Facile one-step synthesis of 3D hierarchical flower-like magnesium peroxide for efficient and fast removal of tetracycline from aqueous solution

Hierarchically three dimensional (3D) flower-like magnesium peroxide (MgO₂) nanostructures were synthesized through a facile one-step precipitation method. The effects of magnesium salt, reaction temperature, precipitant and surfactant on the morphology and structure of MgO₂ were systematically investigated. The as-obtained samples using magnesium sulfate, ammonia and trisodium citrate were composed of 3D flowers assembled by numerous nanosheets, and SO₄^2- played a vital role in the formation of flower-like nanostructures. The 3D flower-like MgO₂ possessed high active oxygen content of 24.10 wt% and large specific surface area of 385 m²/g. Ten mg of flower-like MgO₂ could efficiently degrade 90 % of tetracycline (TC) within 60 min under stirring condition. ESR tests and radical quenching experiments suggested that hydroxyl radicals were crucial for TC degradation. Moreover, the column filled with flower-like MgO₂ could quickly and efficiently eliminate TC with the assistance of air flow, and the degradation efficiency almost had no decrease even after twenty consecutive runs. Significantly, the concentrations of magnesium and iron ions dissolved in the filtrate from the column were far below the limits of drinking water standards. Additionally, the possible degradation pathways of TC were also proposed according to the determination of generated intermediates during the degradation process.