Synthesis of Nano-Calcium Fluoride – Based Materials from Phosphogypsum Waste and their Use in Wastewater Treatment: Adsorption of Reactive Blue 21 Dyes

A novel synthesis process and characterization of nano-calcium fluoride (n-CaF 2 ) single crystal prepared from phosphogypsum waste.The phosphogypsum (CaSO 4 •2H 2 O) powder has been mechanically mixed with NH 4 F in presence of a controlled amount of water.The mixture still sintered for 48 hours until the formation of nano calcium fluoride particles.The n-CaF 2 particles have been characterized by several techniques, The techniques utilized included X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy (SEM).Therefore, it was confirmed that very pure n-CaF 2 was obtained with a Ca/F ratio of 0.5 and an average crystalizing size measured according to the Debye-Scherrer equation of 11 nm.Based on the findings reached, The characterization data revealed successful synthesis of n-CaF 2 from phosphogypsum.Additionally, the adsorption performance of the elaborated n-CaF 2 was tested in Reactive Blue 21 (RB21) anionic dye removal, Adsorption tests were conducted in a batch reactor, focusing on key factors such as contact time, which can significantly influence the adsorption results.adsorption amount, pH, and dye concentration were tested.Hence results show an important adsorption performance of n-CaF 2 with Reactive Blue 21 removal rate up to 90%.