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

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 degrees C and 600 degrees C, designated TiO2@450 degrees C and TiO2@600 degrees 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 degrees C samples displayed higher BET surface area and more oxygen content, TiO2@600 degrees C showed higher crystal dislocation and microstrains. Experimental results show better TC adsorption performance using TiO2@600 degrees C, attributed to its higher dislocation density and microstrains compared to TiO2@450 degrees C. Thus, more TC molecules are proposed to be adsorbed on the TiO2@600 degrees 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 degrees C to possess 85 times the boundary layer of TiO2@600 degrees C, which limit diffusion in the former.

Automated summary

The research explores the effects of annealing TiO2 nanoparticles at different temperatures, showing that TiO2@600 degrees C exhibits higher crystal dislocation and microstrains, resulting in better dye adsorption performance. Experimental results suggest that more TC molecules are adsorbed on TiO2@600 degrees C due to its higher defects.