Dye removal using hydrophobic polyvinylidene fluoride hollow fibre composite membrane by vacuum membrane distillation

2019 ◽  
Vol 135 (6) ◽  
pp. 451-466 ◽  
Author(s):  
Hongbin Li ◽  
Xiangwei Feng ◽  
Wenying Shi ◽  
Haixia Zhang ◽  
Qiyun Du ◽  
...  
Keyword(s):  
Composite Membrane ◽  
Polyvinylidene Fluoride ◽  
Dye Removal ◽  
Fibre Composite ◽  
Membrane Distillation ◽  
Hollow Fibre ◽  
Vacuum Membrane Distillation

Vacuum membrane distillation for seawater desalination: could it compete with reverse osmosis?

2003 ◽  
Vol 3 (5-6) ◽  
pp. 57-66 ◽  
Author(s):  
D. Wirth ◽  
C. Cabassud
Keyword(s):  
Energy Consumption ◽  
Reverse Osmosis ◽  
Membrane Distillation ◽  
Hollow Fibre ◽  
Permeate Flux ◽  
Seawater Desalination ◽  
Industrial Plants ◽  
Low Energy Consumption ◽  
In Series ◽  
Vacuum Membrane Distillation

This work addresses the potentialities of vacuum membrane distillation (VMD) using hollow fibre membranes for seawater desalination. Experiments were carried out with a synthetic salty water containing a concentration of NaCl from 0 up to 300 g/L. A Microza (Pall) hollow fibre module was used. Experimental results show that, for this module, concentration polarisation and heat transfer limitations are not significant and do not modify the permeate flux. This is a great advantage over reverse osmosis (RO). Energy consumption was then studied using computations based on modelling. Two different industrial plants were considered: the first one consisted of hollow fibre modules arranged in series and operated in a single-pass. The second one was designed for a discontinuous operation using a circulation loop. Computations clearly show the interest (low energy consumption) of VMD for seawater desalination in comparison with RO.

Sintering process investigation during polytetrafluoroethylene hollow fibre membrane fabrication by extrusion method

2017 ◽  
Vol 29 (9) ◽  
pp. 1069-1082 ◽  
Author(s):  
Jingxuan Jia ◽  
Guodong Kang ◽  
Tong Zou ◽  
Meng Li ◽  
Meiqing Zhou ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Hollow Fibre ◽  
Test Results ◽  
Sintering Process ◽  
Permeate Flux ◽  
Hollow Fibre Membrane ◽  
Membrane Fabrication ◽  
Fibre Membrane ◽  
Vacuum Membrane Distillation ◽  
Extrusion Method

In this study, the effect of sintering conditions including manner, temperature and duration on properties of polytetrafluoroethylene (PTFE) hollow fibre membrane fabricated by extrusion method was intensively investigated. Different from un-sintered and relaxed sintered, the fixed sintered PTFE hollow fibre membrane was observed to generate a uniform ‘fibril–node’ porous structure and a main crystal transformation to folded chain crystal with smaller size. Consequently, it was found that for fixed setting sintering, both temperature increase from 340°C to 400°C and duration prolongation obviously improved pore size, ethanol permeation performance and mechanical strength. Additionally, the test results revealed that the membrane sintered below virgin melting point (350°C) had a noticeable higher porosity but poorer ethanol permeation performance that could be primarily attributed to increased ratio of closed pore. The sintering condition exhibited evident influence on PTFE hollow fibre membrane thermal stability, though it showed no alteration to the thermal decomposition of PTFE. The obtained PTFE hollow fibre membrane was tested to evaluate their vacuum membrane distillation (VMD) performances. It was found that PTFE membrane from lower sintering temperature delivered a better salt rejection; on the other hand, the permeate flux was improved by increased vacuum pressure during VMD operation.

Effect of non‐solvent on the synthesis of polyvinylidene fluoride membranes for vacuum membrane distillation desalination

2021 ◽  
Author(s):  
Felipe Henrique Sachett ◽  
Jocelei Duarte ◽  
Mara Zeni ◽  
Leonardo Costamilan ◽  
Matheus Poletto ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Vacuum Membrane Distillation

scholarly journals A Single Step Preparation of Photothermally Active Polyvinylidene Fluoride Membranes Using Triethyl Phosphate as a Green Solvent for Distillation Applications

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 896
Author(s):  
Marcello Pagliero ◽  
Antonio Comite ◽  
Camilla Costa ◽  
Ilaria Rizzardi ◽  
Omar Soda
Keyword(s):  
Phase Separation ◽  
Polyvinylidene Fluoride ◽  
Water Shortage ◽  
Membrane Distillation ◽  
Single Step ◽  
Green Solvent ◽  
Triethyl Phosphate ◽  
Nacl Solution ◽  
Preparation Conditions ◽  
Vacuum Membrane Distillation

Membrane distillation is a growing technology that can address the growing problem of water shortage. The implementation of renewable energy and a reduction in the environmental impact of membrane production could improve the sustainability of this process. With this perspective, porous hydrophobic polyvinylidene fluoride (PVDF) membranes were prepared using triethyl phosphate (TEP) as a green solvent, using the non-solvent induced phase separation technique. Different amounts of carbon black were added to dope solutions to improve the photothermal properties of the membranes and to enable direct heating by solar energy. By optimizing the preparation conditions, membranes with porosity values as high as 87% were manufactured. Vacuum membrane distillation tests carried out using a concentrated NaCl solution at 50 °C showed distillate fluxes of up to 36 L/m2 h and a complete salt rejection. Some preliminary studies on the photothermal performance were also conducted and highlighted the possibility of using such membranes in a direct solar membrane distillation configuration.

scholarly journals Electrospun Nanostructured Membrane Engineering Using Reverse Osmosis Recycled Modules: Membrane Distillation Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1601
Author(s):  
Jorge Contreras-Martínez ◽  
Carmen García-Payo ◽  
Mohamed Khayet
Keyword(s):  
Reverse Osmosis ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Electrospinning Technique ◽  
Salt Rejection ◽  
Rejection Factor ◽  
Nanofibrous Membranes ◽  
Membrane Engineering ◽  
Desalination Plants

As a consequence of the increase in reverse osmosis (RO) desalination plants, the number of discarded RO modules for 2020 was estimated to be 14.8 million annually. Currently, these discarded modules are disposed of in nearby landfills generating high volumes of waste. In order to extend their useful life, in this research study, we propose recycling and reusing the internal components of the discarded RO modules, membranes and spacers, in membrane engineering for membrane distillation (MD) technology. After passive cleaning with a sodium hypochlorite aqueous solution, these recycled components were reused as support for polyvinylidene fluoride nanofibrous membranes prepared by electrospinning technique. The prepared membranes were characterized by different techniques and, finally, tested in desalination of high saline solutions (brines) by direct contact membrane distillation (DCMD). The effect of the electrospinning time, which is the same as the thickness of the nanofibrous layer, was studied in order to optimize the permeate flux together with the salt rejection factor and to obtain robust membranes with stable DCMD desalination performance. When the recycled RO membrane or the permeate spacer were used as supports with 60 min electrospinning time, good permeate fluxes were achieved, 43.2 and 18.1 kg m−2 h−1, respectively; with very high salt rejection factors, greater than 99.99%. These results are reasonably competitive compared to other supported and unsupported MD nanofibrous membranes. In contrast, when using the feed spacer as support, inhomogeneous structures were observed on the electrospun nanofibrous layer due to the special characteristics of this spacer resulting in low salt rejection factors and mechanical properties of the electrospun nanofibrous membrane.

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