Week 3: Detecting Fe data data data

For past few days, I have gathered more data than this blog can hold.

Here are some interesting data that make this project of detecting nanoscale Zero Valent Iron seem promising.

1. Using Induced Polarization system, I introduced different amounts of nZVI (Fe cmc-BH) to aerobic and anaerobic system. Here are the resulting Phase Difference. (Phase Difference is defined as the phase difference between applied sinusoidal AC voltage and detected voltage.)

*I found out that in Deoxy condition, the trend seems much less distinct than in atomspheric conditions. This made me think that oxidation of nZVIs is playing a big role in causing these phase shifts.

2. From the previous experiment, there was a need to study the effect of oxidation on phase shift. So I set up an experiment to introduce nZVI exposed to atomspheric condition to observe the effects of oxidation. Here is the resulting data: 

*This result clearly shows that oxidation plays a big role in phase shift. 

3. From the last experiment, I came up with couple hypothesis. The first hypothesis was that Iron Oxide causes greater phase shift than nZVI. As nZVIs become oxidized over time, the phase shift increase. To see if Iron Oxide plays any important role, I left nZVI exposed to atmosphere overnight to prepare Iron Oxide. The solution turned bright orange, which proves that Iron has been sucessfully oxidized. Then, the phase shifts at various concentrations were tested. The resulting data:

*This shows that there are easily observable phase shift cause by Iron Oxide. (The tested frequency range changed from 1-1,000Hz to 1-10,000 Hz now because I found out that the metal detectors use ~30kHz or little bit lower range). 

The data at 10,000 Hz was logarithmically graphed:

*This shows that the Phase Shift has a definite relationship to creation of nZVI. My scope of experiment will be shifted to quantifying the concentration of Iron Oxide.

I did not mention all the experiments, but here are few important leffout things I found out. 
1. nZVI in deoxy condition does not create much signal
2. The Iron Oxide deposit on the IP measurement rods do not have a big impact. 
3. The introduction of nZVI makes the system's phase shift shoot down to near-zero. Before this introduction, phase shift is not zero.