Effects of surface roughness and light scattering on the activation of TiO2 on mortar photocatalytic process

[Display omitted] •Activation of TiO2 by diffuse/direct solar radiation.•Relationship of different roughness scales with the dispersion/activation of TiO2.•Distinct particle sizes of TiO2 and the formation of TiO2 magnetic mesh.•The TiO2 magnetic mesh and photocatalysis system efficiency.•The TiO2 in suspension and the film layer activation effectiveness. To assess the effects of the activation of TiO2 as a function of different roughness scales and light scattering on mortar surfaces. Commercial samples of TiO2 in powder and suspension form were compared using seven mortar samples with distinct treatments of TiO2. Optical profilometer, Scanning Electron Microscopy, and EDS elemental mapping were used to evaluate the influence of roughness on the activation of TiO2. Activation of TiO2 by diffuse solar radiation is as or more important than direct solar radiation; Micro-roughness has no direct relationship with the activation of TiO2; The presence of different roughness scales and the use of the same particle size of TiO2 affect the dispersion process of TiO2; Different particle sizes of TiO2 helped in the formation of TiO2 magnetic mesh which improves system efficiency, and; Suspension of TiO2 does not guarantee better effectiveness of the system due to imperfect film formation.