Exploring degradation properties and mechanisms of emerging contaminants via enhanced directional electron transfer by polarized electric fields regulation in Fe-N4-Cx

Facilitating Proton Coupled Electron Transfer Reaction through the Interfacial Micro Electric Field with Fe─N4 ─C in FeMOFs Glass

The proton-coupled electron transfer(PCET) reaction plays a crucial role in the chemical transformation process andhas become one of the most concerned elementary reactions. However, the complex kinetics of PCET reaction, which requires the simultaneous transfer of protons and electrons, leads to the dilemma that thermodynamics and kinetics cannot bebalanced and restricts its further development. In this, an interface micro-electric field (IMEF) basedon Fe─N4 in FeMOFs (Fe-Based Metal-Organic Frameworks) glass is designed tosynchronize proton/electron interface behavior for the first time to realizeefficient PCET reaction and optimize reaction thermodynamics and kinetics. The IMEF facilitates the separation of photogenerated electrons and holes, and accelerates Fe(III)/Fe(II) cycle. Driven by near-surface electric field force, the protons near surfacemigrate to Fe sites and participate in Fe(IV)═O formation and reaction, lowering the reaction energy barrier. Based on the interface regulation ofIMEF, a high-efficiency PCET reaction is realized, and kinetic reactionrate constant of photocatalytic oxidation of emerging contaminants is increasedby 3.7 times. This study highlights a strategy for IMEFs to modulate PEC Treactions for a wide range of potential applications, including environmental and ecological applications.

Recycling and reutilization of smelting dust as a secondary resource: A review

Smelting dust is a toxic waste produced in metal-mineral pyrometallurgical processes. To eliminate or reduce the adverse environmental impacts of smelting dust, valuable components need to be selectively separated from the toxic components present in the waste. This paper reviews the chemical composition, phase composition and particle size distribution characteristics of smelting dust, and the results show that smelting dust has excellent physicochemical characteristics for recovering valuable metals. The process flow, critical factors, development status, advantages and disadvantages of traditional technologies such as pyrometallurgy, hydrometallurgy and biometallurgy were discussed in depth. Conventional treatment methods typically prioritize separating and reclaiming specific elements with high concentrations. However, these methods face challenges such as excessive chemical usage and limited selectivity, which can hinder the sustainable utilization of smelting dust. With the increasing scarcity of resources and strict environmental requirements, a single treatment process can hardly fulfil the demand, and a physical field-enhanced technology for releasing and separating valuable metals is proposed. Through analysing the effect of electric field, microwave and ultrasound on recovering valuable metals from smelting dust, the enhancement mechanism of physical field on the extraction process was clarified. This paper aimed to provide reference for the resource utilization of smelting dust.

Unraveling the single-atom Fe-N4 catalytic site selectivity generate singlet oxygen via activation of persulfate: Polarizing electric fields changes the electron transfer pathway

Single-atom catalysts have been proved to be an effective material for the removal of organic pollutants from water and wastewater, and yet, the relationship between their internal structures and their roles still remains elusive. In this work, a catalyst Fe (MIL)-SAC with single-atom Fe-N4 active site was prepared. Fe (MIL)-SAC/Peroxydisulfate (PDS) system was able to achieve complete degrade of the Sulfamethoxazole (SMX) with kobs at 0.466 min-1, which was faster than the Fenton system under the same conditions (kobs = 0.422 min-1) and 16 times faster than Fe (MIL) (kobs = 0.029 min-1). Density functional calculations reveal that the Fe-N4 structure will affect the electron transport path and lead to selective generation of 1O2 by triggering S-O breakage and O-O polarization in PDS. Furthermore, Fe (MIL)-SAC/PDS system exhibits strong resistance to common influencing factors and has good application prospects. This work provides a new approach for the selectively generation of 1O2 for the efficient treatment of organic pollutants in aqueous environment.