## 3 Results and Discussion
### Study of the Kinetics of Acetamiprid Photo-Oxidation Using the Photoactive Micorparticles
Interpretation of the Photocatalytic Pathway for Acetamiprid Photo-Oxidation Using Rose Bengal as a Photosensitive  
This section aims to explain the photo-oxidation mechanism of Acetamiprid via singlet oxygen using RB as a photosensitizer (whether supported or free-form). The first step of the mechanism is the Rose Bengal excitation: when the photosensitizer absorbs visible \begin{table}
\begin{tabular}{c c c c} \hline \hline
**pH** & **Photosensitizer** & **\% Degradation** & **Kobs (min\({}^{-1}\))** \\ \hline \multirow{3}{*}{12} & RB & \textgreater{}99 & 0.0159 \\  & P3 & \textgreater{}99 & 0.0159 \\  & P4 & \textgreater{}99 & 0.0159 \\ \hline \multirow{3}{*}{11} & RB & \textgreater{}99 & 0.0158 \\  & P3 & \textgreater{}99 & 0.0157 \\  & P4 & \textgreater{}99 & 0.0158 \\ \hline \multirow{3}{*}{10} & RB & \textgreater{}99 & 0.0154 \\  & P3 & 98 & 0.0147 \\  & P4 & \textgreater{}99 & 0.0148 \\ \hline \multirow{3}{*}{9} & RB & 98 & 0.0130 \\  & P3 & 96 & 0.0107 \\  & P4 & 96 & 0.0107 \\ \hline \multirow{3}{*}{8} & RB & 92 & 0.0084 \\  & P3 & 90 & 0.0075 \\  & P4 & 90 & 0.0076 \\ \hline \multirow{3}{*}{7} & RB & 85 & 0.0063 \\  & P3 & 82 & 0.0057 \\  & P4 & 83 & 0.0059 \\ \hline \multirow{3}{*}{6} & RB & 72 & 0.0042 \\  & P3 & 68 & 0.0038 \\  & P4 & 68 & 0.0038 \\ \hline \multirow{3}{*}{5} & RB & 53 & 0.0025 \\  & P3 & 50 & 0.0023 \\ \cline{1-1}  & P4 & 50 & 0.0023 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Conversions and first-order constants for RB, P3, and P4 in different pH media (t = 300 min). Figure 6: Degradation ratio of Acetamiprid for RB, P3, and P4 (t = 300 min) at different pH media. light (500-600 nm), it transitions from its ground state to an excited singlet state (RB*) and singlet oxygen O\({}_{2}\)(\({}^{1}\Delta_{\beta}\)) is generated from the ground state molecular oxygen O\({}_{2}\)(\({}^{3}\Sigma_{\beta}\)). The subsequent interaction between singlet oxygen and Acetamiprid proceeds through a charge transfer mechanism, wherein O\({}_{2}\)(\({}^{1}\Delta_{\beta}\)) acquires a partial negative charge while simultaneously inducing a partial positive charge on the Acetamiprid molecule. This observation aligns with the previously established literature, which interprets the mechanism of the photo-oxidation reaction of O\({}_{2}\)(\({}^{1}\Delta_{\beta}\)) with substituted amines [64, 65]. [PERSON], who was the first researcher to investigate the photo-oxidation process of Acetamiprid using RB as a photosensitizer, supports this mechanism by indicating that the positive charge density is located on the nitrogen atom of the tertiary amine in the Acetamiprid and does not at the pyridine ring [49, 66]. On the other hand, in a previous study, we reported that O\({}_{2}\)(\({}^{1}\Delta_{\beta}\)) quenching increases the higher basicity of the solvent [31]. This is also suggested to occur in this reaction, where the positively charged form of Acetamiprid is favored as the pH becomes more basic, thereby enhancing the quenching with singlet oxygen (which possesses a negative charge density). The literature reports that in the case of Acetamiprid, oxidation leads to the formation of various secondary amines (such as **b** in Figure 7) and aldehyde hydrates). Under strong oxidizing conditions, these aldehyde hydrates readily oxidize to their corresponding acids such as chloronicotinic acid (**a** in Figure 7) [43, 45, 49, 67]. Furthermore, some authors demonstrate that the organic by-products from the degradation of Acetamiprid can ultimately be mineralized into purely inorganic compounds, such as carbon dioxide, water, nitric acid, and hydrochloric acid [40, 45, 48]. This is highly notable and aligns with the sustainability goals of total eliminating an organic emerging pollutant like the insecticide Acetamiprid in water. The by-products formed during the sensitized photo-oxidation of Acetamiprid were investigated with the aim of confirming the mechanism proposed for the reaction. The analysis was carried out using a GC-MS chromatography system equipped with a quadrupole mass analyzer.