Wei Wang

Synthesis of magnetic Ni–Ag bimetal supported on reduced graphene oxide for enhanced catalytic reduction of 4-nitrophenol.

High-entropy alloys outperform binary alloys in stability and efficiency. Crucially, entropy induces a shift from radical to non-radical species, a mechanism distinct from reported non-radical systems.

The increasingly severe antibiotic pollution has become one of the most critical issues. In this study, a zinc peroxide/peroxymonosulfate (ZnO₂/PMS) double-oxidation system was developed for tetracycline (TC) degradation. A small amount of ZnO₂ (10 mg) and PMS (30 mg) could effectively degrade 82.8% of TC (100 mL, 50 mg/L), and the degradation process could be well described by the pseudo-second-order kinetic model. Meanwhile, the ZnO₂/PMS double-oxidation system showed high adaptability in terms of reaction temperature (2–40 °C), initial pH value (4–12), common inorganic anions (Cl⁻, NO₃⁻, SO₄²⁻ and HCO₃⁻), natural water source and organic pollutant type. The quenching experiment and electron paramagnetic resonance (EPR) characterization results confirmed that the main reactive oxygen species (ROS) was singlet oxygen (¹O₂). Moreover, three possible pathways of TC degradation were deduced according to the analyses of intermediates. On the basis of comparative characterization and experiment results, a synergistic activation mechanism was further proposed for the ZnO₂/PMS double-oxidation system, accounting for the superior degradation performance. The released OH⁻ and H₂O₂ from ZnO₂ could activate PMS to produce major ¹O₂ and minor superoxide radicals (•O₂⁻), respectively.

Carbon nanotubes (CNTs) were considered a promising activator for persulfates due to their high electrical conductivity, large specific surface area and low toxicity. The functional groups and surface defects of CNTs could significantly affect their activation performance. In this study, CNTs with high C=O ratio and defect density (CNT-O-H) were prepared through a facile treatment of raw CNTs with HNO₃ oxidation followed by calcination at 800 °C under an argon atmosphere. X-ray photoelectron spectroscopy (XPS) and Raman results showed that the C=O proportion and defect degree (I_D/I_G) rose to 75% and 1.53, respectively. The obtained CNT-O-H possessed a superior performance towards peroxydisulfate (PDS) activation, and the degradation efficiency of tetracycline (TC) in the CNT-O-H/PDS system was increased to 75.2% from 56.2% of the raw CNTs/PDS system within 40 min. Moreover, the activity of CNT-O-H after use could be easily recovered with re-calcination. In addition, the CNT-O-H/PDS system exhibited high adaptabilities towards wide solution pH (2–10), common coexisting substances and diverse organic pollutants. Singlet oxygen (¹O₂) was confirmed to be the dominant reactive oxygen species (ROS) generated in the CNT-O-H/PDS system. It was inferred that surface C=O groups and defects of CNTs were the key site to activate PDS for TC degradation.

In situzinc cyanamide coordination induced one-step transformation of N-rich organics to N-rich graphene for efficient peroxymonosulfate activation with a turnover frequency of up to 5.50 g⁻¹min⁻¹.

A novel advanced oxidation process (AOP) system with high adaptability and long-term oxidation ability was firstly constructed for organic pollutant degradation via a non-radical process.