UV Photocatalytic Reactor

Safety Procedures

Please be aware of any potential hazards prior to operating any experiment. Methylene blue is a potent textile dye that will stain clothing (and skin, temporarily), so handle with caution and ensure that all connections are properly secure. Hydrogen peroxide is limited to 6% solution and may cause skin irritation. In the even of exposure, run water over the affected areas, contact lab personnel, and if additional medical attention is required use the emergency protocols at the exits to contact EH&S or dial 911. DO NOT DUMP ANY WASTE DOWN THE SINK!

Other Safety Concerns:

• Wear a lab coat and safety glasses at all times

• Beware of pump speed: leaks may occur at high flow rates

• If used, keep the centrifuge balanced.

• Never fully submerge the conductivity probe in the tank; submerge only the metal tip.

Programs, Equipment, and Instruments

• UV reactor

• Pump with speed controller

• Spectrophotometer

• Centrifuge (if TiO₂ present in solution)

• Balance

Objectives

1. Create a calibration curve for spectrophotometer.

2. Determine the apparent rate law for the photocatalytic degradation of methylene blue.

Tips

1. Plan your experiments before coming to the lab.

2. The spectrophotometer has a limited range of about 10 ppm methylene blue.

3. Make enough solution (~500-1000 mL) so that you can sample regularly.

4. High flow rates can break down the catalyst (TiO2) pellets, which will cause the solution to be slightly cloudy. This can cause erroneous readings in the spectrophotometer.

5. A typical reaction "run" takes about 45 min. You'll still need to work efficiently to finish an experimental run in the allotted time.

6. You can produce a calibration curve while simultaneously running the reactor as long as all absorbance measurements are made at the same wavelength.

7. Don't try to derive a full mechanism or its coefficients. Focus on the apparent (observed) rate law.

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