Table 2. Kinetics Parameters Determined by Treatment of Photodegradation Data of Methyl Orange According to 1st and 2nd Order Kinetics.

	1st order kinetics		2nd order kinetics
catalyst	k1	R2	k2	R2
ZnO	0.005	0.98	0.00006	0.91
5% Co–ZnO	0.01	0.95	0.0002	0.82
10% Co–ZnO	0.014	0.95	0.0003	0.78
15% Co–ZnO	0.006	0.98	0.00005	0.91