For the purpose of producing carbons with developed mesoporosity, a wood biochar was thermally treated at 600-800 degrees C in the air/nitrogen atmosphere. The mesopore development was observed when the air flux increased to 50-90 mL/min, and the carbon product having high mesopore surface area (316 m(2)/g) and mesopore pore volume (0.284 cm(3)/g) was produced at the treatment temperature of 700 degrees C. The mesopores were developed mainly in the temperature holding stage of thermal treatment, with size mainly ranged from 20 to 60 angstrom. The carbons' adsorption to the antibiotic tetracycline was enhanced by 5.5-9.2 folds when the air/nitrogen mixture was used instead of nitrogen atmosphere in thermal treatment, and the enhanced adsorption is positively related to the mesopore development. In general, this research provides a facile way to produce carbons with developed mesoporosity, so as to improve their adsorption to bulky organic molecules.