Effect of operational parameters on distillate flux in direct contact membrane distillation (DCMD): Comparison between experimental and model predicted performance

Manawi, Yehia; Khraisheh, Majeda; Fard, Ahmad Kayvani; Benyahia, Farid; Adham, Samer

doi:10.1016/j.desal.2014.01.003

Cited by 120 publications

(56 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further annealing for another day led to a greater decrease in the range of the pore diameter and a sharp peak appeared, although the average mean pore size was further slightly increased to 1.3 μm (which was same as that of the neat membrane). An increased average pore diameter led to an increase in the flux performance [36], justifying that MD applied with the A2 and A3 membranes had the highest flux performance compared to the other samples. In the literature, the pore size distribution of commercial MD membranes generally lies between 0.2 μm and 1 μm as the increase in the maximum pore size greatly decreases the LEP, leading to serious wetting problems [3,6].…”

Section: Improvement Of Membrane Propertiesmentioning

confidence: 80%

Improving Nanofiber Membrane Characteristics and Membrane Distillation Performance of Heat-Pressed Membranes via Annealing Post-Treatment

et al. 2017

View full text Add to dashboard Cite

Electrospun membranes are gaining interest for use in membrane distillation (MD) due to their high porosity and interconnected pore structure; however, they are still susceptible to wetting during MD operation because of their relatively low liquid entry pressure (LEP). In this study, post-treatment had been applied to improve the LEP, as well as its permeation and salt rejection efficiency. The post-treatment included two continuous procedures: heat-pressing and annealing. In this study, annealing was applied on the membranes that had been heat-pressed. It was found that annealing improved the MD performance as the average flux reached 35 L/m 2 ·h or LMH (>10% improvement of the ones without annealing) while still maintaining 99.99% salt rejection. Further tests on LEP, contact angle, and pore size distribution explain the improvement due to annealing well. Fourier transform infrared spectroscopy and X-ray diffraction analyses of the membranes showed that there was an increase in the crystallinity of the polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) membrane; also, peaks indicating the α phase of polyvinylidene fluoride (PVDF) became noticeable after annealing, indicating some β and amorphous states of polymer were converted into the α phase. The changes were favorable for membrane distillation as the non-polar α phase of PVDF reduces the dipolar attraction force between the membrane and water molecules, and the increase in crystallinity would result in higher thermal stability. The present results indicate the positive effect of the heat-press followed by an annealing post-treatment on the membrane characteristics and MD performance.

show abstract

Section: Improvement Of Membrane Propertiesmentioning

confidence: 80%

Improving Nanofiber Membrane Characteristics and Membrane Distillation Performance of Heat-Pressed Membranes via Annealing Post-Treatment

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Nevertheless, their system still needed membrane cleaning and drying after wetting occurrence [29]. Several authors have placed spacers in MD modules and have carried out experimental and theoretical investigations on the subject [30][31][32][33][34]. In their results, they published notable enhancement on heat and mass transfer and consequently the mass flux in spacer filled modules and provided suggestions on optimal spacer geometry, voidage, and hydrodynamic angle [35].…”

Section: Introductionmentioning

confidence: 98%

Wetting prevention in membrane distillation through superhydrophobicity and recharging an air layer on the membrane surface

Rezaei

Warsinger

Lienhard

et al. 2017

Journal of Membrane Science

123

View full text Add to dashboard Cite

Although membrane distillation offers distinctive benefits in some certain areas, i.e., RO concentrate treatment, concentrating solutions in the food industry and solar heat utilization, the occurrence of wetting of the hydrophobic membrane hinders its potential industrial applications.Therefore, wetting prevention is a vital criterion for the treatment of solutions with lower surface tension than water. The present work examines the effect of recharging air bubbles on the membrane surface for the wetting incidence when a surfactant (sodium dodecyl sulfate, SDS) exists in a highly concentrated NaCl aqueous solution. This study shows that the presence of the air bubbles on the surface of the superhydrophobic membrane in a direct contact membrane distillation setup inhibited the occurrence of wetting (~100% salt rejection) even for high concentrations of the surface-active species (up to 0.8 mM SDS) in the feed solution while no undesirable influence on the permeate flux was observed. Introducing air into the feed side of the membrane displaces the liquid which partly tends to penetrate the macroporous structure with air bubbles and therefore increases the liquid entry pressure, and in addition, the simultaneous use of a superhydrophobic membrane enhances the solution contact angle.

show abstract

“…For a model of DCMD to be applicable to large-scale systems, it must account for changes in operational variable values-such as temperature, flow rate, and salinity-along the length of the membrane. Most of the earlier models of DCMD neglected the changing nature of operational variables from inlet to outlet, instead relying on inlet or average conditions for calculation across the entire membrane area [22,23,28,33,37,38]. Neglecting the changing nature of operational variable values along the length of the membrane may produce little error at the bench-scale, but is likely to introduce significant error in more realistic, large-scale membrane modules.…”

mentioning

confidence: 96%

A stepwise model of direct contact membrane distillation for application to large-scale systems: Experimental results and model predictions

2016

View full text Add to dashboard Cite

Effect of operational parameters on distillate flux in direct contact membrane distillation (DCMD): Comparison between experimental and model predicted performance

Cited by 120 publications

References 26 publications

Improving Nanofiber Membrane Characteristics and Membrane Distillation Performance of Heat-Pressed Membranes via Annealing Post-Treatment

Improving Nanofiber Membrane Characteristics and Membrane Distillation Performance of Heat-Pressed Membranes via Annealing Post-Treatment

Wetting prevention in membrane distillation through superhydrophobicity and recharging an air layer on the membrane surface

A stepwise model of direct contact membrane distillation for application to large-scale systems: Experimental results and model predictions

Contact Info

Product

Resources

About