Hence, in their study, unlike in this present work, Dunens et al. were required to further impregnate their ash with iron in order for CNT/CNF growth to occur. In a similar manner,

Diamond [49], using acid etching techniques, demonstrated that the location of the iron and its morphology greatly differed for every fly ash particle within the sample. This, he suggested, was caused by the inhomogeneous nature of coal. The magnetic feature for the as-received sample was fitted with three sextets (SX1_U, SX2_U and SX3_U) and the spectrum for the acetylene-treated sample was analysed with one buy Idasanutlin sextet (SX1_T), while the non-magnetic spectral components for both samples were fitted with two quadrupole split doublets. Conclusions CNFs (and a small amount of CNTs) were successfully produced by directly using an as-received South African coal fly ash. The smooth, glassy and inert surfaces of the South African coal fly ash were covered with irregularly shaped CNFs in the presence of acetylene and hydrogen at temperatures as low as 400°C. Laser Raman spectroscopy confirmed the formation of CNFs. TGA showed that there

were different forms of carbon present, i.e. graphitic and amorphous. On the other hand EDS, XRD and Mössbauer spectroscopy selleck kinase inhibitor confirmed that iron, most likely in the form of iron carbide, was directly associated with the formation of CNFs. Therefore, this study has demonstrated the successful synthesis of carbon nanostructured materials from waste South African coal fly ash without chemical selleck pre-treatments (such as the impregnation of other metals) or thermal modifications. Since CNFs may in the future be beneficial for applications such as particulate nanofillers in polymer matrices, this intervention could result in the reduction of environmental pollutants.

Concomitantly, this may also bring relief to the financial burden involved in the disposal costs of this and related coal fly ash around the world in the long run. Authors’ information NH holds a master’s degree and is currently a PhD student at the University of the Witwatersrand. AS received his PhD after publishing in high impact factor journals and is now working at the Registrar’s office at the University of the Witwatersrand. PF received his PhD from Cambridge University (UK) and is now working as a lecturer at the University of the Witwatersrand. HM holds a PhD and is a lecturer at the School of Physics. DN holds a PhD and is the head of the Mössbauer facility at the School of Physics. DB holds a PhD, is a professor and is the head of the XRD unit at the Wits School of Chemistry. SD holds a PhD and is currently a senior lecturer and research focus area coordinator for CNTs and strong composites in the DST-NRF Centre of Excellence in Strong Materials at the University of the Witwatersrand. Acknowledgements The authors would like to thank Dr P.