4. Conclusions
In this study, the ability of modified mesoporous silica material
SBA-15 with amino functional group (–NH2) to remove Pb(II) ions
from aqueous solutions was investigated by batch technique. It
was found out that: (i), the hybrid silica samples are efficient sorbents
for the removal of Pb(II) ions from aqueous solutions. The
largest sorption capacity was archived on the sorbent prepared
using TEOS/APTES molar ratio of 3.3, because it still has very large
specific surface area. (ii), The optimum pH value for removal Pb(II)
ions from aqueous solution ranged from 5 to 6 and the lead adsorption
approached equilibrium state in short time of about 60 min.
(iii), The abilities of the sorbents were found to be closely related
with the sorbent’s pore structure, pore density, and the accessibility
of the grafted amino groups. (iv), the mechanism proposed for
lead adsorption on the siliceous sorbents modified with –NH2
groups are probably through van der Waals electrostatic interaction
of Pb(II) ions with surface –NH2 groups.