State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin 300387, China; School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin 300387, China; School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
Chemosphere. 2019 Jul;226:553-564. doi: 10.1016/j.chemosphere.2019.03.155. Epub 2019 Mar 28.
To obtain more information on the hydraulic properties of membrane interface, the fiber Bragg grating (FBG) sensing technology was imported to investigate the effect of feed solution (FS) flow rate, draw solution (DS) flow rate and cross-flow direction on the membrane flux and membrane shear-force distribution of forward osmosis (FO) process. Results from experimental work demonstrated that a non-uniform spatial variation of the shear-force distribution exists along the membrane, and higher shear force is distributed in the middle position which resulted in higher diffusion load on the particular location of the membrane rind. Besides, increasing the inlet flow simply to a certain value didn't result in a higher shear force and lower the effect of concentration polarization (CP). Compared to co-current mode, counter-current mode showed the better hydraulic characteristics of higher shear-force, faster scouring frequency and consistent shear-force distribution, which will enhance the utilization of membrane and exhibit higher flux by increasing the inlet flow. Moreover, with the increase of FS and DS flow, the stress distribution showed more uniformed. Higher FS flow is more beneficial to FO process which will reduce ECP and improve flux in comparison to increasing DS flow which will produce adverse influence on ICP and diminish flux.
为了获取更多关于膜界面水力特性的信息，引入光纤布拉格光栅（FBG）传感技术来研究进料溶液（FS）流速、汲取溶液（DS）流速和错流方向对正向渗透（FO）过程中膜通量和膜剪切力分布的影响。实验结果表明，沿膜存在剪切力分布的非均匀空间变化，较高的剪切力分布在中间位置，导致膜皮特定位置的扩散负载较高。此外，将入口流量增加到一定值并不能产生更高的剪切力，也不能降低浓度极化（CP）的影响。与并流模式相比，逆流模式表现出更好的水力特性，具有更高的剪切力、更快的冲刷频率和一致的剪切力分布，这将通过增加入口流量来增强膜的利用并表现出更高的通量。此外，随着 FS 和 DS 流量的增加，应力分布显示出更加均匀。与增加 DS 流量相比，较高的 FS 流量更有利于 FO 过程，因为它可以降低 ECP 并提高通量，而增加 DS 流量会对 ICP 产生不利影响并降低通量。
