Synthesis, processing, characterization, and applications of red mud/carbon nanotube composites

In the present study, red mud/carbon nanotube (RM/CNT) composites were synthesized by decomposition of hydrocarbon gas using the chemical vapor deposition (CVD) method. Red mud, a by-product of the Bayer process of alumina production, was used as a catalyst in this process. Synthesis was done at different growth temperatures (600, 700, 750 and 850 degrees C). The microstructure and morphology of the synthesized nanocomposite was characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Simultaneous Thermal Analysis (STA), and Raman spectra analysis. The prepared nanocomposite, which was prepared at 750 degrees C, was used for Pb (II) adsorption. The adsorption characteristics of the nanocomposite for Pb (II) removal were investigated as a function of pH, adsorbent dose, and contact time. The best result was obtained with 0.05 g of adsorbent at a pH=5 with 40 min of contact time. The results proved that RM/CNT composites are a good adsorbent for lead ions in comparison with unprocessed RM or pristine CNTs. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.