Author(s): Zhuofan Gao; Yang Gao; Xincheng Jin; Yuan Xiang; Huang Zhuo; Zhihui Zhou; Zheyu Fan
Linked Author(s):
Keywords: Support-free; Dopamine modification interlayer; Thin membrane nanocomposite membranes; Nanofiltration applications
Abstract: The uncontrollable interfacial polymerized polyamide structure and weak interlamellar interaction of polyamide (PA) with substrate inhibit the construction of highly efficient sieving membranes owing to the inferior contaminant selectivity induced by defects in PA layers and stability issues. Here, a novel organic solvent resistant nanofiltration (OSN) membrane was developed via support-free interfacial polymerization on the dopamine-modified multi-walled carbon nanotubes constructed interlayer with cross-linked polyimide (cPD) ultrafiltration (UF) substrate. An ultrathin and dense PA membrane was successfully synthesized and transferred onto a preloaded DMCNs cPI substrate surface. Dopamine-modified interlayer offers a positively charged hydrophilic scaffold-like structure for the microporous UF substrate, which can strongly attract and stably support the PA membrane to deduct the peel-off and collapse of the PA layer The optimal thin membrane nanocomposite (TFN) membrane has a high sodium sulfate rejection of 98.8% with water permeance of 1.4 L·m-2·h-1·bar-1 and a high Rose bengal rejection of 99.3% with ethanol permeance of 0.72 L·m-2·h-1·bar-1. The newly developed OSN membranes also demonstrate good stability in harsh solvents, after dimethylformamide (DMF) immersion at 80℃ for 5 consecutive days, the tested membrane still retains over 90% rejection rate of Congo red (Molar weight600 g/mol) in ethanol. To our knowledge, this is the first endeavor of coupling dopamine-modified multi-walled carbon nanotubes constructed interlayer and support-free interfacial polymerized PA membrane to fabricate TFN membrane for nanofiltration applications directly. The work aims to provide valuable insights into designing environmentally friendly and highly controllable TFN membranes by support-free interfacial polymerization.
Year: 2024