Enhancing brilliant green dye adsorption-photodegradation using a TiO₂-modified natural material

The present study investigates the photocatalytic degradation of Brilliant Green (BG) dye using a modified natural material (NM) incorporated with titanium dioxide (TiO₂) under ultraviolet (UV) irradiation. The synthesized catalyst NM-TiO₂-20% was evaluated for degrading BG dye. An optimization process was carried out using a Box-Behnken design to maximize the removal efficiency of BG dye. The optimal parameters obtained were %TiO₂ = 20%, [BG] = 38.02 ppm, and pH = 9.91, resulting in a remarkable removal efficiency of 98.82%. Moreover, NM-TiO₂-20% exhibited remarkable stability over five cycles. Additionally, the scavenging tests of free radicals indicate the involvement of superoxide ions (O₂^•−) and hydroxyl radicals (^•OH) as the species responsible for BG degradation. The present findings underscore the synergistic effect between the low-cost natural material and pristine TiO₂ (this means the synergy effect of adsorption and photocatalysis combination) on the photodegradation of BG dye, as an organic pollutant in contaminated wastewater. This confirms the potential of utilizing natural materials for promising and sustainable depollution applications with NM-based photocatalysts. In this study, NM-TiO₂-20% was identified as the optimal and most effective system, achieving almost complete elimination of the dye molecules compared to NM alone, TiO₂ alone, NM-TiO₂-10%, and NM-TiO₂-15%.