Abstract:

The activated carbon, which was obtained with agricultural waste cotton stalk as raw material, was prepared by the activation of potassium hydroxide and used to adsorb phenol wastewater. The optimum preparation conditions for cotton stalk based activated carbon were carbonized cotton stalk, KOH as activator, mass ratio of KOH and carbonized cotton stalk (material ratio) 1.5:1, activation temperature 800 ℃, activation time 70 min. Under these conditions, the adsorption value of methylene blue was 342.33 mg/g, and the iodine adsorption value was 1 368.65 mg/g. The BET specific surface area was 1 735.94 m²/g, the total pore volume was 0.36 cm³/g, and the average pore size was 2.33 nm. The activated carbon was used to adsorb phenol wastewater. When the amount of activated carbon was 50 mg, the mass concentration of phenol was 60 mg/L, the volume of wasterwater was 50 mL, the pH value was 7 and the adsorption time was 2 h, the removal rate of phenol was up to 98%. The kinetic analysis of the adsorption process showed that the pseudo-second-order kinetic model could better describe the process of the activated carbon adsorption of phenol.

Key words: cotton stalk, activated carbon, phenol, adsorb