Preparation of copper modified biochar and its effect on catalyzing persulfate to remove the tetracycline from water

Copper modified corn stalk biochar(CBC) was prepared by hydrothermal method and used as a catalyst to activate potassium persulfate(PS) to remove tetracycline (TC) from water. The results showed that CBC+PS system had high efficiency and stability for TC removal. Under the conditions of solution pH=7, PS dosage of 3 mmol/L, and CBC dosage of 0.5 g/L, the removal rate of TC with mass concentration of 20 mg/L by the CBC+PS system reached 84.46% within 10 min, and 96.75% after 2 h. Mechanism study indicated that Cu, hydroxyl and carboxyl groups supported on CBC surface could promote electron transfer, and then accelerate the production of reactive oxygen species such as SO4·- and·OH. After 5 cycles experiments, the removal rate of TC could still be maintained at 85.62%, which showed that CBC had good stability and reusability. This study provided an efficient and stable TC removal system, and also provided a new way for the recovery and reuse of corn stalk.