The Preparation Of Tobacco Stem Based Activated Carbon And The Study On The Adsorption Capacity Of Dipropyl Sulfide

Activated carbon is an excellent material for adsorption which canbe used to removal toxic or harmful substance both in liquid phase or gasphase. Using traditional agricultural waste material to prepare activatedcarbon is benefit for both environment protection and the effectiveutilization of resources. In this paper, phosphoric acid was used aschemical activate agent to prepare tobacco stems based activated carbon,two technological parameters that were the concentration of H₃PO₄andactivated temperature were considered to study the influence on theproperties of activated carbon, the mechanism of activation was studied atthe same time. And dipropyl sulfide was used as a proper analog ofmustard gas which is quite hazardous for human, emphasis was paid onthe adsorption process in liquid phase to analyze the adsorption capacity,and the kinetic adsorption process.The texture parameters of activated carbon were determined by lowtemperature nitrogen adsorption, the adsorption capacity of iodine andmethylene blue was investigated too. All samples were microporous material, the nitrogen adsorption isotherms were type I，the specificsurface area were558.06¹965.22m²/g, and total pore volume were0.30¹.18cm³/g. Most of all samples mainly possessed microporous poreand mesoporous pore, pore size were dominated by0.3²nm and2⁶nm，a few samples possessed macropore. If single factor was considered,the specific surface area, iodine and methylene blue adsorption capacityincrease firstly but then decrease along with the increase of H₃PO₄concentration or the activated temperature. The maximum specificsurface area （1965.22m²/g） was achieved under the condition that H₃PO₄concentration was3mol/L and activation temperature was400℃, andthis sample possessed the maximum adsorption capacity of iodine andmethylene blue too. The pyrolysis process of tobacco stem was changedafter impregnation of H₃PO₄, the resulting samples possessed phosphorusfunctional groups.The samples activated at400℃were used to study the adsorptionof dipropyl sulfide, the result showed that the adsorption capacity had asignificant linear correlation with the specific surface area and total porevolume, the adsorption capacity increases with the increase of specificsurface area and total pore volume, the micropore volume influenced theadsorption capacity too. The sample prepared on the condition that H₃PO₄concentration was3mol/L and activation temperature was400℃possessed the maximum adsorption capacity （106.99mg/g）. The adsorption kinetics of dipropyl sulfide over all samples could be welldescribed by the pseudo-second-model equation while pseudo-first-modelequation could not be used to describe the kinetic adsorption processproperly.