Unravelling the effect of crystal dislocation density and microstrain of titanium dioxide nanoparticles on tetracycline removal performance

[Display omitted] •A commercial P25 Degussa TiO2 was annealed at 450 °C and 600 °C, respectively.•Annealing temperature has no significant influence on the morphology and crystal size of the samples.•The crystals of samples annealed at 600 °C exhibit higher dislocation density and microstrain.•Samples annealed at 600 °C showed better performance in Tetracycline removal.•The mechanism for Tetracycline removal is correlated to crystal properties of the as-annealed samples. New approaches are being developed to improve water purification using semiconductor nanomaterials to meet the 6th Sustainable Development Goal (SDG #6) of the United Nations (UN) on water sanitation. The pollutant removal performance of TiO2 nanoparticles is widely known to depend on its surface area/functionalisation. To unravel other intrinsic properties limiting its performance, a commercial Degussa P25 TiO2 was annealed at different temperatures, 450 °C and 600 °C, designated TiO2@450 °C and TiO2@600 °C, respectively. The scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Brunauer-Emmett-Teller (BET), and electron diffraction spectroscopy (EDS) were employed to investigate the morphology, crystallinity, surface area, and bulk chemical composition, respectively of the as-annealed TiO2samples. While TiO2@450 °C samples displayed higher BET surface area and more oxygen content, TiO2@600 °C showed higher crystal dislocation and microstrains. Experimental results show better TC adsorption performance using TiO2@600 °C, attributed to its higher dislocation density and microstrains compared to TiO2@450 °C. Thus, more TC molecules are proposed to be adsorbed on the TiO2@600 °C due to their relatively higher defects. To examine the controlling mechanism of the TC adsorption process, the intra-particle diffusion model reveals TiO2@450 °C to possess 85 times the boundary layer of TiO2@600 °C, which limit diffusion in the former.