Kinetic study of photocatalytic degradation of several pharmaceuticals assisted by sio2 tio2 catalyst in solar bath system

الملخص EN

The photo-catalytic degradation of five pharmaceuticals using TiO2 modified with SiO2, and sun light was monitored.

The initial concentrations used in the solar bath system were100 μg/L for caffeine, diclofenac, glimepiride and ibuprofen, and 25 μg/L for methotrexate.

Kinetic disappearance of caffeine, diclofenac, glimepiride and ibuprofen shows pseudo- first order kinetics, while methotrexate shows a zero order kinetic degradation which was monitored using HPLC/UV at λ = 225 nm, F = 1ml/min and on a C8 reversed phase column.

The rate constants for diclofenac (wastewater 0.3238 sec-1, distilled water 0.4057 sec-1), glimepiride (wastewater 0.2203 sec-1, distilled water 0.2771 sec-1), ibuprofen (wastewater 0.2802 sec-1, distilled water 0.2411 sec-1), caffeine (distilled water 0.416 sec-1) and methotrexate (distilled water 3.1407 mole L-1 sec-1).

The removal efficiency for the drugs was ranged between 79% and 96%.

Keywords: Kinetics, Photo-catalytic degradation, Pharmaceuticals, SiO2 / TiO2, Solar bath.