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Jul 24, 2013
Verdigris Blog: De-inking Innovations
medium_laurel3.jpg The weekly Verdigris blog by Laurel Brunner

It looks like a spelling mistake but adsorption de-inking is real and apparently could be a very effective alternative to flotation de-inking. If it works, adsorption de-inking could be another positive step in the environmental sustainability of the printing and publishing industries.

De-inking is one of those touchpaper topics, guaranteed to get those who care about it well and truly steamed up. The discussions tend rapidly to get very technical and very passionate. Combatants often clothe their arguments in concern for the environment, but they basically come down to concerns about money. For instance there are the regular attacks INGEDE makes on HP. INGEDE ,whose members are mostly European paper mills, claims that HP Indigo prints cannot be de-inked and therefore are a source of pollution that renders digital printing environmentally hostile. HP of course begs to differ on the basis that the INGEDE claim might possibly be true for single loop de-inking systems but isn’t true for the latest generation of triple loop de-inking systems. It comes down to technology and economics and now we have something new, and possibly very exciting, to add to the mix: adsorption de-inking.

The European Fibre and Paper Research Organisations (EFPRO) and the Confederation of European Paper Industries (CEPI) have been looking at a new approach in order to achieve CEPI’s environmental impact goals. Adsorption de-inking apparently has none of the disadvantages of conventional flotation de-inking, regardless of the number of loops. It borrows from the dry cleaning washing machine concept that uses 90% less water than a conventional washing machine. Tiny plastic beads mixed in with the wash, capture dirt through adsorption whereby molecules from one surface (the dirty clothes) are held in the surface chemistry of another (the polymeric beads). Researchers working at Dresden University have looked into applying the same principles to de-inking printed papers.

They found that using adsorption de-inking instead of flotation reduced water usage by 90% and energy usage by 30%. It also improved the brightness of the pulp by 10% and showed a clear reduction in dirt specks, all with reduced fibre loss. The savings are obviously massive and this is only the beginning of this technology’s evolution which has yet to be optimised.

– Laurel Brunner

Verdigris supporters who make the blog possible: Agfa Graphics (, Digital Dots (, drupa (, EFI (, EcoPrint (, Fespa (, Heidelberg (, HP (, Kodak (, Pragati Offset (, Ricoh (, Unity Publishing ( and Xeikon (


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