PHOTOCATALYTIC DEGRADATION OF AN ORGANIC DYE IN SOME AQUEOUS BUFFER SOLUTIONS USING NANO TITANIUM DIOXIDE: A KINETIC STUDY

hotocatalytic degradation of an organic dye, emerald green, on nano titanium dioxide (anatase 99.5%) at basic buffer pH of 7, 8 and 9 has been investigated. The effects of various operating parameters such as initial concentration of dye, catalyst dosage, bufferic pH and irradiation time on photocatalytic degradation have been studied in a photoreactor cell containing high pressure mercury lamp to obtain the optimum conditions. COD removal was found to be 65-71% confirming considerable mineralization. The photodegradation of the dye obeyed a pseudo-first order kinetics according to the Langmuir-Hinshelwood model at all used buffer pH. The observed rate constants (k(obs)) of photocatalytic degradation were 3.3 x 10(-2) min(-1), 7.09 x 10(-2) min(-1) and 1.32 x 10(-1) min(-1) at buffer pH of 7-9 respectively. Furthermore, the Langmuir-Hinshelwood rate constants, k(r), and adsorption constants, K-A are reported for current process at various buffer pH.