Harnessing carbon dots from parthenium weed for photocatalytic degradation of malachite green and Fe3+ ion sensing

Abstract

Environmental pollutants, such as invasive weeds and synthetic dyes, pose significant threats to ecosystems and human health. Parthenium weed (PW), an aggressive invader, disrupts native biodiversity, while synthetic dyes, particularly Malachite Green (MG), is persistent and considered parasiticide in aquaculture. This study explores synthesis of green fluorescent carbon dots (WCDs) from flowers of PW using simple pyrolysis method for photodegradation and sensing of Fe³⁺ ions. The synthesized WCDs, with a spherical size of 3.57 nm, demonstrated remarkable efficiency in the degradation of MG dye, achieving a degradation efficiency of 96.5% within 120 min of reaction time. The degradation kinetics followed a first-order reaction with a rate constant of 0.0257 min⁻¹ at pH 10.0. Furthermore, WCDs exhibited a low limit of detection (LoD) 4.4 μM and limit of quantification (LoQ) 14.6 μM for ferric ion sensing, underscoring their potential for sensitive detection applications. The band gap of WCDs was determined to be 2.65 eV, indicative of their optical properties and potential for photocatalytic applications. The synthesis of WCDs from an abundant and renewable biomass source underscores the eco-friendly nature of the proposed approach, further enhancing its potential for real-world applications.

Graphical Abstract