Synthesis and photocatalytic evaluation of visible Light-Activated (Fe,S)codopedTiO₂ in Metanil yellow degradation

Abstract

In this study, visible-light-active (Fe, S)-codopedTiO₂ photocatalysts were synthesized via a sol–gel method using titanium tetraisopropoxide (TTIP) as the precursor. The structural, optical, morphological, and elemental characteristics of the synthesized photocatalysts were comprehensively analyzed using XRD, FT-IR, SEM–EDX, HR-TEM, and UV–Vis DRS techniques. Metanil Yellow (MY), an azo dye, was selected as a model pollutant to evaluate the photocatalytic efficiency of the synthesized (Fe, S)-codopedTiO₂ photocatalyst under visible-light irradiation. The results revealed that the (Fe, S)-codopedTiO₂ photocatalyst (150mg/100 mL) completely degraded MY (20 ppm) within 30 minutes under visible-light exposure. Furthermore, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) analyses confirmed a 99% mineralization efficiency. The degradation reaction followed pseudo-first-order kinetics with an apparent rate constant of 0.051 × 10⁻³ min⁻¹ (R² = 0.978). The photocatalyst exhibited excellent stability and reusability, maintaining high degradation efficiency over five consecutive cycles without significant loss of activity. The enhanced photocatalytic performance of the (Fe, S)-codopedTiO₂ is attributed to the effective suppression of electron–hole recombination and improved visible-light absorption. The synthesized nanoparticles were stable, well-crystallized, and environmentally benign, making them suitable for the treatment of organic pollutants in industrial and agricultural wastewater under sunlight. Therefore, the fabricated (Fe, S)-codopedTiO₂ photocatalyst is demonstrated to be an efficient and cost-effective material, as only a small amount of photocatalyst is required for environmental remediation applications.