Removal of Nitrate Anion by Carbonaceous Materials Prepared from Bamboo and Coconut Shell

抄録

The adsorption behavior of nitrate anion was investigated from aqueous solution using activated carbon (AC) prepared from coconut shells and charcoal (CB) prepared from bamboo. The adsorption of nitrate anions on these adsorbents exhibited maximum values in the region of equilibrium pH 2–4, and was explained by the adsorption of the Langmuir type. The adsorption capacity and the adsorption equilibrium constant for AC were 2.66 × 10^–1 mmol·g^–1 and 2.72 dm³·mmol^–1, respectively, and those for CB were 1.04 × 10^–1 mmol·g^–1 and 3.53 dm³·mmol^–1, respectively, at 303 K. The order of the adsorption capacity was the same as the order of their specific surface areas. This suggests that the specific surface area is one of the factors that determine the adsorption ability for nitrate anions. The theoretical curves calculated using these values were in good agreement with the experimental data. From the obtained thermodynamic parameters, it was found that the adsorption of nitrate anions on AC and CB contributes to the hydrophobic interaction.