Abstract
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•Ca4La6(SiO4)6O has been prepared by mechanosynthesis and solid-state reaction at 1200 °C.•Compounds were characterized by XRD, FTIR, solid 29Si Nuclear Magnetic Resonanceand, and TGA.•Adsorbed amount of methylene blue reached 385 mg. g−1 for milled sample.•The kinetics data were well described using pseudo-second-order, suggesting a chemi-sorption process.
This paper focused on the synthesis and characterization of silicate britholites (Ca4La6(SiO4)6O). Ca4La6(SiO4)6O has been prepared by two synthetic routes: mechanosynthesis and solid-state reaction at 1200 °C. The obtained compounds were characterized by powder X-ray diffraction, infrared absorption spectroscopy, solid 29Si Nuclear Magnetic Resonanceand, and thermal analysis. To determine the influence of the synthetic method on the distribution of lanthanum between the two cationic sites, a refinement by Rietveld method was carried out. Using mechanochemical method, Lanthanum was preferentially located in the sites Me (1), while it has a marked preference for the sites Me (2) using heat treatment method. Thermal analysis revealed that the amount of water and carbone dioxyde decreased after milling during 24 h. Further, the compounds were used to remove methylene blue dye from aqueous solution. At equilibrium, the adsorbed amount of methylene blue reached 385 mg. g−1 for the milled sample. For the calcined material, the dye uptake was reduced to 236 mg. g−1. The kinetics data were well described using pseudo-second-order model, suggesting a chemi-sorption process. Regeneration experiments displayed about 93 % and 80 % removal efficiency, for milled and calcined samples, respectively, after four cycles.