The combination of a semiconductor metal oxide with green low-cost adsorbent materials has prompted the emergence of new natural resources having higher efficiency for treating dye wastewater. This study investigated the characterisation and performance of synthesised nano flower-like rutile TiO₂ (F–TiO₂) via the facile hydrothermal method and sintered commercial TiO₂ (C–TiO₂). Both C–TiO₂ and F–TiO₂ were immobilised on green super adsorbent basil seed. The details of the structural properties were analysed by Rietveld refinement and the deconvolution method to verify the purity. The synthesised F–TiO₂ immobilised on basil seed (B–F–TiO₂) was found to have optimum physical and morphology properties. Kinetic and equilibrium studies illustrated that the adsorption behaviour of B–F–TiO₂ could be better described by pseudo-second-order kinetic (chemisorption). The maximum uptake capacity (49.47 mg g−1) with the highest removal of methylene blue (98.95%) was obtained at an equilibrium time of 180 min following photocatalysis and self-cleaning. A large antibacterial ring area (1.83 mm2) was also obtained from B–F–TiO₂. The removal of methylene blue dye for B–F–TiO₂ increased as the recycle times increased (3 times) due to the increase of the surface area exposed to methylene blue as the weight of B–F–TiO₂ immobilised on basil seed decreased. This demonstrates that B–F–TiO₂ provides better potential to apply as a multifunction green super adsorbent for dye wastewater treatment compared to B–C–TiO₂.
