Theoretical and experimental approaches of liquid entry pressure determination in membrane distillation processes

2017 ◽  
Vol 99 ◽  
pp. 172-176 ◽  
Author(s):  
Chansoo Park ◽  
Dongsoo Shin ◽  
Chang-Kyu Lee ◽  
Yong-Soo Lee ◽  
Jong-Oh Kim
Keyword(s):  
Membrane Distillation ◽  
Entry Pressure ◽  
Experimental Approaches

scholarly journals Theoretical and Experimental Approaches of Liquid Entry Pressure Determination in Membrane Distillation Processes

2014 ◽  
Vol 58 (2) ◽  
pp. 81-91 ◽  
Author(s):  
Gábor Rácz ◽  
Steffen Kerker ◽  
Zoltán Kovács ◽  
Gyula Vatai ◽  
Mehrdad Ebrahimi ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Entry Pressure ◽  
Experimental Approaches

Experimental determination of liquid entry pressure (LEP) in vacuum membrane distillation for oily wastewaters

2015 ◽  
Vol 6 (3) ◽  
pp. 237-249 ◽  
Author(s):  
Gabor Racz ◽  
Steffen Kerker ◽  
Oliver Schmitz ◽  
Benjamin Schnabel ◽  
Zoltan Kovacs ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Membrane Distillation ◽  
Entry Pressure ◽  
Vacuum Membrane Distillation

scholarly journals HYDROPHOBIZATION OF PET TRACK-ETCHED MEMBRANES FOR DIRECT CONTACT MEMBRANE DISTILLATION OF LIQUID RADIOACTIVE WASTES

2020 ◽  
Vol 17 (2) ◽  
pp. 45-54
Author(s):  
A.B. Yeszhanov ◽  
Keyword(s):  
Direct Contact ◽  
Gamma Ray ◽  
Water Flux ◽  
Atomic Emission ◽  
Membrane Distillation ◽  
Radioactive Wastes ◽  
Low Level ◽  
Direct Contact Membrane Distillation ◽  
Hydrophobic Membranes ◽  
Entry Pressure

This article provides the results of liquid low-level radioactive wastes treatment by direct contact membrane distillation using polyethylene terephthalate hydrophobic track-etched membranes. The hydrophobization of track-etched membranes was carried out by UV-induced graft polymerization of triethoxyvinylsilane with styrene and coating with fluorine-containing silanes. Hydrophobic membranes were investigated by scanning electron microscope, Fourier-transform infrared spectroscopy, contact anglemeasurements, and liquid entry pressure analysis. Prepared membranes were tested in treatment of liquid low-level radioactive wastes by membrane distillation. The influence of pore sizes on water flux and rejection degree was studied. Rejection degree was evaluated by conductometry and atomic emission method. Decontamination factors evaluated by gamma-ray spectroscopy for 60Co, 137Cs, and 241Am are 85.4, 1900 and 5.4 for membranes modified with polystyrene and triethoxyvinylsilanewith pore diameters of 142 nm; 85.0, 1462 and 4 for membranes modified with perfluorododecyltrichlorosilanewith pore diameters of 150 nm respectively.

scholarly journals Factors Affecting Membrane Distillation Process for Seawater Desalination

2018 ◽  
Vol 22 (1) ◽  
Author(s):  
Ngo Thi Tra My ◽  
Vo Thi Yen Nhi ◽  
Bui Xuan Thanh
Keyword(s):  
Contact Angle ◽  
Membrane Separation ◽  
Membrane Distillation ◽  
Process Efficiency ◽  
Membrane Properties ◽  
Permeate Flux ◽  
Factors Affecting ◽  
Entry Pressure ◽  
Membrane Lifetime ◽  
Membrane Wetting

Membrane distillation (MD), a process based on the thermal principle, is a combination of distillation and membrane separation in the same unit. There are many factors that can affect the MD performance, but the membrane characteristics are the most important in this process. The changes in the membrane properties affect the process efficiency, the permeate flux as well as the membrane lifetime. Some of the membrane properties mentioned in this paper include liquid entry pressure (LEP), contact angle, pore size, porosity, thickness, thermal conductivity, support layer, tortuosity, etc. This review paper aims to evaluate the membrane properties in order to reduce membrane wetting and to improve desalination efficiency. From this review, it can be seen that the LEP and contact angle are the important factors which directly affect the hydrophobicity of the membrane. When LEP and the contact angle increase, the hydrophobicity of the membrane increases. Thus, the membrane is durable and the MD system works efficiently. The remaining factors indirectly affect the operation of the MD system through LEP and contact angle (hydrophobicity).

scholarly journals Phenol solutions treatment by using hydrophobized track-etched membranes

2020 ◽  
Vol 99 (3) ◽  
pp. 99-109
Author(s):  
A.B. Yeszhanov ◽  
◽  
S.S. Dosmagambetova ◽  
Keyword(s):  
Water Treatment ◽  
Water Flux ◽  
Membrane Distillation ◽  
Water Bodies ◽  
Permeate Flux ◽  
Sanitary Condition ◽  
Direct Contact Membrane Distillation ◽  
Membrane Characterization ◽  
Entry Pressure ◽  
Flux Measurements

