Heat-mass transfer and energy efficiency in direct contact membrane distillation: Effects of membrane properties, temperature, and salt concentration
Hu, Y.; Chen, G.; Huang, M.; Qiao, J.; yang, X. (2025). Heat-mass transfer and energy efficiency in direct contact membrane distillation: Effects of membrane properties, temperature, and salt concentration. J. Membr. Sci. 735: 124533. https://dx.doi.org/10.1016/j.memsci.2025.124533
In: Journal of Membrane Science. Elsevier: Amsterdam. ISSN 0376-7388; e-ISSN 1873-3123, more
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| Author keywords |
Direct contact membrane distillation;Heat & mass transfer;Polarization phenomena;Energy efficiency;Water recovery;thermal efficiency;concentration polarization;seawater desalination;water;performance;transport;salinity;design;brines;dcmd |
| Authors | | Top |
- Hu, Y.
- Chen, G.
- Huang, M.
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| Abstract |
Direct contact membrane distillation (DCMD), a promising membrane separation technology, holds great potential for treating high-salinity wastewater. However, energy efficiency and long-term operational stability remain critical challenges for its industrial application. This study systematically investigated the effects of membrane properties, feed temperature, and salt concentration on the heat-mass transfer characteristics of DCMD. Transfer behaviors were quantitatively analyzed based on the membrane mass transfer coefficient (k(m)), temperature polarization coefficient (TPC), and concentration polarization coefficient (CPC). Results indicated that larger-pore (0.45 mu m) PTFE membranes yielded higher initial flux (35 kg/m(2)h), but suffered from lower porosity and intensified salt crystallization, leading to inferior long-term performance. Conversely, smaller-pore membranes (0.22 mu m) demonstrated better stability under high salinity, with flux decline delayed from 6 h for PTFE-0.45 to approximately 9 h and 14 h for PTFE-0.22 and PVDF-0.22, respectively. A feed temperature of 60 degrees C was found to optimally balance flux stability and energy efficiency, maintaining comparable GOR to 70 degrees C while reducing thermal losses and delaying performance decline. Under high salt concentration (1.5 X), severe scaling led to > 90 % reduction in k(m), while TPC increasing markedly with water recovery, identifying temperature polarization as the dominant factor that rendered performance instability. These findings provide fundamental insights into limiting factors of the DCMD process in near zero liquid discharge applications, offering practical guidance for membrane selection and process scale-up. |
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