Degradation of tetracycline via peroxymonosulfate activation by highly reusable Titanium dioxide/impregnated Zirconium-chitosan beads

The nano-sized powder photocatalysts are prone to agglomeration and poor reusability, which cause secondary pollution. To avoid the loss of powder photocatalyst, Titanium dioxide/(TiO₂)/impregnated Zirconium (Zr)-chitosan beads were prepared using a simple cross-linking reaction for the peroxymonosulfate activation to aid the tetracycline degradation. The beads' structural, morphological and optical properties were studied using different techniques. The prepared catalysts effectively degraded 97% of tetracycline (10 mg/L) in 20 min of visible light illumination. The sulfate radicals, superoxide radicals, holes and singlet oxygen were found to be the predominant reactive groups that boosted the tetracycline degradation. The key intermediates were analyzed, and the degradation pathway of tetracycline was proposed. The reusable microspheres exhibited maximum reusability up to 10 cycles with an 11% loss in degradation efficiency. Overall, the important advantages of photocatalytic 3D beads include higher reusability, minimal catalytic mass loss during recovery process and stronger visible light utilization via band gap alteration, opening a new horizon toward effective wastewater management.