Bio-mimetically inspired 3D-printed honeycombed support (spacer) for the reduction of reverse solute flux and fouling of osmotic energy driven membranes

Shear stress on a membrane's surface is one of the main factors that reduces concentration polarization and fouling and increases salt rejection. Therefore, it is in need to design a support to equally and effectively distribute the shear stress on a membrane's surface. In this study, sustainable fabrication method: 3D printing was utilized, and a bio-mimetically inspired a novel support composed of honeycombs that has full contact with the membrane surface and creates a shear web to enhance shear distribution in order to decrease fouling and reverse the solute flux of a forward osmosis system is introduced. The results showed that well-distributed shear highly reduced foulant adhesion on the membrane surface and reverse solute diffusion. As the orientations of hexagons also affect shear distribution, they were oriented both vertically and horizontally, and compared with the support of commercially available membrane spacers. The vertically oriented hexagonal-type shear distributing support (V-HEX) showed a better performance in reducing reverse solute flux and in reducing foulant adhesion to 50% compared to the effect of a commercially available spacer (COM). V-HEX was also tested as a draw support and as a feed support combined with the commercially available spacer, and it was still successful in reducing reverse solute diffusion. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.