ABSTRACT
A series of biochars were prepared by pyrolyzing cotton stalk at different carbonization temperature (300–700°C). The element composition and pore structure were characterized by elemental analyzer and BET surface area analyzer, and the adsorption capability of biochars for the removal of p-nitrotoluene from aqueous solution was evaluated. The results showed that the carbon content and aromaticity of the biochar produced from cotton stalk increased with the increase of pyrolysis temperature, whereas the polarity of biochar decreased. The micropore of biochar was suddenly developed and surface area was sharply enlarged when the carbonization temperature rised from 600°C to 700°C. The pseudo- second-order kinetic equation could be used to better describe the sorption process of p-nitrotoluene onto biochar, while the adsorption isotherms was better fitted by langmuir equation, and the five kinds of biochars followed an order of CB700 > CB600 > CB500 > CB400 > CB300.
