Sustainable synthesis of carbon nanomaterials from waste tire-derived char using microwave pyrolysis

The increasing accumulation of non-biodegradable waste tires poses significant environmental challenges, necessitating innovative recycling solutions.This study investigates the use of waste tire-derived char (WTRC) for the synthesis of carbon nanomaterials (CNMs) through microwave-assisted pyrolysis.Waste tire rubber crumbs (WTRCs) were pyrolyzed at 600 W for 20 minutes to produce char, which was subsequently purified and utilized as a precursor for CNMs synthesis.CNMs were synthesized using tire-derived char and ferrocene as a catalyst at varying microwave power levels (600-1000 W), reaction times (10-40 min), and catalyst-to-precursor ratios (25-100 wt%).Comprehensive characterization techniques, including FT-IR, XRD, Raman spectroscopy, TEM, and FESEM, revealed that Carbon nanofibers (CNFs) synthesized at 1000 W under optimal conditions exhibited bamboo-shaped, tubular structures with diameters ranging from 425 to 881 nm.XRD confirmed the graphitic nature of the CNFs, while Raman spectroscopy indicated a moderate degree of graphitization (I/ I = 1.61).TEM analysis confirmed a tip-growth mechanism, where residual iron-based catalyst nanoparticles were embedded at the tips of the fibers, promoting CNFs elongation.FESEM analyses showed residual ironbased catalyst particles embedded within the CNFs, highlighting the importance of further refining synthesis conditions to enhance purity.These CNFs, with their porous structure and high surface area, hold potential for adsorption-based applications such as wastewater treatment and pollutant removal.