椰壳类活性炭孔隙结构对苯并噻吩脱附活化能的影响

Effect of the porosity property of coconut shell-based activated carbon on desorption activation energy for benzothiophene

主要研究活性炭孔隙结构对苯并噻吩脱附活化能及吸附性能的影响。使用ASAP 2010测定了3种椰壳制活性炭SY-6、SY-13和SY-19的BET比表面及其孔隙结构,采用程序升温脱附技术(TPD)测定了苯并噻吩在3种活性炭上的脱附活化能,用静态吸附法进行了苯并噻吩在不同活性炭上的吸附等温线,并讨论了活性炭孔隙结构对苯并噻吩脱附活化能及吸附性能的影响。结果表明,3种活性炭SY-6、SY-13和SY-19的比表面积分别为1106、1070和689m2/g,其平均孔径分别为1.96、2.58和2.16nm。苯并噻吩在SY-6、SY-19和SY-13活性炭上的脱附活化能依次为58.84、53.02和42.57kJ/mol,3种活性炭对苯并噻吩吸附容量的大小依次为SY-6>SY-19>SY-13。活性炭平均孔径越小,其表面对苯并噻吩的作用力越大,苯并噻吩在其表面上的脱附活化能越大。Freundlich模型能够较好的来描述苯并噻吩在活性炭上的吸附。

In this work, the effect of textural property of activated carbons on desorption activation energy and adsorption capacity for benzothiophene was investigated. Textural parameters of three kinds of the activated carbons,namely SY-6,SY-13 and SY-19,were respectively measured by ASAP 2010. The desorption activation en- ergies of benzothiophene on the activated carbons were determined by means of temperature-programmed desorption technique （TPD）. Static adsorption experiments were conducted out to determine the isotherms of benzothiophene on the activated carbons. The influence of the textural property of the activated carbons on desorption activation energy and the adsorption capacity for benzothiophene was discussed. Results showed that the BET surface areas of the activated carbons, SY-6,SY-13 and SY-19 were respectively 1106,1070 and 689, and their average pore diameters were respectively 1.96,2.58 and 2.16nm. The TPD results indicated that the desorption activation energy of benzothiophene on the activated carbons, SY-6, SY-19 and SY-13 were respectively 58.84,53.02 and 42. 57kJ/mol. The isotherms showed that amount adsorbed of the activated carbons for benzothiophene followed the order of SY-6〉SY-19〉SY-13. The smaller the average pore diameter of the activated carbon was,the stronger its adsorption for benzothiophene was and the higher the activation energy required for benzothiophene desorption on its surface was. And the freundlich adsorption isotherm model can be properly used to formulate the adsorption behavior of benzothiophene on the activated carbons.