the eXternal mind

This was my final paper for my independent research project in a laboratory class, Ch 15, at Caltech. I’m currently in finals week so I have about 4 finals to take and 1 more assignment to finish.

Abstract:

Brita(R) water filters are popular personal and home water filtration systems that claim to reduce, among many impurities, the concentration of copper in tap water by at least 74% and chlorine by at least 94%. These claims and the performance of the filters were tested by filtering residential tap water and then collecting filtrated samples at various points along the filtration process up to 40 gallons (Brita(R) ’s claim of the filter’s lifespan). By using mercury electrode differential pulse cyclic voltammetry and uv-vis spectrometry (on DPD colorimetric reaction), the concentrations of copper and chlorine, respectively, were determined in unfiltrated and filtrated tap water. The results showed that there was an average of 36.10% +/- 2.43% reduction of copper and 72.49% +/- 0.03% reduction of chlorine throughout the 151 L (40 gallons) filtering of the Brita(R) water filter. There was also a detectable difference (5.48% change for copper and 17.12% change for chlorine), albeit small, between new filters and filters due to be replaced after 151 L. Under real world usage of the Brita(R) water filter (and not in prepared laboratory samples), Brita(R) ’s claims about percent reduction are overestimated by ~43% for copper and 13% for chlorine.

Full Paper: Analyzing the Effectiveness of Brita® Water Filters (PDF, 565 KB).