Evaluation of the effectiveness of CuONPs/SiO2-based treatments for building stones against the growth of phototrophic microorganisms

Abstract

Colonization by phototrophic microorganisms causes a range of problems for building façades, The combination of biological physical and chemical agents accelerates the decay of materials. For this reason, in recent years there has been a growing interest in the application of multifunctional treatments that combine consolidant and biocidal action. In this study, the effectiveness of a nano-structured CuONPs/SiO2-based multifunctional treatment for the prevention of algal growth was evaluated on two different stones by using two complementary techniques, namely Chlorophyll a fluorescence and spectrophotometric determination. The results showed a delay in the algal colonization for two reasons: (1) The SiO2 matrix modified the roughness and surface tension, thus delaying the initial setting, and (2) the CuONPs decreased the viability of the phototrophic organisms at longer exposure times.