Scavenging organic micropollutants from water with nanofibrous hypercrosslinked cyclodextrin membranes derived from green resources

Abstract

As a principal constituent of living organisms, water is crucial to sustain life on Earth. However, its pollution by major human activities leading to clean water scarcity is a significant issue. Industrial activities release toxic pollutants, such as textile dyes and polycyclic aromatic hydrocarbons (PAHs), which pollute water resources and endanger the marine ecosystem and human life. To address this issue, we developed a highly effective sorbent platform based on a nanofibrous membrane, comprising hypercrosslinked cyclodextrin networks (HCNs). Cyclodextrins (CDs) are cyclic oligosaccharides with a truncated cone shape featuring a partially hydrophobic cavity interior, which can form complexes with organic micropollutants. The nanofibrous HCN membrane was produced via the electrospinning of highly concentrated CD solutions containing a naturally occurring graphitic acid linker. The thermal crosslinking of the nanofibrous membrane resulted in a robust covalent polymer network of CD macrocycles, which can retain its shape in aqueous and organic solvents. The membrane was produced by exclusively using green resources including a novel natural crosslinker (i.e., graphitic acid), which has not been previously employed for any CD-based materials. Molecular modeling revealed that the crosslinking had a negligible effect on the host–guest complexation of the nanofibrous CD networks. The HCN membrane was used for scavenging textile dyes and PAHs from polluted water, and it demonstrated high sorption performance (Qmax = 692 mg g−1 dye), and excellent reusability upon the application of acidic methanol treatment. The nanofibrous HCN membrane can be used for rapid and efficient scavenging of organic micropollutants in aqueous environments.