The Preparation Of Manganese Oxide-coated Carbon Nanotubes And Mechanism Research On Adsorption Of Lead (Ⅱ)

Carbon nanotubes(CNTs)being a novel kind of catalysts carrier for its difference from common ones were studied to remove trace Pb(â…¡)to be coated by manganese oxide as research purpose.Adsorption mechanism was discussed of the novel composite adsorbent which was used to adsorb Pb(â…¡).The novel composite adsorbent,manganese oxide coated carbon nanotubes (MnO₂/CNTs),was prepared and used to remove Pb(â…¡)from aqueous solution through a redox process by putting(CH₃COO)₂ Mn into CNTs suspension firstly and stirred vigorously,then a certain KMnO₄ solution was added under continue stirring. The XRD revealed that manganese oxide covered MnO₂/CNTs was an amorphous phase and the BET revealed that the pore width became narrow and the surface area became larger.The Pb(â…¡)removal capacity of MnO₂/CNTs decreased with the decrease of pH.The Pb(â…¡)adsorption capacity and removal efficiency by MnO₂/CNTs was mainly depended on the solution pH value.From the Langrnuir isotherms,maximum adsorption capacity(Q₀)was determined as 78.74 mg/g). Comparing with CNTs,significant improvement of Pb(â…¡)adsorption shows MnO₂/CNTs can be good Pb(â…¡)absorbers.Although Pb(â…¡)adsorption by MnO₂/CNTs occurred rapidly within the first 15 min of contact time,contact time needed at least 2h in order to attain adsorption equilibrium and the kinetic adsorption can be described by the pseudo-second-order rate equation.Thermodynamics of Pb(â…¡) was studied at various temperatures of 283,303 and 323 K and the thermodynamic parameters were also determined.The novel composite adsorbent has more capability to remove heavy metal icons than the common ones.An efficient,economical and convenient method to remove trace toxic heavy metal solution was introduced in this research.