Chromium
(VI) biosorption by immobilized Aspergillus
niger in
continuous flow system with special reference to FTIR analysis
S. Chhikara2, A. Hooda1, L. Rana1 and R. Dhankhar*1
1Department
of Environmental Science,2University Institute of Engineering
Technology, M.D. University,
Rohtak - 124 001, India
(Received: April 15, 2009; Revised
received: August
20, 2009; Accepted: September 22, 2009)
Abstract: Aspergillus niger
was treated with acid and immobilized in calcium alginate matrix. The dynamic
removal of Cr (VI) ion was studied using continuously fed column packed with
immobilized biosorbent beads. Column experiments were
carried out to study the effect of various bed heights (20, 30, 40 cm) under
different flow rates (5, 7.5, 10 ml min-1) on efficiency of biosorption. The maximum time (1020 minutes; 17 hr) before
breakthrough point was observed in case of 40 cm bed height with flow rate of? 5ml min-1.
FTIR analysis of acid treated immobilized A.niger was
used for a qualitative and preliminary analysis of chemical functional groups
present on its cell wall which provided the information on nature of cell wall
and Cr (VI) interaction during the process of biosorption.
The IR spectra of biosorbent recorded before and
after chromium biosorption had shown some changes in
the band patterns,? which were finally
analyzed? and was found that chemical
interaction such as ion-exchange between carboxyl? (-COOH), hydroxyl? (-OH) and amine (-NH2) group of biosorbent and Chromium ion were mainly involved in biosorption of Cr (VI) onto A. niger
cell wall surface. The biosorbed metal was eluted
from biosorbent by using 0.1 M H2SO4
as eluant. Immobilized biosorbent
could be reused for, five consecutive biosorption and
desorption cycles without apparent loss of efficiency
after its reconditioning. Considering all above factors together this paper
discusses the efficient chromium biosorption process
carried out by?
immobilized? A. niger
biosorbent.
Key words: Aspergillus niger,
Chromium, Biosorbent, Heavy metal
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