Carbon quantum dots doped thin-film nanocomposite (TFN) membrane on macroporous ceramic hollow fiber support via one-step interfacial polymerization

Abstract

The amino (NH2) modified carbon quantum dots (N-CDs) doped thin film nanocomposite (TFN) membranes were prepared on the macroporous ceramic hollow fiber (CHF) substrate with a pore size of about 300 nm through one-step interfacial polymerization (IP) process. The abundant hydroxyl, carboxyl, and amino groups of aqueous phase additives (N-CDs and polyvinyl alcohol (PVA)) provide attachment sites for ethylenediamine (EDA) to build a modified membrane structure. Molecular dynamics (MD) simulation was employed to study the diffusion process in IP. The results show that the addition of N-CDs reduced the EDA diffusion coefficient significantly from (4.58 ± 0.50) × 10−5 cm2/s to (1.44 ± 0.10) × 10−5 cm2/s. The wrinkled and ultra-thin polyamide (PA) layer with a thickness of 28 ± 3 nm was observed by the field-emission scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and dynamic contact angle were used to characterize the chemical structure and hydrophilicity. The effect of additives concentration on pervaporation (PV) performance for ethanol (EtOH) dehydration has been investigated systematically. The resultant membrane exhibited excellent performance with the total permeation flux of 3.15 kg·m−2·h−1 and separation factor of 1127. Besides, there was no significant performance decline during the 160 h long-term stability test, indicating that the membranes own the potential application in industry.