Polymer-enhanced nickel ferrite catalyst for the efficient reduction of 4-nitrophenol as a hazard pollutant

Abstract

The synthesized nickel ferrite (NiFe₂O₄)/poly(aniline-co-o-toluidine) (PAOT) nanocomposite was successfully characterized using XRD, FTIR, SEM, and EDX, confirming the formation of a stable spinel structure with uniform particle distribution (32–68 nm). The material exhibited a low bandgap energy of 1.24 eV and retained magnetic properties, enabling easy recovery and reuse for up to four cycles. The catalytic activity of the NiFe₂O₄/PAOT nanocomposite was evaluated for the visible-light-assisted reduction of 4-nitrophenol (4-NP) without external reducing agents. The catalyst achieved reduction efficiencies of 85.83% at 2 ppm, 95% at 10 ppm, and 99% at 15 ppm within 60 min, with improved performance at higher catalyst dosages and temperatures (e.g., 50 °C with 20 mg). Kinetic analysis revealed pseudo-first-order behavior. Compared to other reported catalysts, NiFe₂O₄/PAOT offers green synthesis, high efficiency, magnetic recoverability, and operational simplicity, making it a promising material for sustainable wastewater treatment.