[Activating Efficiency of Iron-copper Bimetallic Organic Framework MIL-101(Fe,Cu) Toward H O for Degradation of Dyes].

Practical use of heterogeneous Fenton-like catalysis is inhibited by poor mass transfer and slow conversion of Fe(Ⅲ) to Fe(Ⅱ). In this study, we prepared a novel iron-copper bimetallic organic framework (MIL-101 (Fe,Cu)) using the solvothermal method, and carefully investigated its interfacial characters, catalytic efficacy toward dyes with methylene blue as a model pollutant, and the catalytic activating mechanisms involved in it. The MIL-101(Fe,Cu) exhibited a three-dimensional octahedral shape with a complete crystal structure. The specific BET surface area and average pore size were determined to be as high as 667.2 m ·g and 1.9 nm, respectively. These characteristics benefits the exposure of the reactive sites and accelerates mass transfer accordingly. The MIL-101(Fe,Cu)/H O exhibited promising efficiency toward the degradation of methylene blue in a wide pH range; moreover, at a pH value of 5, the removal efficiency observed was as high as 100% after 20 min of reaction, which was 43.1% and 88.9% higher than that of MIL-101(Fe)/H O and H O, respectively. Hydroxyl radical ( ·OH) is a dominant active species involved in the degradation of methylene blue using MIL-101(Fe,Cu)/H O as indicated in radicals quenching experiments. The results of species transformation in Fe and Cu indicated that Cu(Ⅱ) doping provided more active sites, and the Cu(Ⅱ)/Cu(Ⅰ) and Fe(Ⅲ)/Fe(Ⅱ) cycles synergistically facilitated ·OH generation to improve the Fenton-like catalytic efficiency accordingly. The MIL-101(Fe,Cu) as a novel heterogeneous Fenton-like catalyst achieved good performance without any significant pH adjustment and is practically viable for industrial wastewater treatment.