Development of a Recyclable Remediation System for Gaseous BTEX: Combination of Iron Oxides Nanoparticles Adsorbents and Electrochemistry

We designed a two-step green technique to remove and recycle selected gaseous air pollutants. The first step includes the assessment of adsorption efficiencies of BTEX (benzene, toluene, ethylbenzene, and xylenes) on magnetite, hematite, and their composite surfaces. Improvement of the synthesis method led to BTEX adsorption (>85%; 200 ppmv) on 1.0 g of nanoparticles within a time scale of minutes. The second element included the design of an electrochemical reactor for the regeneration of used nanoparticles. NaOH showed superior performance as an electrolyte in comparison to NaCl and Na₂CO₃. The stripping efficiency for cathodic regeneration was higher than the anodic one. Under optimized conditions, the stripping efficiency was up to 85%. Iron oxides nanoparticles were regenerated (∼90%). Using high-resolution transmission electron microscopy, X-ray diffraction, NanoScan, and Brunauer–Emmett–Teller, selected physical and chemical properties of nanosurfaces were analyzed, revealing that the physical properties of nanoparticles remained unchanged during the regeneration process

Non-Invasive Imaging Method of Microwave Near Field Based on Solid State Quantum Sensing

In this paper, we propose a non-invasive imaging method of microwave near field using a diamond containing nitrogen-vacancy centers. We applied synchronous pulsed sequence combined with charge coupled device camera to measure the amplitude of the microwave magnetic field. A full reconstruction formulation of the local field vector, including the amplitude and phase, is developed by measuring both left and right circular polarizations along the four nitrogen-vacancy axes. Compared to the raster scanning approach, the two dimensional imaging method is promising for application to circuit failure analysis. A diamond film with micrometer thinness enables high-resolution near field imaging. The proposed method is expected to have applications in monolithic-microwave-integrated circuit chip local diagnosis, antenna characterization, and field mode imaging of microwave cavities and waveguides

Development of a Green Technology for Mercury Recycling from Spent Compact Fluorescent Lamps Using Iron Oxides Nanoparticles and Electrochemistry

The widespread use of energy efficient mercury containing lamps and impending regulations on the control of mercury emissions has necessitated the development of green mercury control technologies such as nanosorbent capture and electrolysis regeneration. Herein we describe a two-step green technique to remove and recycle mercury from spent compact fluorescent lamps (CFLs). The first element included the assessment of capture efficiencies of mercury vapor on magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃), naturally abundant and ubiquitous components of atmospheric dust particles. Around 60 μg of mercury vapor can be removed up to 90% by 1.0 g of magnetite nanoparticles, within a time scale of minutes. The second step included the development of an electrochemical system for the mercury recycling and regeneration of used nanoparticles. Under optimized conditions, up to 85% of mercury was recovered as elemental mercury. Postelectrolysis regenerated iron oxide nanoparticles were used in several sorption–electrolysis cycles without loss of the adsorption capacity, morphology, and surface area. The low energy usage for electrolysis can be supplied by the solar panels. The implications of our results within the context of green technology are herein discussed