Mitigation of Membrane Wetting by Applying a Low Temperature Membrane Distillation

Abstract

The formation of deposits on the membrane surface during membrane distillation is considered as one of the main reasons for membrane wetting. To assess the intensity of this phenomenon, long-term studies were performed comparing the membrane wettability with non-fouling feed (NaCl solutions) and feeds containing various foulants (lake and Baltic Sea water). The polypropylene membranes used were non-wetted by NaCl solutions during several hundred hours of water desalination. However, the occurrence of CaCO3 or other salt crystallization caused the membranes to be partially wetted, especially when periodical membrane cleaning was applied. The scaling intensity was significantly reduced by lowering the feed temperature from 353 to 315 K, which additionally resulted in the limitation of the degree of membrane wetting.

Removal of ketoprofen from surface water in a submerged photocatalytic membrane reactor utilizing membrane distillation: effect of process parameters and evaluation of long‐term performance

“…In the case of surface water treatment it should be noted that the rising temperature results in an enhanced intensity of CaCO 3 precipitation 57 . Scaling in MD not only reduces the permeate flux but also accelerates membrane wetting 58 . Due to these undesired phenomena the heating temperature of the feed was limited to 60 °C.…”

“…57 Scaling in MD not only reduces the permeate flux but also accelerates membrane wetting. 58 Due to these undesired phenomena the heating temperature of the feed was limited to 60 °C. All experiments presented in this section were conducted at TiO 2 concentration of 1.0 g L −1 .…”

Desiccant solutions, membrane technologies, and regeneration techniques in liquid desiccant air conditioning system

“…The reported regeneration temperatures for this technique are found to be above 40 C. That implies, the lower the regeneration temperature of a desiccant solution, the lower will be the re-cooling energy utilization and the overall power consumption of LDACs. Thermal regeneration technique is further subcategorized based on the membrane distillation configurations which are direct contact, air gap, sweep gas, and vacuum membrane distillation method 124,125 as shown in Figure 9. Among these distillation methods, Vacuum membrane distillation can serve as both thermal and non-thermal desiccant regeneration techniques owing to the possibilities of leveraging on its vacuum effect over temperature raising.…”

“…Thermal regeneration technique is further sub‐categorized based on the membrane distillation configurations which are direct contact, air gap, sweep gas, and vacuum membrane distillation method 124,125 as shown in Figure 9. Among these distillation methods, Vacuum membrane distillation can serve as both thermal and non‐thermal desiccant regeneration techniques owing to the possibilities of leveraging on its vacuum effect over temperature raising.…”

Boron Removal by Membrane Distillation: A Comparison Study

“…LEP can be evaluated by [ 22 , 23 , 24 ]: where are the liquid surface tension, contact angle, and maximum pore size, respectively. It was proposed to use poly(vinyl alcohol) (PVA) as a coating material [ 25 ] or a cover for the membrane surface by surface micropillars [ 26 ] to resolve these issues.…”