Langmuir-Hinshelwood kinetic expression for the photocatalytic degradation of Metanil Yellow aqueous solutions by ZnO catalyst.

摘要

The kinetics studies of the adsorption and degrdn. phenomena involved in the photocatalytic degrdn. of Metanil Yellow (MY) were investigated using a batch reactor and UV light irradn. Expts. were performed in a suspended ZnO system at natural pH of 6.93 and catalyst concn. of 1 g L-1. The initial concn. of MY varied between 10-50 mg L-1. The kinetic anal. of the photodecompn. of MY showed that the disappearance followed satisfactorily the pseudo first-order according to Langmuir-Hinshelwood model. From the results, the adsorption was found to be an essential factor in the photodegradability of the dye. The linear transform of the Langmuir isotherm curve was further used to det. the characteristic parameters which were: max. absorbable dye quantity Qmax = 6.802 mg g-1 and adsorption equil. const. Kads = 0.168 L mg-1. The adsorption const. calcd. from the linear form of this model, KLH = 0.155 L mg-1 was found reasonably similar to Kads deduced from isotherm adsorption. [on SciFinder(R)]