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

Abstract

Pyrolysis is a feasible solution for environmental problems related to the inadequate disposal of waste tires, as it leads to the recovery of pyrolytic products such as carbon black, liquid fuels and gases. The characteristics of pyrolytic carbon black can be enhanced through chemical activation in order to produce the required properties for its application. In the search to make the waste tire pyrolysis process profitable, new applications of the pyrolytic solid products have been explored, such as for the fabrication of energy-storage devices and precursor in the synthesis of nanomaterials. In this study, waste tires powder was chemically activated using acid (H2SO4) and/or alkali (KOH) to recover pyrolytic carbon black with different characteristics. H2SO4 removed surface impurities more thoroughly, improving the carbon black’s surface area, while KOH increased its oxygen content, which improved the carbon black’s stability in water suspension. Pyrolytic carbon black was fully characterized by elemental analysis, inductively coupled plasma–optical emission spectrometry (ICP-OES), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), N2 adsorption/desorption, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS), dynamic light scattering (DLS), and ζ potential measurement. In addition, the pyrolytic carbon black was used to explore its feasibility as a precursor for the synthesis of carbon dots; synthesized carbon dots were analyzed preliminarily by SEM and with a fluorescence microplate reader, revealing differences in their morphology and fluorescence intensity. The results presented in this study demonstrate the effect of the activating agent on pyrolytic carbon black from waste tires and provide evidence of the feasibility of using waste tires for the synthesis of nanomaterials such as carbon dots.

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

“…The presence of sulfates may not be due to H 2 SO 4 activation of the precursor because CDs from nonactivated carbon black had a low concentration of sulfates. Sulfates may be formed during chemical oxidation with the precursor, which reported a sulfur content between 1.4% and 4.5% [ 33 ]. The low concentration of chloride might be due to the dilution preparations of the required chemical agents and from the double-distilled water used during dialysis.…”

“…Four different processes were performed to modify the characteristics of the recovered carbon black: (1) pyrolysis, (2) H 2 SO 4 activation and pyrolysis, (3) KOH activation and pyrolysis, and (4) H 2 SO 4 activation, KOH activation, and pyrolysis. The complete characterization of the carbon black recovered from each process is presented in our previous research [ 33 ]. The differences presented in their elemental composition, surface area, and Raman spectra (I D /I G ratio), obtained by an Organic Elemental CHNS-O Analyzer Flash 2000 (Thermo Scientific TM , Waltham, MA, USA), an Autosorb IQ TPX Quantachrome gas adsorption analyzer (Boynton Beach, FL, USA) using the BET method, and a LabRAM HR Evolution (Horiba, Jobin Yvon, Longjumeau, France), respectively, are presented in Table 1 .…”

“…Carbon black was recovered from waste tire powder with a particle size of 75–125 µm obtained from LT Lehigh Technologies (Tucker, GA, USA). The detailed methodology is reported in [ 33 ]. In brief, when chemical activation (either H 2 SO 4 or KOH) was used, waste tire powder was impregnated at 80 °C with an activating agent/tire ratio of 4 before being filtered and dried.…”

“…In brief, when chemical activation (either H 2 SO 4 or KOH) was used, waste tire powder was impregnated at 80 °C with an activating agent/tire ratio of 4 before being filtered and dried. The activation temperature, weight ratio, and activation agents were chosen based on optimal values reported in the literature for improving the properties of carbon black [ 19 , 21 , 33 ]. The pyrolysis process was performed on a Lindberg Blue M tubular muffle (Thermo Scientific, Watertown, WI, USA) with a heating rate of 10 ᵒC/min until reaching 950 °C with a nitrogen flow of 200 mL/min.…”

Recent Advances in Waste Plastic Transformation into Valuable Platinum‐Group Metal‐Free Electrocatalysts for Oxygen Reduction Reaction

“…In recent times, González‐González et al. produced pyrolytic carbon‐black from the scrap tires using a combination of direct pyrolysis and chemical activation (using H 2 SO 4 and KOH) as a potential candidate for nanomaterial precursor [84] . Inspired by the extraordinary characteristics offered by the scrap tire‐derived carbon nanomaterials, Hood et al.…”