A paper/polymer hybrid CD-like microfluidic SpinChip integrated with DNA-functionalized graphene oxide nanosensors for multiplex qLAMP detection

© 2017 The Royal Society of Chemistry. A paper/poly(methyl methacrylate) (PMMA) hybrid CD-like microfluidic SpinChip integrated with DNA probe-functionalized graphene oxide (GO) nanosensors was developed for multiplex quantitative LAMP detection (mqLAMP). This approach can simply and effectively address a major challenging problem of multiplexing in current LAMP methods

Highly Efficient Antibacterial and Pb(II) Removal Effects of Ag-CoFe₂O₄‑GO Nanocomposite

Ag-CoFe₂O₄-graphene oxide (Ag-CoFe₂O₄-GO) nanocomposite was synthesized by doping silver and CoFe₂O₄ nanoparticles on the surface of GO, which was used to purify both bacteria and Pb­(II) contaminated water. The Ag-CoFe₂O₄-GO nanomaterial was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), cyclic voltammetry (CV), and magnetic property tests. It can be found that Ag-CoFe₂O₄-GO nanocomposite exhibited excellent antibacterial activity against Gram-negative <i>Escherichia coli</i> and Gram-positive <i>Staphylococcus aureus</i> compared with CoFe₂O₄, Ag-CoFe₂O₄, and CoFe₂O₄-GO composite. This superior disinfecting effect was possibly attributed to the combination of GO nanosheets and Ag nanoparticles. Several antibacterial factors including temperature, time, and pH were also investigated. It was obvious that <i>E. coli</i> was more susceptible than <i>S. aureus</i> toward all the four types of nanomaterials. The structural difference of bacterial membranes should be responsible for the resistant discrepancy. We also found that Ag-CoFe₂O₄-GO inactivated both bacteria in an irreversibly stronger manner than Ag-CoFe₂O₄ and CoFe₂O₄-GO. The Pb­(II) removal efficiency with all the nanomaterials showed significant dependence on the surface area and zeta potential of the materials. In this work, not only did we demonstrate the simultaneous superior removal efficiency of bacteria and Pb­(II) by Ag-CoFe₂O₄-GO but also the antibacterial mechanism was discussed to have a better understanding of the interaction between Ag-CoFe₂O₄-GO and bacteria. In a word, taking into consideration the easy magnetic separation, bulk availability, and irreversibly high antibacterial activity of Ag-CoFe₂O₄-GO, it is the very promising candidate material for advanced antimicrobial or Pb­(II) contaminated water treatment

The inter-connected porous CuOx-NbOx/kit-CeO2 catalyst:Enhanced activity, resistance of SO2 and H2O for the removal of NOx

In order to remove NOx from multiple sources with complex operating conditions, catalysts with excellent low-temperature activity and strong water and sulfur resistance are in high demand. Herein, we designed an efficient inter-connected porous CuOx-NbOx/kit-CeO2 catalyst for the selective catalytic reduction of NOx with NH3 (NH3-SCR). The catalyst exhibited relatively outstanding NH3-SCR activity in the low temperature range (100–300 °C) and showed remarkable stability and excellent resistance to SO2 and H2O. The inter-connected porous structure allowed the adsorption and diffusion of gaseous reactants, meanwhile, the interaction between Cu, Nb and Ce enhanced the surface acidity, redox properties and surface oxygen activity of the CuOx-NbOx/kit-CeO2 catalyst. On the basis of in situ DRIFTs studies, Eley-Rideal process was expected to be the dominant pathway with the coexistence of Langmuir–Hinshelwood mechanism at 250 °C

Novel Flexible Self-Standing Pt/Al₂O₃ Nanofibrous Membranes: Synthesis and Multifunctionality for Environmental Remediation

