Abstract:
The removal of Pb(II) and Pb(II)-citric acid (Pb(II)-CA) from aqueous solutions by sawdust activated carbon
(SDAC) was investigated. The higher adsorptive removal of Pb(II) from aqueous solutions containing
Pb(II)-CA than Pb(II) only was observed due to the presence of CA in the former system. The mechanism
of adsorption process was studied by conducting pH as well as kinetic studies. Batch adsorption experiments
were conducted to study the effect of adsorbent dose, initial concentration and temperature for
the removal of Pb(II) from Pb(II) only and Pb(II)-CA aqueous systems. The adsorption was maximum for
the initial pH in the range of 6.5–8.0 and 2.0–5.0 for Pb(II) and Pb(II)-CA, respectively. The solution pH,
zero point charge (pHzpc) and species distribution of Pb(II) and Pb(II)-CA were found to play an important
role in the adsorption of Pb(II) and Pb(II)-CA onto SDAC from water and wastewaters. SDAC exhibited
very high adsorption potential for Pb(II) ions in presence of CA than when Pb(II) ions alone were present.
The kinetic and equilibrium adsorption data were well modeled using pseudo-first-order kinetics and
Langmuir isotherm model, respectively.
