C. LAVANYA, NITU SEHRAWAT1, RAJESH DHANKHAR2 AND SUNIL CHHIKARA*
University Institute of Engineering and Technology, Maharshi Dayanand University, Rohtak-124 001 (Haryana),
India
*(e-mail : chhikaras14@rediffmail.com; Mobile : 9255115900)
(Received : November 20, 2018; Accepted : January 15, 2019)
ABSTRACT
The purpose of this study was to establish the optimum experimental conditions for the removal of methyl
red (MR) from aqueous solutions. Yeast biomass, Sacchromyces cerevisiae was pre-treated with the help of
0.1 M H2SO4 and 0.1 N NaOH and entrapped in the calcium alginate matrix in the form of spherical beads.
The studies were carried out under various experimental conditions such as biosorbent dose (0.1-1.2 g/l),
solution pH (1.5-12.0), contact time and initial dye ion concentration (10-300 mg/l) and biomass percentage
in beads were considered in order to assess their influence on the biosorption process. The maximal
removal of methyl red was found to be at a pH of 3.0 i. e. 88.71, 93.26 and 96.86 mg of methyl red/g of
biosorbent, respectively, for acid treated, untreated and base treated fungal biosorbent. The increase of
adsorbent dose up to 1 g of fungal biomass resulted in an increase of adsorption efficiency for different
biosorbents and further increase in the biosorbent dose showed decrease of methyl red dye uptake by per
unit mass of biosorbent. The maximum capacity for dye uptake by the yeast biosorbent was observed to be
174, 180 and 198 mg of methyl red for acid treated, untreated and base treated S. cerevisiae biosorbents
at initial concentration of 300 mg of methyl red in the solution. The optimum contact time was observed to
be 60 min. The experimental data were observed to fit well in the Langmuir model of adsorption isotherm
analysis. Thermodynamic studies revealed the spontaneous and exothermic nature of the adsorption
process as revealed by b (Langmuir constant), RL (separation factor) and ∆G (Gibb’s free energy). The
kinetics of biosorption process was well explained by pseudo-second order kinetic model with high r2
values. Characterization of functional groups present on the biosorbent surface was done using Fourier
transform infrared spectroscopy.
Key words :Sacchromyces cerevisiae, biosorption, FTIR, methyl red, isotherm