In order to understand the adsorption mechanism for removing heterocyclic sulfur/nitrogen compounds from liquid hydrocarbons on activated carbon, the liquid-phase adsorption of quinoline, indole, benzothiophene, dibenzothiophene as well as naphthalene and fluorene on four activated carbons were conducted in both batch and fixed-bed adsorption systems by using model fuels. The four activated carbons with different surface chemistries were prepared by oxidation with ammonium persulfate (APS) and heat treatment, and their oxygen-containing functional groups (OCFGs) on the surface were characterized by the temperature-programmed desorption (TPD). The influences of surface OCFGs and co-existing compounds on the adsorptive removal of heterocyclic sulfur/nitrogen compounds were examined. The results showed that the OCFGs play a decisive role in the adsorptive removal of nitrogen compounds. For the carbon adsorbents with no OCFGs, the adsorption is conducted dominantly through the π–π stacking interaction and the affinity of adsorbates is dependent on the size of their π systems. For the carbon adsorbent with bound OCFGs, the adsorption is dominantly based on the acid–base interaction and the π–H interaction, resulting in the much higher capacity and selectivity for nitrogen compounds. The carbon adsorbent with phenol, carboxylic anhydride, and lactone groups, but no carboxylic groups gives the highest capacity and selectivity for indole, probably through the H-bond interaction. The effect of the co-existing compounds depends on their adsorption mechanism and affinity. Careful design and modification of carbon adsorbents are able to selectively remove the undesired compounds from the liquid hydrocarbons.

The radical polymerization of styrene was investigated in the presence of five diaryl diselenide compounds with different substitution groups on the benzene ring under visible light irradiation. It showed that bis(2,6-dimethylphenyl) diselenide (DmXDS) with two methyl groups on every benzene ring was the most efficient mediator for preparing polymers with a predetermined molecular weight and narrow molecular weight distribution. The reasons were analyzed through a quantum calculation method. The polymerization behavior of styrene in the presence of DmXDS was further investigated in depth. The results showed a typical living radical polymerization process. Polymers retaining the selenide structures at both the α- and ω-ends were verified by NMR and MALDI-TOF. Such end capped selenide groups could be transformed into terminal vinyl groups with a high efficiency under oxidative conditions, which offers a route to prepare “macromonomers” with a narrow molecular weight distribution.

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.