In spite of intensive research investigating the prevalent Pt/Al₂O₃ catalysts, achieving macroscopic morphology beyond the powder form limitations remains highly challenging. Meanwhile, current impregnation-based preparation approaches show the drawbacks of tedious procedures and inefficient use of noble metals. Therefore, it is important to search for new methods for the fabrication of Pt/Al₂O₃ catalysts with a novel morphology. In this study, a novel Pt/Al₂O₃ nanofibrous membrane catalyst is fabricated via a facile one-pot electrospinning process. The embedding of Pt nanoparticles is performed simultaneously with the formation of Al₂O₃ nanofibers. The Pt/Al₂O₃ membranes show remarkable mechanical properties with tensile stresses as high as 44.14 MPa. Notably, the Pt/Al₂O₃ membranes exhibit multifunctionality with excellent performance characteristics. The catalytic experiments indicate that 100% of bisphenol A is removed within 60 min, and 100% of CO is completely converted to CO₂ at 242 °C when Pt/Al₂O₃ membranes are used as catalysts. The membranes also exhibit excellent filtration performance, clearly decreasing the turbidity of water, and meet the high efficiency of particulate air filter standards. The excellent flexibility, satisfying mechanical property, and multifunctionality extend the range of potential application of the Pt/Al₂O₃ membranes. Moreover, the facile synthesis suggests new possibilities for the fabrication of many membrane-form Al₂O₃-supported catalysts

Fabrication of TiO₂–Bi₂WO₆ Binanosheet for Enhanced Solar Photocatalytic Disinfection of <i>E. coli</i>: Insights on the Mechanism

TiO₂–Bi₂WO₆ binanosheet (TBWO), synthesized by a facile two-step hydrothermal method, was used as an effective visible-light-driven photocatalyst for the inactivation of <i>E. coli</i> and was characterized by TEM, SEM, XRD, FTIR, XPS, and BET. A series of TBWOs with different doping ratios of TiO₂ loading from 10 to 55 wt % were synthesized. Among all of the TBWOs, 40% TBWO exhibited the best bacteria disinfection efficiency, and the quantity of viable bacteria could reach 10° with 40% TBWO (100 μg/mL) after being illuminated for 4 h. Furthermore, the confocal fluorescent-based cell live/dead test and the SEM technology were applied to verify the photocatalytically lethal effect toward <i>E. coli</i> and the rupture of bacterial membranes. The leak of bacterial contents, including the bacterial genome represented by relevant 16srDNA, and total protein were detected by PCR and bicinchoninic acid assay. In this work, the antibacterial mechanism was studied by employing photoelectrochemical techniques, electron spin resonance (ESR), and scavengers of different reactive species, revealing the pivotal roles of electron hole (h⁺) and electron (e^–) in the photocatalytic process. In addition, the •O₂^– and •OH radicals were also detected in the TBWOs system by ESR. It was found that the adsorption of visible light and separation of photogenerated carriers within TiO₂ have been largely promoted after being coupled with Bi₂WO₆, which should be responsible for the improved bactericidal effect

Energy-saving removal of methyl orange in high salinity wastewater by electrochemical oxidation via a novel Ti/SnO2-Sb anode-Air diffusion cathode system

Electrochemical oxidation is an effective method in removal of organic pollutant from high salinity waste-water (NaCl), by producing active chlorine at anode or hydrogen peroxide at cathode. To solve the existing problems including low efficiency, high cost and energy consumption, a Ti/SnO2-Sb anode (TSSA)-air diffusion cathode (TSSA-ADC) system was investigated for methyl orange (MO) removal from NaCl solution, using single TSSA system as control. The phase composition of TSSA was examined by X-ray diffraction. Accumulated concentrations of active chlorine, hydrogen peroxide, MO removal rate, TOC, pH value were recorded at different current densities. The results indicated that Sb-doped rutile SnO2 was formed on the TSSA. The TSSA and the ADC exhibited good catalysis to chlorine evolution and oxygen reduction, respectively. Although MO were almost completely removed in both systems, higher TOC removal, shorter running time and lower energy consumption were attained in the TSSA-ADC system. pH value was more stable (6.0-6.4) in the TSSA-ADC system than that in the TSSA system (6.0-9.4), predicting its stronger capacity in anti-scaling when treating high salinity wastewater with hard ions like Ca2+ and Mg2+. (C) 2015 Elsevier B.V. All rights reserved