Liquid and vapor phase adsorption of BTX in lignin derived activated carbon: Equilibrium and kinetics study

Benzene, toluene and xylene (BTX) are few of the chemicals that cause environmental pollution in both liquid and vapor phase. In vapor phase, they are classified as volatile organic compounds (VOCs) and cause both indoor and outdoor air pollution. Although different kinds of activated carbons have been used for the adsorptive removal of BTX, the fundamental equilibrium and kinetic data of VOC adsorption in porous carbon are very rare in literature. It order to focus on such fundamental data, in this work, activated carbon was synthesized from de-alkaline lignin precursor by one-step chemical activation with KOH. The resultant carbon has the BET surface area of 2250 m2/g and total pore volume 1.1 cm3/g. Equilibrium and kinetics of liquid phase BTX adsorption were measured upto 100 ppm concentration of each the component in water. In vapor phase adsorption, automated VTI-SA + sorption analyzer was employed with nitrogen as carrier gas and equilibrium and kinetic data were recorded as a function of varying relative pressure or dew point (p/p0) of BTX. For adsorption isotherms, Henry's law, Langmuir, Freundlich and Sips models were successfully employed, whereas for adsorption kinetics, pseudofirst order, pseudosecond order and micropore diffusion model were used to calculate the necessary adsorption parameters.