Optimization of the geometry of co-spacers in the feed chamber of thin-film desalination membranes

Abstract

This study addresses two critical challenges in thin-film composite (TFC) reverse osmosis membranes—the non-uniform distribution of flow and the mechanical fatigue of the active layer—through the design and optimization of a novel structure that integrates baffles, collectors, and spacers into a configuration designed to homogenize flow and reduce foulant accumulation. To achieve this, a combined approach involving global sensitivity analysis, numerical simulations, and a Box–Behnken experimental design was employed to maximize flow velocity and minimize pressure drop, while validation through finite element analysis (FEA) and computational fluid dynamics (CFD) demonstrated stability and high performance under real operating conditions. The results revealed a significant reduction in pressure drop, the elimination of stagnant zones, and the mitigation of fouling, together with a threefold increase in flow velocity, thereby enhancing mass transfer and reducing concentration polarization; additionally, the structure exhibited outstanding mechanical strength, withstanding pressures of up to 80 bar with minimal deformation (<0.02 mm/mm). Overall, this configuration not only optimizes the efficiency of reverse osmosis systems but also provides a sustainable solution for desalination by extending membrane lifespan, reducing operational costs, and lowering energy consumption, thus representing a significant technical advancement and a viable alternative for the future development of this technology.