Interdisciplinary Graduate Programme, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore; Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One #06-08, Singapore 637141, Singapore; Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One #06-08, Singapore 637141, Singapore.
Water Res. 2021 Dec 1;207:117818. doi: 10.1016/j.watres.2021.117818. Epub 2021 Oct 29.
Feed spacers are an essential part of spiral wound modules for reverse osmosis (RO). They create flow channels between membrane sheets and manipulate hydrodynamic conditions to control membrane fouling. In this work, additive manufacturing (Polyjet) was used to print novel sinusoidal spacers with wavy axial filaments connected by perpendicular (ST) or slanted (SL) transverse filaments. When tested with 2 g/L NaCl solution, conventional and SL spacers had similar flux while the ST spacer had about 5-7% lower flux. The pressure losses for ST and SL spacers increased by up to 3 folds depending on the flow condition. In the colloidal silica fouling and biofouling tests, the sinusoidal spacers showed lower membrane permeability decrease of 46% for ST, 41% for SL vs 56% for conventional and 26% for ST, 22% for SL vs 33% for conventional, respectively. Optical coherence tomography images from colloidal silica fouling and confocal images from biofouling tests revealed that fouling patterns were closely associated with the local hydrodynamic conditions. Overall, sinusoidal spacers showed promising results in controlling membrane fouling, but there is potential for further optimizations to reduce channel pressure loss.
在反渗透（RO）中，给料间隔物是螺旋缠绕模块的重要组成部分。它们在膜片之间形成流道，并控制水动力条件以控制膜污染。在这项工作中，采用增材制造（Polyjet）技术打印具有正弦波形状的间隔物，其波状轴向纤维通过垂直（ST）或倾斜（SL）的横向纤维连接。当用 2g/L 的 NaCl 溶液进行测试时，常规间隔物和 SL 间隔物具有相似的通量，而 ST 间隔物的通量约低 5-7%。ST 和 SL 间隔物的压力损失取决于流动条件，最高增加了 3 倍。在胶体二氧化硅污染和生物污染测试中，正弦波间隔物的膜渗透率降低分别为 ST 46%、SL 41%，而常规间隔物为 56%、ST 26%、SL 22%、常规间隔物为 33%。胶体二氧化硅污染的光学相干断层扫描图像和生物污染测试的共焦图像表明，污染模式与局部水动力条件密切相关。总体而言，正弦波间隔物在控制膜污染方面表现出良好的效果，但仍有进一步优化以降低通道压力损失的潜力。
