Abstract The main reason for the lower water flux, than expected, in the forward osmosis (FO) process, is the internal concentration polarization (DICP). Usually, the structural parameter (S) is used as an indicator of the intensity of DICP. Small S value is desirable for the FO membrane due to the low DICP. However, due to design and construction problems, structural parameter reduction has some drawbacks. In this work, DICP reduction in FO membranes will be investigated using an approach other than structural parameter reduction. Accordingly, during the FO process, the feed solution (FS) valve is opened and closed at a constant period of time (feed valve timing (FVT)). Four types of FO membranes with different S parameters were used. The effects of the implementation of the proposed protocol on the water flux (Jw), reverse salt flux (Js), specific reverse solute flux (Js/Jw) and effective driving force were investigated. The effects of the S parameter and draw solution (DS) concentration also investigated separately. The results showed that the proposed protocol significantly increased Jw. Also, the values of Js/Jw decreased with increasing the FVT values and reached the lowest level in the practical recovery time (PRT).

中文翻译：

---

将正向渗透膜中的内部浓差极化降至最低的最先进方案

摘要 在正向渗透 (FO) 过程中，水通量低于预期的主要原因是内部浓差极化 (DICP)。通常，结构参数（S）用作 DICP 强度的指标。由于低 DICP，FO 膜需要小的 S 值。然而，由于设计和施工问题，降低结构参数存在一些弊端。在这项工作中，将使用结构参数减少以外的方法研究 FO 膜中 DICP 的减少。因此，在 FO 过程中，进料溶液 (FS) 阀以恒定的时间段 (进料阀定时 (FVT)) 打开和关闭。使用了具有不同 S 参数的四种类型的 FO 膜。实施拟议协议对水通量 (Jw)、反向盐通量 (Js)、研究了特定的反向溶质通量 (Js/Jw) 和有效驱动力。S 参数和汲取溶液 (DS) 浓度的影响也分别进行了研究。结果表明，所提出的协议显着增加了 Jw。此外，Js/Jw 的值随着 FVT 值的增加而降低，并在实际恢复时间 (PRT) 中达到最低水平。