Intensification of degradation of imidacloprid in aqueous solutions by combination of hydrodynamic cavitation with various advanced oxidation processes (AOPs)

The degradation of imidacloprid (a systemic chloronicotinoid insecticide) has been carried out in the aqueous solutions using the combination of hydrodynamic cavitation (HC) with various other advanced oxidation processes such as fenton, photo-fenton, photolytic and photocatalytic processes. HC + fenton process significantly enhanced the rate of degradation of imidacloprid, which lead to a complete degradation of imidacloprid within 15 min of operation using the molar ratio of imidacloprid:H2O2 as 1:40 and the molar ratio of FeSO4·7H2O:H2O2 as 1:40. Similar results of an increase in the rate of degradation of imidacloprid have also been obtained in case of HC + photo-fenton process. Synergetic index of 3.636 and 2.912 have been obtained using HC + fenton and HC + photo-fenton processes respectively. The combination of hydrodynamic cavitation with photolytic and photocatalytic processes have also resulted in the enhancement in the rate of degradation of imidacloprid, however synergetic effect has not been observed. Comparison of efficiency of all the processes applied has also been done by computing extent of mineralization achieved and energy requirement of the process.