The scavenger test is not necessary in photocatalytic dye-degradation experiment test using spectrophotometer. But 1-2 ml of Isopropyl alcohol or Ethylene-diamine-tetra-acetic acid (EDTA) is sufficient to be added into 100 ml of methylene blue dye before photo-degradation test.

For reference to this experimental procedure , https://doi.org/10.1016/j.ch.phi.2022.100119 can be referred to.

Manan Mehta, thanks for the explanation. Please can you check the Doi and resend again? The Doi is not correct. Thanks

John Busayo Adeoye , please also refer to https://doi.org/10.1016/j.solmat.2018.06.049

Other interesting paper is by Tamanna Bhuyan et al, volume 17, article no. 288 2015(year) springer netherlands.

For a scavenger test in the photodegradation of Methylene Blue (MB) dye (100 mL), you need to add specific scavengers to quench reactive species like hydroxyl radicals (•OH), holes (h⁺), superoxide radicals (•O₂⁻), and electrons (e⁻) to determine their role in the degradation process. The typical concentration range for scavengers is 1–10 mM in the final solution.

For a 100 mL MB solution, you can use the following scavengers and amounts:

• Isopropanol (IPA) for •OH quenching: Add 76 µL (for 10 mM final concentration).
• EDTA-2Na for h⁺ scavenging: Add 37.2 mg (for 1 mM final concentration).
• Benzoquinone (BQ) for •O₂⁻ quenching: Add 10.8 mg (for 1 mM final concentration).
• Ammonium Oxalate (AO) for h⁺ scavenging: Add 14.2 mg (for 1 mM final concentration).
• Silver Nitrate (AgNO₃) for e⁻ scavenging: Add 17 mg (for 1 mM final concentration).

It’s best to prepare stock solutions (e.g., 10–100 mM) for easier addition. Ensure proper dissolution by stirring or sonication. Always include a control experiment without scavengers for comparison. If needed, adjust scavenger concentrations (0.1–20 mM) based on preliminary results.