Waste agricultural biomass (sugarcane bagasse) was carbonized to prepare AC, which was purchased from Sugarcane Industry Research Institute (Guangxi, China). The obtained raw material was first pre-treated by washing, drying, and cutting. Thus, the sample of 0.6 × 0.8 mm was prepared. Other chemicals such as commercial activated carbon (named AC-commercial), urea, potassium hydroxide, toluene and hydrochloric acid were provided by Sinopharm Chemical Reagent Co., Ltd.
First, the pre-treated sugarcane bagasse (SB) sample was mixed with urea at a urea/SB weight ratio of 15 wt%. Then, the distilled water was added to dissolve urea into the solution. After agitation for 12 h, the solution was dried 105 °C until water was removed. Thereafter, the dried sample was carbonized under 600 °C with nitrogen protection. After carbonization for 30 min, heating was stopped and sample was cooled by nitrogen gas to 30 °C. The carbonized SB was then collected and washed through distilled water until pH was 7.0. Finally, N-doped sample was activated with KOH (KOH/sample weight ratio was 2.0), and the activated temperature was 500, 600, 700 and 800 °C. The prepared ACs was named as AC-x, where x meant the activation temperature (°C).
First, the pre-treated sugarcane bagasse (SB) sample was mixed with urea at a urea/SB weight ratio of 15 wt%. Then, the distilled water was added to dissolve urea into the solution. After agitation for 12 h, the solution was dried 105 °C until water was removed. Thereafter, the dried sample was carbonized under 600 °C with nitrogen protection. After carbonization for 30 min, heating was stopped and sample was cooled by nitrogen gas to 30 °C. The carbonized SB was then collected and washed through distilled water until pH was 7.0. Finally, N-doped sample was activated with KOH (KOH/sample weight ratio was 2.0), and the activated temperature was 500, 600, 700 and 800 °C. The prepared ACs was named as AC-x, where x meant the activation temperature (°C).