Comparative study of in situ and ex situ incorporation of carbon quantum dots into cellulose acetate nanofibers: effects on pollutant dye removal

Abstract This study investigates the synthesis and characterization of cellulose acetate (CA) nanofiber composites incorporating carbon quantum dots (CQDs) for photocatalytic applications. The CQDs were synthesized via an electrochemical carbonization process using a two-electrode system and were integrated into CA nanofibers using both in situ and ex situ methods. The chemical composition was analyzed by Fourier-transform infrared spectroscopy (FTIR), confirming the successful incorporation of CQDs into the nanofibers. The optical properties of the CQDs embedded in the nanofibers were assessed via UV–Vis spectroscopy, and the morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM images revealed uniform, smooth nanofibers, and TEM analysis showed a better dispersion of CQDs in the in situ nanofibers compared to ex situ samples. The photocatalytic degradation of methylene blue dye under UV light was used to evaluate the photocatalytic efficiency of the materials. The results indicated that the in situ CQDs/CA nanofibers exhibited superior photocatalytic activity, with a significant increase in the degradation rate compared to the nanofibers by the ex situ process. These findings suggest that the incorporation method of CQDs plays a crucial role in enhancing the photocatalytic performance of the nanofibers.