Experiment

Experiment: Methods for removing iodine from water

· Column

· Vacuum flask

· Funnels

· Burette

· 7 conical flask

_· Cu(NO₃)₂

· Iodine

· Distilled water

· Charcoal

· Copper (II) Sulfate

· Chuck

We made an iodine solution to use for our experiment to simulate radioactive iodine, in all purposes for our lab, regular iodine will behave the same as the radioactive isotopes.

We are using the spectrophotometer to measure the concentration.

- We started out by making the solution: iodine and demineralized water

- Copper (II) sulfate solution to precipitate with the iodine solution

The first thing we did was to calibrate the spectrophotometer by using distilled water. This gave us a baseline to compare our results to. Secondly, we took a measure of the absorption of the prepared iodine solution that we made. We do not know the exact mol/L of the iodine solution, but it is not important for our investigation because we prepared only one solution that was used consistently for all of our experiments

First Test: Precipitations

Reading on the internet we found a few sources that claimed Copper Iodide to be a solid precipitate. Following this we looked for a few solutions containing copper to try and make a precipitation.

We hoped that

Instead what happened:

Cobber (II) sulfate solution + iodine solution produced a green solution. The reason for the green solution being formed is simply that when you add something blue to something yellow it will produce something green. Needless to say, there was no precipitate formed.

So instead we tried a different Copper Solution to try and force a precipitation.

Cu (NO₃)₂ + iodine = green/yellow – Once again, no precipitation

Limitation: we did not have access to the right solutions – Looking on the internet further, the ions that we needed were tin, titanium, lead, silver (I), mercury (I), and mercury (II). However, many of these ions were not available and others, especially lead and mercury, would not be appropriate solutions when speaking about drinking water.

So we tried a second method, instead of precipitates we chose to try different filtering methods.

On the internet we read that blue green algae has some adsorptive properties, so we tried to collect blue-green algae from the bay and we used a plankton net, but we found out that blue-green algae is to small so a smaller filter is needed to collect them. But they do exist in the bay. They actually have done testing on blue green algae before pertaining specifically to radiation and Japan after the atom bomb was dropped. Apparently the process is long, but it is supposed to be effective in many regards. However, we were unable to find a study on how it affected the algae.

Next, we tried to filter iodine solution trough charcoal in a burette (filter). We used charcoal that we made using a campfire and then crushed it into an activated state.

We did this in two different ways:

1: We took the green combination of the blue Cobber (II) sulfate solution and the yellow iodine solution and filtered through the burette with a vacuum. The solution that appeared in the vacuum flask was blue. Therefore the yellow iodine solution was gone. It is also interesting to note that the shade of blue was significantly diminished compared to the original suggesting that some of the copper solution was also adsorbed.

2: We took the yellow iodine solution and filtered through charcoal as in no. 1. This time the solution came out transparent with no color. We took quantitative data of this also. Using a spectrophotometer we found the absorbance of light. A spectrometer is a tool that takes light and passes it through a sample. In this case, the sample was the solution that was passed through the charcoal. The spectrophotometer can compare the amount of light that is passed and the amount of light that gets through to the other side to determine the content and sometimes concentration of a solution. In this case, we choose to compare our values to that of distilled water which in theory should have all light pass through.

We followed the same procedure for chalk to test it as a method of filtration.

Experimental Results:

Substance	Absorbance Value
Water	0.000
Iodine	0.300
Solution passed through charcoal	0.020
Solution passed through Chalk	0.029

From these we were able to work out that when passed through charcoal, 93.3% of the iodine was filtered out and when passed through chalk 90.3% was filtered out. We kept the amount of charcoal and chalk approximately constant at 7.955g and 8.015g respectively.

Conclusion:

We did not have sufficient results to warrant us making any real suggestions for the people of Japan. What we can say however, is that charcoal is a much more efficient filter than chalk in that it yielded better results and was quicker. Furthermore, we can say that because of the nature of charcoal and how we can make it easily by burning wood in a lower oxygen environment, it could be said to be a very viable solution for people simply wishing to purify small quantities of drinking water without access to any chemicals. However, on a large scale, charcoal is not a very viable solution. I would be more efficient investing in larger scale filters, especially carbon filters. Another viable option could be a precipitation reaction for a large scale operation assuming that one has access to the correct chemicals and filtering equipment. Another major issue that was raised throughout the investigation was: Where does the nuclear waste go after you have isolated it from your drinking water? True, you can now safely drink the water, but without proper facilities or equipment to handle and dispose of this kind of waste it could lead to even further problems.

(Tyrel & Ellen)