Sustainable synthesis of multiple-metal-doped Fe2O3 nanoparticles with enhanced photocatalytic performance from Fe-bearing dust

An Fe-abundant solid waste, fabric filter dust (FFD) was used as the starting material for the preparation of metal-doped Fe2O3 (M−Fe2O3) nanoparticles for the photocatalytic degradation of MO aqueous solution. Valuable elements including Fe, Ti, Al, Na, Si, Ca, and Mg were extracted from the dust by hydrochloric acid leaching, transformed into sediments by increasing the pH of the lixivium orderly, and converted into M−Fe2O3 nanoparticles by the sol–gel technology. The effects of pH for the precipitation process and firing temperature for the sol–gel method were investigated systematically. The M−Fe2O3 samples were characterised using X-ray diffraction, field emission scanning electron microscopy, Brunauer–Emmett–Teller analysis, UV–vis spectra, and energy dispersive spectroscopy. The performances of the dust-derived nanoparticles during photocatalytic process were appraised by visible light photodegradation of methyl orange (MO) aqueous solution, indicating that the M−Fe2O3 (M = Ti and Al) sample prepared with a precipitation pH of 4 and a firing temperature of 500 °C exhibits the most impressive photocatalytic behaviour. The product produces a degradation rate of 82.99% for 100 mL of MO solution (10 mg/L) after visible-light degradation for 180 min, which is increased from 38.94% achieved by an undoped Fe2O3 sample prepared under the same conditions.