Development of a chemical-free floatation technology for the purification of vein graphite and characterization of the products

Abstract

A novel and simple flotation technique has been developed to prepare high-purity graphite from impure graphite. In this method, a suspension of pristine powdered graphite (PG) is dispersed and stirred in water without adding froth formers or supportive chemicals. This makes fine particles of graphite move upwards and float on water. X-ray diffraction (XRD) analysis reveals that the floated graphite (FG) has a lower c-axis parameter, indicating the removal of interlayer impurities. A notable increase in the intensity ratio of the D band to G band in the Raman spectra indicates that the FG has more edge defects due to their smaller crystallite sizes. Transmission electron microscopic (TEM) analysis shows the number of layers in FG has been reduced to 16 from 68 in PG. The absence of C=O vibration of Fourier Transformed Infrared (FT-IR) spectroscopy in treated and untreated samples suggests that their layers are not significantly oxidized. However, X-ray photoelectron spectroscopic (XPS) analysis shows the presence of C–O–C ether functionalities, possibly on edge planes. Further, the product has higher purity with increased carbon content. Therefore, the technique is helpful for the value enhancement of graphite, the reduction of the chemical cost of the conventional techniques, environmental friendliness, and improvement of its applications.

Assessment of Graphite, Graphene, and Hydrophilic-Treated Graphene Electrodes to Improve Power Generation and Wastewater Treatment in Microbial Fuel Cells

“…Graphene mappings ( Figure 3 b) show a composition of carbon 88.87% and oxygen 10.40%, followed by sulfur, and silicon, 0.53%, and 0.2%, respectively. In both graphite and graphene, a distribution of carbon and oxygen typical of these materials was observed [ 21 , 22 ], and the presence of the other elements is attributed to depositions from wastewater to which the materials were exposed. Finally, Figure 3 c shows the spectral map of the HTG with a homogeneous surface composition of carbon (85.55%) and oxygen (8.31%).…”

Novel Platinum-Free Counter-Electrode with PEDOT: PSS-Treated Graphite/Activated Carbon for Efficient Dye-Sensitized Solar Cells

“…The counter electrodes were prepared using Sri Lankan natural vein graphite (GR) akes sourced from the Bogala mines in Sri Lanka. The powdered graphite samples were obtained by following the method outlined by Kumara et al [27]. Speci cally, the graphite akes were subjected to ball milling for 20 minutes, followed by sieving to achieve particles smaller than 63 µm.…”