Efficient visible light-driven Photodegradation of malachite green dye using carbon quantum dots-MXene nanocomposite: Synthesis, characterization, and performance evaluation

Abstract

Background

Removal of azo dyes is one of important issue in water treatment studies and many of research works focused on it. Current work represents a simple and economical feasible to synthesize carbon quantum dots (CQDs) integrated with Ti₃C₂(OH)₂ MXene nanocomposite (CQDs/MXene) for rapid photodegradation of Malachite green (MG) under visible light irradiation. In practice, CQDs were synthesized via a hydrothermal method from Petroselinum crispum leaves, while Ti₃C₂(OH)₂ nanosheets resulted from a simple etching process of Ti₃AlC₂ using an alkaline solution (KOH with a trace amount of water).

Methods

Subsequently, nanocomposites (CQDs/MXene) were prepared by a self-assembly process through sonication-assisted mixing process under ambient conditions. The prepared catalysts were characterized using various analyses like analysis employing field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and an energy dispersion X-ray (EDX) spectrometer to determine the chemical composition. The optimum measurement of this activity of the CQDs/MXene was attained through adjusting several constraints such as pH, dye concentration, amount of temperature and photocatalyst.

Significant findings

The kinetics of the degradation process were represented using the Langmuir–Hinshelwood model, with a rate constant (k) of 0.1382 min⁻¹. This means that the degradation of MG dye follows a first-order reaction with respect to the dye concentration. In addition, the study also looked at the reusability of the prepared CQDs/MXene nanophotocatalyst and found that it exhibited outstanding stability after three reaction cycles. This suggests that the nanophotocatalyst is a promising material for efficient and sustainable degradation of MG dye. The nanocomposite displays high photocatalytic activity with the ability to reduce 96.1 % of the MG dye concentration after being exposed to 25 min of visible light.