1,3‐Diamino‐2‐propanol or 2‐aminoethanethiol modified active layer of thin‐film composite forward osmosis membrane

Abstract

This work proposes three easy and effective methods to improve the density of the active layer of the thin-film composite (TFC) forward osmosis (FO) membrane. Amino groups are introduced to the polyamide layer to react with the exposed acid chloride groups after a small molecule of 1,3-diamino-2-propanol (DH) or 2-aminoethanethiol (AE) or DH-AE being introduced. This may lead to a higher degree of crosslinking and form a more complex and networked aggregate structure. In this work, three modified membranes are successfully prepared, and a series of characterizations are carried out. The result is that all methods can improve the density of the active layer and increase the salt rejection without adversely affecting the selectivity. The hydrophilicity of the TFC-DH film is significantly improved, the reverse salt flux of the TFC-AE film is remarkably improved, and the effect of the TFC-DH-AE film is between the TFC-DH film and the TFC-AE film. Therefore, the method of adding a small molecular material can increase the degree of polymerization. The method of introducing an inorganic element provides a valuable solution for designing and developing a novel and efficient FO film, which is simple and easy to be operated.

Zwitterion-functionalized MIL-125-NH2-based thin-film nanocomposite forward osmosis membranes: towards improved performance for salt rejection and heavy metal removal

“…16 Regarding the operation mechanism, the FO process is adopted as a low-pressure process and demonstrates more practical resistance to fouling than the RO process, which is set to function at a higher hydraulic pressure. [17][18][19] It must be taken into consideration that a low hydraulic pressure is not solely responsible for the reduction of the FO membrane fouling; they also suffer from the fouling process, low water penetration, and high reverse salt penetration. To obtain better antifouling features along with high selectivity and water permeability, it is imperative to engineer and modify the applied membranes diligently.…”