In this work

the effects of different metal ions loaded onto activated carbon on the adsorption of benzothiophene were investigated.Six kinds of transition metal ions were separately loaded on the activated carbon by the impregnation method.Isotherms of benzothiophene on the activated carbon were separately measured at different temperature

and then the variation of the adsorption of benzothiophene on the activated carbon was discussed with the help of the hard and soft acid and base (HSAB)principle.The results showed that loading Ag＋，Ni2＋，Cu2＋ or Zn2＋ ion on the activated carbon obviously improved its adsorption of benzothiophene

while loading Fe3＋or Co3＋ion on the activated carbon caused a decrease in its adsorption of benzothiophene in comparison with the original unloaded activated carbon

which was due to the variation of the nature of soft and hard acid on the surface of the activated carbon. Absolute hardness calculation using the density functional theory (DFT) indicated that benzothiophene belonged to soft bases. Since Ag＋ was a soft acid

the loading of Ag＋ ion on the activated carbon led to an increase in the soft acid on its surface and thus improved its adsorption of benzothiophene

and since Ni2＋，Cu2＋ and Zn2＋ ions belonged to borderline acids

the loading of these ions on the activated carbon led to an increase in the borderline acids on its surface and thus improved its adsorption of benzothiophene to some extent. Since Fe3＋and Co3＋ions belonged to hard acids

the loading of Fe3＋or Co3＋ion on the activated carbon led to an increase in the hard acid on its surface and consequently a decrease in its adsorption of benzothiophene.