Distillation of high concentrated salt solution by vacuum multi effect membrane distillation (VMEMD) of memsys

2015 ◽  
Vol 10 (3) ◽  
pp. 478-485 ◽  
Author(s):  
M. Wenzel ◽  
S. Büttner ◽  
W. Heinzl ◽  
S. Heinzl
Keyword(s):  
Salt Solution ◽  
Salt Water ◽  
Membrane Distillation ◽  
Separation Process ◽  
Recovery Ratio ◽  
Distillation Process ◽  
High Recovery ◽  
Distillate Output ◽  
Hydrophobic Membranes

Vacuum multi effect membrane distillation (VMEMD) is a thermal separation process with microporous hydrophobic membranes that is able to concentrate liquids with high salt concentrations close to saturation. This document describes the technology, test runs with high concentrated salt solution, observed phenomena and experiences gathered from the testing with VMEMD modules by memsys. Salt influences the distillation process in direction to lower distillate output due to boiling point elevation of the salt water. The process proofs reliability in a 365 days long-term testing with feed at conductivities between 130′000 μS/cm and 240′000 μS/cm (approximately 9.5–22wt% salt in solution) and distillate output with less than 10 μS/cm. The testing program delivers experience for the layout of modules with high recovery ratio.

Effect of Membrane Material Properties on Efficiency of Membrane Distillation

2011 ◽  
Vol 695 ◽  
pp. 85-88 ◽  
Author(s):  
Hwan Kim ◽  
June Seok Choi ◽  
Sang Ho Lee
Keyword(s):  
Membrane Distillation ◽  
Contaminated Water ◽  
Initial Screening ◽  
Membrane Material ◽  
Membrane Materials ◽  
Flat Sheet ◽  
Hydrophobic Membranes ◽  
The Stability ◽  
Physical And Chemical

Membrane distillation (MD) integrates membrane technology with evaporation process to produce fresh water from seawater or contaminated water. In this study, we investigated the effect of membrane materials on the efficiency of membrane distillation process. Flat sheet hydrophobic membranes (PVDF, PTFE) with different characterizes were chosen as well as hollow fiber membranes (PE). Laboratory-scale systems were developed for initial screening of various membranes. The performance of the membrane was analyzed in terms of water permeability and salt rejection. Synthetic seawater (TDS = 35,000 mg/L) was used for the lab-scale tests. A simple model to analyze the transport of water through MD membranes was developed to interpret experimental results. In addition, long-term performances of the membranes were compared to examine the stability of membrane materials and fouling tendency using real seawater. Based on the lab-scale experiments, techniques to improve the performance of the membranes were examined by applying physical and chemical modification.

Comparing Tests on the Durability of Concrete after Long-Term Immersion in Different Salt Solution

2014 ◽  
Vol 501-504 ◽  
pp. 1087-1091 ◽  
Author(s):  
Xiao Ping Su ◽  
Li Zhang
Keyword(s):  
Elastic Modulus ◽  
Salt Solution ◽  
Saline Soil ◽  
Salt Water ◽  
Dynamic Elastic Modulus ◽  
Salt Crystallization ◽  
Soluble Salts ◽  
Concrete Damage ◽  
Damage Law

The western region of Jilin province is one of the areas with the most serious saline soil, which is the type of inland soda salt. In order to study the damage law of concrete under the condition of long-term erosion by the soluble salts in saline soil or groundwater or saturated salt water, three groups of salt solution, Na2SO4, NaCl, NaHCO3 solution, were made according to the content of soluble salts in saline soil of Daan city in spring, and water was as a comparison. The comparing tests of long-term immersion were conducted on the normal concrete specimens with the size of 40mm×40mm×160mm. The results show that there is little change on the appearance, mass and dynamic elastic modulus of concrete soaked in water. But for the concrete soaked in salt solution, the loss rate of mass changes from reduction to growth, the relative dynamic elastic modulus of concrete grows at first and declines later. Through analysis of electron microscope scanning, energy spectrum and chemical composition of concrete samples, concrete damage caused by salts includes chemical erosion and salt crystallization damage. Na2SO4 mainly influences the dynamic elastic modulus of concrete, NaCl mainly influences the mass of concrete due to its strong penetration, while NaHCO3, ranking between the two salts above, largely influences not only the mass of concrete, but also the dynamic elastic modulus of concrete.

scholarly journals Bicontinuous and cellular structure design of PVDF membranes by using binary solvents for the membrane distillation process

RSC Advances ◽  
2018 ◽  
Vol 8 (44) ◽  
pp. 25159-25167 ◽  
Author(s):  
Ziyi Wang ◽  
Yuanyuan Tang ◽  
Baoan Li
Keyword(s):  
Cellular Structure ◽  
Membrane Distillation ◽  
Structure Design ◽  
Binary Solvents ◽  
Distillation Process ◽  
Potential Structure ◽  
Bicontinuous Structure ◽  
Long Term Performance ◽  
Term Performance

The membrane with bicontinuous structure rather than cellular structure was identified as the potential structure for MD processes with much higher tensile strength, narrower pore size distribution, higher MD flux and more excellent long-term performance.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

scholarly journals Membrane Distillation Process

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 144
Author(s):  
Alessandra Criscuoli
Keyword(s):  
Water Stress ◽  
New Technologies ◽  
Membrane Distillation ◽  
Distillation Process

The water stress that we have been experiencing in the last few years is driving the development of new technologies for the purification and recovery of water [...]

scholarly journals Long-Term Stability of Different Kinds of Gas Nanobubbles in Deionized and Salt Water

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1808
Author(s):  
Yali Zhou ◽  
Zhenyao Han ◽  
Chunlin He ◽  
Qin Feng ◽  
Kaituo Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Bubble Size ◽  
Ostwald Ripening ◽  
Salt Water ◽  
Dlvo Theory ◽  
Deionized Water ◽  
Hydrodynamic Cavitation ◽  
Term Stability ◽  
Long Term Stability

Nanobubbles have many potential applications depending on their types. The long-term stability of different gas nanobubbles is necessary to be studied considering their applications. In the present study, five kinds of nanobubbles (N2, O2, Ar + 8%H2, air and CO2) in deionized water and a salt aqueous solution were prepared by the hydrodynamic cavitation method. The mean size and zeta potential of the nanobubbles were measured by a light scattering system, while the pH and Eh of the nanobubble suspensions were measured as a function of time. The nanobubble stability was predicted and discussed by the total potential energies between two bubbles by the extended Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The nanobubbles, except CO2, in deionized water showed a long-term stability for 60 days, while they were not stable in the 1 mM (milli mol/L) salt aqueous solution. During the 60 days, the bubble size gradually increased and decreased in deionized water. This size change was discussed by the Ostwald ripening effect coupled with the bubble interaction evaluated by the extended DLVO theory. On the other hand, CO2 nanobubbles in deionized water were not stable and disappeared after 5 days, while the CO2 nanobubbles in 1 mM of NaCl and CaCl2 aqueous solution became stable for 2 weeks. The floating and disappearing phenomena of nanobubbles were estimated and discussed by calculating the relationship between the terminal velocity of the floating bubble and bubble size.

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