The role of particle size of particulate nano-zinc oxide wood preservatives on termite mortality and leach resistance

Abstract

Historically most residential wood preservatives were aqueous soluble metal formulations, but recently metals ground to submicron size and dispersed in water to give particulate formulations have gained importance. In this study, the specific role nano-zinc oxide (ZnO) particle size and leach resistance plays in termite mortality resulting from exposure to particulate ZnO-treated wood was investigated. Southern yellow pine (SYP) sapwood impregnated with three concentrations of two particle sizes (30 and 70 nm) of ZnO were compared to wood treated with soluble zinc sulphate (ZnSO4) preservative for leach resistance and termite resistance. Less than four percent leached from the particulate nano-ZnO-treated specimens, while 13 to 25% of the zinc sulphate leached from the soluble treated wood. Nano-ZnO was essentially non-leachable from wood treated with 5% formulation for the 30-nm particle size. In a no-choice laboratory test, eastern subterranean termites (Reticulitermes flavipes) consumed less than 10% of the leached nano-ZnO-treated wood with 93 to 100% mortality in all treatment concentrations. In contrast, termites consumed 10 to 12% of the leached ZnSO4-treated wood, but with lower mortality: 29% in the 1% treatment group and less than 10% (5 and 8%, respectively) in the group of wood blocks treated with 2.5 and 5.0% ZnSO4. We conclude that termites were repelled from consuming wood treated with nano-ZnO, but when consumed it was more toxic to eastern subterranean termites than wood treated with the soluble metal oxide formulation. There were no differences in leaching or termite mortality between the two particle sizes of nano-ZnO.

Insecticidal effects of zinc oxide nanoparticles and Beauveria bassiana TS11 on Trialeurodes vaporariorum (Westwood, 1856) (Hemiptera: Aleyrodidae)

“…It should be taken into consideration that nanoparticles, especially the synthesized zinc nanopartilces, besides their insecticidal activity and also their slower effect than imidacloprid and Amitraz insecticides, have a lower risk of resistance to these nanoparticles in comparison to commercial insecticides . Clausen et al, (2011) investigated the efficiency of ZnSO 4 and ZnO nanoparticles on mortality of Reticulitermes flavipes (Kollar, 1837) (Isoptera, Rhinotermitidae). Their results confirmed that R. flavipes feeding on wood impregnated with ZnO nanoparticles, decreased to less than 4 % in comparison to control treatment.…”

Study on properties of simul wood (Bombax ceiba L.) impregnated with styrene acrylonitrile copolymer, TiO2, and nanoclay

“…Apart from their efficacy as thermal stabilizers [22,23], their nanometric size makes them suitable for synergistic effects with organoclays, allowing combining both fire resistance performances and enhanced mechanical properties. The WPCs reinforced by nanoclay or metal oxides alone have been well documented [11,24,25]. However, to combine multiple natures of different nanoparticles into polymer matrix and hence further impregnation into wood has not been reported so far.…”

Biological resistance of pine wood treated with nano-sized zinc oxide and zinc borate against brown-rot fungi

“…Several results have already been published regarding the increase in wood resistance against termites and rot fungi when treated with nano-ZnO and nano-ZnB (Manning and Laks 1998;Clausen et al 2011;Németh et al 2013). Among the benefits of applying nano-sized agents to the wood cell wall is the ability to achieve a greater degree of penetration into the cell wall (Kartal et al 2009).…”

“…However, some of those have been recently banned due to health and environmental issues. As a result, the development of environmentally friendly wood-protecting agents with low toxic impact has obtained great attention (Clausen et al 2011;Shabir Mahr et al 2013;Lykidis et al 2013) and is probably going to obtain more in the future.…”