Improved photocatalytic degradation of methylene blue under visible light using acrylic nanocomposite contained silane grafted nano TiO2

[Display omitted] •TiO2 nanoparticles were surface modified by APTES at different concentrations.•Acrylic latex used to prepare paints contained pure and silane grafted TiO2 nanoparticles.•Mechanical and surface properties of pristine and nanocomposite acrylics films were evaluated.•Pure and modified nanoparticles were used to degrade methylene blue in colored wastewater.•Photocatalytic degradation of methylene blue stain by acrylic paints was evaluated. Removal of organic dyes from wastewater by photocatalytic oxidation (PCO) under visible light has attracted attention of many scientists. In this research, TiO2 nanoparticles were surface modified by aminopropyltriethoxysilane (APTES) at different concentrations (1, 3, 5, 7, and 10 wt%). The nanoparticles were applied to acrylic latex at 1, 3, and 5 wt% to prepare photocatalytic nanocomposite paints. The modified nanoparticles were evaluated for photocatalytic degradation of methylene blue in an aqueous solution as model-polluted wastewater. The modified nanoparticles showed 30, 29, and 22% enhancement in photocatalytic degradation of methylene blue compared to the pure TiO2 nanoparticles under UV, visible and solar lights, respectively. Using the modified nanoparticles in the acrylic film caused 31.6 and 56.3% improvement in the tensile strength and toughness compared to the pure nanoparticles containing sample. The modified nanoparticles considerably enhanced the light absorbance capacity of the acrylic paint. On this basis, the modified paints (at 3 wt% loading of nanoparticles) showed 29, 27, and 20% improvements in discoloration of methylene blue stain compared to the pure nano TiO2 containing nanocomposite under UV, visible, and solar lights, respectively.