Abstract: In order to investigate the feasibility of preparing activated carbons under low-temperature activation using phosphoric acid, activated carbons were prepared from cotton stalk by phosphoric acid activation under activation temperature from 300 to 450℃. The properties of activated carbons were determined by the following terms: adsorption capacities to iodine, methylene blue and caramel, pore characteristics by measuring adsorption isotherms of nitrogen at 77 K, and surface chemistry by Boehm method. Results show that the increase of activation temperature from 300 to 350℃ remarkably enhanced the porosity development and the adsorption capacities to methylene blue and caramel. Low-temperature activation using phosphoric acid could prepare activated carbon with well-developed porosity and strong polarity under activation temperature of 350℃, which are visualized by its surface area of 1244 m²/g, content of surface functional groups of 10.4 mmol/g, adsorption capacity to methylene blue of 190 mL/g and caramel decolorization rate of 100%.

Key words: activated carbon, cotton stalk, low-temperature activation, phosphoric acid