scholarly journals Development of A Novel Corrugated Polyvinylidene difluoride Membrane via Improved Imprinting Technique for Membrane Distillation

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 865 ◽  
Author(s):  
Normi Izati Mat Nawi ◽  
Muhammad Roil Bilad ◽  
Nurazrina Zolkhiflee ◽  
Nik Abdul Hadi Nordin ◽  
Woei Jye Lau ◽  
...  
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Water Flux ◽  
Cross Flow ◽  
Membrane Distillation ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Widespread Application ◽  
Polyvinylidene Difluoride ◽  
Term Operation

Membrane distillation (MD) is an attractive technology for desalination, mainly because its performance that is almost independent of feed solute concentration as opposed to the reverse osmosis process. However, its widespread application is still limited by the low water flux, low wetting resistance and high scaling vulnerability. This study focuses on addressing those limitations by developing a novel corrugated polyvinylidene difluoride (PVDF) membrane via an improved imprinting technique for MD. Corrugations on the membrane surface are designed to offer an effective surface area and at the same time act as a turbulence promoter to induce hydrodynamic by reducing temperature polarization. Results show that imprinting of spacer could help to induce surface corrugation. Pore defect could be minimized by employing a dual layer membrane. In short term run experiment, the corrugated membrane shows a flux of 23.1 Lm−2h−1 and a salt rejection of >99%, higher than the referenced flat membrane (flux of 18.0 Lm−2h−1 and similar rejection). The flux advantage can be ascribed by the larger effective surface area of the membrane coupled with larger pore size. The flux advantage could be maintained in the long-term operation of 50 h at a value of 8.6 Lm−2h−1. However, the flux performance slightly deteriorates over time mainly due to wetting and scaling. An attempt to overcome this limitation should be a focus of the future study, especially by exploring the role of cross-flow velocity in combination with the corrugated surface in inducing local mixing and enhancing system performance.

scholarly journals Synthesis of a hierarchical nanoporous carbon material with controllable pore size and effective surface area for high-performance electrochemical capacitors

RSC Advances ◽  
2017 ◽  
Vol 7 (24) ◽  
pp. 14516-14527 ◽  
Author(s):  
Bing Hu ◽  
Ling-Bin Kong ◽  
Long Kang ◽  
Kun Yan ◽  
Tong Zhang ◽  
...  
Keyword(s):  
Pore Size ◽  
Linear Relationship ◽  
Specific Capacitance ◽  
Surface Area ◽  
Carbon Material ◽  
High Performance ◽  
Electrode Materials ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Nanoporous Carbon Material

There is an excellent linear relationship between E-SSA and specific capacitance of HNC-IPNs as electrode materials for EDLCs.

Microstructure and Gas Sensing Property of Porous SnO2 Sputtered Films

2007 ◽  
Vol 539-543 ◽  
pp. 3508-3513 ◽  
Author(s):  
Toshinari Yamazaki ◽  
Cheng Ji Jin ◽  
Yan Bai Shen ◽  
Toshio Kikuta ◽  
Noriyuki Nakatani
Keyword(s):  
Surface Area ◽  
Gas Sensing ◽  
Columnar Structure ◽  
Oxide Semiconductor ◽  
Bet Surface Area ◽  
Semiconductor Film ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Discharge Gas ◽  
Film Porosity

It is often said that the sensitivity of a gas sensor made of an oxide semiconductor film is enhanced by making the film porous. However, the porosity of sensor films has not been sufficiently examined. In this study, SnO2 films were deposited using DC magnetron sputtering under various substrate temperatures and discharge gas pressures. In addition to the structural analysis by means of X-ray diffraction and scanning electron microscopy, the density and the BET surface area were measured to clarify the film porosity. The sensitivity to H2 gas of undoped and Pd-doped SnO2 films upon exposure to 1000 ppm H2 was measured at 300 . SnO2 films generally showed a columnar structure. The film deposited at a low temperature and a high pressure showed a low density and a large effective surface area. The H2 sensitivity increased as the density decreased, that is, as the effective surface area increased.

