Ni-Mo bimetallic layered double hydroxide encapsulated ZIF-67 catalyst with nanoflower-like porous structure promotes the activation of calcium sulfite for the degradation of chloroquine phosphate

Chloroquine phosphate (CQP) is a drug widely used in clinical anti malaria and treatment of novel coronavirus pneumonia. Meanwhile, it has persistence in water. This substance has become a new type of environmental pollution that requires urgent attention and effective remediation strategies. Therefore, in this study, nickel molybdenum layered double hydroxide (NixMoy-LDH) was coated on ZIF-67 through hydrothermal treatment and used as a catalyst to activate CaSO 3 for the degradation of CQP. Investigated the effects of catalyst ratio, initial pH, and coexisting substances in the system on the degradation of CQP. Under the optimal metal ratio synthesis conditions, NiMo4-LDH@ZIF-67/CaSO 3 achieved a 95.6% CQP degradation rate within 30 min, demonstrating excellent activity. Comprehensive characterization shows that the close interaction between ZIF-67 and NixMoy-LDH can improve the stability of the catalyst, accelerate the redox cycle of Ni ions, and enhance the activation of CaSO 3 . Quenching experiments, electron paramagnetic resonance, and competitive dynamics confirm that SO 4 •− , •OH and 1 O 2 , species contribute to the degradation process. By combining LC-MS and DFT calculations, the possible degradation pathways of CQP were analyzed, the main intermediates were identified, and the toxicity of the intermediates was evaluated. It is worth noting that after five cycles, the degradation rate of pollutants by the catalyst remained at 93%, proving that the catalyst has excellent stability. The catalyst has excellent reusability and effectiveness in various pollutants and different water bodies. This work emphasizes that the NiMo4-LDH@ZIF-67/CaSO 3 system is a promising pharmaceutical wastewater treatment technology.