Membrane technologies have been widely applied in water treatment, wastewater reclamation and seawater desalination. Feed spacer present in spiral wound membrane (SWM) modules plays a pivotal role in creating flow channels, promoting fluid mixing and enhancing mass transfer. However, it induces the increase of feed channel pressure (FCP) drop and localized stagnant zones that provokes membrane fouling. For the first time, we comprehensively review the research evolvement on feed spacer in SWM modules for water treatment over the last 20 years, to reveal the impacts of feed spacer on the hydrodynamics and biofouling in the spacer-filled channel, and to discuss the potential approaches and current limitations for the modification of feed spacer. The research process can be divided into three phases, with research focus shifting from hydrodynamics in Phase Ⅰ (the year of 2001–2008), to biofouling in Phase Ⅱ (the year of 2009–2015), and then to novel spacer designs in Phase Ⅲ (the year of 2016–2020). The spacer configuration has a momentous impact on the hydraulic performance regarding flow velocity field, shear stress, mass transfer and FCP drop. Biofouling initially occurs on feed spacer, especially around spacer filaments and the contact zones with membrane surface, and ultimately degrades the overall membrane performance indicating the importance of controlling spacer biofouling. The modification of feed spacer is mainly achieved by altering surface chemistry or introducing novel configurations. However, the stability of spacer coating and the economy and practicality of 3D-printed spacer remain a predicament to be tackled. Future studies are suggested to focus on the standardization of testing conditions for spacer evaluation, the effect of hydrodynamics on membrane fouling control, the design and fabrication of novel feed spacer adaptable for SWM modules, the application of feed spacer for drinking water production, organic fouling control in spacer-filled channel and the role of permeate spacer on membrane performance.

膜技术已广泛应用于水处理，废水回收和海水淡化中。螺旋缠绕膜（SWM）模块中存在的进料隔片在创建流动通道，促进流体混合和增强质量传递方面起着关键作用。但是，它会导致进料通道压力（FCP）下降和局部停滞区增加，从而引起膜污染。我们首次全面回顾了过去20年中用于水处理的SWM模块中进料隔片的研究进展，以揭示进料隔片对隔片填充通道中水动力和生物污损的影响，并讨论了其潜力。进料垫片的修改方法和当前限制。研究过程可以分为三个阶段，研究重点从第一阶段的流体动力学（2001-2008年），转移到第二阶段的生物污垢（2009-2015年），然后到第三阶段的新型隔垫设计（2016-2020年）。间隔件的配置对水力性能具有重大影响，涉及流速场，剪切应力，传质和FCP下降。生物污垢最初发生在进料隔离物上，特别是在隔离物细丝和与膜表面的接触区周围，并最终降低了整个膜的性能，表明控制隔离物生物污损的重要性。进料垫片的修改主要是通过改变表面化学或引入新的构型来实现的。然而，间隔物涂层的稳定性以及3D打印间隔物的经济性和实用性仍然是要解决的难题。