Effect of operating conditions on water transport during the concentration of sucrose solutions by osmotic distillation

Influence of salt concentration on DCMD performance for treatment of highly concentrated NaCl, KCl, MgCl2 and MgSO4 solutions

“…This behavior is mainly attributed to the decrease of the water vapor pressure [18,19] with the addition of solute in water due to the decrease in water activity in the feed solution. Furthermore, there is also the contribution of the temperature polarization effect [20] and concentration polarization effect [21]. It can be seen that a remarkably discrepancy is presented in flux decline of the solutions tested, especially at higher concentrations.…”

“…On the other hand, The enhancement of circulation velocity would increase shear stress along the feed boundary layer in the membrane module [21], which is beneficial to reduce the boundary layer thickness. The temperature and non-volatile solute concentration at the membrane surface become closer to the corresponding bulk temperature and bulk concentration [29,30]; thus, the temperature and concentration polarization effect on permeate flux is getting less, resulting in higher transmembrane temperature difference, greater water vapor pressure difference (i.e., the driving force of mass transfer) and greater permeate flux.…”

Membrane Distillation: Principle, Advances, Limitations and Future Prospects in Food Industry

“…Consequently, the temperature at the gas/liquid interface approaches to the bulk temperature at the permeate side. This will tend to increase driving force across the membrane; resulting an increase in MD flux (Courel et al, 2000;Hongvaleerat et al, 2008). It is important to note that as the permeate used in the MD is distilled water and in the OD is hypertonic salt solution; the extent of the effect of flow rate is more prominent in the latter configuration.…”

Raw Juice Concentration by Osmotic Membrane Distillation Process with Hydrophobic Polymeric Membranes

“…Additionally, experimental data showing a higher permeate flux for OMD in the case of real juices are also presented (Bélafi-Bakó and Koroknai 2006;Nagaraj et al 2006;Hongvaleerat et al 2008). For a given activity and temperature difference, the driving force in the OMD process is actually bigger than the sum of the individual values related to osmotic dehydration and MD alone, so the link leads to a synergistic effect (Bélafi-Bakó and Koroknai 2006;Courel et al 2000). On the other hand, articles which focused on the quality of the juices do not discuss the influence of the experimental process conditions, e.g., type of the membrane, temperature, or types of stripping solutions.…”