On The Standardization Of The Photocatalytic Gas/Solid Tests

The central problem for standardization of photocatalytic efficiency of whatever substrate on an illuminated catalyst is the rate evaluation. For gas/solid experiments different reactors, like batch or flow-through either continuous stirred-tank reactor (CSTR) or plug flow reactor (PFR), could be envisaged. The basic equations governing these reactors and the rate expression for them are presented here. Experiments show that a CSTR configuration presents a lot of advantages for practical use, as any volume, any shape of catalyst and any flow of gas into the reactor can possibly be used. A CSTR configuration is superior to the standardized PFR as the resistance to mass transfer can be reduced by inside forced ventilation. Consequently, it gives an evaluation of the photocatalytic rate more close to the actual surface one. The rate for CSTR at steady state must be calculated as r(Co) = Co F η/(1− η), where η is the conversion.