Catalytic ozonation of antibiotics by using Mg(OH)2 nanosheet with dot-sheet hierarchical structure as novel nanoconfined catalyst

Antibiotic pollution has caused important concern for international and national sustainability. Catalytic ozonation is a quick and efficient technique to remove contaminants in aquatic environment. This study firstly developed a nanosheet-growth technique for synthesizing Li-doped Mg(OH)(2) with dot-sheet hierarchical structure as catalyst to ozonize antibiotics. Metronidazole could be totally removed through ozonation catalyzed by Li-doped Mg(OH)(2) in 10 min. Approximately 97% of metronidazole was eliminated in 10 min even the catalyst was used for 4 times. Reaction rate constant of Li-doped Mg(OH)(2) treatment was about 3.45 times that of nano-Mg(OH)(2) treatment, illustrating that the dot-sheet hierarchical structure of Li-doped Mg(OH)(2) exhibited nano-confinement effect on the catalytic ozonation. Approximately 70.4% of metronidazole was mineralized by cat-alytic ozonation using Li-doped Mg(OH)(2). Temperature of 25 ? was more suitable for catalytic ozonation of metronidazole by Li-doped Mg(OH)(2). Ions generally inhibited the catalytic ozonation of metronidazole while only 0.005 mol L-1 of Cl- slightly enhanced the ozonation rate, illustrating complicated mechanisms existed for ozonation of metronidazole catalyzed by Li-doped Mg(OH)(2). The possible mechanisms of the ozonation of metronidazole using Li-doped Mg(OH)(2) included direct ozonation and ozonation catalyzed by radical & BULL;O-2(-), reactive oxygen species O-1(2) and intermediate (H2O2). The synthesized Mg(OH)(2) nanosheet with dot-sheet hierarchical structure is a novel nanoconfined material with excellent reusability and catalytic performance.

Automated summary

Antibiotic pollution is a major concern for sustainability, and catalytic ozonation is an efficient technique for removing contaminants in water. This study developed a nanosheet-growth technique to synthesize a Li-doped Mg(OH)(2) catalyst for ozonizing antibiotics, achieving complete removal of metronidazole in just 10 minutes. The Li-doped Mg(OH)(2) catalyst exhibited a nano-confinement effect and had a significantly higher reaction rate compared to nano-Mg(OH)(2). The synthesized Mg(OH)(2) nanosheet with a dot-sheet hierarchical structure showed excellent reusability and catalytic performance.