Enhanced Photocatalytic Activity of Polythiophene-Modified Strontium Ferrite Nanohybrids for Crystal Violet Degradation Under Visible Light

Dye-contaminated wastewater presents a serious environmental challenge, demanding efficient and sustainable treatment methods. Crystal violet (CV) is a water-soluble, toxic, and persistent organic dye that poses serious health risks and contributes significantly to environmental pollution. The objective of this study is to investigate the use of polythiophene (PTh)-decorated SrFe₁₂O₁₉ nanoparticles as photocatalysts for the efficient and sustainable degradation of CV dye in contaminated wastewater. The materials were characterized using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (SEM–EDS), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), and X-ray diffraction (XRD). The FTIR and XRD studies confirmed the successful modification of the SrFe₁₂O₁₉ nanoparticles with PTh and a progressive decrease in band gap energy with increasing PTh loading, from 2.40 eV for SrFe₁₂O₁₉ to 1.63 eV for 5% PTh/SrFe₁₂O₁₉ (UV–Vis). This reduction in band gap significantly improved light absorption and photocatalytic activity. The 5%-PTh/SrFe₁₂O₁₉ nanohybrid demonstrated superior performance, achieving 97% CV degradation within 120 min. Degradation products were analyzed using LCMS, and a possible degradation pathway was proposed. The findings not only contribute to the development of eco-friendly, energy-efficient solutions for dye-contaminated water but also pave the way for scalable applications in industrial effluent treatment, addressing a critical environmental challenge and promoting the use of renewable light sources for pollution control.