## 3 Results  
### Investigation of Experimental Parameters for Catalytic Activity  
The photocatalytic activity was studied in relation to the experimental parameters of green photocatalyst dosage, initial pollutant concentration (amoxicillin), exposure time, and the effect of pH. The optimal photocatalyst dosage for pollutant degradation was evaluated under pH 6, an initial pollutant concentration of 10 mg L\({}^{-1}\), and a reaction time of 60 min. The results showed that the photocatalyst dosage had an impact on amoxicillin degradation efficiency. Efficiency increased from 35.6% to 45.1% as the green photocatalyst dosage rose from 1 to 1.5 g L\({}^{-1}\). However, increasing the dosage further led to a decline in efficiency, reaching 13.8%, 22.1%, and 18.4% for 2 g L\({}^{-1}\), 2.5 g L\({}^{-1}\), and 3 g L\({}^{-1}\), respectively. Thus, the optimal dosage was determined to be 1.5 g L\({}^{-1}\), as the highest degradation efficiency was observed within the initial range of 1 to 1.5 g L\({}^{-1}\). Higher dosages resulted in diminishing returns, likely due to increased light scattering or catalyst aggregation. A similar behavior was observed in previous studies. [PERSON] et al. (2024) [28] investigated the photocatalytic degradation of amoxicillin, and [PERSON] et al. (2024) [29] studied tetracycline degradation. In both studies, different photocatalysts were used, but the trend of an optimal dosage followed by decreased efficiency with higher dosages was consistently observed. The increase in catalyst dosage may cause turbidity in the medium and particle aggregation, which in turn reduces the photocatalytic degradation efficiency [28; 30]. Figure 2 shows the degradation of amoxicillin at different initial concentrations. It can be observed that, as the initial concentration of the antibiotic increases, the degradation efficiency decreases. A similar behavior was observed by [PERSON] et al. (2022) [30], who studied the photocatalytic degradation of cefixime and doxycycline under visible light irradiation using a ternary nanocomposite. [PERSON] et al. (2024) [29] reported that increasing the concentration of antibiotics can block the active sites on the surface of the catalyst, reducing the efficiency. They also observed that the generation of electron-hole pairs is negatively affected, which contributes to the decrease in degradation efficiency. Figure 2: Investigation of the initial pollutant concentration (pH = 6, exposure time = 60 min, green photocatalyst dosage = 1 g L\({}^{-1}\)). Figure 3 shows that an extended reaction time increases degradation. This occurs due to the continuous generation of more reactive species, which further enhances the photodegradation efficiency. This behavior was observed in the photodegradation of methylene blue dye under visible light [31]. A previous study [32] synthesized a copper and titanium photocatalyst, achieving 90% photodegradation of amoxicillin after 24 h of reaction under visible light, using a photocatalyst dose of 0.4 g L\({}^{-1}\). In contrast, this study's green photocatalyst, at a dose of 1.0 g L\({}^{-1}\), achieved 80.9% degradation in just 420 min (7 h) under UV light. These findings suggest that the proposed method may offer a more time-efficient alternative while maintaining effective photocatalytic performance. Table 1 shows the influence of the initial pH of the solution on the amoxicillin photodegradation. This analysis is important because the charges on both the amoxicillin molecule and the catalyst surface interact, and this interaction can cause electrostatic repulsion or attraction, affecting the efficiency of photodegradation. It is observed that the highest efficiency of photodegradation occurs at pH = 6.0. [PERSON] et al. (2022) [33] explain that amoxicillin has three pKa values corresponding to the functional groups, such as the carboxyl group, amine group, and phenol group, with pKa values of 4.2, 7.4, and 9.6, respectively.