Rotating disk photocatalytic reactor: development, characterization, and evaluation for the destruction of organic pollutants in water

This work focuses on the development, characterization and evaluation of the TiO2 Rotating Disk Photocatalytic Reactor (RDPR) for the treatment of organic pollutants in water. A commercial TiO2-based catalyst in the form of composite ceramic balls was used as the immobilized photocatalyst on the rotating disk. LiCl tracer studies conducted at different disk angular velocities, ranging from 20 to 5 rpm, proved that the mixing in the RDPR is close to that of an ideal CSTR. Two different techniques, an overflow method and the potassium ferrioxalate actinometry method were employed for determining the liquid holdup and turnover time of the rotating disk with glass beads substituted for TiO2 coated beads. The two methods were in agreement and only the overflow method was employed for determining the same parameters for the rotating disk when loaded with TiO2 composite ceramic balls. Power law correlations were obtained in all cases. TiO2-assisted photocatalytic degradation of 4-chlorobenzoic acid (4-CBA) was investigated in the RDPR at a specified angular velocity of the rotating disk (4 rpm), initial pH=3.0, and room temperature using near-UV radiation.