Bioaccumulation of Cr(VI) from Tannery Wastewater Using Saccharomyces Cerevisiae
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Date
2018-06
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Addis Ababa University
Abstract
Chrome tanning is the most and widely used types of tanning process and the wastewater
generated by these industries is a major source of chromium pollution in the form of
Cr(III)&Cr(VI) which are released into the environment either after treated inefficiently or with
no treatment and become a cause for many human health problem. Several researchers have
published papers to find the solution for removal of Cr(VI) but at its low concentration and this
research work investigates at high concentration of Cr(VI). Cell suspensions of S.cerevisiae at
its exponential growth phase were added to 250ml plastic flasks of containing 50ml of YPD
media at pH value of (3,5&8), initial Cr(VI) concentration of (5, 50&100mg/ml) and incubation
time of(3,5&7 days) and shaken at 200rpm an
from tannery wastewater using S.cerevisiae shows good result after Cr(VI)-contaminated
wastewater has been treated at different treatment variables of pH, initial Cr(VI) concentration.
Cr(VI) uptake efficiency of S.cerevisiae increases at low values of pH, Cr(VI) and incubation
time and decreases at high values of these variables. And it can be conclude that Cr(VI)uptake
efficiency is better at low values of the variables and the optimum conditions obtained by using
the full factorial experimental design are pH value of 4.5, Cr(VI)concentration of 5mg/ml and
incubation time of 5 days resulting 84.25 % theoretical Cr(VI) uptake efficiency . Cell viability
test assay of this work shows the possibility of Cr (VI) removal at its high concentration using
living cells that are tolerant to high concentration though the efficiency decreases as
concentration increases due to inhibition. Bioaccumulation of Cr(VI) by the cell S.cerevisiae is
analyzed by FTIR by comparing their IR spectrum of functional groups of the Cr(VI) free and
Cr(VI) loaded S.cerevisiae cell wall that showed change of wavenumbers of biocomponents of
cell wall of the two cells which confirms the binding of chromium ion with the functional groups
of cell wall of S.cerevisiae and produces Cr complex compounds /precipitates. Freundlic
equilibrium and pseudo second order kinetic model are used for expressing
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Keywords
Tannery Wastewater, Hexavalent Chromium, Bioaccumulation, FTIR analysis, Scerevisiae yeast cell