Molecular dynamics study on the structure and antifouling performance of aromatic polyamide membrane with sulfonamide group

Aromatic polyamide (APA)-based reverse osmosis (RO) membrane is commonly used for desalination and drinking water purification due to its high water flux, high salt rejection, structural robustness, and environ-mental friendliness. Membrane fouling is one of the most serious problems in its practical application. In this study, two reliable atomistic models of cross-linked APA and APA modified with 2-aminoethanesulfonamide molecule (AESA-APA) membranes were constructed. The structure, water dynamic, and antifouling perfor-mance were investigated in detail via molecular dynamic simulation and density functional theory. Compared with APA membrane, the hydrophilicity, water flux, and antifouling performance of AESA-APA membrane are improved by grafting AESA group. The simulated results reveal that a protective water shell is formed because of the strong hydrophilicity of the AESA-APA membrane, and the foulant sodium alginate (SA) is difficult to get into the interior region of the AESA-APA membrane. The potential mean force analysis demonstrates that it is easier for SA to wash away from the surface of AESA-APA membrane than APA membrane in practical application. The comprehensive understanding on the structure and antifouling property of the sulfonamide-modified APA membrane is beneficial to the development of novel and high-performance APA-based RO membranes.

Automated summary

In this study, the structure, water dynamic, and antifouling performance of cross-linked APA and APA modified with AESA membranes were investigated using molecular dynamic simulation and density functional theory. The results showed that the hydrophilicity, water flux, and antifouling performance of AESA-APA membrane were improved compared to APA membrane. The protective water shell formed by the strong hydrophilicity of the AESA-APA membrane prevented foulant from entering its interior region. The comprehensive understanding of the sulfonamide-modified APA membrane is beneficial for the development of novel and high-performance APA-based RO membranes.