二苯并噻吩在球形活性炭上的吸附平衡和动力学研究

Adsorption equilibrium and kinetics of dibenzothiophene on activated carbon spheres

考察了3种不同孔结构的球形活性炭(氢氧化钾和水蒸汽活化的苯乙烯基球形活性炭以及沥青基球形活性炭,PACSKOH、PACSsteam、ACSpitch)对二苯并噻吩(DBT)的吸附行为。结果表明,DBT在球形活性炭上的吸附符合Freundlich吸附等温线,吸附容量与比表面积无关,而与孔径<0.8nm的超微孔孔容相关。PACSKOH中微孔和<0.8nm的超微孔含量最多,对DBT的吸附容量最大,它的吸附容量分别是PACSsteam和ACSpitch的1.4和1.6倍。球形活性炭对DBT的吸附符合准二级动力学方程,PACSsteam中孔和大孔径的微孔含量最多,初始吸附速率最大,吸附半衰期最短;ACSpitch中孔含量少,初始吸附速率最小;PACSKOH<0.8nm的超微孔含量多,DBT需要沿孔壁方向取向,并平行孔壁进入超微孔,导致吸附半衰期最长。

The adsorption equilibrium and kinetics of dibenzothiophene on three activated carbon spheres （ACS） （polystyrene-based ACS by KOH activation （PACSKOH） and by steam activation （PACSsteam）, and ACS derived from pitch （ACSpitch）） were investigated. The results revealed that the equilibrium data for DBT adsorption fitted the Freundlich Model well. The adsorption of DBT is rather related to the volume of small-micropores （〈 0.8nm） than to the surface area. PACSKOH showed highest adsorption capacity towards DBT, which is 1.4 and 1.6 times larger than those of PACSsteam and ACSpitch, respectively. The adsorption of DBT can be best described by a pseudo-second-order equation. PACSsteam showed highest initial adsorption rate and smallest adsorption half-life time. ACSpitch have smallest initial adsorption rate due to the low volume of mesopores. PACSKOH need the highest adsorption half-life time because DBT has to be parallel to the pore entrance into the micropores （〈 0.8nm）.