Efficient adsorptive removal of Congo red from aqueous solution by synthesized zeolitic imidazolate framework-8 |
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Authors: | Canlan Jiang Boming Fu Hao Cai |
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Institution: | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China |
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Abstract: | Dyes exposure in aquatic environment creates risks to human health and biota due to their intrinsic toxic mutagenic and carcinogenic characteristics. In this work, a metal-organic frameworks materials, zeolitic imidazolate framework-8 (ZIF-8), was synthesized through hydrothermal reaction for the adsorptive removal of harmful Congo red (CR) from aqueous solution. Results showed that the maximum adsorption capacity of CR onto ZIF-8 was ultrahigh as 1250 mg g?1. Adsorption behaviors can be successfully fitted by the pseudo-second order kinetic model and the Langmuir isotherm equation. Solution conditions (pH condition and the co-exist anions) may influent the adsorption behaviors. The adsorption performance at various temperatures indicated the process was a spontaneous and endothermic adsorption reaction. The enhanced adsorption capacity was determined due to large surface area of ZIF-8 and the strong interactions between surface groups of ZIF-8 and CR molecules including the electrostatic interaction between external active sites Zn?OH on ZIF-8 -and ?SO3 or –N=N– sites in CR molecule, and the π–π interaction. |
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Keywords: | Zeolitic imidazolate framework-8 (ZIF-8) Congo red (CR) adsorption isotherm adsorption kinetic |
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