• Question: What behaviour are you testing / looking for?

    Asked by to Hattie, Ben on 17 Jun 2014. This question was also asked by .
    • Photo: Ben Butler

      Ben Butler answered on 17 Jun 2014:

      I’m looking at the behaviour of frozen seawater. Sea ice, which is just frozen seawater, covers large parts of our planet but at the moment the ice in the Arctic is melting quite quickly!

      My research is looking at how the ice behaves when it gets warmed up a little bit, and will hopefully help us predict what is going to happen to the Arctic and Antarctic ice in the future

    • Photo: Harriet Aitken

      Harriet Aitken answered on 18 Jun 2014:

      Hi Immi2000,

      I do lots of different types of tests, but the most important is to see how clean my water is. The main chemical I am trying to remove is arsenic, and there a few other things I do to support the main test – arsenic analysis of my water – to try to understand why and how arsenic is being removed!

      The other tests I do are looking at corrosion rates – my arsenic is removed by rust generated in my system so the general rule *should* be the more rust I have the more rust is removed…

      This isn’t always the case! Arsenic is pretty horrible chemical in any form, but when it is dissolved in water it is usually found in its pentavalent (+5) or trivalent (+3) form. The trivalent form is very difficult to remove compared to the pentavalent because at the normal pH of drinking water the trivalent form is a neutral ion which means it isn’t attracted to the rust surface. So no mater how much rust you have, you might not be able to remove any arsenic. So it’s important to measure pH and also to try to find out what type of arsenic I have so I do speciation tests.

      But you also get different kinds rusts which exhibit different surface charges which are able to attract the arsenic ions if they are in the right form. Some rust surfaces become neutral at pH 7 so above this again, you might have the same problem – no arsenic remove no matter how much rust you have. To figure out what rusts I have I do characterization tests, some are really simple like identification by colour but we also do more complex testing called X-Ray Diffraction (XRD).

      There are so many different things to look at to help me understand the reactions going on, but I do get to use a lot of cool equipment and I’ve learnt so much in the process.

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