ABSTRACT
The adsorption of copper(ll),
cadmium(ll) and chromium(lll) ions from aqueous solutions by unmodified and
Schiff base-modified silica was investigated in this study. The pure silica and
the Schiff base immobilized silica i.e., 3-aminopropyl trimethoxysilane
(APTS)-modified and Salicylaldehyde-APTS modified silica were characterised using
Fourier Transform Infra-Red (FTIR) spectral analysis. The influences of
experimental conditions such as pH, contact time, initial metal concentration
and temperature were determined in a batch adsorption technique. The amount of
metal ions adsorbed by the adsorbents was determined Spectrophotometrically
using AAS. Results showed that optimum adsorption of the metal ions occurred at
a pH of 7 by the pure silica and percentage amounts of Cu(ll), Cd(ll) and
Cr(lll) ions adsorbed were 98.86 %, 97.14 % and 99.60 % respectively. That of
3-aminopropyl trimethoxysilane (APTS)-modified silica occurred at a pH of 5 and
percentage amounts of Cu(ll), Cd(ll) and Cr(lll) ions adsorbed were 99.39 %,
96.64 % and 99.91 % respectively while that of Salicylaldehyde-APTS modified
silica occurred at a pH 6.0 and percentage amounts of Cu(ll), Cd(ll) and
Cr(lll) ions adsorbed were 96.36 %, 97.78 % and 99.92 % respectively.
Equilibrium batch adsorption of the metal ions was achieved within 60 min. An
increase in the metal ions adsorption with an increase in concentration was
observed for the range of concentrations investigated. Removal efficiencies of
the adsorbents followed the trend: Salicylaldehyde-APTS modified >
APTS-modified > pure silica. An optimum amount of chromium adsorbed by pure
silica was 10.75 mg/g; that of APTSmodified silica was 10.77 mg/g and 10.98
mg/g by salicylaldehyde-APTS. For Copper(ll) ions, it was observed that the
optimum amount adsorbed by pure silica, APTS-modified and
salicyaldehyde-APTS-modified were 9.13 mg/g, 9.44 mg/g and 9.81 mg/g
respectively. Cadmium(ll) ions adsorbed by pure silica, APTS-modified silica
and salicylaldehyde-APTSmodified silica respectively were 7.91 mg/g, 8.87 mg/g
and 9.48 mg/g. Results showed that 99.92% of Chromium(lll), 97.78 % of
Copper(ll) and 96.36% of Cadmium(ll) were sequestered by the adsorbents i.e.
salicylaldehyde-APTS-modified silica, APTS-modified and pure silica in that
order and the trend followed: Cr(lll) > Cu(ll) > Cd(ll). Three
equilibrium isotherm models namely: Langmuir, Freundlich and
Dubinin-Radushkevich isotherms applied to the experimental adsorption data
showed that Langmuir isotherm gave the best fit with regression coefficient, R2
of 0.972. Kinetic study also showed that pseudo second- order equation gave the
best fit for the experimental data with correlation coefficients >0.990,
indicating that the rate-controlling step for the adsorption process may be
chemical reaction. The thermodynamic parameters obtained indicate that the
adsorption of the metal ions unto the adsorbents is feasible and exothermic.
Desorption studies showed that about 24.33% of the metal ions were desorbed
with the eluting agents: acids, bases and neutral solutions. This study
therefore reveals that these adsorbents could be good materials for the removal
of these heavy metal ions from aqueous solutions and may possibly be useful for
treating industrial waste waters.
AMANZE, A (2023). Adsorption of Cu(II), Cd(II) and Cr(III) ions from aqueous solutions using silica support immobilized with 3-aminopropyl trimethoxysilane salicylate:- Amanze, Kenneth O.. Repository.mouau.edu.ng: Retrieved Sep 08, 2024, from https://repository.mouau.edu.ng/work/view/adsorption-of-cuii-cdii-and-criii-ions-from-aqueous-solutions-using-silica-support-immobilized-with-3-aminopropyl-trimethoxysilane-salicylate-amanze-kenneth-o-7-2
AMANZE, AMANZE. "Adsorption of Cu(II), Cd(II) and Cr(III) ions from aqueous solutions using silica support immobilized with 3-aminopropyl trimethoxysilane salicylate:- Amanze, Kenneth O." Repository.mouau.edu.ng. Repository.mouau.edu.ng, 22 Nov. 2023, https://repository.mouau.edu.ng/work/view/adsorption-of-cuii-cdii-and-criii-ions-from-aqueous-solutions-using-silica-support-immobilized-with-3-aminopropyl-trimethoxysilane-salicylate-amanze-kenneth-o-7-2. Accessed 08 Sep. 2024.
AMANZE, AMANZE. "Adsorption of Cu(II), Cd(II) and Cr(III) ions from aqueous solutions using silica support immobilized with 3-aminopropyl trimethoxysilane salicylate:- Amanze, Kenneth O.". Repository.mouau.edu.ng, Repository.mouau.edu.ng, 22 Nov. 2023. Web. 08 Sep. 2024. < https://repository.mouau.edu.ng/work/view/adsorption-of-cuii-cdii-and-criii-ions-from-aqueous-solutions-using-silica-support-immobilized-with-3-aminopropyl-trimethoxysilane-salicylate-amanze-kenneth-o-7-2 >.
AMANZE, AMANZE. "Adsorption of Cu(II), Cd(II) and Cr(III) ions from aqueous solutions using silica support immobilized with 3-aminopropyl trimethoxysilane salicylate:- Amanze, Kenneth O." Repository.mouau.edu.ng (2023). Accessed 08 Sep. 2024. https://repository.mouau.edu.ng/work/view/adsorption-of-cuii-cdii-and-criii-ions-from-aqueous-solutions-using-silica-support-immobilized-with-3-aminopropyl-trimethoxysilane-salicylate-amanze-kenneth-o-7-2