Novel sustainable composites made of car's waste and sodium titanate for the efficient photocatalytic removal of the bromophenol blue dye: study under solar and UV-Vis light

In this research, W-doped sodium nanotube titanate (NaTNT) nanoparticles were used for the photocatalytic degradation of the bromophenol blue (BPB) dye. The NaTNT powder was mixed with car's tire powder (TP) to enhance its light absorption or was supported on recycled car's air filters (AFs) to facilitate its removal from the cleaned water after the degradation of the BPB. The SEM analysis indicated that the NaTNT nanoparticles and the TP had sizes in the range of 150-325 nm and 8-37 µm, respectively. Both powders were also studied by X-ray diffraction and found that the sodium titanate corresponds to the Na₂Ti₆O₁₃ with monoclinic phase, while the TP is formed by rubber, silicon, ZnS, and ZnO. The photocatalytic activity of the NaTNT powder was evaluated for the degradation of BPB dye (20 ppm) and obtained a maximum degradation of 95 and 80% under UV-Vis and natural solar light, respectively, after 4 h of irradiation. For the NaTNT + TP composite mixture, the maximum degradation was 87 and 68% under UV-Vis and solar light, respectively. The NaTNT and NaTNT + TP powders were supported on the AFs to form the AF + NaTNT and AF + NaTNT + TP composites. Those ones produced maximum degradation of 86% and 74% (under UV-Vis light), respectively. Besides, several initial pHs were tested for the contaminated water and determined that the maximum degradation of BPB (93-95%) is reached for the pHs of 3 and 7. Reuse experiments (3 cycles) revealed that the diminution of the BPB degradation percentage was 23% and 20% for the NaTNT and NaTNT + TP powders, respectively. Overall, it was demonstrated that the wasted car's air filters can be used as a support for photocatalytic powders, and this combination of AF + powder degrades the BPB with high efficiency.