Study of sulfuric acid treatment of activated carbon used to enhance mixed VOC removal

• The sulfuric acid-treated activated carbon has a more narrow and uniform pore distribution than untreated activated carbon.
• The sulfuric acid treatment increases the surface oxygen group species of activated carbon.
• The amount of toluene and benzene adsorbed on acid-treated activated carbon were larger than on untreated activated carbon.

The objective of this work was to study the effect of sulfuric acid treatments of activated carbons on single and binary VOCs adsorptions. Commercial activated carbon (AC) and 5, 10 vol% sulfuric acid treated activated carbon (5S-AC, 10S-AC) were prepared. The physical-chemical properties of activated carbons were characterized by N2 adsorption-desorption isotherms, temperature-programmed desorption (TPD). Measurements of the adsorption behavior of pure concentrations and mixture of benzene and toluene on activated carbon were a flow-typed fixed bed system at room temperature under atmospheric pressure. Of all samples examined, the 10S-AC exhibited the highest adsorption capacity for both benzene and toluene, having both longer breakthrough and separation times. The adsorption amount of toluene and benzene on 10-S-AC was increased by 18% and 47%, compared with that on the AC. This is attributed to the surface oxygen group species of activated carbon and changes the porosity of adsorbents due to sulfuric acid treatment.