Amino-embedded carbon quantum dots incorporated thin-film nanocomposite membrane for desalination by pervaporation

Abstract

This study provides an in-depth investigation on the incorporation of carbon quantum dots (CQDs) in fabricating novel thin-film nanocomposite (TFN) membranes to address the high demand for highly water-permeable pervaporation (PV) membranes for desalination processes, especially for treating high-salinity water, brine, or wastewater. CQDs have emerged as a green nanofiller for improving membrane performance owing to its excellent biocompatibility, non-toxicity, uniform dispersion, and rich functional groups. Herein, we synthesize amino-embedded carbon quantum dots (ACQDs) via a simple one-pot hydrothermal method and employ them in interfacial polymerization to fabricate the ACQD-TFN membrane. Benefiting from the incorporation of ACQDs, the optimized ACQD-TFN membrane exhibited an enhanced water flux of 23.2 kg·m−2·h−1 at 70 °C during the treatment of a 10 wt% NaCl solution, which was 44% higher performance than that of the unmodified thin-film composite membrane. The ACQD-TFN membrane's salt rejection remained at 99.9% even after 96,000 ppm·h chlorine exposure, exhibiting excellent chlorine resistance. Also, the ACQD-TFN membrane's regular surface microstructure and increased hydrophilicity endowed good anti-fouling property, and its flux recovery rate reached 91% after 5 fouling-cleaning cycles. This work provides a feasible strategy for fabricating highly permeable, chlorine-resistant, and anti-fouling PV membranes for desalination applications.