RESULTS AND DISCUSSION
3.1 Effect of pH In the pH range 4.0 to 8.5 the rate of degradation of Basic fuchsin was investigated. The results are reported in Table 1.
Table 1: Effect of pH
[Basic fuchsin] = 0.8 × 10-5 M Light intensity = 60.0 mW cm-2
CuO/Al2O3 = 0.12 g pH Rate constant (k) × 105 (sec-1) 4.0 4.40 4.5 5.68 5.0 …show more content…
Oxygen anion radicals are produced by the reaction of O2 molecule and electron (e-) from conduction band of the semiconductor. As the optimum pH is in acidic range, this super oxide anion radical will combine with proton forming HO2● radical. With the formation of more HO2● radicals, the rate of photocatalytic degradation of the dye increases. Above 7.0, a decrease in the rate of photocatalytic degradation of Basic fuchsin was found, which may be due to the fact that cationic form of Basic fuchsin is converted to its neutral form, which does not face any attraction towards almost …show more content…
It may be ascribed to the fact that as the concentration of the Basic fuchsin was increased, more dye molecules were free for excitation and electron transfer/consecutive energy and hence, an increase in the rate of degradation of the dye was noticed. There was a decrease in degradation rate on increasing the concentration of dye above 0.8 × 10-5 M. May be it happened due to the fact that after a specific concentration, the dye may start acting as an internal filter and it will not allowed the enough light intensity to reach the surface of the photocatalyst at the bottom of reaction
3.1 Effect of pH In the pH range 4.0 to 8.5 the rate of degradation of Basic fuchsin was investigated. The results are reported in Table 1.
Table 1: Effect of pH
[Basic fuchsin] = 0.8 × 10-5 M Light intensity = 60.0 mW cm-2
CuO/Al2O3 = 0.12 g pH Rate constant (k) × 105 (sec-1) 4.0 4.40 4.5 5.68 5.0 …show more content…
Oxygen anion radicals are produced by the reaction of O2 molecule and electron (e-) from conduction band of the semiconductor. As the optimum pH is in acidic range, this super oxide anion radical will combine with proton forming HO2● radical. With the formation of more HO2● radicals, the rate of photocatalytic degradation of the dye increases. Above 7.0, a decrease in the rate of photocatalytic degradation of Basic fuchsin was found, which may be due to the fact that cationic form of Basic fuchsin is converted to its neutral form, which does not face any attraction towards almost …show more content…
It may be ascribed to the fact that as the concentration of the Basic fuchsin was increased, more dye molecules were free for excitation and electron transfer/consecutive energy and hence, an increase in the rate of degradation of the dye was noticed. There was a decrease in degradation rate on increasing the concentration of dye above 0.8 × 10-5 M. May be it happened due to the fact that after a specific concentration, the dye may start acting as an internal filter and it will not allowed the enough light intensity to reach the surface of the photocatalyst at the bottom of reaction