A heterogeneous peroxymonosulfate catalyst built by Fe-based metal-organic framework for the dye degradation

The regulatory control on dyes is an important issue, as their discharge into the environment can pose significant risks to human health. MIL-101(Fe) prepared by a solvothermal method was used as a catalyst to generate sulfate (SO₄^•-) and hydroxyl (HO^•) radicals from peroxymonosulfate (PMS) for the treatment of orange G (OG). The structural properties of MIL-101(Fe) were assessed by a number of characterization approaches (e.g., Fourier-transform infrared spectroscopy). The factors controlling the removal of OG were explored by a response surface methodology with central composite design (RSM-CCD) plus adaptive neuro-fuzzy inference system (ANFIS). The synthetized MIL-101(Fe) had uniform octahedral nanocrystals with rough surfaces and porous structures. The maximum catalytic removal efficiency of OG with MIL-101(Fe)/PMS process was 74% (the final concentration of Fe²⁺ as 0.19 mg/L and reaction rate of 434.2 μmol/g/h). The catalytic removal of OG could be defined by the non-linear kinetic models based on RSM. The OG removal efficiency declined noticeably with the addition of radical scavengers such as ethanol (EtOH) and tert-butanol (TBA) along with some mineral anions. Accordingly, MIL-101(Fe)/PMS is identified as an effective remediation option for the dyes based on advanced oxidation process (AOPs) based on high treatment efficiency at low dosage of low cost catalyst.