Fe-Nanoporous Carbon Derived from MIL-53(Fe): A Heterogeneous Catalyst for Mineralization of Organic Pollutants

Abstract

Catalytic electrodes were prepared via carbonization of MIL-53(Fe) on the surface of porous carbon felt electrodes (CF) for use in wastewater treatment by the heterogeneous electro-Fenton (EF) process. The best results were obtained when the carbon felt was pretreated with nitric acid, enhancing the affinity of the MIL-53(Fe) for the surface. Following a series of optimization experiments, carbonization conditions of 800 °C for 5 h were used to form Fe-nanoporous carbon (MOFs@CF). The as-prepared electrodes were used as both cathode and heterogeneous catalyst in the EF process for the mineralization of exemplar dye Acid Orange 7 (AO7). Total organic carbon (TOC) removal of 46.1% was obtained within 8 h of electrolysis at around neutral pH (6.5) and the electrode retained over 80% of its original efficiency over five treatment cycles.

Accelerated Fe2+ Regeneration in an Effective Electro-Fenton Process by Boosting Internal Electron Transfer to a Nitrogen-Conjugated Fe(III) Complex

“…Electro-Fenton (EF) represents an important eco-friendly version of advanced oxidation processes (AOPs), since the risk in the transportation and operation of H 2 O 2 in the conventional Fenton process could be avoided. − In the EF process, a two-electron oxygen reduction reaction (ORR) occurs at the cathode to generate H 2 O 2 , which could subsequently react with ferrous ions (Fe 2+ ) to produce hydroxyl radicals (·OH) . The high redox potential of ·OH (1.8–2.7 V) renders strong oxidation ability to the degradation of various organic recalcitrant pollutants including dyestuffs, pharmaceuticals, and pesticides from food, tanning, and petrochemical industries. − However, the EF process suffers from low utilization efficiency of H 2 O 2 for the generation of ·OH as well as undesirable precipitation of iron oxy-hydroxides, because of the rapid accumulation of Fe 3+ via eq but slow regeneration of Fe 2+ via eq . − …”

A Highly Stable Metal–Organic Framework-Engineered FeS2/C Nanocatalyst for Heterogeneous Electro-Fenton Treatment: Validation in Wastewater at Mild pH

“…To our knowledge, MOFbased suspended catalysts have never been employed, and only a small number of MOFmodified cathodes has been reported. [45][46][47] This article addresses the synthesis and novel use of a MOF-engineered FeS2/C nanocomposite, fabricated via simultaneous carbonization and sulfidation of an Fe-MOF precursor that was prepared at room temperature. For the first time, the nanomaterial has been introduced as heterogeneous EF catalyst, focusing on the treatment of fluoxetine spiked into urban wastewater at mild pH as case study because the pollution of freshwater 48,49 and seawater 49,50 by pharmaceuticals has become a serious menace for all living beings.…”

Magnetic MIL(Fe)-type MOF-derived N-doped nano-ZVI@C rods as heterogeneous catalyst for the electro-Fenton degradation of gemfibrozil in a complex aqueous matrix

“…In contrast, the application of MOFs to EF process is much more incipient. They have never been employed as suspended catalysts, and only a reduced number of articles have reported the use of MOF-modified cathodes [33][34][35]. Among the latter group, Le et al [36,37] have described the successful preparation of carbon-felt cathode modified with a Zn-MOF (i.e., ZIF-8), whose subsequent carbonization enhanced the degradation of Acid Orange 7 dye by EF process.…”