The Use of the Exfoliated Graphite for the Removal of the Aqueous Naphthenic Acids

Ahmed Moustafa, Seoktae Kang, and Mohamed Gamal El-Din


Naphthenic Acids (NAs), Exfoliated graphite, Oil Sand Process-affected waters


NAs are the primary toxic compounds in the Oil Sand Process-affected Waters (OSPW) (MacKinnon and Retallack 1981). They are water soluble hydrocarbons at high pH values and responsible for the acidic content of bitumen. NAs removal using the exfoliated graphite (EG) is a promising remediation tool, especially that a reported (130g/g) of hydrocarbons are effectively removed from water using the EG. The purpose of the current research is to study the removal efficiency of the NAs using different samples of EG. Those EG samples were prepared at different exfoliation temperatures and then characterized using the Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The isotherm experiments took place to assess the adsorption capacity of the EGs and the quantifications of aqueous NAs were obtained by the FT-IR spectroscopy before and after the adsorption (Jivraj et al., 1995). However the lower expansion volume and surface area of the EG sample fabricated at 500 ÂșC (EG-500) than that of the EG-800, higher removal efficiency was observed for EG-500. The pH values of solutions were measured before and after adsorption and lower pH was detected for the sample contained EG-500. Samples were investigated using the electron dispersive spectroscopy (EDS) and the results showed that the EG-500 contained higher residual sulphur. This acidic content decreases the solubility of the NAs and facilitates the adsorption for the EG-500. Accordingly a pH buffer was used in the following experiments and the results showed higher removal efficiency for EG-800. The maximum removal efficiency reached was almost 70% of the total NAs in solutions.

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