Background
There is a method of solar water disinfection (SODIS) that lets water be naturally heated by the sun's rays over a period of about six hours. When the amount of UV radiation has peaked, then the water is safe to drink. The water container is a recycled plastic water bottle, which is what makes this method so cheap. However, this is the least efficient method of solar water disinfection.
Purpose
Experimental research on the gaphchromic polymer will allow us to fabricate a polymer that will change color when the bottle has recieved the allowable amount of UV radiation that indicates pasteurization.
Materials
- Gaphchromic polymer
- UV retardant (sunscreen)
- UV filter
- Solar simulator
Procedure
The solar simulator is approximately 1 kW/sq meter when the sample is 35-40 centimeters away from the front of the lense of the solar simulator. Combine the gaphchromic polymer with the UV filter and sunscreen, and then leave the sample 35-40 centimeters away from the front of the lense. Take samples from the gaphchromic polymer every ten minutes for 6 hours.
Applying Sun Screen Layer
- Dissolve sunscreen in acetonitrile (ACN)
- Centrifuge to remove TiO2 Particles
- Collect superatant (This is solution that will be sprayed onto gaphchromic)
- Spray even, thin coat of ACN onto film, solvent dries leaving sunscreen
Suggestion:
- Spray single film w/ gradient of different ACN/sunscreen components and expose to 1,000 W/sq meter to identify concentration. (need to appropriately attenuate energy/color change)
