Photocatalytic degradation of pharmaceuticals using natural sand-based TiO2 catalysts: Preparation, characterization, and reactivity

[Display omitted] •Dune sand is used as a source of silica and natural support for new photocatalysts.•The Ti–O–Si chemical bonds prove the successful immobilization of TiO2 on supports.•Photocatalytic experiments demonstrated the effective degradation of common drugs.•Both TiO2-DS and TiO2-SP demonstrated effortless separation via simple filtration.•New supported catalysts based on natural materials for large-scale implementation. Quartz sand collected from the dunes of Taghit, a region of Bechar in southwestern Algeria, served a dual purpose in this study. Firstly, it acted as a natural support for the TiO2 photocatalyst. Secondly, it served as a low-cost precursor for silica extraction through an alkaline fusion process. TiO2 nanoparticles were efficiently immobilized on both Dune Sand (TiO2-DS) and extracted silica (TiO2-SP) using an organometallic coating approach, providing a versatile TiO2-based photocatalyst solution. Characterizing the prepared catalysts included techniques such as ICP, N2 adsorption XRD, FTIR, FESEM, and XPS. It was noted that TiO2 exhibited a well-coated layer on both dune sand and extracted silica, demonstrating a prominent anatase crystalline phase. Chemical composition analysis revealed the presence of chemical bonds between Ti and Si in the TiO2-SP and TiO2-DS samples. Moreover, TiO2 particles showed improved dispersion on the surface of TiO2-SP compared to TiO2-DS due to the larger specific surface area of the extracted silica resulting in SBET of 83.74 m2.g−1 for TiO2-SP compared to 30.15 m2.g−1 for TiO2-DS. The photocatalytic performance of TiO2-DS and TiO2-SP was compared to P25 in the abatement of three common pharmaceutical compounds: amoxicillin (AMO), ibuprofen (IBU), and acetaminophen (ACT), with a focus on the influence of the support material on photoactivity. TiO2-SP exhibited a slight advantage in terms of mineralization with 90 %, 92 %, and 99 % after 300 min for ACT, AMO, and IBU, respectively, Whereas the TiO2-DS catalyst resulted in slightly lower results of 81 %, 85 %, and 97 % for the same drugs over the same irradiation period. Additionally, both TiO2-SP and TiO2-DS demonstrated easy separation from the reaction medium by quick sedimentation upon agitation cessation. In contrast, P25 remained in a colloidal suspension.