Showing papers on "Laminar flow reactor published in 2020"

Nitrate radical generation via continuous generation of dinitrogen pentoxide in a laminar flow reactor coupled to an oxidation flow reactor

Abstract: . Oxidation flow reactors (OFRs) are an emerging tool for studying the formation and oxidative aging of organic aerosols and other applications. The majority of OFR studies to date have involved the generation of the hydroxyl radical (OH) to mimic daytime oxidative aging processes. In contrast, the use of the nitrate radical ( NO3 ) in modern OFRs to mimic nighttime oxidative aging processes has been limited due to the complexity of conventional techniques that are used to generate NO3 . Here, we present a new method that uses a laminar flow reactor (LFR) to continuously generate dinitrogen pentoxide ( N2O5 ) in the gas phase at room temperature from the NO2 + O3 and NO2 + NO3 reactions. The N2O5 is then injected into a dark Potential Aerosol Mass (PAM) OFR and decomposes to generate NO3 ; hereafter, this method is referred to as “OFR-i N2O5 ” (where “i” stands for “injected”). To assess the applicability of the OFR-i N2O5 method towards different chemical systems, we present experimental and model characterization of the integrated NO3 exposure, NO3:O3 , NO2:NO3 , and NO2:O2 as a function of LFR and OFR conditions. These parameters were used to investigate the fate of representative organic peroxy radicals ( RO2 ) and aromatic alkyl radicals generated from volatile organic compound (VOC) + NO3 reactions, and VOCs that are reactive towards both O3 and NO3 . Finally, we demonstrate the OFR-i N2O5 method by generating and characterizing secondary organic aerosol from the β -pinene + NO3 reaction.

Continuous Flow Synthesis of Iron Oxide Nanoparticles Using Water-in-Oil Microemulsion

Abstract: A continuous laminar flow reactor for the synthesis of nanopowder in microemulsion is described. The reactor is suitable for separated handling with nucleation, growth, and stabilization processes. The synthesis of iron oxide nanoparticles was selected as a model case. A water−sodium dodecyl sulphate−cyclohexene system was used as the microemulsion system for dissolving reactive aqueous solution, precursor, and a particle stabilizer. The product was purified and transferred to the aqueous phase. The result was a colloid solution of iron oxide nanoparticles in water of 50–200 nm in size with a zeta potential ranging from –25 to –57 mV. The product was characterized by UV-VIS spectroscopy, powder XRD, dynamic light scattering, electron microscopy, and electron diffraction. The results showed that water-in-oil microemulsion method is useful for the synthesis of nanopowders to obtain large amounts of stable product.