*3.5. Photocatalytic Activity*

The photocatalytic behavior of the catalyst was evaluated by the photodegradation of imidacloprid in an aqueous solution with an initial concentration of 10 mg/L under 300 watts of W lamp. First, 10 mg of photocatalyst was added to 10 mL of IMI solution. The suspension was stirred using a magnetic stirrer in the dark at room temperature for 1 h before irradiation. The solution was collected every 30 min to 150 min using a syringe with a microspore filter (0.45 μm). The concentration of IMI was analyzed by UV-Vis spectrophotometry at 268 nm, and the removal efficiency was calculated via Equation (4) [69].

Where C0 is the initial concentration of IMI, and Ct is the concentration of IMI after t minutes.

To study the reaction kinetic, the obtained data were fitted by a first-order kinetic model which is shown in Equation (2).

$$\ln(\text{C}\_0/\text{C}) = \text{kt} \tag{4}$$

where k is the pseudo-first-order rate constant, C0 is the initial IMI concentration, and C is imidacloprid equilibrium concentration in aqueous solution at time t.
