Sonophotocatalytic mineralization of antipyrine in aqueous solution

• The UV/H2O2/Fe/US process is an alternative for mineralization of antipyrine.
• 92% of TOC is removed after 50 min.
• Antipyirine photodegradation proceeds mainly through a radical mechanism.
• Important synergistic effect (45.3%) between sonolysis and photoFenton.

The mineralization of aqueous solutions of antipyrine, an emerging contaminant, using an innovative homogeneous sono-photocatalytic oxidation process (H2O2/UV/Fe/Ultrasound) was evaluated in an artificial UV lamp.At the selected operation conditions [H2O2] = 1500 ppm, pH = 2.7, amplitude = 100%, pulse length (cycles) = 0.3 during 15 min and then 1, 92% of TOC is removed after 50 min treating an aqueous solution containing 50 ppm of antipyrine. An important synergistic effect between sonolysis and photoFenton (UV/H2O2/Fe) of 45.4% was quantified using the first order rate constants for TOC.Comparison experiments of scavenger-loaded conditions demonstrate that the antipyirine photodegradation proceeds mainly through a radical mechanism probably beginning by the cleavage of the NN bond of penta heterocycle leading to the formation of aromatic acids (anthranilic and 1,4-benzenedicarboxylic acids) then followed by the opening of phenyl ring to form small molecular organic acids (mainly 2-butenedioic, 4-oxo-pentanoic and butanedioic acids), which may be decomposed further into CO2.

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