Over the thirteen years I’ve been employed as ‘Technical Support’ on various chemical plants and processes I’ve had a good number of unusual requests : What would be the relative stability of iridium verses ruthenium acetate when mixed with soil? Why does the calcium level in our product seem to trend with the extent of local rainfall? What are these cheap carbon monoxide sensor actually made of? Can I tell someone if the black solid coming out of their new plumbing is coming from their old lead piping? The cork is stuck in this wine bottle, do I know clever way to get it out (I did – I used the differential expansion rates of glass (fast) and cork (slow) and heated the neck of the bottle under hot running water).
But last week I believe I had a question to top them all. “My white horse has poo staining on the skin of his buttocks – what would I suggest to get it off? I’ve already tried bleach, Napisan and oven cleaner.” First let me say I would not advise the application of any of these products to the skin or any animal or any human for that matter. I once worked with a chap you used bleach to remove silver oxide stains from his skin at the end of a shift – it is true that it removed the silver, but it also removed a significant amount of skin (so don’t try this one at home.)
I wondered if the question came to me because Mrs W is a vet or whether as the senior chemist on site this was a question I would be expected to answer? I like to think the latter, but I guess when my applied biochemistry lectures covered the removal of stains from horses rear quarters I must have dosed off and missed that section.
In fact advice on the removal of metal / metal salt residues from reactor walls was a relatively common question in my last but one job. However generally this was related to ruthenium or palladium and not poo! However a question is a problem, and a problem can always be broken down and then a solution can be devised by finding the key part of the deconstructed problem. It was fortunate that I had been of enquiring mind when changing the nappy of our son a few weeks ago and was reminded that poo comes in many colours. So my wife being a vet (and thus an expert in all things excreted) I asked, because she was on hand and I’d never pondered the question before in the last 40 years, what is it that makes poo brown? The answer? Old discarded blood cells. So of course the reason behind the colour of blood is the iron in the hemoglobin . So my question was really – how can you solubilise an iron salt impregnated into skin to be able to wash it out? It is clear that the use of bleach (hypochlorite) or nappy cleaner (peroxide) was never going to help.
So I asked myself – how would I remove iron salts from a reactor? Nitric or hydrochloride acids would both be good choices, but in my case this would be rather bad news for the horse. Then I thought again, what could I use to complex the iron and render it soluble? Well that is something of a schoolboy question when you think like that – EDTA would surely be a great choice. I recall my Ph.D supervisor demonstrating some iron chemistry in a champagne bottle in a lecture and getting his reagent levels a little wrong a coating the first two rows of the lecture theatre in iron oxide – and then a number of us in the lab having a lot of buckets of clothes to clean on his behalf, we used EDTA solutions. To bring this ever lengthening story to a close – it worked. The horse is fit to go to a show in the summer and the groom made me a proposal of marriage she was so surprised that I had suggested something that worked. Of course I politely declined, but figure this was the most effective problem solving I’ve done on site this month and the most obscure question I’ve get been asked in my role as Technical Support. Do keep them coming though…