Facile biosynthesis of Ag/AgCl/TiO2@Fe2O3 ternary heterojunction nanocomposite: Characterization and photocatalytic activity for real wastewater treatment under sunlight

There is a significant increase in the demand for visible-light (VL) sensitive photocatalysts that can efficiently eliminate pollutants from water and wastewater. Moreover, the significance of developing environmentally friendly techniques for synthesizing nanostructured photocatalysts possessing modifiable surface plasmon band is steadily growing and deserves careful consideration. This research aimed to create a ternary heterojunction nanocomposite (NC) photocatalyst using a simple biosynthesis method to enhance the photoactivity of the NC under sunlight. The photocatalyst was synthesized using aqueous leaf extract (ALE) of Mangifera indica as a reducing and stabilizing agent. The biosynthesized Ag/AgCl/TiO2@Fe2O3 NC (BSNC) with a particle size of ∼40 nm, a specific surface area of 21.53 m2.g−1, a magnetization saturation value of 25.9 emu.g−1, and a bandgap energy of 1.63 eV was obtained using an AgNO3/ALE (R) ratio of 0.6. Various techniques were employed to assess the effect of the ratio (R) on the features of the synthesized products. The BSNC effectively degraded the organic pollutants of a real petroleum refinery wastewater (PRWW) within a span of 60 minutes under sunlight exposure. The maximum removal of COD reached 99.89 % when the pH and photocatalyst concentration were 3 and 0.8 g.L−1, respectively, all at the ambient temperature. The outstanding photocatalytic performance of BSNC under sunlight, along with the broadening of the absorption spectrum into the VL range, can be attributed to surface plasmon resonance and efficient charge separation facilitated by the heterostructure composed of Ag, AgCl, TiO2, and Fe2O3. The remarkable durability of the BSNC was demonstrated through a series of recycling experiments spanning seven cycles and the structure was not damaged, showcasing its exceptional long-term photocatalytic stability. The simplicity of operation and the ability to harness solar energy have made the BSNC a notable and reusable choice for effectively degrading toxic organic pollutants in wastewater using sunlight. [Display omitted] •Novel biosynthesis of Ag/AgCl/TiO2@Fe2O3 heterojunction nanocomposite is reported.•Aqueous leaf extract of Mangifera indica mediated the synthesis as reducing agent.•Surface plasmon resonance of Ag/AgCl and Fe2O3 extended light absorption of TiO2.•The BSNC showed a reasonable reusability for wastewater treatment under sunlight.•Wastewater treatment was optimized based on the potential operational parameter