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摘要
Biochar derived from sugarcane bagasse was prepared at different pyrolysis temperatures and holding times for adsorption of dimetridazole and metronidazole from aqueous solution. The optimal pyrolysis temperature and holding time were 500 A degrees C and 120 min, respectively. The removal efficiencies of dimetridazole and metronidazole were 98.0% and 88.8%, respectively, at biochar dosage of 4.0 g L-1 and solution temperature of 30 A degrees C. Kinetics data were fitted by four kinetics models, and results indicated that adsorption was governed by pseudo-second-order kinetics. Adsorption is a multi-step process that involves film diffusion and pore filling. In addition, five isotherm models were employed to describe the adsorption equilibrium. Brunauer-Emmett-Teller model presented better fitting for the adsorption equilibrium, and the maximum adsorption capacities were 72.17 and 23.61 mg g(- 1) for dimetridazole and metronidazole, respectively. The calculated values of Delta G(0) and Delta H-0 indicated the non-spontaneous and exothermic nature of the adsorption process at the range of temperature studied. Thermodynamic studies also revealed that physical and chemical adsorptions were co-action. The adsorption mechanisms of dimetridazole and metronidazole onto biochar were mainly hydrogen bonding and pi-pi interaction. All the results revealed that sugarcane bagasse biochar can be used as alternative to costly adsorbents for the removal of dimetridazole and metronidazole from aqueous solution.
