Equilibrium and Thermodynamic Studies for Adsorption of 1,4-Benzoquinone by Fly Ash

Li Guoting; Feng Yanmin; Chai  Xiaoqi; He Xiaoshuang

Equilibrium and Thermodynamic Studies for Adsorption of 1,4-Benzoquinone by Fly Ash

2015

Li Guoting | Feng Yanmin | Chai Xiaoqi | He Xiaoshuang

Fly ash, an industrial waste from thermal power plants, was used for the adsorptive removal of 1,4-benzoquinone, one of the oxidation intermediates generated in AOPs. Effect of fly ash dosage and solution pH was investigated. The highest 1,4-benzoquinone uptake occurred at pH 7.0. Neutral and alkaline conditions were more favourable for the adsorptive removal of 1,4-benzoquinone. Isotherm data at 288, 298 and 308 K were simulated by Langmuir, Freundlich, Temkin, Redlich-Peterson, Koble-Corrigan and Dubinin-Radushkevich isotherm models. Both the Koble-Corrigan and Dubinin-Radushkevich isotherms can predict equilibrium adsorption behaviour better at different reaction temperatures. The reaction enthalpy was 29.42 kJ/mol and the entropy achieved 164.52 J/mol·K. The change of Gibbs free energy achieved -19.48 kJ/mol at 298 K. The above indicates that the sorption process was spontaneous and endothermic. This also reveals that, fly ash has the potential for the adsorptive removal of 1,4-benzoquinone.

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