the best pH might need to be experimentally determined, as the specific components of the mixed plant extract and the type of antibiotic (e.g., tetracycline, ampicillin) may interact differently with the photocatalyst under varying pH levels.

Acidic pH plays a significant role in the photocatalytic degradation of antibiotics using mixed plant extracts. Here's why:

1. Increased Reactivity: Many photocatalysts, like titanium dioxide (TiO2), exhibit enhanced reactivity at lower pH levels. An acidic environment can increase the rate of electron-hole pair generation under UV light.

2. Protonation of Antibiotics: At acidic pH, the ionization state of antibiotics may change, potentially making them more susceptible to degradation. Protonation can enhance the interaction between the antibiotic molecules and the photocatalyst.

3. Increased Solubility: Some antibiotics are more soluble in acidic conditions, which can facilitate their interaction with the photocatalyst and improve degradation efficiency.

4. Enhanced Reactive Species Formation: Acidic conditions can promote the formation of reactive oxygen species (ROS), such as hydroxyl radicals (•OH), which are crucial for the degradation process.

5. Synergistic Effects: Mixed plant extracts can contain various phytochemicals that may work synergistically to enhance photocatalytic activity, especially in an acidic medium.

Thank you sir.