Swiss wood researchers Empa have developed a chemically modified nanocellulose sponge that could find use mopping up in oil spills.
The new, absorbable material is said to be light enough so that as it absorbs the oil spill, it remains floating on the surface and can then be recovered. It can be produced in an environmentally-friendly manner from recycled paper, wood or agricultural by-products.
The Empa researchers Tanja Zimmermann and Philippe Tingaut, in collaboration with Gilles Sèbe from the University of Bordeaux, say the highly absorbent “silylated” nanocellulose sponge separates the oil film from the water, and then can then be easily recovered. In laboratory tests the sponges absorbed up to 50 times their own weight of mineral oil or engine oil.
Nanofibrillated Cellulose (NFC), the basic material for the sponges, is extracted from cellulose-containing materials like wood pulp, agricultural by products (such as straw) or waste materials (such as recycled paper) by adding water to them and pressing the aqueous pulp through several narrow nozzles at high pressure. This produces a suspension with gel-like properties containing long and interconnected cellulose nanofibres.
The sponges keep their shape to such an extent that they could be removed with pincers from the water. Empa says it is seeking a partner of wood based sponges for commercial development.
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