Layered double hydroxides for remediation of industrial wastewater containing manganese and fluoride.
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Date
2018
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Abstract
This work describes an environmentally-friendly procedure for the removal of manganese and fluoride
from industrial wastewaters (IW) using layered double hydroxides (LDHs) and calcined layered double
oxides (LDOs). Ternary Mg-Mn-Al LDHs (LDH-IW) were produced from IW containing a high concentration
of manganese, which decreased from (99.420 ± 3.110) mg L 1 to (0.003 ± 0.001) mg L 1 after the
synthesis procedure. Synthetic Mg-Al LDH was also produced for comparison purposes. Both materials
were calcined and the resulting oxides (LDO and LDO-IW) were used for the removal of fluoride present
in the same IW. The materials were characterized by X-ray diffraction, electron energy-loss spectroscopy,
thermal analysis, Raman spectroscopy, and electron microscopy. The kinetics and adsorption isotherms
for fluoride removal from aqueous solutions were studied in batch mode. For both LDO and LDO-IW, the
adsorption of fluoride followed pseudo-second order reaction kinetics. Langmuir-type adsorption was
observed for LDO, while adsorption by LDO-IW was according to the Freundlich model. The results
showed that the oxides were able to remove 94% of the fluoride present in the IW at an initial concentration
of 162 mg L 1. The procedure reduced the concentrations of the pollutants (manganese and
fluoride) to levels that complied with Brazilian effluent standards.
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Keywords
Wastewater, Pollutants removal, Fluoride, Manganese
Citation
TEIXEIRA, M. A. et al. Layered double hydroxides for remediation of industrial wastewater containing manganese and fluoride. Journal of Cleaner Production, v. 171, p. 275-284, 2018. Disponível em: <https://www.sciencedirect.com/science/article/pii/S0959652617323016>. Acesso em: 05 abr. 2018.