Adsorption of quinoline from liquid hydrocarbons on graphite oxide and activated carbons

Four carbon-based adsorbents (activated carbon, oxidatively modified activated carbon, graphite, and graphite oxide) were investigated as adsorbents for selectively removing quinoline from a model hydrocarbon fuel. The surface chemical properties of these carbon-based adsorbents were characterized by temperature-programmed desorption coupled with mass spectrometry (TPD-MS), X-ray photoelectron spectroscopy (XRD), elementary analysis (EA) and nitrogen adsorption-desorption analysis in detail. The influences of the textural structures and the surface functional groups of these carbon adsorbents on their adsorption performance were examined. The activated carbon modified by ammonium persulfate oxidation (APS) can achieve an adsorption capacity as high as 35.7 mg-N g(-1). The results indicated that the oxygen-containing functional groups on the surface play a crucial role in determining their adsorptive performance for quinoline. In addition, enhancement of the interlayer distance in the graphite oxide results in a dramatic increase in the adsorption capacity of the graphite oxide. The accessibility of the oxygen functional groups on the surface for quinoline is important to the adsorption behavior. Considering its high adsorption capacity and good regenerability, the graphite oxide may also be a promising adsorbent for selectively adsorptive removal of nitrogen compounds from liquid hydrocarbon streams.