Sustainable and Green Synthesis and Characterization of Nano MnO _x ‐CeO ₂ Materials; Removal and Kinetic Studies of Carmoisine Dye

ABSTRACT Sustainable and green synthesis approaches were used to prepare nano‐disperse MnO x ‐CeO 2 photo‐catalysts (MnO x ‐CeO 2 500 and MnO x ‐CeO 2 700 ). These were characterized by XRD, TEM, low‐temperature nitrogen adsorption and XPS techniques. These materials were used to remove carmoisine azo dye from water. XRD studies established the formation of phase Mn‐Ce‐O solid solutions based on cerium dioxide, as well as the presence of Mn 2 O 3 and Mn 3 O 4 . The particle sizes of MnO x ‐CeO 2 500 and MnO x ‐CeO 2 700 were 8–10 and 20–30 nm while the specific surface areas were 128 and 54 m 2 /g. According to XPS the content of high‐energy oxygen (responsible for catalytic activity) decreased at high temperatures. The efficiency of removing carmoisine azo dye in the presence of ammonium persulfate was about 93% in a neutral medium with MnO x ‐CeO 2 500 material. Recycling was carried out and MnO x ‐CeO 2 500 material was effective for 89% removal after 20 cycles. The 89% removal capacity of MnO x ‐CeO 2 500 material after 20 recycles made it an economic one from an industrial point of view.