Potential antifouling properties of copper loaded zeolites on fouling diatoms

Biofouling is a phenomenon affecting all the infrastructures immerged in marine and freshwater environments. This colonization leads to a deterioration of the surfaces implied and affects the performances of the different structures as the decrease of ship speed or the increase of fuel consumption. Polemics around harmful antifouling coatings being more and more concerning, an alternative to toxic compounds is here proposed. The effect of three different zeolites, pure or copper loaded, is evaluated on two fouling diatoms, Cylindrotheca closterium and Amphora sp. These organisms display different sensitivities to copper usually used in antifouling paint. Finally, it has been shown that pure zeolites had stimulating effect on microalgae growth while copper loaded ones seemed efficient to inhibit their development. However, natural zeolite appeared less effective than the two synthetic after 7 days incubation. These differences seemed to be due to the bonds created by copper in the materials and to the leaching of metallic ions. Finally, the constant release of active agent in the medium by the minerals appeared to be the key for an interesting application in antifouling systems.