No abstract

No abstract

Separation of mixed ion, especially Cl- and SO42-, is essential for reduced energy consumption and achievement of the minimal or zero-liquid discharge. Membrane technology has attracted significant attention in this respect owing to its good system coupling and maturity. However, it remains challenging to fabricate highly selective nanofilm with fine-tuning pore and structure that is suitable for the separation of Cl- and SO42-. Herein, we report an asymmetric alicyclic polyamide nanofilm with enhanced interconnectivity pore by manipulating the molecular geometry structure, composed of the porous aromatic polyamide dendrimer layer, and the dense alicyclic polyamide layer with hollow stripes. This resulted membrane shows a 107.14% separation rate of Cl- and SO42-, and a water flux (for Na2SO4) of ~2.2 times that of the pristine polyamide membrane. We estimate this fine-tuning pore approach resulting from alicyclic structure also might be employed in other separation membranes such as gas, solvent or neutral molecules.

Herein, we report an asymmetric alicyclic polyamide nanofilm with an enhanced pore interconnectivity established by manipulating the molecular geometric structure, composed of a porous aromatic polyamide dendrimer layer and a dense alicyclic polyamide layer with hollow stripes. The experimental and simulated data demonstrate that the alicyclic polyamide nanofilm with an asymmetric structure exhibits a negative surface charge and contains more interconnected voids ranging from 1.95 to 3.0 Å, which facilitates the rejection of SO 4 2À with a higher charge density and the passage of Cl À with a smaller hydrated radius, resulting in a good Cl À /SO 4 2À separation selectivity. The resulting membrane attains a 197.11 separation selectivity for Cl À and SO 4 2À and a water flux (for Na 2 SO 4 ) ~2.2 times that of the pristine polyamide membrane. This fine-tuning pore approach resulting from the considered alicyclic structure can also be employed in other separation membranes, such as membranes for gas, solvent, or neutral molecular separation.

No abstract