Preparation of N, Cl Co-Doped Lignin Carbon Quantum Dots and Detection of Microplastics in Water

The research on rapid and efficient detection of microplastics in water is still in its early stages. Fluorescence feature recognition represents an important and innovative approach to microplastic detection. While carbon quantum dots have been widely used in various environmental detection methods, their use for detecting microplastics in water environments has been rarely reported. In this study, N and Cl co-doped carbon quantum dots were synthesized via a hydrothermal method. The heteroatom doping process endowed them with blue luminescence properties, and their adsorption for microplastics was improved through the introduction of positive and negative charges and intermolecular forces. By utilizing a combined mechanism of fluorescence and Rayleigh scattering, the detection of polystyrene microplastics with three different particle sizes was achieved. In the detection process, it exhibits excellent light stability. Notably, the nano-polystyrene exhibited a good nonlinear relationship within the range of 0.01 g/L to 0.001 g/L, with R2 values of 0.923 and 0.980 and a detection limit of 0.4 mg/L. These findings provide a novel approach for the detection of nano microplastics.