Cyclodextrin Polymer-Embedded NiS/FeS Composite as a Fenton-like Catalyst for the Degradation of Cresol Red

Herein, a heterogeneous Fenton-like catalyst was designed by immobilizing iron oxide (FeS) and nickel sulfide (NiS) on the surface of β-cyclodextrin (β-CD), creating a NiS/FeS@β-CD composite for degrading triphenylmethane cresol red dye. Varied instruments were used to study the physical and chemical characteristics of the NiS/FeS@β-CD catalyst. The appropriate catalytic conditions of the Fenton-like degradation of cresol red by NiS/FeS@β-CD were identified, clarifying that the higher degradation % fulfilled 99.86% with an adsorption % of 27.44% at a cresol red concentration = 50 mg/L, NiS/FeS@β-CD dose = 0.01 g, pH = 3, processing temperature = 30 °C, H₂O₂ concentration = 100 mg/L, and H₂O₂ volume = 1 mL. The kinetic assessments depicted the preference of the second order to represent the Fenton-like degradation of cresol red by NiS/FeS@β-CD. The mechanistic proposition of the adsorption/Fenton-like degradation of cresol red was understood using a quenching test and XPS analysis. Finally, to confirm the durability of NiS/FeS@β-CD, a reusability test was proceeded on the catalyst for five adsorption/Fenton-like degradation runs, with identifying the leaching concentrations of nickel and iron from the catalyst by ICP-OES after each run.