The washing machines were developed by researchers at the University of Graz in Styria.
For decades, librarians and paper conservators have been aware that paper produced since the 1880s only has a limited shelf life due to its acid content.
The first signs of deterioration were already apparent in the 1950s, according to researcher Volker Ribitsch from the Chemistry Institute of the University of Graz.
He said: "The chemical compound disintegrates, thereby producing sulphuric acid as an intermediate, which in turn destroys the cellulose."
Around 40 million printed works are likely to be threatened in Europe, including irreplaceable pieces dating back to World War I and World War II.
In cooperation with paper restorer Patricia Engel from the Danube University Krems he developed a system in which special nanoparticles are used in a solvent with a very low boiling point and very low surface tension. The nanoparticles consist of magnesium and calcium compounds and have a cellulose compound as a shell.
Ribitsch said: "The whole thing now looks like a 20-litre pressure cooker, in which the books take a bath."
In this metal cylinder, the mixture of solvent and nanoparticles is enriched with nitrogen and pressurised, so that the de-acidifying particles can be homogeneously distributed in the books.
At the same time, they increase the mechanical strength of the paper. Since no aqueous solvents are used, there is no lengthy drying process. The cleaning process itself takes about half an hour.
As the tests on the mobile prototype sponsored by the Austrian Ministry of Science have shown, the ink and colours remain completely unchanged after the wash cycle. After the successful tests, the device and technology is now set to be developed further.
The prototype can only clean up to six books in pocket format, but the researchers want to work on a bigger version.
Ribitsch said: "The device should finally be able to clean up to 100 kilograms of books in one cycle."
Story courtesy of Central European News.