Janus Membrane with a Dense Hydrophilic Surface Layer for Robust Fouling and Wetting Resistance in Membrane Distillation: New Insights into Wetting Resistance

Author(s):  
Dejun Feng ◽  
Yuanmiaoliang Chen ◽  
Zhangxin Wang ◽  
Shihong Lin
2018 ◽  
Vol 450 ◽  
pp. 57-65 ◽  
Author(s):  
Kunpeng Wang ◽  
Deyin Hou ◽  
Jun Wang ◽  
Zhangxin Wang ◽  
Binghui Tian ◽  
...  

Author(s):  
Hideyuki YOSHIDA ◽  
Yusuke MORITA ◽  
Koji HATTORI ◽  
Makoto TAKENAKA ◽  
Ken IKEUCHI

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 924
Author(s):  
Mochammad Purwanto ◽  
Nindita Cahya Kusuma ◽  
Ma’rup Ali Sudrajat ◽  
Juhana Jaafar ◽  
Atikah Mohd Nasir ◽  
...  

Hollow fiber membranes of polyvinylidene fluoride (PVDF) were prepared by incorporating varying concentrations of hydrophilic surface-modifying macromolecules (LSMM) and a constant amount of polyethylene glycol (PEG) additives. The membranes were fabricated by the dry-wet spinning technique. The prepared hollow fiber membranes were dip-coated by hydrophobic surface-modifying macromolecules (BSMM) as the final step fabrication. The additives combination is aimed to produce hollow fiber membranes with high flux permeation and high salt rejection in the matter of seawater desalination application. This study prepares hollow fiber membranes from the formulation of 18 wt. % of PVDF mixed with 5 wt. % of PEG and 3, 4, and 5 wt. % of LSMM. The membranes are then dip-coated with 1 wt. % of BSMM. The effect of LSMM loading on hydrophobicity, morphology, average pore size, surface porosity, and membrane performance is investigated. Coating modification on LSMM membranes showed an increase in contact angle up to 57% of pure, unmodified PVDF/PEG membranes, which made the fabricated membranes at least passable when hydrophobicity was considered as one main characteristic. Furthermore, The PVDF/PEG/4LSMM-BSMM membrane exhibits 161 °C of melting point as characterized by the DSC. This value indicates an improvement of thermal behavior shows so as the fabricated membranes are desirable for membrane distillation operation conditions range. Based on the results, it can be concluded that PVDF/PEG membranes with the use of LSMM and BSMM combination could enhance the permeate flux up to 81.32 kg·m−2·h−1 at the maximum, with stable salt rejection around 99.9%, and these are found to be potential for seawater desalination application.


Author(s):  
D. N. Braski ◽  
P. D. Goodell ◽  
J. V. Cathcart ◽  
R. H. Kane

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.


Author(s):  
W. H. Wu ◽  
R. M. Glaeser

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.


Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).


Author(s):  
V. N. Filimonenko ◽  
M. H. Richman ◽  
J. Gurland

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.


Author(s):  
B. Van Meerbeek ◽  
L. J. Conn ◽  
E. S. Duke

Restoration of decayed teeth with tooth-colored materials that can be bonded to tooth tissue has been a highly desirable property in restorative dentistry for many years. Advantages of such an adhesive restorative technique over conventional techniques using non-adhesive metal-based restoratives include improved restoration retention with minimal sacrifice of sound tooth tissue for retention purposes, superior adaptation and sealing of the restoration margins in prevention of caries recurrence, improved stress distribution across the tooth-restoration interface throughout the whole tooth, and even reinforcement of weakened tooth structures. The dental adhesive technology is rapidly changing. An efficient resin bond to enamel has already long been achieved. Its bonding mechanism has been fully elucidated and has proven to be a durable and reliable clinical treatment. However, bonding to dentin represents a greater challenge. After the failures of a dentin acid-etch technique in imitation of the enamel phosphoric-acid-etch technique and a bonding procedure based on chemical adhesion, modern dentin adhesives are currently believed to bond to dentin by a micromechanical hybridization process. This process is developed by an initial demineralization of the dentin surface layer with acid etchants exposing a collagen fibril arrangement with interfibrillar microporosities that subsequently become impregnated by low-viscosity monomers. Although the development of such a hybridization process has well been documented in the literature, questions remain with respect to parameters of-primary importance to adhesive efficacy.


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