• PHAM THI NGOC LAN

Articles written in Bulletin of Materials Science

• Lead ions removal from aqueous solution using modified carbon nanotubes

Surface-modified carbon nanotubes (CNTs) were prepared in order to remove lead ions (Pb$^{2+}$) from aqueoussolution. The modification of CNTs was conducted by oxidation, using a mixture of nitric acid (HNO$_3$) and sulphuric acid(H$_2$SO$_4$). The adsorption behaviour was well fitted to the Langmuir model and the maximum adsorption capacity of Pb$^{2+}$ was found to be 100 mg g$^{−1}$. The adsorption of Pb$^{2+}$ reached equilibrium in 80 min. The experimental data were well fitted to a pseudo-second-order rate model rather than a pseudo-first-order model. The activation energy and activation enthalpy of the adsorption calculated from Arrhenius and Eyring equations were, respectively, 21.08 and 18.56 kJ mol$^{−1}$, which reflect the outside surface adsorption and ion exchange mechanism. The thermodynamical studies showed that the adsorption of Pb$^{2+}$ was a spontaneous and endothermic process. The ion exchange mechanism of Pb$^{2+}$ removal was confirmed by the pH and electrical conductivity data in solution before and after adsorption.

• # Bulletin of Materials Science

Current Issue
Volume 42 | Issue 5
October 2019

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Posted on July 25, 2019