WITHDRAWN: One-pot simple green synthesis of water-soluble cleaner fluorescent carbon dots from cellulose and its sensitive detection of iron ion

Abstract

Abstract Fluorescent carbon nanoparticles as a new kind of fluorescent material have attracted considerable research interest in a wide range of applications due to their low-cost, low-toxicity and good biocompatibility. In this work, one-pot simple and green approach for the synthesis water-soluble cleaner fluorescent carbon dots has been developed using hydrothermal method of cellulose in the presence of ammonium carbonate. The preparation conditions such as hydrothermal temperature, hydrothermal time, and amount of cellulose were optimized. The results indicated that the optimum preparation conditions of the carbon dots were 2.0 g cellulose into 25 mL of the cellulose dosage, 180 o C of hydrothermal temperature, and 12 h of hydrothermal time. The structure and morphology of carbon dots were characterized by fourier transform infrared spectroscopy and transmission electron microscopy. The CDs are mainly spherical morphology with an average diameter of 1.5 nm. The influences of concentration of carbon dots, acidity and different solvent on the fluorescent intensity of as-prepared carbon dots solution were investigated. The fluorescence of as-prepared carbon dots could be quenched by the iron ions because of the electron or energy transfer from the selective interaction between oxygen-containing groups on the surface of carbon dots and iron ions, which realized a sensitive detection of iron ions. The effects of environmental factors on the fluorescence intensity in details were investigated; and the obtained results showed that the optimum conditions for its interaction with iron ions were: 1.0×10 -6 g/mL of concentration of carbon dots, 5.5 of buffer solution acidity, and 15 min of time. The proposed method has been successfully applied for the determination of iron ions in water and soil samples with satisfactory results. Moreover, it is attractive that as-prepared carbon dots can be used as an effective fluorescent probe for the detection of iron ions with good selectivity in an aqueous solution.