Preparation of Fluorescent Carbon-Based Dots from Waste Tire Pyrolysis

Abstract

The pyrolysis of waste tire has been proposed as an alternative route to its recycling producing residual oils that can be used as fuels. In this work, a physicochemical process to obtain carbonbased dots (CBD) from carbon black (CB L) derivatives of tires is described. For this, the CB L was treated with different acids to produce CB L1 and CB L2 particles suspension. The pH of the suspension was adjusted to 5.6 to precipitate remaining impurities. Afterwards, the supernatant was ultra-centrifuged and the yellow pale solid, the purified CBD obtained by roto evaporation, was characterized by ultraviolet-visible spectrophotometer (UV-Vis), photoluminescence (PL) at 320-380 nm, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared microscopy (µFTIR), and X-ray photoelectron spectroscopy (XPS). This material showed the typical excitation wavelength dependent emission and a PL quantum yield of 19.29% and was constituted by a well-defined spherical shaped and single sheets of "graphene quantum dots" with undefined shape, with potential applications in optoelectronic and fluorescence imaging devices.

Characterization of Chemically Activated Pyrolytic Carbon Black Derived from Waste Tires as a Candidate for Nanomaterial Precursor

“…As can be seen in Figure 8, all the carbon black precursors generated spherically-shaped nanoparticles. Typically, carbon dots are spherical shaped [88][89][90][91], which is in agreement with carbon dots synthesized in this study; however, it has been reported that carbon dots from waste tires synthesized by a physicochemical method was not spherically shaped and monodisperse [43].…”

“…Differences in the intensity of fluorescence emission were observed: a higher intensity in fluorescence emission at the range of 590 ± 35 nm in all carbon dots samples, and a higher fluorescence emission in the fraction from 0-10 kDa, regardless of the precursor. It has been previously reported that carbon dots from pyrolytic carbon black presented their maximum fluorescence signal at 415 nm [43]. In our study, the maximum fluorescence emission was observed at longer wavelengths, possibly associated with a higher oxidation degree [97,98] caused during the chemical oxidation with HNO 3 .…”

“…The use of ordinary carbon black from waste tires to synthesize carbon dots has been attempted. Mohammad et al converted tires into carbon dots of 2-3 nm through an hydrothermal process for their use as photosensitizers [42], while other studies have suggested the use of carbon dots from tires in fluorescence imaging and optoelectronic devices [43]. These recent works have focused on the characterization and applications of the carbon dots produced.…”

Synthesis, Purification, and Characterization of Carbon Dots from Non-Activated and Activated Pyrolytic Carbon Black

“…It has been reported that carbon dots from pyrolytic carbon black presented a PL peak at 415 nm at the maximum excitation wavelength (380 nm) [ 70 ]. As can be seen in Figure 10 , in our study, a bathochromic shift (shift to longer wavelengths) was observed in all carbon dot samples compared to those reported in the literature.…”

Study on novel fluorescent carbon nanomaterials in food analysis

“…Heavy metal ions such as Hg 2+ , Au 3+ , Cr 6+ , Ag + , Fe 2+ , Cu 2+ , and Fe 3+, which are easily accumulated in animals and plants, are a significant factor that contributes to water or environmental a wide basic surface region, regardless of the form they are (Parra et al, 2020;Verma et al, 2020). Various studies on the synthesis and use of carbon quantum dots have been conducted in recent years.…”