03 Al2O3 27.76 Fe2O3 0.62 FeO 4.99 MnO 0.08 CaO 5.00 MgO 1.43 Na2O 0.14 K2O 0.90 Particle size distributions were obtained from the TEM micrographs. The particle size distributions of as-received and acetylene-treated coal fly ash (at different temperatures) were also determined using a Malvern particle size analyser (Master Sizer 2000, Malvern Instruments Ltd., Worcestershire, Selleck BYL719 UK). Both these materials were analysed by dispersing them in two different solutions: (1) water and (2) a Luminespib order Dolapix solution (100 ml water:2 ml Dolapix (Zschimmer & Schwarz, Lahnstein, Germany)). Laser Raman spectroscopy was used to ascertain the

type of carbonaceous materials that were formed. The thermal stability of the acetylene-treated fly ash products was determined by using a PerkinElmer Pyris 1 thermogravimetric analyser (TGA; PerkinElmer, Waltham, MA, USA). In these measurements, a 10 mg sample was heated to 900°C at a rate of 10°C/min under air (20 ml/min). The specific surface areas

of approximately 200 mg of as-received and acetylene-treated fly ash materials (between 400°C and 700°C) were determined using the Brunauer-Emmett-Teller Acadesine clinical trial (BET) surface area method by N2 adsorption using an ASAP 2000 Micrometrics Tristar surface area and porosity analyser (Micromeritics Instrument Co., Norcross, GA, USA). Both materials were degassed at 150°C for 4 h under nitrogen before testing to remove the moisture. Mössbauer spectroscopy measurements were carried out in transmission mode with a 10 miC 57Co(Rh) source. Measurements were performed at room

temperature on the as-received and acetylene-treated fly ash samples at 700°C. Results and discussion Morphological studies The sizes, shapes and morphologies of the as-received and acetylene-treated fly ash were investigated using TEM. The results can be observed in Figure 1a,b,c,d,e,f. The as-received fly ash materials (Figure 1a) appeared to be spherically shaped. Fly Galeterone ash agglomerates shaped like these have often been observed with inorganic salts and may be caused by inter-particulate fusion during the cooling of the fly ash [40]. In Figure 1b,c,d,e, it was observed that the glassy, smooth-shaped fly ash particles began to be coated with regularly and irregularly shaped CNFs when subjected to acetylene. In Figure 1c,d, it was noted that the types of CNMs that were formed varied from large CNFs to smaller CNTs. While the exact growth mechanism of CNTs/CNFs formed from fly ash as a catalyst has not been fully ascertained, it appeared that tip growth could not be discounted (as seen by the red-coloured circles in Figure 1e,f). This type of growth has typically been observed when either iron (Fe) or cobalt (Co) was used as a catalyst for CNM formation. While it is known from previous studies that at least 2.5% of iron is required as a catalyst for CNF formation when using fly ash [36], the XRF data (Table 1) obtained for the South African coal fly revealed that at least 5.