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Title
Biosorption of methylene blue onto Foumanat tea waste: Equilibrium and thermodynamic studies
Authors
A. EBRAHIMIAN and E. SABERIKHAH
Received
October 2, 2012
Published
Volume 47 Issue 7-8 July-August
Keywords
biosorption, methylene blue, tea waste, isotherm, thermodynamic, adsorption mechanism
Abstract
The sorption of methylene blue (MB) from an aqueous solution by Foumanat tea waste was studied in a batch system.
Three widely used isotherms (Langmuir, Freundlich and Temkin) were examined for MB sorption at different
temperatures. The four Langmuir linear equations were discussed, and the Langmuir parameters were obtained from
them. Langmuir-1 is the most popular linear form and it has the highest coefficient of determination, compared with the
other Langmuir linear equation. The maximum saturated monolayer sorption capacity of tea waste for MB was 244
mg/g at 303 K. Various thermodynamic parameters, such as ∆G°, ∆H°, ∆S° and Ea, were calculated. The findings of
this investigation suggested that physical sorption plays a role in controlling sorption. We investigated the adsorption
mechanism by FTIR and SEM techniques. FTIR data indicated that MB binding occurred mostly at –OH and C=O
groups of tea waste.
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