Abstract
In this paper, a mechanochemical synthesis method was proposed to prepare three compounds of strontium oxybritholites with the chemical formula Sr10-xLax(PO4)6-x(SiO4)xO, where x = 1, 3 and 5. Milled and calcined compounds were characterized using several analytical methods including powder X-ray diffraction (XRD), Infrared spectroscopy (FT-IR), 31P and 29Si MAS NMR, Scanning Electron Microscopy (SEM), TGA, and BET analyses. Upon calcination, the surface area of the samples decreased. Strontium oxybritholites displayed pure apatitic structures crystallizing in an hexagonal system with the space group P63/m. The SEM images of calcined compounds exhibited an amelioration of the crystallinity degree and a decrease in the size of the crystals. Solid 31P and 29Si NMR data displayed one resonance peak indicating a single crystallographic site for phosphor in the structure. The 29Si spectra exhibited a single resonance peak corresponding to Q0 type silicon species. The compounds were further used to remove a cationic dye (basic blue 41) from water. The highest adsorption ca-pacity was reached using the milled powders (80 mg/g). It was about 65 mg/g for the calcined ones. The adsorption kinetics of Basic Blue 41 using the prepared compounds was well described by the pseudo second order model while the adsorption isotherms obeyed to Langmuir model. The thermodynamic study revealed that the process is spontaneous and endothermic.