Optimization of Preparation Technology for PET-Based Carbon Dots by Response Surface Method and Its Application.

Area of Science:

• Materials Science
• Nanotechnology
• Waste Management

Background:

• Polyethylene terephthalate (PET) waste poses environmental challenges.
• Developing high-value applications for recycled PET is crucial for sustainable waste management.
• Carbon Dots (CDs) offer unique optical properties with diverse applications.

Purpose of the Study:

• To develop a high-value utilization strategy for PET waste through the synthesis of PET-based Carbon Dots (PET-CDs).
• To optimize the synthesis conditions for PET-CDs using response surface methodology, focusing on maximizing fluorescence quantum yield (QY).
• To evaluate the potential applications of the synthesized PET-CDs in light-blocking films and fluorescence anti-counterfeiting technologies.

Main Methods:

• One-step hydrothermal synthesis using PET waste, pyromellitic acid (PMA), and ammonia (NH3·H2O) as precursors.
• Response surface methodology (RSM) employed to optimize precursor ratios and reaction parameters for PET-CD synthesis.
• Characterization of PET-CDs' optical properties (excitation-independent emission, QY), morphology, surface chemistry, and particle size.

Main Results:

• Optimized synthesis conditions yielded PET-CDs with a high fluorescence quantum yield (QY) of 83.34%.
• The synthesized PET-CDs exhibit excitation-independent emission (360–440 nm), with optimal excitation at 410 nm and emission at 485 nm.
• PET-CDs possess spherical morphology (1.61–4.92 nm size, 2.88 nm average) with surface amino and carboxyl groups.
• PET-CDs demonstrated effective UV and blue light blocking, comparable to commercial anti-blue light glasses.
• PET-CDs enabled the creation of patterns visible under UV light but invisible in visible light, suitable for anti-counterfeiting.

Conclusions:

• The developed hydrothermal method provides an efficient and high-value recycling pathway for PET waste.
• Optimized PET-CDs exhibit excellent fluorescence properties and significant potential for advanced material applications.
• PET-CDs are viable for use in light-blocking films and sophisticated fluorescence anti-counterfeiting solutions, contributing to both waste reduction and technological innovation.