Waste Egg Tray Paper Pulp Derived Carbon Dots for Detection of Fe³⁺ Ions via Fluorescence On-Off Process

Development of rapid and cost effective techniques for detecting metal ions is important to prevent water pollution and ensure public safety. Herein, we report the synthesis of fluorescent carbon dots (t-CDs) from waste egg tray paper pulp by one step hydrothermal treatment. The synthesized t-CDs have been characterized by various analytical techniques. The prepared t-CDs demonstrated excitation dependent emission and particle sizes ranges from 7 nm to 14 nm with mean diameter of 9 nm. Our study show that the fluorescence of the t-CDs is efficiently turn off upon addition of Fe³⁺ due to the formation of complex between Fe³⁺ and the surface functional groups of t-CDs which enables aggregation and electron transfer process, resulting in fluorescence quenching. There is a linear relationship between the fluorescence quenching of the t-CDs versus the concentration of the Fe³⁺ in the ranges, 0-40 µM with limit of detection of 1.418 µM. Further, the t-CDs is applied as sensor for detection of Fe³⁺ in real water samples, demonstrating its utility in environment monitoring.