| Summary: | Synthesis of MCM-41 and NH2-MCM-41 as adsorbents of Hg(II) in aqueous
solution had been done. MCM-41 was synthesized through hydrothermal process
used Na2SiO3 solution and cethyltrimethylammonium bromide (CTAB) adjusted
at pH = 10 by using 1 M H2SO4 solution. NH2-MCM-41 was made by refluxing a
mixture of MCM-41 and (3-aminopropyl)trimethoxysilane (APTMS) in toluene at
temperature of 60 oC for 12 h. The solid products were characterized by infrared
spectrofotometry (FTIR), X-ray diffraction (XRD), Tranmission Electron
Microscope (TEM), and N2 physisorption method using a gas sorption analyzer
based on the BET equation. The synthesized MCM-41 and NH2-MCM-41 were
applied as adsorbents of Hg(II) in aqueous solution at various pH, contact time,
and concentration of Hg (II).
Characterization of solid products by using FTIR spectroscopy showed the
existence of Si-OH and Si�O�Si groups in both MCM-41 and NH2-MCM-41
structure. Observed aminopropyl groups in NH2-MCM-41 spectra indicated that
the enchoring process was successful. Both the XRD pattern and TEM image
displays consistency results that MCM-41 and NH2-MCM-41 had an ordered
hexagonal pore structure. Results of N2 physisorption analysis showed that after
anchoring process, the size of BET surface area, pore diameter, and total pore
volume were decreases. The adsorption study of Hg (II) on solid MCM-41 and
NH2-MCM-41 showed the maximum adsorption occurs at pH = 4. The adsorption
kinetics study of Hg (II) using MCM-41 coincide well the first order kinetic with
value of k1 1.73 x 10-3 minute-1, while adsorption of Hg(II) using NH2-MCM-41
coincide well the second order kinetic with value of k2 3.97 x 10-5 (g/mol.minute).
NH2-MCM-41 possesed greater adsorption capacities, i.e. 63,29 mg/g (3,16 x 10-4
mol/g) than MCM-41, i.e. 14,21 mg/g (7,09 x 10-5 mol/g), it means that
modification of MCM-41 to NH2-MCM-41 was proved to increase the adsorption
capacity for Hg(II).
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