• Applied Chemistry for Engineering
• /
• v.33 no.1
• /
• pp.90-95
• /
• 2022

In the present work, biochar was prepared using Achyanthes japonica stem as a by-product of herbal medicine. In order to apply the prepared biochar to water treatment process, the adsorption characteristics of zinc and iron ions dissolved in water were investigated. When the experiments were performed for 2 h to remove 70 and 100 mg/L of zinc ions, the adsorption amounts of 32.3 and 31.0 mg/g were obtained, respectively. It was also found that the adsorption amount of Achyanthes japonica stem biochar for the removal process of zinc ion was three times higher than that of the activated carbon. In addition, when the experiments were performed for 2 h to treat 70 and 100 mg/L of iron ions, high adsorption amounts of 50.1 and 54.3 mg/g were achieved, respectively. In order to further enhance the removal efficiency of zinc and iron ions, a steam activation process was performed on the biochar of Achyanthes japonica stem. As a result, the removal efficiencies of 70 and 100 mg/L of zinc ions increased to 80 and 60%, respectively. Also, the removal efficiencies of 70 and 100 mg/L of iron ions were improved to 100 and 82%, respectively. In addition, when the biochar of Achyanthes japonica stem with a steam activation was compared with the untreated biochar of Achyanthes japonica stem, the specific surface area increased 37.3 times, and the total and macroporpous pore volumes were improved by 28.4 and 136 times, respectively. Therefore, the results can be used for economically and practically adsorbing zinc and iron ions contained in water.