Oyster shell-derived CuFe₂O₄-Hap nanocomposite for healthy houses: Bacterial and formaldehyde elimination

Bacterial infections and the threat of volatile organic compounds (VOCs) to human beings have attracted increasing concerns over the years. The simultaneous and effective eradication of bacteria while purifying indoor air has become an urgent issue. Herein, a biomass-based CuFe₂O₄-Hap was prepared via an ion-exchange method by loading CuFe₂O₄ with flower-shaped hydroxyapatite (Hap) obtained from oyster shells. Based on the experimental results and theoretical basis, the introduction of CuFe₂O₄ reduced the work function of hydroxyapatite and inhibited the recombination of photogenerated carriers. After irradiated for 15 min (300 W xenon lamp), the CuFe₂O₄-Hap photocatalysts exhibited excellent antibacterial efficiencies against Staphylococcus aureus (99.6 ± 0.35) % and Escherichia coli (99.7 ± 0.23) %, respectively. In addition, the functional coating prepared with CuFe₂O₄-Hap as the active material exhibited approximately 100 % HCHO conversion rate within 10 min under the full-spectrum light irradiation. The excellent photocatalytic decomposition performance could be attributed to the large specific surface area of nano-flower-shaped hydroxyapatite and the fast separation efficiency of photogenerated carriers. Overall, the proposed strategy is expected to stimulate further research into the biomass valorization for a healthier and environment-friendly lifestyle.