Isothermal Adsorption Characteristics of Phenol from Straw Biochar

Abstract

Peanut straw, sugarcane residue, cotton straw, was used as raw material to prepare the biochar adsorbent at 500°C, which were named PBC, SBC, and CBC. Phenol was subject to batch adsorption in aqueous medium by the prepared biochar. The results of adsorption experiments show that the kind of raw materials significantly affects its adsorption effect on phenol. The adsorption capacity of phenol from three kinds of biochar was PBC > SBC > CBC. In addition, the initial concentration of phenol in waste water, the temperature and time of adsorption can also affect the adsorption effect. The removal rates of phenol by three biochar decreased with increasing initial concentration of phenol. High temperature is beneficial to adsorption. When the initial concentration of phenol was 20 mg/L and the adsorption temperature was 45 °C, the removal rate of phenol was up to 99.7% after PBC adsorption. The reaction increased rapidly at the beginning of 60 min and reached the adsorption equilibrium after 180 min. The isothermal adsorption line for phenol conforms to the Langmuir mode and the Freundlich mode. The results provided a theoretical basis for the removal of organic pollutants such as phenol.