Department of Construction Environment Engineering, KICT School, University of Science & Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea.
Department of Land, Water and Environment Research, Korea Institute of Civil Engineering and Building Technology (KICT), 283, Goyangdae-Ro, Ilsanseo-Gu, Goyang-Si, Gyeonggi- Do, 10223, Republic of Korea.
Chemosphere. 2019 Dec;236:124289. doi: 10.1016/j.chemosphere.2019.07.020. Epub 2019 Jul 8.
Four commercially available hydrophobic membranes with different pore sizes were separately used in a direct contact membrane distillation (DCMD) apparatus to investigate the effect of fouling on the mass transfer coefficient, and the dominant mass transport mode under different conditions defined by the temperature, membrane material, flow regime, and membrane pore size. Both ultrapure deionized water and simulated industrial wastewater were considered as the feed water. The results of the investigation confirmed that the fouling layer impacted the mass transport directly by resisting it, and indirectly by altering the heat transfer mechanism. In addition to the surface fouling layer, a significant number of particles were also observed to accumulate in the membrane pores. It was further determined that the contribution of Poiseuille flow to the entire mass transport was significant at higher temperatures when using a membrane with large pores. This highlighted the need for careful consideration of Poiseuille flow in the modeling and simulation of a membrane distillation (MD) mass transport process. It was also observed that the flow rate did not affect the Poiseuille flow and therefore did not directly impact the entire mass transfer. The study findings provide systematic insight for the development of a strategy for selecting an appropriate operating feed for DCMD and adjusting the permeate temperature to fit the prevailing water demand and environmental conditions.
四种具有不同孔径的市售疏水性膜分别在直接接触式膜蒸馏（DCMD）装置中使用，以研究污染对传质系数的影响，以及在不同条件下（由温度、膜材料、流动状态和膜孔径定义）的主要传质模式。超纯水和模拟工业废水都被用作进料水。研究结果证实，污染层直接通过阻碍和间接通过改变传热机制对传质产生影响。除了表面污染层外，还观察到大量颗粒在膜孔中积累。进一步确定，在使用大孔径膜时，较高温度下泊肃叶流对整个传质的贡献显著。这突出表明，在膜蒸馏（MD）传质过程的建模和模拟中，需要仔细考虑泊肃叶流。还观察到流速不影响泊肃叶流，因此不会直接影响整个传质。该研究结果为开发适用于 DCMD 的合适操作进料的策略以及调整渗透温度以适应当前水需求和环境条件提供了系统的见解。
