was to enhance the process performance and the permeate flux Jp (L/m2·h) by optimizing the operating parameters: temperature difference ΔT, feed velocity Vf, salt concentration [NaCl], and glucose concentration [Gluc]. The results are a high permeate quality, with 99.9% electrical conductivity reduction and more than 99.9% chemical oxygen demand (COD) removal rate. The predicted optimum permeate flux Jp was 34.1 L/m2·h at ΔT = 55.2 °C and Vf = 0.086 m/s, the two most significant parameters. The model created showed a high degree of correlation between the experimental and the predicted responses, with high statistical significance.

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