Synthesis of FeCo alloy encapsulated nitrogen-doped graphitized carbon: High catalytic activation and low metal ion leaching in microwave assisted Fenton reaction

Catalytic Degradation of Organic Contaminants by Microwave-Assisted Persulfate Activation System: Performance and Mechanism

In this study, a nickel ferrite (NiFe2O4) system was constructed to purify a phenol solution in water. During the process, the influences of several critical operating parameters including the NiFe2O4 amount, PS dosage, MW power, initial pH value, and different natural water anions were systematically studied. The results indicated that the constructed system performed excellently regarding the removal efficiency (97.74%) of phenol within 30 min. Meanwhile, the influence of co-existing anions such as Cl−, NO3−, H2PO4−, and HCO3− was also studied, which displayed an inhibiting action on phenol degradation, while HA facilitated it. To explore the reaction mechanism of this system, major free radical quenching experiments were conducted, and it was confirmed that both SO4•− and HO• were primary radicals. Moreover, stability experiments confirmed the apt stability of the NiFe2O4 system. Besides, the mineralization and toxicity analysis performed during phenol degradation also confirmed the superiority of the as-constructed system. Furthermore, the possible degradation mechanism of phenol was proposed. Hence, this system could be applied in advanced wastewater treatment.

Degradation of norfloxacin by MOF-derived lamellar carbon nanocomposites based on microwave-driven Fenton reaction: Improved Fe(III)/Fe(II) cycle

In this paper, a new type of iron-based magnetic nanoparticle material embedding mesoporous carbon (Fe@C₇₀₀) was prepared by simple pyrolysis of a MIL-101-Fe precursor and employed in the microwave-catalyzed degradation of norfloxacin (NOR) with the presence of H₂O₂. Characterization results showed successful anchoring of Fe⁰ nanoparticles in the carbon matrix. Under optimal treatment conditions (Calcination temperature = 700 °C, H₂O₂ dosage = 40 mM, MW power = 500 W, NOR dosage = 50 mg L^-1 and initial pH = 4), the degradation efficiency of NOR reached 95.22%. The catalyst showed exceptional degradation properties over a relatively wide pH range. The mesoporous carbon in the catalyst promoted electron transfer, enhanced the Fe(III)/Fe(II) cycle, increased contact between Fe⁰ and Fe²⁺ with H₂O₂, and accelerated the production of ·OH. Furthermore, density functional theory (DFT) calculations were used to predict the fragile active sites in NOR and to analyze the degradation pathway of NOR in combination with intermediates. Fe@C₇₀₀ retained good activity after 5 cycles. Reduced toxicity of intermediates predicted by T.E.S.T. compared to NOR. This study presented a new avenue for the rational design of Fe⁰-carbon composites as microwave-assisted Fenton-like catalysts for potential applications in wastewater treatment.