The use of diffusion denuders for studying the reactivity of marble surfaces: an application to the evaluation of protectives

A particularly desirable property of protectives is their inertness, a characteristics which is frequently overlooked. If these products are to find a really successful use, then the properties of existing products will require better understanding so that new types of protectives can be developed. Two commercially available protectives were investigated from the point of view of their reactivlty towards SO2 by using a diffusional technique. From measurement of SO2 concentration, a reactivity coefficient and the corresponding deposition velocity have been calculated. Experiments on three types of marble have also been carried out by means of an exposure chamber to highlight the advantages of the diffusional technique used.