Sonophotocatalytic degradation of methyl orange using ZnO nano-aggregates

[Display omitted] •A simple, facile and fast solution combustion method applied for ZnO nano-aggregate synthesis.•ZnO nano-aggregates efficiently utilized for sono and photocatalytic degradation of MO dye.•Strong synergism observed between UV light and ZnO nano-aggregates for photocatalytic degradation.•No synergism observed between sonocatalytic and photocatalytic degradation.•The presence of air influences the sonocatalytic as well as photocatalytic degradation. A simple, facile and rapid solution combustion method utilizing dextrose as fuel was employed to synthesize zinc oxide (ZnO) nano-aggregates at high temperature 450°C. The synthesized nanomaterials were characterized in terms of their morphological, structural, compositional, optical and photocatalytic properties. The detailed characterizations confirmed that the synthesized ZnO nano-aggregate possessed high density and exhibit well-crystallinity with good optical properties. The sonophotocatalytic properties of the synthesized ZnO nano-aggregates was carried out by performing the degradation of methyl orange (MO) dye under UV light. A strong synergism was observed between UV light and ZnO nano-aggregates for the photodegradation process, whereas sonolytic and photolytic degradation processes were found to operate independently. The presence of air in the aqueous suspensions of MO dye was also shown a significant impact in the photodegradation rate.