Iron Oxide-Silica Xerogel Synthesized Using Recovered Liquid and Their Fenton Degradation of Rhodamine B in Water

Iron oxide-silica hybrid xerogels were repeatedly synthesized using the liquid recovered during the drying of wet gels obtained in the previous run. The hybrid xerogels were characterized by SEM, FT-IR, and N 2 -sorption, DR UV–Vis techniques. The results indicate that the hybrid xerogels possess high surface areas from 514 to 601 m 2 /g with highly dispersed Fe species. The synthesized iron oxide-silica hybrid xerogels showed high adsorption capacity and Fenton-like catalytic activity toward Rhodamine B in aqueous solution over a wide pH range of 3–11. It was demonstrated that the hybrid xerogels remained excellent recyclability and stability for 5 cycles, with above 99% of the degradation efficiency being achieved and low iorn-leaching per cycle.