Photocatalytic Degradation of Typical Bisphenol Compounds Using Zr-NiFe2O4@ZIF-67/ZIF-8 in Collaboration With Peroxydisulfate/Peroxymonosulfate

Abstract

As the amount of tetrachlorobisphenol A (TCBPA) that causes potential adverse effects on human health in the environment is continually increasing. It is therefore important to develop new materials for the adsorption or degradation of these compounds using various techniques. In this study, two novel magnetic recyclable composite catalysts Zr–NiFe₂O₄@ZIF-67 and Zr–NiFe₂O₄@ZIF-8 were synthesized. These catalysts degraded tetrachlorobisphenol A (TCBPA) in water by activating peroxydisulfate (PDS)/peroxymonosulfate (PMS), respectively. The results show that the Zr–NiFe₂O₄@ZIF-67-5%/LED/(NH₄)₂S₂O₈ system can degrade 95% of TCBPA (20 mg/L) within 30 min, whereas the Zr–NiFe₂O₄@ZIF-8-10%/LED/KHSO₅ system degrades 90% of TCBPA within 30 min. In instances of metal leaching at low concentrations, nickel and iron ions declined to 0.008 mg·L⁻¹, TCBPA exhibits highly efficient and sustainable catalytic properties, maintaining over 80% efficacy across six cycles. The online infrared test experiment results showed the major functional groups disappearing within approximately 130 s. The results of electron paramagnetic resonance and free-radical-quenching experiments showed that SO₄˙⁻, ˙OH, ¹O₂, and O₂˙⁻ were involved in the degradation of TCBPA. The possible degradation paths are isomerization polymerization, dechlorination, hydroxylation, ring-opening by oxidation, and further transformation into small molecules of acids, aldehydes, alcohols and other compounds. Thus, in this study, a reliable technique for the degradation of halogenated bisphenol compounds is developed. Overall, the photocatalytic degradation of organic pollutants in water utilizing polymetallic composites as catalysts represents an innovative approach to water treatment, demonstrating enhanced catalytic activity and recyclability, with promising prospects for significant advancements in both theoretical research and practical applications.