Isotherm, Kinetic and Thermodynamic Studies for Adsorptionof Cd(II) from Aqueous Solution onto Mesoporous Bamboo Activated Carbon

抄録

In this study, activated carbons were prepared from Moso bamboo by N₂ carbonization under N₂ gas atmosphere, using H₃PO₄ as activator and oxidized by (NH₄)₂S₂O₈ for the removal of Cd(II). The physicochemical properties of the prepared activated carbons (BAP) and commercially available bead-shaped activated carbon (BAC) were compared. The characterization results showed that BAP had higher surface area and mesopore volume compared with BAC, and the oxidized sample BAP1 had more surface functional groups. Adsorption equilibrium data were analyzed by the Langmuir and the Freundlich models. The adsorption equilibrium data were well described by the Langmuir model and the maximum adsorption capacity of BAP1-Na was found to be 0.721 mmol/g, which was greater than that of BAC1-Na. In the adsorption thermodynamics parameters study, the adsorption was spontaneous, favorable and exothermic. The experimental kinetic data were best fitted to pseudo-second-order model, and adsorption rate of BAP1-Na was faster than that of BAC1-Na. The prepared BAC1-Na showed better adsorption capacity for Cd(II) adsorption, and pH, oxidation time, adsorbent dosage and temperature also affected adsorption capacity of Cd(II).