González-González Reyna Berenice, González Lucy T, Iglesias-González Sigfrido, González-González Everardo, Martinez-Chapa Sergio O, Madou Marc, Alvarez Mario Moisés, Mendoza Alberto
Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, Monterrey 64849, N.L., Mexico.
Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA 92697, USA.
Nanomaterials (Basel). 2020 Nov 6;10(11):2213. doi: 10.3390/nano10112213.
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 (HSO) and/or alkali (KOH) to recover pyrolytic carbon black with different characteristics. HSO 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), N 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.
热解是解决与废旧轮胎处置不当相关环境问题的一种可行方案，因为它能回收热解产物，如炭黑、液体燃料和气体。通过化学活化可以增强热解炭黑的特性，以产生其应用所需的性能。为了使废旧轮胎热解过程有利可图，人们探索了热解固体产物的新应用，例如用于制造储能装置和作为纳米材料合成的前驱体。在本研究中，使用酸（H₂SO₄）和/或碱（KOH）对废旧轮胎粉末进行化学活化，以回收具有不同特性的热解炭黑。H₂SO₄更彻底地去除了表面杂质，提高了炭黑的表面积，而KOH增加了其氧含量，从而提高了炭黑在水悬浮液中的稳定性。通过元素分析、电感耦合等离子体发射光谱法（ICP - OES）、傅里叶变换红外光谱法（FTIR）、拉曼光谱法、X射线衍射（XRD）、N₂吸附/脱附、扫描电子显微镜 - 能量色散X射线光谱法（SEM - EDS）、动态光散射（DLS）和ζ电位测量对热解炭黑进行了全面表征。此外，还利用热解炭黑探索了其作为碳点合成前驱体的可行性；对合成的碳点通过SEM和荧光微孔板读数仪进行了初步分析，揭示了它们在形态和荧光强度上的差异。本研究结果证明了活化剂对废旧轮胎热解炭黑的影响，并提供了利用废旧轮胎合成碳点等纳米材料可行性的证据。
