BIOSORPTION OF SELECTED HEAVY METALS FROM AQUEOUS SOLUTIONS BY DEAD BIOMASS OF FRESH WATER GREEN ALGAE Cosmarium panamense
BIOSORPTION OF SELECTED HEAVY METALS FROM AQUEOUS SOLUTIONS BY DEAD BIOMASS OF FRESH WATER GREEN ALGAE Cosmarium panamense
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Date
2011-08
Authors
ONWUKA, JUDE CHINEDU
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Abstract
This study investigated biosorption of Cd(II), Cr(VI), Co(II), Pb(II), and Ni(II) ions by fresh
water dead algal biomass Cosmarium panamense from aqueous solution. Batch experiments
were conducted to determine the biosorption behaviour of the biomass and it was observed that
the adsorption capacity for Cd(II), Cr(VI), Co(II), Pb(II), and Ni(II) ions by the biomass are
initial metal ion concentration, biosorbent dose, shaking time, pH and temperature dependence.
The maximum adsorption capacities for Cd(II), Cr(VI), Co(II), Pb(II), and Ni(II) ions are
12.89mgCd/g, 109.9mgCr/g, 16.69mgCo/g, 19.72mgPb/g and 10.73mgNi/g of the biomass
respectively at initial concentration of 20mg/l and pH of 5.05 for Cd(II), 2.05 for Cr(VI), 4.05
for Co(II), 4.02 for Pb(II), and 5.02 for Ni(II). The equilibrium data of the selected metals was
well described by Langmuir isotherm model, which was used to determine thermodynamic
parameters (free enegy change, enthalpy change and entropy change) of the metal ions sorption
process. The nature of the sorption process was found to be endothermic and spontaneous.
Uptake kinetics of the selected heavy metal ions follow pseudo - second order model. Effect
of biosorption on various properties of the algal biomass, as adsorbent, was characterized by
Neutron Activation Analysis (NAA) and Energy dispersive X – ray (EDAX), Thermal
Gravimetric Analysis – Differential Scanning Calorimetry (TGA – DSC), Scanning Electron
Microscope (SEM) images and Fourier Transform Infra – red (FTIR). EDAX revealed
variation in the amount or number of elements available for detection before and after
biosorption while TGA – DSC showed that heat flow absorbed by the heavy metal treated algal
biomass, to begin decomposition at the same temperature with the native biomass, are higher
than the heat absorbed by the native biomass. TGA – DSC also revealed that percent residue
weight of the native algal biomass, remaining after decomposition is higher than that of the
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various heavy metal treated algal biomass samples. FTIR analysis showed the presence of
amino, carboxyl, hydroxyl, carbonyl, phosphonate, silica, methyl and methylene functional
group which are responsible for the biosorption of these metal ions on the algal biomass. This
results indicate that the biomass of Cosmarium panamense is an efficient biosorbent for the
removal of Cd(II), Cr(VI), Co(II), Pb(II) and Ni(II) ions from aqueous solutions.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY ZARIA, NIGERIA.
IN PARTIAL FULFILLMENT FOR THE REQUIREMENTS FOR THE AWARD OF
MASTER OF SCIENCE IN ANALYTICAL CHEMISTRY
DEPARTMENT OF CHEMISTRY,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA.
Keywords
BIOSORPTION,, SELECTED,, HEAVY METALS,, AQUEOUS,, SOLUTIONS,, DEAD,, BIOMASS,, FRESH WATER,, GREEN ALGAE,, Cosmarium panamense