scholarly journals Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
T. Jiříček ◽  
M. Komárek ◽  
T. Lederer
Keyword(s):  
Complex Structure ◽  
Waste Water Treatment ◽  
Membrane Distillation ◽  
Heat Losses ◽  
Membrane Thickness ◽  
Waste Waters ◽  
New Materials ◽  
Membrane Performance ◽  
Direct Contact Membrane Distillation ◽  
Nanofiber Membranes

Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest flux was achieved with the thinnest membranes and the best energy efficiency was achieved with the thickest membranes. All membranes had salt retention above 99%. Nanotechnology offers the potential to find modern solutions for desalination of waste waters, by introducing new materials with revolutionary properties, but new membranes must be developed according to the target application.

scholarly journals Experimental Evaluation of the Thermal Polarization in Direct Contact Membrane Distillation Using Electrospun Nanofiber Membranes Doped With Molecular Probes

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 638 ◽  
Author(s):  
Sergio Santoro ◽  
Ivan Vidorreta ◽  
Isabel Coelhoso ◽  
Joao Lima ◽  
Giovanni Desiderio ◽  
...  
Keyword(s):  
Experimental Evaluation ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Low Grade ◽  
Electrospun Nanofiber ◽  
Direct Contact Membrane Distillation ◽  
Thermal Polarization ◽  
Nanofiber Membranes ◽  
The Impact

Membrane distillation (MD) has recently gained considerable attention as a valid process for the production of fresh-water due to its ability to exploit low grade waste heat for operation and to ensure a nearly feed concentration-independent production of high-purity distillate. Limitations have been related to polarization phenomena negatively affecting the thermal efficiency of the process and, as a consequence, its productivity. Several theoretical models have been developed to predict the impact of the operating conditions of the process on the thermal polarization, but there is a lack of experimental validation. In this study, electrospun nanofiber membranes (ENMs) made of Poly(vinylidene fluoride) (PVDF) and doped with (1, 10-phenanthroline) ruthenium (II) Ru(phen)3 were tested at different operating conditions (i.e., temperature and velocity of the feed) in direct contact membrane distillation (DCMD). The temperature sensitive luminophore, Ru(phen)3, allowed the on-line and non-invasive mapping of the temperature at the membrane surface during the process and the experimental evaluation of the effect of the temperature and velocity of the feed on the thermal polarization.

scholarly journals Mechanical Vibration for the Control of Membrane Fouling in Direct Contact Membrane Distillation

Symmetry ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 126 ◽  
Author(s):  
Frank Huang ◽  
Carolyn Medin ◽  
Allie Arning
Keyword(s):  
Packing Density ◽  
Membrane Fouling ◽  
Direct Contact ◽  
Mechanical Vibration ◽  
Water Flux ◽  
Similar Rate ◽  
Membrane Distillation ◽  
Membrane Performance ◽  
Direct Contact Membrane Distillation ◽  
Flux Decline

One of the biggest challenges for direct contact membrane distillation (DCMD) in treating wastewater from flue gas desulfurization (FGD) is the rapid deterioration of membrane performance resulting from precipitate fouling. Chemical pretreatment, such as lime-soda ash softening, has been used to mitigate the issue, however, with significant operating costs. In this study, mechanical vibration of 42.5 Hz was applied to lab-scale DCMD systems to determine its effectiveness of fouling control for simulated FGD water. Liquid entry pressure and mass transfer limit of the fabricated hollow fiber membranes were determined and used as the operational constraints in the fouling experiments so that the observed membrane performance was influenced solely by precipitate fouling. Minimal improvement of water flux was observed when applying vibration after significant (~16%) water-flux decline. Initiating vibration at the onset of the experiments prior to the exposure of foulants, however, was promising for the reduction of membrane fouling. The water-flux decline rate was reduced by about 50% when compared to the rate observed without vibration. Increasing the module packing density from 16% to 50% resulted in a similar rate of water-flux decline, indicating that the fouling propensity was not increased with packing density in the presence of vibration.

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