Fe^(3+)/Cu^(2+)/Ag^+改性高比表面活性炭对乙腈中二苯并噻吩的吸附

Adsorption of Dibenzothiophene in Acetonitrile on Fe^(3+)/Cu^(2+)/Ag^+ Modified Activated Carbons with High Specific Surface Area

应用浸渍法,采用Fe3+、Cu2+和Ag+对高比表面活性炭(AC)进行改性,制备出3种改性的AC(Fe3+/AC、Cu2+/AC和Ag+/AC).采用静态吸附法测定改性AC吸附乙腈溶液中二苯并噻吩(DBT)的吸附等温线,应用程序升温脱附法(TPD)测定DBT在未改性AC及3种改性AC上的脱附峰面积,并采用Boehm滴定法测定这4种吸附剂的表面总酸性基团含量.结果表明:与未改性的AC相比,Fe3+/AC、Cu2+/AC和Ag+/AC表面的总酸性基团含量增加,其对乙腈溶液中DBT的吸附容量也增大;各吸附剂表面的总酸性基团含量顺序为Fe3+/AC>Cu2+/AC>Ag+/AC>未改性AC,它们对乙腈溶液中DBT的吸附能力在298K下分别提高了30%、20%、14%.以上结果表明AC类吸附剂的吸附容量与其表面的酸性基团含量成正比;应用浸渍法可提高吸附剂表面的酸性基团含量,从而增加吸附剂表面吸附乙腈溶液中DBT的吸附活性位,提高对DBT的吸附能力.

In this paper, first, activated carbon （AC） with high specific surface area was modified with metal ions Fe^3 ＋ , Cu^2 ＋ and Ag ^＋ through an impregnation process, and three kinds of modified AC, namely, Fe^3 ＋/AC, Cu^2 ＋ / AC and Ag^＋/AC, were prepared. Next, the products were used to adsorb the dibenzothiophene （DBT） in acetonitrile solution, and the corresponding isotherms were obtained by means of the static adsorption method. Then, the desorption peak areas of DBT desorbed from the AC before and after the modification were measured through temperature-programmed desorption （TPD） experiments. Finally, the total amount of acidic functional groups on the surfaces of these four kinds of AC was measured via the Boehm titration. The results show that, after the modification, both the total amount of acidic functional groups and the adsorption capacity for DBT increase, that the total amount of acidic functional groups follows the order of Fe^3 ＋/AC 〉 Cu^2 ＋/AC 〉 Ag^ ＋/AC 〉 AC, with the adsorption capacity respectively increasing by 30%, 20% and 14%. It is thus concluded that the adsorption capacity of AC absorbents is proportional to the total amount of acidic functional groups, and that the loading of Fe3^＋ , Cu^2＋ and Ag ^＋ on AC enhances the adsorption of DBT in aeetonitrile solution due to the increase of active sites on AC surfaces for DBT adsorption.