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The Suitability of Peanut Shells and Palm Shells for
Use as Bed Packing Media in Biofilters
-- Y Nitipavachon, P Chetpattananondh,
M A Connor and K Prasertsit
The characteristics of peanut shells and palm shells used as packing media in biofilters treating
air-contaminated with methanol, toluene or mixtures of methanol and toluene for over 200 days were
investigated. Although the characteristics of the two packings were different, they both appeared suitable for use
as media in biofilters treating air-contaminated with methanol or toluene, since their maximum
Elimination Capacity (ECmax) values were comparable to those obtained using other media. The ECmax values for peanut shells were slightly higher than those for palm shells, and the peanut shells had a much lower bulk
density, which would certainly have cost advantages. However, the results also showed that palm shells
could retain their structural integrity better than peanut shells and so required replacing less frequently.
This means that local availability and costs of the two materials are likely to determine which should be
selected. Use of peanut shells or palm shells should be of considerable benefit to Thai industries considering
installing biofilters to remove Volatile Organic Compounds (VOCs), as it makes the cost of bed packing materials
much more affordable than if more conventional packing materials had to be used.
© 2010 IUP. All Rights Reserved.
Biosorption of Congo Red from Aqueous Solution
Using Guava (Psidium guajava) Leaf Powder: Equilibrium
and Kinetic Studies
-- D Appala Naidu, P Vijay, P King and V S R K Prasad
Biosorption is a potentially attractive technology for treatment of wastewater for removal of dyes from
dilute solutions. Studies carried out through environmental biotechnology have shown that many
biosorbents present in the nature have great capacity for removal of dyes. Biosorption of Congo red on Psidium guajava was studied and compared by using batch techniques. The biosorption experiments were carried out
under various conditions, such as different contact times, pH, initial concentrations, biosorbent dosage,
biosorbent average particle size and different temperatures. About 0.1 g of Psidium guajava was found to be enough to remove 92% of Congo red at the concentration of 20 mg/L from 30 mL aqueous solution in 60 min.
The optimum pH was found to be 1.0. The pseudo-first-order and pseudo-second-order kinetic models
were used to describe the kinetic data. The dynamic data were fitted with the pseudo-second-order kinetic
model for Congo red dye. The experimental equilibrium data were tested by the biosorption isotherms like
Langmuir, Freundlich, Redlich-Peterson and Temkin, and their equilibrium parameters were determined. The
best fitted model to the experimental equilibrium data for Psidium guajava was Langmuir for Congo red dye.
© 2010 IUP. All Rights Reserved.
Role of Illumination and Dissolved Oxygen
Concentration on Purple Membrane Production by Halobacterium halobium
-- Prasanna B D, Dinesh Goudar, Chetan Shetty,
Gurunath Katagi and Shivraj Ghatge
The role of illumination and dissolved oxygen (DO) concentration on the production of Purple
Membrane (PM) by batch culture of Halobacterium
halobium was studied. Continuous illumination was found to
be deleterious for the biomass growth. Illumination was required to stimulate the PM synthesis. Higher
DO resulted in higher biomass concentration, but in lesser PM content per gram of biomass even in the
presence of illumination. Growth under illumination in aerobic condition (DO of 35% saturation) for 96 h resulted
in the biomass concentration of 0.342 g/L and PM content of 973.7 mg/g of biomass.
© 2010 IUP. All Rights Reserved.
Parameter Analysis of a 500 W PEM Fuel Cell Stack
Using Design of Experiments
-- A Leela Manohar, S V Naidu,
V Dharma Rao and B Sreenivasulu
In this paper, the influences of gas pressure and flow rate parameters on fuel cell performance are
studied. The fuel cell is operated at various pressures and flow rates that are regulated by mass flow
controllers placed upstream of the stack. In this study, the four types of control factors considered are pressures of
the fuel and oxidant and the flow rates of the fuel and oxidant to select the optimized conditions for fuel
cell operation. Each factor has two levels, leading to a full factorial design requiring
24 experiments leading to 16 experiments and fractional factorial experiments,
24-1, leading to eight experiments. The experimental
data collected were analyzed by statistical sensitivity analysis by checking the effect of one variable parameter
on the other. The mixed interaction between the factors was also considered along with the main interaction
to explain the model developed using the design of experiments. From the analysis, maximum fuel
cell performance was found to be hydrogen flow rate, oxygen flow rate and the interaction between the
hydrogen pressure and oxygen flow rate compared to all other factors and their interactions. These fractional
factorial experiments, presently applied to fuel cell systems, can be extended to other ranges and factors with
various levels, with a goal to minimize the variation caused by various factors that influence the fuel cell
performance, but with less number of trials compared to full factorial experiments.
© 2010 IUP. All Rights Reserved.
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