A STUDY OF LEAD AND CHROMIUM ADSORPTION USING CARBON NANOMATERIALS

Rapid development of industries in the world has been the maJor contributor to
pollution of water resources such as heavy metals. These heavy metals are very
hazardous to both human and environment since they do not degrade into harmless
end product but they eventually will be accumulated in living organisms and thus
causing various illnesses and syndromes. Many methods have been researched in
order to remove these dangerous heavy metals and one of the best methods is
adsorption. Present study was undertaken to investigate ability of carbon nanotubes
(CNTs) and carbon nanofibers (CNFs) as adsorbents in adsorption process of
removing lead and chromium ions from aqueous solutions. The analyses of metal
ions removal were performed on four operation parameters which were initial ion
concentration, contact time, pH and temperature. The experiments were carried out
using a bath shaker at constant speed of 200 rpm. BET surface area of CNFs was
found to be 194.99 m2/g, while for CNTs, the BET surface area was found to be to be
478.99 m2/g. Batch adsorption test showed that adsorption of lead and chromium
uptakes increase as the contact time increases till equilibrium. Besides, it was found
that higher initial metal concentration resulted to better adsorption uptake till it
reached its limit as the adsorbate per adsorbent ratio increased. Adsorption is
optimum from pH 5 to 9 for chromium, while for lead, ph 6 and ph 9 are considered
as optimum pH. Increased in temperature will slightly promote desorption of lead.
However, it does not affect much on chromium adsorption. The equilibrium data
fitted to Freundlich isotherm better for both metals in comparison with Langmuir
isotherm, indicating that the adsorption processes are multilayer.