Enhanced visible light photocatalysis with E-waste-based V₂O₅/zinc–ferrite: BTEX degradation and mechanism

BACKGROUND: BTEX removal is attracting increased attention owing to the detrimental impacts caused to human health, the foremost being neurological impairments. Thus, this study intended to assess the efficiency of zinc–ferrite/V₂O₅ (ZFV) nanocomposite for photocatalytic degradation of BTEX isomers in aqueous solution. Furthermore, the developed catalyst was magnetically separable, which may reduce the ecological impacts of the catalyst. RESULTS: The ZFV nanocomposite was prepared by a solvothermal process using V₂O₅ (extracted from treated E-waste) and zinc–ferrite (synthesized through a chemical co-precipitation method). The integration of elements in the ZFV nanocomposite was confirmed using powder X-ray diffraction, Fourier transform infrared, Raman, diffuse reflectance and electrochemical impedance spectroscopies and scanning electron microscopy. Maximum BTEX degradation of 95% was achieved at 50 mg L⁻¹ initial BTEX concentration, 0.50 g L⁻¹ catalyst and pH 3. A minor decrease in the degradation efficiency (10%) of the catalyst was observed at the fifth cycle. The presence of H₂O₂ increased the degradation efficiency to 98% owing to the prevention of electron–hole recombination, while NaCl (60%), Na₂CO₃ (63%), NaNO₃ (80%) and Na₂SO₄ (72%) decreased the degradation efficiency due to their hydroxyl scavenging properties. The degradation pathway was elucidated using gas chromatography with mass spectral studies. CONCLUSIONS: The findings of the present study relating to BTEX degradation using the magnetic ZFV nanocomposite and the degradation mechanism throw light on the environmental applications of the ZFV composite. The composite could be an alternative for the remediation of BTEX-contaminated wastewaters.