Phenols are one of the most common surface water pollution. The discharge of phenolic waters into water bodies and streams sharply degrade their general sanitary condition, since these compounds have a toxic effect, and phenols can intensively absorb oxygen dissolved in water, which negatively affects the life of organisms in water bodies. Therefore, water treatment of phenols is an important environmental problem. In this study, the hydrophobic polyethylene terephthalate track-etched membranes (PET TeMs) were tested in water treatment from phenol by direct contact membrane distillation (DCMD). Hydrophobic PET TeMs were obtained by UV-graft polymerization of styrene, triethoxyvinylsilane with the addition of vinylimidazole (VIM), as well as by coating with fluorine-containing silanes. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and liquid entry pressure (LEP) analysis were used for membrane characterization. The contact angle after modification of PET TeMs was reached more than 130°. The efficiency of water purification from phenol was evaluated by water-flux measurements and fluorimetric method. The phenols solution was used at a concentration of 0.5, 1 and 2 g/l. The largest permeate flux of hydrophobized membranes was 1.1 kg/ m2•h.

scholarly journals Water as the Pore Former in the Synthesis of Hydrophobic PVDF Flat Sheet Membranes for Use in Membrane Distillation

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Lebea Nathnael Nthunya ◽  
Leonardo Gutierrez ◽  
Edward N. Nxumalo ◽  
Sabelo D. Mhlanga
Keyword(s):  
Phase Inversion ◽  
Water Flux ◽  
Membrane Distillation ◽  
Contact Angles ◽  
Pore Former ◽  
Membrane Pore ◽  
Flat Sheet ◽  
Entry Pressure ◽  
Membrane Contact ◽  
Maximum Pore Size

Although PVDF flat sheet membranes have been widely tested in MD, their synthesis and modifications currently require increased use of green and inexpensive materials. In this study, flat sheet PVDF membranes were synthesized using phase inversion and water as the pore former. Remarkably, the water added in the casting solution improved the membrane pore sizes; where the maximum pore size was 0.58 µm. Also, the incorporation of f-SiO2NPs in the membrane matrix considerably enhanced the membrane hydrophobicity. Specifically, the membrane contact angles increased from 96° to 153°. Additionally, other parameters investigated were mechanical strength and liquid entry pressure (LEP). The maximum recorded values were 2.26 MPa and 239 kPa, respectively. The modified membranes (i.e., using water as the pore former and f-SiO2NPs) were the most efficient, showing maximum salt rejection of 99.9% and water flux of 11.6 LMH; thus, indicating their capability to be used as efficient materials for the recovery of high purity water in MD.

Membrane Distillation: Experimental evaluation of Liquid Entry Pressure in commercial membranes with textile dye solutions

2021 ◽  
Vol 44 ◽  
pp. 102339
Author(s):  
Regilene de Sousa Silva ◽  
Heloisa Ramlow ◽  
Bianca de Castro Santos ◽  
Heloísa Bremm Madalosso ◽  
Ricardo Antonio Francisco Machado ◽  
...  
Keyword(s):  
Experimental Evaluation ◽  
Membrane Distillation ◽  
Textile Dye ◽  
Entry Pressure ◽  
Dye Solutions

Learned Placebo Effects in the Immune System

2014 ◽  
Vol 222 (3) ◽  
pp. 148-153 ◽  
Author(s):  
Sabine Vits ◽  
Manfred Schedlowski
Keyword(s):  
Nervous System ◽  
Immune System ◽  
Associative Learning ◽  
Placebo Response ◽  
Immunosuppressive Drug ◽  
Immune Functions ◽  
Placebo Effects ◽  
New Therapeutic Approaches ◽  
Biological Variables ◽  
Experimental Approaches

Associative learning processes are one of the major neuropsychological mechanisms steering the placebo response in different physiological systems and end organ functions. Learned placebo effects on immune functions are based on the bidirectional communication between the central nervous system (CNS) and the peripheral immune system. Based on this “hardware,” experimental evidence in animals and humans showed that humoral and cellular immune functions can be affected by behavioral conditioning processes. We will first highlight and summarize data documenting the variety of experimental approaches conditioning protocols employed, affecting different immunological functions by associative learning. Taking a well-established paradigm employing a conditioned taste aversion model in rats with the immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus (US) as an example, we will then summarize the efferent and afferent communication pathways as well as central processes activated during a learned immunosuppression. In addition, the potential clinical relevance of learned placebo effects on the outcome of immune-related diseases has been demonstrated in a number of different clinical conditions in rodents. More importantly, the learned immunosuppression is not restricted to experimental animals but can be also induced in humans. These data so far show that (i) behavioral conditioned immunosuppression is not limited to a single event but can be reproduced over time, (ii) immunosuppression cannot be induced by mere expectation, (iii) psychological and biological variables can be identified as predictors for this learned immunosuppression. Together with experimental approaches employing a placebo-controlled dose reduction these data provide a basis for new therapeutic approaches to the treatment of diseases where a suppression of immune functions is required via modulation of nervous system-immune system communication by learned placebo effects.

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