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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 12, No. 4, 2015, pp. 1363-1372
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Bioline Code: st15126
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 12, No. 4, 2015, pp. 1363-1372
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Preparation of activated carbons from bio-waste: effect of surface functional groups on methylene blue adsorption
Manoj Kumar Reddy, P.; Krushnamurty, K.; Mahammadunnisa, S.K.; Dayamani, A. & Ch., Subrahmanyam
Abstract
Low-cost activated carbons were prepared by
physical activation of bio-waste rice husk. Various physicochemical
characterization techniques confirmed the high
surface area and oxygen functional groups on the surface. It
has been confirmed that activation under humidified carbon
dioxide followed by ozonation resulted the highest number
of surface functional groups on activated carbon. Nitrogen
adsorption–desorption isotherms confirmed the highest
surface area (417 m2/g), whereas elemental analysis
ensured the increasing oxygen content after activation.
Temperature-programmed decomposition quantified these
surface oxygen functional groups, and it was concluded
that ozonation increased both acidic and basic groups. The
developed activated carbons were tested during the
removal of a model dye methylene blue from aqueous
medium in the concentration range 10–30 mg/L. Typical
results indicated that adsorption studies are consistent with
the Langmuir isotherm model with maximum monolayer
adsorption capacity of 28.5 mg/g, and the dimensionless
separation factor (RL) values between 0.006 and 0.030
confirmed a favorable adsorption. Methylene blue adsorption
followed pseudo-second order kinetics indicating MB
was adsorbed onto the surface via chemical interaction.
Keywords
Carbon dioxide; Isotherm; Kinetics; Ozone; Rice husk; Temperature-programmed decomposition
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