Department of Metallurgical and Materials Engineering, Polytechnic School, University of São Paulo (USP), Av. Professor Mello Moraes 2463, São Paulo 05508-030, SP, Brazil
Abel Cardoso Gonzaga Neto
Department of Metallurgical and Materials Engineering, Polytechnic School, University of São Paulo (USP), Av. Professor Mello Moraes 2463, São Paulo 05508-030, SP, Brazil
Kleber Bitencourt Vaccioli
Department of Metallurgical and Materials Engineering, Polytechnic School, University of São Paulo (USP), Av. Professor Mello Moraes 2463, São Paulo 05508-030, SP, Brazil
Hugo Rafael Vallejo Angulo
Department of Metallurgical and Materials Engineering, Polytechnic School, University of São Paulo (USP), Av. Professor Mello Moraes 2463, São Paulo 05508-030, SP, Brazil
Leonardo Gondim de Andrade e Silva
Instituto de Pesquisas Energéticas e Nucleares, IPEN/CNEN, Cidade Universitária, Av. Prof. Lineu Prestes 2242, São Paulo 05508-000, SP, Brazil
Samuel Marcio Toffoli
Department of Metallurgical and Materials Engineering, Polytechnic School, University of São Paulo (USP), Av. Professor Mello Moraes 2463, São Paulo 05508-030, SP, Brazil
Ticiane Sanches Valera
Department of Metallurgical and Materials Engineering, Polytechnic School, University of São Paulo (USP), Av. Professor Mello Moraes 2463, São Paulo 05508-030, SP, Brazil
This paper presents a comparison of traditional thermal and chemical reduction methods with more recent ionizing radiation reduction via gamma rays and electron beams (e-beams). For GO, all synthesis protocols were adapted to increase production scale and are a contribution of this work. The typical Raman D-band of the GO was prominent (ID/IG ratio increased sixfold). When comparing the GO reduction techniques, dramatic differences in efficiency and GO particle characteristics were observed. Although thermal and chemical reduction are effective reduction methods, as shown through the use of FTIR spectroscopy and the C/O ratio from EDS chemical analysis, the thermal process renders great weight losses, whereas chemical processing may involve the use of hazardous chemical compounds. On the other hand, comparing the gamma rays and e-beam for 80 kGy, the Raman spectra and chemical analysis suggested that the e-beam caused a greater GO reduction: C/O ratio from EDS of 5.4 and 4.1, respectively. In addition to being fast and effective, ionizing radiation reduction processes allow easier control of the reduction degree by adjusting the radiation dose. When the dose increased from 40 to 80 kGy, the Raman spectra and EDS showed that the ID/IG and C/O ratios increased by 15 and 116%, respectively.
