Effect of Isomorphic Metal Substitution on the Fenton and Photo-Fenton Degradation of Methylene Blue Using Fe-Based Metal–Organic Frameworks

Abstract

The removal of toxic organic compounds (TOCs) using highly porous solids such as metal−organic frameworks (MOFs) has gained significant attention over the past decade. In this study, it has been demonstrated that the efficiency of PCN-250 as a heterogeneous catalyst porous coordination network (PCN) for both Fenton and photo-Fenton reactions can be improved by the isomorphic substitution of Mn and Co for Fe, while it can be inhibited by the substitution of Ni for Fe. Furthermore, the Mnsubstituted sample named PCN-250(Fe 2 Mn) decomposed 100% of methylene blue (MB) in solution in 300 min and displayed good recyclability over three cycles. This work establishes that the highly porous, commercially available, and robust family of MOFs named PCN-250 has the potential to be used as catalysts for Fenton and photo-Fenton reactions as well as broader advanced oxidation processes (AOP) for water purification applications. Overall, this work successfully demonstrates not only the ability to perform isomorphic substitution of various metals within MOFs but also the effect of the substitution on the resulting catalytic performance.

Thermal decarboxylation for the generation of hierarchical porosity in isostructural metal–organic frameworks containing open metal sites

“… 5,26–28 PCN-250 has isostructural variants of both redox-active and redox-inactive clusters generated via one-pot solvothermal methods in high yield. 29–32 Both redox-active (Fe 3 , Fe/Ni, Fe/Mn, Fe/Co, and Fe/Zn) and redox-inactive metal clusters (Al 3 , In 3 , and Sc 3 ) were studied to understand the influence on the hierarchical porosity generation. To control the metal ratios in the MOF, the heterogeneous metal clusters were presynthesized before synthesis of the MOF (procedure in ESI † ).…”

Terephthalate and trimesate metal–organic frameworks of Mn, Co, and Ni: exploring photostability by spectroscopy

“…12 Owing to visible light response and excellent redox behavior, these MOF photocatalysts are being explored for CO 2 reduction, solar water splitting, photoreduction, photochemical transformations of small molecules, and photocatalytic degradation of organic pollutants. [13][14][15][16][17][18][19] One of the requirements for an efficient photocatalyst is its long-term photostability. Since the metalligand interactions in MOFs are coordinative, they are subjected to break under UV/visible irradiations.…”

Heterogeneous Photo-Fenton Catalytic Degradation of Practical Pharmaceutical Wastewater by Modified Attapulgite Supported Multi-Metal Oxides

“…However, excessive use of H 2 O 2 may lead to the quenching of hydroxyl radical, thus reducing the catalytic effect [41,42]. This phenomenon can be expressed as the following reaction (Equations (6) and 7).…”

“…As an emerging wastewater treatment method, advanced oxidation technology has attracted the attention of many experts and scholars in recent years, among which methods heterogeneous photo-Fenton catalysis technology has been successfully applied to the treatment of refractory organic wastewater [6]. Both homogeneous Fenton and Fenton-like methods can effectively degrade refractory organic compounds in water, but they have some disadvantages, such as the release of large amounts of iron ions in water, increased chromaticity, heavy mud production, and unrecyclable catalysts.…”