Removal of reactive brilliant orange X-GN from aqueous solutions by MG-Al layered double hydroxides
Wu, Pingxiao (The Key Lab. of Environmental Prot. and Eco-Remediation of Guangdong Regular Higher Education Inst.)
Zhang, Qian (South China University of Technology. College of Environmental Science and Engineering)
Dai, Yaping (South China University of Technology. College of Environmental Science and Engineering)
Zhu, Nengwu (The Key Lab. of Environmental Prot. and Eco-Remediation of Guangdong Regular Higher Education Inst.)
Li, Ping (Ministry of Education. The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters)
Wu, Jinhua (The Key Lab. of Environmental Prot. and Eco-Remediation of Guangdong Regular Higher Education Inst.)
Dang, Zhi (The Key Lab. of Environmental Prot. and Eco-Remediation of Guangdong Regular Higher Education Inst.)

Data:	2011
Resum:	Among the many techniques used to remove toxic dyes from the environment, layered double hydroxides (LDH) are considered to be especially environmentally friendly, but, this quality may be altered by variations in the octahedral Mg/Al molar ratios in the LDH structure. The aim of the present study was to synthesize environmentally sound LDH for use as an economically viable sorbent for the adsorption of reactive brilliant orange X-GN. Layered double hydroxides with Mg/Al molar ratios of 2:1 and 4:1 were prepared by co-precipitation. The materials obtained were characterized by powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray fluorescence spectroscopy (XRF), and surface-area analysis. Batch experiments were carried out to investigate the effects of contact time, pH, adsorbent dosage, and initial dye concentration on the adsorption behavior of the reactive brilliant orange X-GN by Mg-Al LDH. The results showed that the optimum pH value for dye adsorption was 3. 0, at which the adsorption capacities of the reactive brilliant orange X-GN by the 2:1 LDH and the 4:1 LDH at 298 K were 79. 370 mg/g and 83. 343 mg/g, respectively. Further analysis of the dye-adsorption kinetics show that they fit the pseudo second-order model well. The adsorption equilibrium data showed that the Langmuir model provided better correlation of the equilibrium data than the Freundlich model. This result indicates that LDH provide specific homogeneous sites where monolayer dye adsorption occurs. The results of XRD and FTIR analyses of LDH before and after the dye adsorption demonstrated that the adsorption mechanisms were ion exchange and coulombic attraction.
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Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Dye adsorption ; Layered double hydroxides ; Reactive brilliant orange X-GN
Publicat a:	Clays and Clay Minerals, Vol. 59, Núm. 5 (2011) , p. 438-445, ISSN 1552-8367

DOI: 10.1346/CCMN.2011.0590501

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