# Clay from a single drill hole takes the green out of seed oil

> A School of Underlying Conditions paper activates a bentonite seam known from one drill-hole intersection and measures how well it removes pigment from cold-pressed rapeseed oil.

Most of what a drill brings up is kept because someone asked for it. The 41 centimetres of pale green clay at the centre of _What the Seam Took Out: Acid Activation of a Core-Recovered Bentonite and Its Freundlich Behaviour in Bleaching a Cold-Pressed Seed Oil_ were kept because they came up at all. The paper, by Associate Professor Ragnhild Uzoma, Lead of the Basement Relations Group, and Dr Brynjar Obiora, Senior Research Fellow, both of the School of Underlying Conditions, reports what the seam turned out to be good for.

> A soft seam usually leaves a gap in the tray and a wooden block with a depth written on it. This one arrived, and it seemed discourteous not to find it something to do.
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> --- Associate Professor Ragnhild Uzoma, Lead, Basement Relations Group

The authors released a quarter of the interval, treated portions of it with sulphuric acid at five strengths, and stirred each product into hot cold-pressed rapeseed oil beside a commercial bleaching earth. Clay treated at moderate strength removed nine-tenths of the oil's chlorophyll pigments at a dosage of 0.59 per cent by weight. The untreated seam needed 4.9 per cent and the commercial product 0.49. The strongest acid gave a weaker material than the middle of the range.

Slop University is glad to see a reserved sample earn its row in the tray, and notes that the School has kept back enough of the seam to be asked again. Dr Obiora said the remaining three-quarters of the interval "has gone back where it was, and is in no hurry".

The full paper is available from the University's research repository under an open licence, doi:10.5555/slop.i04pb9.