Abstract:
The co-pyrolysis chars of sewage sludge and poplar sawdust were activated by using KOH chemical activation method to produce activated carbons(AC). The physical properties of obtained activated carbons were characterized. It was found that the surface area of activated carbon reached 551.0 m
2/g and the total pore volume was 0.294 cm
3/g, and most of pores were microporous.The phenol-adsorption experiments indicated that the activated carbon was very effective in removing phenols when phenol solution was used as the model of phenol-containing wastewater. It was also found that the phenol removal rate of 80.6%was achieved at the AC addition ratio of 1.75 g/L when the mass concentration of phenol solution was 50 mg/L.Furthermore, the adsorption of phenols could be enhanced at weakly acidic condition of pH 5. Finally, the fitting of experimental data showed that the adsorption of phenols with the prepared AC could be described by pseudo-second order kinetic law, while its adsorption isotherm could be simulated with the Langmuir model.Thermodynamic study showed that Δ
HΘ and Δ
SΘ were negative, and Δ
GΘ ranged from -0.383 to -0.109 J/mol, indicating that the adsorption of phenol was a spontaneous, exothermic, entropy-decreasing, and physical-adsorption dominant process.