Enhanced visible-light photocatalytic degradation of organic pollutants using fibrous silica titania and Ti3AlC2 catalysts for sustainable wastewater treatment†

Visible light photocatalysis offers a green and sustainable approach to wastewater treatment and environmental remediation. This study focuses on the synthesis of fibrous silica titania (FST) via a green method and comprehensively evaluates its photocatalytic performance compared with Ti₃AlC₂ powder. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed superior crystallinity and unique lamellar structures in FST, contributing to its enhanced photocatalytic activity. The FST catalyst achieved remarkable degradation efficiencies of 93% for MB and 96% for rhodamine B (RB) under visible light, outperforming the bare Ti₃AlC₂ powder. This promising performance is attributed to FST's narrow band gap (∼2.98 eV), high surface area, and minimal photogenerated charge carrier recombination. Kinetic studies showed excellent agreement with pseudo-first-order kinetics, with R² values of 0.9801 and 0.988 for MB and RB, respectively. Reusability tests demonstrated sustained efficiency, with degradation rates remaining above 80% after four cycles. GC-MS analysis identified intermediates formed during photocatalytic degradation, ultimately converting them into harmless products, i.e., CO₂ and H₂O. These findings highlight FST as an economical, sustainable, and efficient photocatalyst for organic pollutant degradation compared to Ti₃AlC₂.