Pressure measurements are performed everyday with simple devices, and in the field of analytical chemistry the pressure-based signaling strategy offers two important advantages, signal amplification and particular applicability in point-of-care settings. Herein, by using vancomycin (Van)-functionalized platinum nanoparticles (PtNPs@Van) and aptamer-coated magnetic CuFe2O4 nanoprobes dual-recognition units integrated with a catalyzed breakdown of H2O2 for O2 generation, we demonstrated that gas pressure can be used as a readout means for highly sensitive pathogenic bacteria identification and quantification. Using Staphylococcus aureus (S. aureus) as a test case, integration of the molecular dual-recognition component with the catalyzed gas-generation reaction leads to a significant pressure change (ΔP), and the correlation between the concentration of S. aureus and the ΔP signal was found to be linear from 5.0 to 1.0 × 104 cfu/mL with a detection limit of 1.0 cfu/mL. Other nontarget bacteria show negative results, verifying the high specificity of the present strategy. When employed to assay S. aureus in saliva and milk samples, the approach shows recoveries from 93.3% to 107.1% with relative standard derivation (RSD) less than 8.8%. By the integration of catalyzed gas-generation reaction with the designed molecular recognition event, obviously the pressure-based signaling strategy could facilitate pathogenic bacteria identification and quantification not only in the laboratory but also in point-of-care settings, which could have great potential in the application of food safety and infectious disease diagnosis.
To effectively treat the hydrophobic organic contaminant and utilize an industrial solid waste manganese residue (MR), a novel starch-derived carbon (SC)-decorated and Cu-doped (Fe,Cu)S/CuFe 2 O 4 solid solution (CFS/CFO@SC) was prepared from MR via mechanical activation treatment of precursor materials followed by one-step pyrolysis and applied as a photo-Fenton catalyst to treat a hydrophobic organic compound, 17α-ethinylestradiol (EE2). Characterization results showed that the CFS/CFO@SC solid solution with unique crystal and electronic structures exhibited high adsorption capacity and catalytic activity , ascribed to that Cu doping and C decorating enhanced its hydrophobicity and BET surface area. The CFS/CFO@SC showed excellent degradation efficiency with nearly 100% of EE2 removal rate in 40 min (degradation rate constant of 0.112 min −1 ), and a high mineralization degree with 95.2% of TOC removal in 180 min. This could be ascribed to that C decorating and the formation of CFS/CFO solid solution promoted the charge transfer in a continuous band, resulting in effective separation of photogenerated holes–electrons (h + –e – ). The strong interaction of Fe–Cu collaborating with the photoelectron could effectively accelerate the recycle of Fe 3+ /Fe 2+ and Cu 2+ /Cu + , thus generating more active radicals. Moreover, CFS/CFO@SC showed promising stability and recyclability with the EE2 removal rates all >95% after five cycles. This work brings a valuable approach for the rational design of high-performance Fe-based photo-Fenton catalysts for environmental remediation and the valorization of MR.
Caihong Liu,Xihui Jiang,Zhiqiang Sun,Rui Gao,Min Wang,Qiang He,Jun Ma
Catalytic membranes that enable simultaneous micropollutant degradation during oil/water separation have emerged as a promising candidate for treating complex emulsified oily wastewater. However, this hybrid system suffers from membrane fouling and subsequent radical quenching. Herein, we overcome these challenges by developing a novel hierarchical filtration-catalysis ceramic membrane to achieve efficient gradient decontamination. This membrane comprises a top hydrophilic MWCNT layer deposited on a CuFe2O4-immobilized ceramic membrane to construct CCuFeCM. A pristine ceramic membrane (CM) and a CuFe2O4-immobilized membrane (CuFeCM) served as controls. Our results demonstrated that CCuFeCM presents the most alleviated fouling potential (∼18% of flux decline) and TOC removal (91%) when treating synthetic textile wastewater containing a mineral oil-in-water emulsion with RhB. Besides that, CCuFeCM achieves the highest PMS-based RhB degradation capability (100%) and initial reaction rate (0.684 min–1). Quenching experiments and EPR analyses show that SO4–•, •OH, and 1O2 are responsible for the CCuFeCM/PMS oxidation system, and 1O2 is the dominant reactive species. The synergistic effect of oil separation and catalytic decomposition is mainly ascribed to the ordered arrangement of selective separation in advance to avoid interference with subsequent AOPs, which allows for micropollutants that are transmitted into internal membrane channels for confined catalytic oxidation. Furthermore, replication filtration tests indicate that CCuFeCM shows durable stable degradation and antifouling performance after simple cleaning. The specific functionality of oil isolation, catalyst anchor, and mass transfer effect reaction compartmentation provides a novel strategy for efficient gradient removal of multiple pollutants in water, which highlights promising application potential under realistic conditions.
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