Hydrodynamic cavitation using double orifice- plates for the generation of hydroxyl radicals

Abstract

The generation of hydroxyl radicals (OH•) by hydrodynamic cavitation (HC) using single and double orifice plates was studied. Five orifice plates with different configurations (size and number of orifice, total orifice area) were tested. The formation of OH• was measured by iodide dosimeter method using spectrophotometer at 355 nm wavelength. The effects of plate configurations and double plate arrangements on OH• generation were investigated in 60 minutes of reaction time using an inlet pressure of 45 psi and initial potassium iodide (KI) concentration of 20 g/L. The generation of OH• were expressed in terms of concentration and percentage of increase of iodine liberation. The liberated iodine for single plate ranged from 0.26 to 0.56 g/L (84 to 180% increase). The highest liberation was achieved using plate with the lowest total flow area of orifice, which had the smallest cavitation number. The double plate arrangement produced the highest iodine liberation (1.30 g/L; 420% increase) with the highest cavitational yield (2.9 × 10-1 mg/J) as compared to those of single plate arrangement. In double plate arrangement, the enhancement was dependent on the configuration and arrangement of the plates.