Minimize the trade-off between wetting resistance and water permeance in membrane distillation with ion-sieving coating layer

2021 ◽  
pp. 133165
Author(s):  
Longjie Jiang ◽  
Lin Chen ◽  
Liang Zhu
Keyword(s):  
Coating Layer ◽  
Membrane Distillation ◽  
Trade Off ◽  
Water Permeance

scholarly journals Trade-off in membrane distillation with monolithic omniphobic membranes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Wei Wang ◽  
Xuewei Du ◽  
Hamed Vahabi ◽  
Song Zhao ◽  
Yiming Yin ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Trade Off

Thermal-exergy efficiency trade-off optimization of pressure retarded membrane distillation based on TOPSIS model

Desalination ◽  
2022 ◽  
Vol 523 ◽  
pp. 115446
Author(s):  
Han Cao ◽  
Yanpeng Mao ◽  
Wenlong Wang ◽  
Yibo Gao ◽  
Miaomiao Zhang ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Exergy Efficiency ◽  
Trade Off ◽  
Topsis Model

scholarly journals Analysis of Polyvinylidene Fluoride Membranes Fabricated for Membrane Distillation

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 437
Author(s):  
Minchul Ahn ◽  
Hyeongrak Cho ◽  
Yongjun Choi ◽  
Seockheon Lee ◽  
Sangho Lee
Keyword(s):  
Water Vapor ◽  
Polyvinylidene Fluoride ◽  
Water Productivity ◽  
Water Vapor Permeability ◽  
Membrane Distillation ◽  
Inversion Method ◽  
Vapor Permeability ◽  
Trade Off ◽  
Depth Analysis ◽  
Phase Inversion Method

The optimization of the properties for MD membranes is challenging due to the trade-off between water productivity and wetting tendency. Herein, this study presents a novel methodology to examine the properties of MD membranes. Seven polyvinylidene fluoride (PVDF) membranes were synthesized under different conditions by the phase inversion method and characterized to measure flux, rejection, contact angle (CA), liquid entry pressure (LEP), and pore sizes. Then, water vapor permeability (Bw), salt leakage ratio (Lw), and fiber radius (Rf) were calculated for the in-depth analysis. Results showed that the water vapor permeability and salt leakage ratio of the prepared membranes ranged from 7.76 × 10−8 s/m to 20.19 × 10−8 s/m and from 0.0020 to 0.0151, respectively. The Rf calculated using the Purcell model was in the range from 0.598 μm to 1.690 μm. Since the Rf was relatively small, the prepared membranes can have high LEP (more than 1.13 bar) even at low CA (less than 90.8°). The trade-off relations between the water vapor permeability and the other properties could be confirmed from the results of the prepared membranes. Based on these results, the properties of an efficient MD membrane were suggested as a guideline for the membrane development.

Elucidating the Trade-off between Membrane Wetting Resistance and Water Vapor Flux in Membrane Distillation

2020 ◽  
Vol 54 (16) ◽  
pp. 10333-10341 ◽  
Author(s):  
Chenxi Li ◽  
Xuesong Li ◽  
Xuewei Du ◽  
Ying Zhang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Membrane Distillation ◽  
Water Vapor Flux ◽  
Trade Off ◽  
Vapor Flux ◽  
Membrane Wetting

scholarly journals Minimum Net Driving Temperature Concept for Membrane Distillation

Membranes ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 100
Author(s):  
Bastiaan Blankert ◽  
Johannes S. Vrouwenvelder ◽  
Geert-Jan Witkamp ◽  
Noreddine Ghaffour
Keyword(s):  
Temperature Difference ◽  
Driving Force ◽  
Membrane Distillation ◽  
Membrane Thickness ◽  
Similar Magnitude ◽  
Trade Off ◽  
Optimal Values ◽  
Single Effect ◽  
Heat Requirement ◽  
Temperature Concept

In this study, we analyzed the heat requirement of membrane distillation (MD) to investigate the trade-off between the evaporation efficiency and driving force efficiency in a single effect MD system. We found that there exists a non-zero net driving temperature difference that maximizes efficiency. This is the minimum net driving temperature difference necessary for a rational operational strategy because below the minimum net driving temperature, both the productivity and efficiency can be increased by increasing the temperature difference. The minimum net driving temperature has a similar magnitude to the boiling point elevation (~0.5 °C for seawater), and depends on the properties of the membrane and the heat exchanger. The minimum net driving temperature difference concept can be used to understand the occurrence of optimal values of other parameters, such as flux, membrane thickness, and membrane length, if these parameters are varied in a way that consequently varies the net driving temperature difference.

scholarly journals Impacts of Multilayer Hybrid Coating on PSF Hollow Fiber Membrane for Enhanced Gas Separation

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 335
Author(s):  
Rosyiela Azwa Roslan ◽  
Woei Jye Lau ◽  
Gwo Sung Lai ◽  
Abdul Karim Zulhairun ◽  
Yin Fong Yeong ◽  
...  
Keyword(s):  
Gas Separation ◽  
Hollow Fiber ◽  
Coating Layer ◽  
Gas Permeability ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Selective Layer ◽  
Trade Off ◽  
Selective Coating ◽  
Gas Molecules

One of the most critical issues encountered by polymeric membranes for the gas separation process is the trade-off effect between gas permeability and selectivity. The aim of this work is to develop a simple yet effective coating technique to modify the surface properties of commonly used polysulfone (PSF) hollow fiber membranes to address the trade-off effect for CO2/CH4 and O2/N2 separation. In this study, multilayer coated PSF hollow fibers were fabricated by incorporating a graphene oxide (GO) nanosheet into the selective coating layer made of polyether block amide (Pebax). In order to prevent the penetration of Pebax coating solution into the membrane substrate, a gutter layer of polydimethylsiloxane (PDMS) was formed between the substrate and Pebax layer. The impacts of GO loadings (0.0–1.0 wt%) on the Pebax layer properties and the membrane performances were then investigated. XPS data clearly showed the existence of GO in the membrane selective layer, and the higher the amount of GO incorporated the greater the sp2 hybridization state of carbon detected. In terms of coating layer morphology, increasing the GO amount only affected the membrane surface roughness without altering the entire coating layer thickness. Our findings indicated that the addition of 0.8 wt% GO into the Pebax coating layer could produce the best performing multilayer coated membrane, showing 56.1% and 20.9% enhancements in the CO2/CH4 and O2/N2 gas pair selectivities, respectively, in comparison to the membrane without GO incorporation. The improvement is due to the increased tortuous path in the selective layer, which created a higher resistance to the larger gas molecules (CH4 and N2) compared to the smaller gas molecules (CO2 and O2). The best performing membrane also demonstrated a lower degree of plasticization and a very stable performance over the entire 50-h operation, recording CO2/CH4 and O2/N2 gas pair selectivities of 52.57 (CO2 permeance: 28.08 GPU) and 8.05 (O2 permeance: 5.32 GPU), respectively.

A Flow-Preserving Algorithm for the Time-Cost Trade-Off Problem

1982 ◽  
Vol 14 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Suleyman Tufekci
Keyword(s):  
Time Cost ◽  
Trade Off

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

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