Surface functionalization/silane modification of CeO2 nanoparticles and their influences on photocatalytic activity of acrylic films for methylene blue removal

In this study, the photocatalytic degradation of methylene blue (MB) as model organic pollutant by pure and silane modified CeO2 nanoparticles was assessed. The surface modification was performed using 3-aminopropyltriethoxysilane (APTES) at different silane concentrations. The nanoparticles were previously functionalized using hydrothermal process to increase silane grafting ratio. The grafting of silane molecules to the nanoparticles surface was confirmed using FTIR and XPS analysis. It was found that hydrothermal treatment increased the surface OH groups and silane grafting ratio by about 30 and 55 %, respectively. Surface modification of the functionalized CeO2 nanoparticles enhanced photocatalytic degradation of MB polluted wastewater up to 85.7 and 104 % compared to the pure nanoparticles under UV and solar lights, respectively. The pure and modified nanoparticles were applied at 1, 3 and 5 wt% to an acrylic latex. The prepared acrylic nanocomposite films were evaluated for photocatalytic degradation of MB stain and also for mechanical properties. It was found that silane modification of nanoparticles caused about 62 % decrement in the water contact angle (i.e. increment in hydrophobicity), 540 % improvement in the tensile strength and 18.6 times enhancement in the modulus of the acrylic film compared to the pure nano CeO2 containing acrylic film, respectively.