Saturday, 8 November 2014

Jack's project first steps: just a phase we are going through!

I thought it might be helpful to other students (and Jack and me!) to share some thoughts on the Y13 lab projects. I shall work through them all, but since it is on my mind, I thought I would say a few words about Jack Condron's project. Jack asked if he could develop a device for cleaning contaminated drinking water. His idea was to create a cheap and simple solution for helping solve one of the major challenges in developing countries: access to clean drinking water. A laudable ambition, and one that has and continues to occupy the minds of many scientists, engineers in both research organisations and commercial organisations. One patent image is shown on the LHS. The key to this project is simplicity and a solution that is independent of any power supply: i.e. purification might result from a shake or a hand operated mini-pump.

The first thing to point out is that Jack's initial thoughts, combined with his determination and drive was enough to get me behind him. We then started thinking about "proof of concept" experiments, the need for certain materials and reagents and in particular how we might "mimic" the system we are trying to develop. One of the great things about the UTC's Innovation Labs is the access we have to a 3D printer, and, more importantly, George Rule's ingenuity. So, Jack and George created a small "printed" chamber for testing the extraction of water from a "dirty" mixture. I have shown a competing design above, Jack's design is currently our in house design and will remain undisclosed for now. In simple terms, Jack's design comprises, two, 2ml compartments that can be connected, with a dialysis membrane providing an interface. This will allow us to establish whether our "chemistry" can achieve the desired result.

We sat down and thought about the model experimental system and our through our discussions it became clear that "phase transitions" and an understanding of solubility of molecules in water and organic solvents was only superficially taught at A level. Moreover, the use of a simple and safe polymer for creating phases, such as polyethylene glycol (PEG, for short), was also something for which a strong theoretical base was off curriculum. At this point Jack was beginning to wonder what had happened to his desire to save lives! (Me too!). I then thought, we need to "see" the movement of contaminating species between phases and across membranes. We needed a dye that was water insoluble, but reasonably soluble in ethanol and polyethylene glycol. Orcein, came to the rescue (top LHS).

We now have water, orcein, ethanol, PEG (at three mean molecular weight lengths), an experimental chamber and a water soluble dye (still under investigation). Jack also, threw in bleach tablets for good measure, thinking about the use of calcium hypochlorite (top RHS) for water purification, and as a compound that we might need to eliminate. So we now have to understand not only the physical chemistry of such mixtures, but also the reactivity of a strong oxidising agent as well. 

Jack has been exploring how these molecules behave in solution when mixed in a range of combinations. We are on a journey rich in chemistry and one that seems to be taking us farther and farther away from the end point, but (I like to think) deeper and deeper into fundamental chemistry. The visual demonstration of PEG:water phases (used to drive counter current distribution separation technology), the mixing of ethanol in water and the differential partitioning of dyes has been the first "learning" phase (sorry!). Jack has already noted that polymer length (PEG is shown top LHS) can also influence the absorbance maximum of the dye (purple to red shifts are reproducibly obtained). Dye precipitation at water PEG interfaces can be followed with time and then of course there is the observed "bleaching" of absorbance caused by the bleaching tablets. Does "bleach" affect all 8 component of the dye? Can we explain the bleaching of polyaromatic dyes and does the same phenomenon occur with similar water soluble polyaromatic dyes?

How does this help us with the initial aim? Well it helps us in many ways. First and foremost it is training a young enthusiastic scientist at the UTC, how challenging research can be, even when the problem seems (at face value) so simple. It is providing Jack with a terrific foundation in the relationship between pure and applied chemistry and empowering him as an investigative scientist. The fact that he is a Y13 student at the UTC, constantly amazes me! Jack is at an early stage in the project and I shall follow up at Christmas with project and he will write the third and final blog!

To follow, Kelly's project: fingerprints, identical twins, epigenetics and Alan Turing's legacy.

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