| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 100 === Adsorption of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and copper (Cu2+) by multi-walled carbon nanotubes (MWCNTs) with and without oxidation by nitric acid were investigated in this study. The adsorption capacities of 2-NP and 4-NP by A-MWCNT were larger than H-MWCNT, because of steric obstructions and water clustering. On the other hand, H-MWCNT had better adsorption capacity of Cu2+ than A-MWCNT, because the functional groups generated more negatively charged surface. Furthermore, MWCNTs had better adsorption capacity of 2-NP than 4-NP due to the electronic distribution. The adsorption of 2-NP and 4-NP by MWCNTs were endothermic while the adsorption of Cu2+ was exothermic. The enthalpy change and free energy change suggested that the adsorption of 2-NP, 4-NP, and Cu2+ onto MWCNTs were physisorptions. The adsorption at different pH values showed that the adsorption of 2-NP and 4-NP by H-MWCNT had the same trend, relating to the molecular dissociation and surface charge, while the adsorption of Cu2+ was affected by the surface charge and precipitation. When 2-NP or 4-NP were present, the adsorption of Cu2+ was promoted, because complexes of 2-NP/Cu and 4-NP/Cu may form after 2- and 4-NP dissociated. When pH values were lower than 7, the adsorption of 2-NP and 4-NP would be inhibited by Cu2+ due to the shielding from hydration of Cu2+.
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