This study has revealed how the strong metal-support interaction (SMSI) between carbon nanotubes (CNTs) and Mn 0.65 Fe 2.35 O 4 (MnFeO) in boosting peroxymonosulfate (PMS) activation for rapid sulfamethoxazole (SMX) degradation. As synergized by CNTs, the PMS-activation efficiency of MnFeO could be enhanced by>24 times, but with the similar PMS-activation mechanism. It was explored that the SMSI-induced abundant surface hydroxyl groups, in cooperation with the highly hydrophobic CNTs, favored the rapid in situ interfacial degradation of SMX. This feature also endowed the MnFeO-CNTs catalyst resistance to high salinity waters containing inorganic anions (e.g., Cl - and NO 3 – ) of weak complexing abilities. Moreover, the SMSI allowed the greatly accelerated redox cycle rate of Mn species by electron-rich CNTs, resulting in efficient PMS activation. Furthermore, the application feasibility of the MnFeO-CNTs/PMS system was demonstrated for a SMX-spiked real reverse osmosis (RO) concentrate. It was found that higher concentration of PMS could realize the complete removal of SMX, despite the existence of electron-rich tyrosine-like substances would compete with the SMX degradation in the MnFeO-CNTs/PMS system. This study demonstrated that the SMSI could boost the PMS activation , and could serve as an effective material strategy for in situ interfacial organics degradation in the high salinity wastewater.
Ya Yang,Yulian Li,Peidong Hong,Zijian Wu,Chao Xie,Kaisheng Zhang,Li Lianxiang,Junyong He,Lingtao Kong,Jinhuai Liu
Developing highly-effective catalysts through a facile method for activating peroxymonosulfate (PMS) to degrade recalcitrant pollutants is highly desirable. In this work, porous carbon-coated iron-manganese oxides (MnFeO@C) was facilely synthesized. The porous carbon film on the surface of MnFeO@C was beneficial to adsorption of bisphenol A (BPA) and flow of electrons. The catalytic degradation performance toward BPA was significantly improved with the increase of surface roughness and porosity of MnFeO@C after calcination. In particular, MnFeO@C derived at 300 °C (MnFeO@C-300) exhibited the highest degradation rate benefiting from the existence of Mn 2 O 3 . More than 95% BPA could be removed in 30 min by MnFeO@C-300/PMS system and remained efficient in a wide pH range from 3.0 to 10.0, especially in alkaline conditions. The intermediates of BPA degradation were identified and the degradation pathways involved hydroxyl oxidation and benzene ring-opening were proposed based on GC–MS results. The removal rate of BPA can maintain more than 80% following five cycles. Thus, the as-prepared MnFeO@C-300 composites are available to serve as efficient and eco-friendly catalysts for advanced catalytic oxidation of recalcitrant pollutants.
Bacteriophage-based biosensors have the potential for rapid, convenient, and sensitive detection of Staphylococcus aureus in food products; however, their effectiveness is often limited by the host range of the bacteriophage. This study presents a new colorimetric biosensor using the S. aureus phage SapYZU04 exhibiting a broad host range, and a MnFeO nanozyme for the effective detection of S. aureus in food products. Notably, SapYZU04 exhibited excellent features, such as a high titre (1.0 × 10 10 PFU/mL), a short latency period (5 min), a large burst size (210 PFU/cell), a wide host spectrum (98.95%, 94/95), and good stability at pH 3.0–12.0. The biosensor, referred to as SapYZU04@MnFeO was constructed by immobilising SapYZU04 on the MnFeO nanozyme via electrostatic interactions. SapYZU04@MnFeO demonstrated a broad detection range of bacterial concentrations, particularly within the range of 3 × 10 2 to 3 × 10 9 CFU/mL, with a low detection limit of 65 CFU/mL and rapid detection time (14 min). Furthermore, it exhibited high accuracy in detecting and quantifying live S. aureus with recovery rates ranging from 92.21% to 105.56%. The chromogenic system demonstrated high selectivity for S. aureus and was unaffected by other interfering microorganisms or food preservatives, highlighting its specificity and interference-resistance. Whole-genome sequencing of SapYZU04 suggested that the selectivity, sensitivity, and specificity of SapYZU04@MnFeO could be attributed to the tail fibre proteins of the phage. In conclusion, the SapYZU04@MnFeO biosensor is a highly effective tool for identifying viable S. aureus strains in the food industry.
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