LAUSR

Abstract Monolithic tubular activated carbons were prepared from cotton stalks by chemical activation using phosphorous acid and zinc chloride and referred to as AC-P and AC-Z, respectively. These tubular carbons can be stacked into a honeycomb-like configuration, which has potential in the emission control of volatile organic compounds. Dynamic adsorption of toluene on the tubular activated carbons was tested. AC-P had a specific surface area of 1256 m2/g, 73.4% of which was contributed by mesopores; while AC-Z had a specific surface area of 795 m2/g, 60% of which was contributed by micropores. FTIR spectra revealed that AC-Z possessed less oxygen-containing polar groups than AC-P, which contributed to its higher hydrophobicity. TG analysis also suggested that less water was adsorbed on AC-Z. At a flow rate of 150 mL/min and toluene concentration of 1000 ppm, the dynamic toluene adsorption capacity of AC-P was as high as 328 mg/g under dry conditions owing to its high specific surface area; however, it decreased to only 94 mg/g under wet conditions (80% relative humidity, 25 °C) due to its hydrophilicity. In contrast, AC-Z having high hydrophobicity showed a dynamic toluene adsorption capacity of 258 mg/g under dry conditions, which remained at 221 mg/g under wet conditions.