Magnetic nanohybrid derived from MIL-53(Fe) as an efficient catalyst for catalytic ozonation of cefixime and process optimization by optimal design
Bardia Rezvani, Seyed Reza Nabavi, Milad Ghani
Abstract
The catalytic activity of metal-organic frameworks (MOFs) in the degradation of environmental pollutants has garnered considerable interest recently. FTIR, FE-SEM, EDS , XRD, XPS , VSM , TEM , and N2 sorption-desorption isotherms were used to characterize Fe-based nanohybrids derived from MIL-53(Fe). In the catalytic ozonation of cefixime (CFX), the nanohybrid (CM-500) synthesized at 500 °C exhibited high efficiency. The enhanced catalytic activity of CM-500 may have been caused by Lewis acid sites (LAS), iron oxides , and oxygenated functional groups of the mesoporous carbon substrate that remained after pyrolysis of the organic framework. During 15 min of continuous ozonation , the CM-500/O 3 process was the most effective at removing CFX with a removal efficiency of 97%, significantly higher than single ozonation with a degradation efficiency of 43% under the same conditions. Modeling and optimization of process conditions were conducted using a novel and efficient class of experimental design, namely optimal design with the fewest possible runs. Calculated CFX degradation kinetic rate constants were 0.212 min -1 with CM-500, 0.043 min -1 with MIL-53 (Fe), and 0.038 min -1 for ozonation alone. Mineralization (measured COD and TOC) is significantly higher in the CM-500/O 3 system compared to single ozonation. Moreover, the scavenging experiment confirmed that the reactive oxygen species in the catalytic ozonation of CFX are surface-adsorbed superoxide and hydroxyl radicals . Due to CM-500's sustained activity and magnetic properties , it is expected that it has a high catalytic capacity for treating pharmaceutical wastewater.