The establishment of high-performance anti-fouling nanofiltration membranes via cooperation of annular supramolecular Cucurbit[6]uril and dendritic polyamidoamine

In this work, annular supramolecular cucurbit[6]uril (CB6) and dendritic polyamidoamine (PAMAM) were employed to construct high-performance nanofiltration (NF) membranes via one-step interfacial polymerization (IP) process. The obtained membrane features not only the enlarged polyamide tunnels based on the large steric hindrance of CB6 and PAMAM but also the novel hydrophobic rotaxane tunnels based on the host-guest chemistry between CB6 and piperazine (PIP) or PAMAM. The CB6/PAMAM-modified membrane achieved nearly four times enhancement of pure water permeability (PWP) compared to the unmodified traditional membranes with still high Na2SO4 rejection. This indicates the positive contribution of CB6/PAMAM-modification to overcome the “trade-off” effect limiting NF development. In addition, the modified membrane shows the industry-leading separation performance for monovalent and bivalent anions due to the cooperation between the modified pore-size and surface charge. More valuably, CB6/PAMAM-modified membrane manifests the strong anti-fouling property not only in inorganic salt system but also in organic pollutant system based on the modified surface characteristics, indicating its broader application fields. This provides a feasible method to prepare a high-performance anti-fouling NF membrane.