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Isothermal, kinetic and
thermodynamic studies on basic dye sorption onto tartaric
acid esterified wheat straw
Renmin Gong*, Yaqian Liu, Yan Jiang and Chengcheng Li
College of Life Science,
Anhui Normal University, Wuhu, 241000, P R China.
*Corresponding author. E-mail:
renmin.gong@yahoo.com.
Tel: +86-553-3345968.
Accepted
11 November, 2009 |
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In this paper, a new cation sorbent, which bore carboxyl and
hydroxyl groups of tartaric acid (TA) derived from
esterified wheat straw (EWS), was originally prepared by
solid phase thermochemistry method. The isotherm, kinetics
and thermodynamics of basic dye sorptions from aqueous
solution onto EWS were investigated for the first time. Two
basic dyes, methylene blue (MB) and crystal violet (CV) were
selected as sorbates. The isothermal data correlated with
the Langmuir model better than the Freundlich model. The
maximum sorption capacity (Qm) of EWS for
MB and CV was 129.87 and 112.36 mg/g,
respectively. The equilibriums of dye sorptions were
respectively reached about 13 and 18 h for MB and CV. The
sorption processes could be described by the
pseudo-second-order kinetic model and there were two
intra-particle diffusion steps in the dye sorption
processes. The thermodynamic study indicated that the dye
sorptions were spontaneous and endothermic in nature.
Key
words:
Isotherm, kinetics, thermodynamics, basic dye, sorption. |
