Use of Treated Fly Ash in the Design of a Fe3O4@FA@GO@BiOCl Nanocomposite Photocatalyst for Dye Removal from Aqueous Solutions

Rusul  Hussain Jaber; Shahlaa  Esmail Ebrahim; Fatehah  Mohd Omar

doi:10.22153/kej.2026.03.003

Authors

Rusul Hussain Jaber Department of Environmental Engineering , College of Engineering, University of Baghdad, Baghdad, Iraq https://orcid.org/0009-0002-0832-5857
Shahlaa Esmail Ebrahim Department of Environmental Engineering , College of Engineering, University of Baghdad, Baghdad, Iraq https://orcid.org/0000-0002-8954-1270
Fatehah Mohd Omar Environmental Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia https://orcid.org/0000-0003-3265-743X

DOI:

https://doi.org/10.22153/kej.2026.03.003

Keywords:

Fe3O4@FA@GO@BiOCl; visible light photocatalysis; fly ash; methyl orange degradation; core/shell heterojunction; magnetic nanocomposite; advanced oxidation processes (AOPs); wastewater treatment

Abstract

A visible-light photocatalyst for methyl orange (MO) degradation was synthesised and evaluated as a Fe₃O₄@FA@GO@BiOCl magnetic nanocomposite. Treated fly ash, a byproduct of a power plant, was employed as mesoporous support to facilitate the adhesion of the dye to the surface and the dispersion of the active sites. BiOCl was the shell that reacted to visible light, graphene oxide allowed charges to move easily between the two materials and Fe₃O₄ enabled the use magnets to recover the material. Structural analyses revealed the formation of a stable core/shell heterojunction with soft magnetic properties. Under ideal conditions, MO was completely decolorised in 45 min, a process that followed pseudo-first-order kinetics. After 90 min of irradiation, 92.4% of the total organic carbon had been removed, indicating substantial mineralisation aside from adsorption. The photocatalyst exhibited stability after three applications and could be recovered with a magnet. The integration of fly ash valorisation and visible-light photocatalysis is a sustainable approach for wastewater remediation in a circular economy, as evidenced by the current findings.

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