Keywords: photolysis, reaction order, path length, optical density, effectiveness factor, environmental remediation, reactor selection, photolytic reactors, reaction rate, toxic waste, kinetics, advanced oxidation process, reactor size, environmental pollution, plug flow reactors, mixed flow reactors, wastewater treatment
Role of optical density on the choice of photolytic reactor
Photolysis and photo–catalysis are two classifications of advanced oxidation processes for treating toxic wastes. Stark–Einstein law and Lambert–Beer's law equation are widely used to explain the kinetics of the photolytic reactions. The optical density influences the rate of reaction. The influence of optical density on transmittance and order of reaction has been analysed. An effectiveness factor for photolysis has been defined and its variation with optical density has been analysed. The choice of plug flow or mixed flow reactor has been discussed with reference to order, effectiveness factor and optical density. It is observed that maintaining optical density at the highest level constantly would result in achieving highest rate of reaction and hence the smallest size of reactor. Several reactor configurations for achieving constant optical density have been proposed.