Two new silica-based composites were prepared as adsorbents for the capture of Ni(II) ions. The first
strategy consists in coating chitosan on colloidal fumed silica after acidic treatment yielding the composite
SiO2 + CS. The second route involves in a first step surface condensation of triethoxysilylbutyronitrile,
followed by acidic hydrolysis of the surface-bound nitrile groups affording silica particles covered by carboxylic
group. In a third step, chitosan has been grafted on the surface-bound C( O)OH groups yielding
the composite SiO2(CO2H) + CS. The novel hybrid materials were characterized by IR spectroscopy, scanning
electron andAFM microscopy, and zeta potential measurements. Batch experiments were conducted
to study the sorption performance of these composites for Ni(II) removal from aqueous NiCl2 solution at
different pH. Both Langmuir, Freundlich, and Temkin isotherm models provide good fits with the experimental
data. It was shown that these low-cost materials present a promising capacity to adsorb Ni(II)
ions. At pH 7, the maximum adsorption capacity qmaxof Ni(II) on the adsorbent, is found to be 182 mg g−1
for SiO2 + CS, and 210 mg g−1 for SiO2(CO2H) + CS.
Two new silica-based composites were prepared as adsorbents for the capture of Ni(II) ions. The firststrategy consists in coating chitosan on colloidal fumed silica after acidic treatment yielding the compositeSiO2 + CS. The second route involves in a first step surface condensation of triethoxysilylbutyronitrile,followed by acidic hydrolysis of the surface-bound nitrile groups affording silica particles covered by carboxylicgroup. In a third step, chitosan has been grafted on the surface-bound C( O)OH groups yieldingthe composite SiO2(CO2H) + CS. The novel hybrid materials were characterized by IR spectroscopy, scanningelectron andAFM microscopy, and zeta potential measurements. Batch experiments were conductedto study the sorption performance of these composites for Ni(II) removal from aqueous NiCl2 solution atdifferent pH. Both Langmuir, Freundlich, and Temkin isotherm models provide good fits with the experimentaldata. It was shown that these low-cost materials present a promising capacity to adsorb Ni(II)ions. At pH 7, the maximum adsorption capacity qmaxof Ni(II) on the adsorbent, is found to be 182 mg g−1for SiO2 + CS, and 210 mg g−1 for SiO2(CO2H) + CS.
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