|
چکیده
|
The efficient elimination of heavy metal ions including Pb(II) from aqueous solutions, which provide serious risks for the human and environment, by various adsorbents has received much interest. Herein, Ti3C2Tx as a two-dimensional transition metal carbide (MXenes) and Ti3C2Tx/ZIF-67-belt were synthesized and employed as adsorbents for Pb(II) from contaminated water. The developed Ti3C2Tx/ZIF-67-belt hybrid nano-composite exhibited 526.3 mg.g-1 maximum capacity of adsorption for Pb(II), within only 15 min. Its excellent performance was related to the advantages of both the layered structure as well as the presence of different functional groups (Fluorine, Oxygen, Nitrogen, and hydroxyl groups). The results showed that Pb(II) adsorption equilibrium followed the Langmuir and its kinetics was based on pseudo-second-order models. The hybrid nanocomposites were simply regenerated and represented high reusability over six cycles. The features of a simple preparation method, excellent performance, regenerable, and high stability in aqueous solution provide the developed nano-composite a promising candidate for adsorptive processes. Based on the DFT calculations, adsorption energy of Pb(II) on the MXene/ZIF-67-belt was found to be -0.8 eV as compared to +0.3 eV for ZIF-67, confirmed that synergetic effects of MXene and ZIF-67 were in favor of Pb(II) adsorption due to the enhancement of charge transfer. In addition, the pure MXene possessed more negative adsorption energy (-1.1 eV) for Pb(II) adsorption in comparing with the composite, contrary to the experimental results, indicating different mechanisms involved in the Pb(II) adsorption.
|