Day-To-Day Variability of Protein Transport Used as a Method for Analyzing Peritoneal Permeability in CAPD

1991 ◽  
Vol 11 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Désirée Zemel ◽  
Raymond T. Krediet ◽  
Gerardus C.M. Koomen ◽  
Dirk G. Struijk ◽  
Lambertus Arisz
Keyword(s):  
Surface Area ◽  
Structural Changes ◽  
Protein Transport ◽  
Intrinsic Permeability ◽  
Effective Surface Area ◽  
Intraindividual Variation ◽  
Effective Surface ◽  
Peritoneal Surface ◽  
Beta 2 ◽  
Beta 2 Microglobulin

The transperitoneal transport of macromolecules is dependent on both effective peritoneal surface area and intrinsic permeability of the peritoneum. For passage of small solutes, the effective surface area is the main determinant. We hypothesized that day-to-day variations in peritoneal clearances are caused by changes in the effective surface area and not in the intrinsic permeability. Four CAPD {continuous ambulatory peritoneal dialysis) patients without peritonitis were investigated on 28 consecutive days. Concentrations of beta-2-microglobulin, albumin, IgG, and alpha-2-macroglobulin were determined daily in dialysate {night bags) and weekly in serum. Clearances and their coefficients of variation were calculated. Mean coefficients of the intraindividual variation of protein clearances increased, the higher the molecular weight: they ranged from 12% for beta-2microglobulin clearance to 22% for alpha-2-macroglobulin clearance. Correlations were present between the clearances of albumin, IgG, and alpha-2-macroglobulin, but not between any of these and beta-2-microglobulin clearance. In all patients, protein clearance {C) was a power function of the free diffusion coefficient in water {D) according to the equation: C=a. Db in which b represents the restriction coefficient of the peritoneum, and thus intrinsic permeability. The coefficient of variation of the restriction coefficient was low (range 4–6%). This supports our assumption that the intrinsic permeability is fairly constant on the short term. Day-to-day variations in protein clearances are thus mainly caused by alterations in the effective peritoneal surface area. Longterm follow-up of the restriction coefficient in individual patients might identify those at risk for the development of structural changes in the peritoneal membrane.

scholarly journals Interplay of the Factors Affecting Water Flux and Salt Rejection in Membrane Distillation: A State-of-the-Art Critical Review

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2841
Author(s):  
Lin Chen ◽  
Pei Xu ◽  
Huiyao Wang
Keyword(s):  
Water Flux ◽  
Feed Solution ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Membrane Properties ◽  
Membrane Thickness ◽  
Membrane Pore ◽  
Factors Affecting ◽  
Term Operation ◽  
Salt Rejection

High water flux and elevated rejection of salts and contaminants are two primary goals for membrane distillation (MD). It is imperative to study the factors affecting water flux and solute transport in MD, the fundamental mechanisms, and practical applications to improve system performance. In this review, we analyzed in-depth the effects of membrane characteristics (e.g., membrane pore size and distribution, porosity, tortuosity, membrane thickness, hydrophobicity, and liquid entry pressure), feed solution composition (e.g., salts, non-volatile and volatile organics, surfactants such as non-ionic and ionic types, trace organic compounds, natural organic matter, and viscosity), and operating conditions (e.g., temperature, flow velocity, and membrane degradation during long-term operation). Intrinsic interactions between the feed solution and the membrane due to hydrophobic interaction and/or electro-interaction (electro-repulsion and adsorption on membrane surface) were also discussed. The interplay among the factors was developed to qualitatively predict water flux and salt rejection considering feed solution, membrane properties, and operating conditions. This review provides a structured understanding of the intrinsic mechanisms of the factors affecting mass transport, heat transfer, and salt rejection in MD and the intra-relationship between these factors from a systematic perspective.

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