Adsorption of Chlortetracycline and Oxytetracycline to Modified Rice Husk Biochar
Rice husk biochar(BC)was modified using KOH and KMnO4 to obtain modified biochars K-BC,Mn-BC and co-modified biochar K-Mn-BC.The microstructure and composition of the modified biochar were characterized using SEM,FTIR and BET.Single-factor experiments were conducted to study the effect of biochar modification on the adsorption behavior and removal efficiency of chlortetracycline(CTC)and oxytetracycline(OTC)by biochar before and after modification at different initial concentrations,pH values,and temperatures.The results show that the activation of KOH can produce more carbon structural defects,increasing the specific surface area and pore volume up to 685.99 m2/g and 0.34 cm3/g,respectively,more than double that of the original biochar.The pseudo-second-order kinetics and Freundlich model can well describe the process of adsorption of CTC and OTC to biochar.Thermodynamic analysis shows that the adsorption of CTC and OTC by rice husk biochar was a spontaneous endothermic process.Solution pH and divalent cations had great influence on the adsorption.Rice husk biochar adsorbed CTC and OTC in water mainly through hydrogen bonding,electrostatic interaction and π-π stacking.The adsorption capacity of K-BC was significantly higher than that of BC,with stronger environmental adaptability,indicating great potential to remove CTC and OTC from water.
万方数据
维普
