Using water-soluble preservatives in the form of nanoparticles could be a new method of wood preservation.
Nanoparticle fluorides for wood protection
Traditional wood preservatives are commonly copper, boron or arsenic based. Not surprisingly there is significant research into better, less toxic ways to treat wood to protect it from decay and timber pests.
New preservation methods such as wood modification techniques, including acetylation, have been evaluated. Acetylation chemically modifies the wood, reducing moisture content to a level that cannot support decay. It also makes the wood stronger, but it doesn’t appear to be completely resistant to all species of termite. Another avenue is using nanoparticles for increased penetration of preservatives into the wood. This technique certainly appears to boost the performance of the traditional wood preservatives. Specifically, researchers have started to evaluate the use of nano metal fluorides as a wood preservative.1
Sodium fluoride is known to have potential as a wood preservative, and may even be superior to traditional preservatives. Indeed, fluorides in general have the benefit that they are effective at low concentrations. However, on the downside, sodium fluoride readily leaches from wood when wet. The reduction in efficacy coupled with the environmental impact of leaching means the use of sodium fluoride commercially is somewhat problematic.
However, in this latest research, scientists have evaluated the use of low water soluble fluorides (magnesium and calcium fluoride), synthesised as nanoparticles to gain penetration into the timber. Samples of Scots pine sapwood (Pinus sylvestris) treated with the experimental solutions were exposed to Coptotermes formosanus for eight weeks. Wood treated with 0.5 M concentration solutions of either fluoride provided 100% mortality of termites. Weight loss due to consumption by termites was minimal (less than 1%), with combinations of calcium and magnesium fluoride potentially providing the best performance. The authors concluded that nanoparticle fluorides certainly have potential as wood preservatives.
1Usmani, S.M., Plarre, R., Huebert, T., Kemnitz, E., 2020. Termite resistance of pine wood treated with nano metal fluorides. EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS 78, 493–499. https://doi.org/10.1007/s00107-020-01522-z