Search results for "Chemical Engineering"
showing 10 items of 5892 documents
Catalyst-free vapour-solid technique for deposition of Bi2Te3 and Bi2Se3 nanowires/nanobelts with topological insulator properties.
2015
We present a simple two-stage vapour–solid synthesis method for the growth of bismuth chalcogenide (Bi2Te3, Bi2Se3) topological insulator nanowires/nanobelts by using Bi2Se3 or Bi2Te3 powders as source materials. During the first stage of the synthesis process nanoplateteles, serving as “catalysts” for further nanowire/nanobelt growth, are formed. At a second stage of the synthesis, the introduction of a N2 flow at 35 Torr pressure in the chamber induces the formation of free standing nanowires/nanobelts. The synthesised nanostructures demonstrate a layered single-crystalline structure and Bi : Se and Bi : Te ratios 40 : 60 at% for both Bi2Se3 and Bi2Te3 nanowires/nanobelts. The presence of…
Formation Kinetics of Mixed Self-Assembled Monolayers of Alkanethiols on GaAs(100)
2017
International audience; We report on the formation kinetics of mixed self-assembled monolayers (SAMs) comprising 16-mercaptohexadecanoic acid (MHDA) and 11-mercapto-1-undecanol (MUDO) thiols on GaAs(100) substrates. These compounds were selected for their potential in constructing highly selective and efficient architectures for biosensing applications. The molecular composition and quality of one-compound and mixed SAMs were determined by the Fourier transform infrared absorption spectroscopy measurements. The formation of enhanced-quality mixed SAMs was investigated as a function of the molecular composition of the thiol mixture and the proportion of ethanol/water solvent used during thei…
Comparative Investigation on the Soil Burial Degradation Behaviour of Polymer Films for Agriculture before and after Photo-Oxidation
2020
Polymer films based on biodegradable polymers, polyethylene (PE) and modified PE with oxo-degradable additive were prepared by film blowing. Carbon black (1%) was added to all the films. Commercial biodegradable Ecovio®
Energy harvesting by waste acid/base neutralization via bipolar membrane reverse electrodialysis
2020
Bipolar Membrane Reverse Electrodialysis (BMRED) can be used to produce electricity exploiting acid-base neutralization, thus representing a valuable route in reusing waste streams. The present work investigates the performance of a lab-scale BMRED module under several operating conditions. By feeding the stack with 1 M HCl and NaOH streams, a maximum power density of ~17 W m−2 was obtained at 100 A m−2 with a 10-triplet stack with a flow velocity of 1 cm s−1, while an energy density of ~10 kWh m−3 acid could be extracted by a complete neutralization. Parasitic currents along feed and drain manifolds significantly affected the performance of the stack when equipped with a higher number of t…
Formaldehyde: Catalytic Oxidation as a Promising Soft Way of Elimination
2013
International audience; Compared to other molecules such as benzene, toluene, xylene, and chlorinated compounds, the catalytic oxidation of formaldehyde has been studied rarely. However, standards for the emission level of this pollutant will become more restrictive because of its extreme toxicity even at very low concentrations in air. As a consequence, the development of a highly efficient process for its selective elimination is needed. Complete catalytic oxidation of formaldehyde into CO2 and H2O using noble-metal-based catalysts is a promising method to convert this pollutant at room temperature, making this process energetically attractive from an industrial point of view. However, th…
Compatibilization of blends of polyethylene with a semirigid liquid crystalline polymer by PE-g-LCP copolymers
1997
The blends of thermoplastics with liquid crystalline polymers show, in general, poor properties because of the lack of adherence between the two phases. The use of ad hoc synthesized copolymers containing the monomer units of the two polymers has been recently considered by some of us for blend compatibilization, and the results appear promising. In this work, new PE-g-LCP copolymers, prepared either by the synthesis of the LCP in the presence of a functionalized PE, or by reactive blending of the latter polymer with preformed LCP, have been employed as compatibilizing additives for blends of PE with a semirigid LCP. The morphology and the rheological and mechanical properties of the ternar…
CHP (combined heat and power) retrofit for a large MED-TVC (multiple effect distillation along with thermal vapour compression) desalination plant: H…
2016
Abstract Integrated power plants in “dual purpose” configuration may represent a viable option for energy cost abatement of desalted water produced by MED-TVC (Multiple Effect Distillation along with Thermal Vapour Compression). In this paper an existing large MED-TVC plant with a 36,000 m 3 /day capacity is studied: a plant retrofit is designed, based on a steam power plant with condensation and steam extraction used to drive the steam ejector. As the plant operates in CHP (Combined Heat and Power) mode, the possibility to assess the integrated “CHP + MED-TVC” as high efficiency cogeneration according to Directive 2004/8/EC is discussed. Based on a model developed in Engineering Equation S…
How composition and process parameters affect volatile active compounds in biopolymer films
2012
Abstract Active edible films based on chitosan and containing an active aroma compound have been investigated. The influence of the composition of the film forming solution (solvent, plasticizers, nanoparticles, emulsifiers and aroma traps) and process parameters (temperature and viscosity) on drying kinetics, water content, colour, aroma compound retention and partition coefficient was studied. Solvent evaporation rate was increased by addition of ethanol. Water evaporation was delayed by glycerol. The aroma retention during film drying was directly related to the water content. The drying temperature had opposite influences according to the composition of the solvent and additives. Increa…
Iron oxide-based magnetic photocatalysts: Recent developments, challenges, and environmental applications
2021
Abstract Magnetic separation of the solid photocatalyst from the reacting suspension has received great interest in recent research because it offers a suitable way for removing and recycling the heterogeneous photocatalytic material particles preventing the agglomeration and sedimentation during and after their use. The use of iron oxides such as heterogeneous photocatalysts is an appropriate choice to obtain a suitable photocatalyst easily separable from the fluid. This chapter presents a detailed investigation of iron oxide-based magnetic photocatalysts (IOMPs). We will discuss the required conditions for the synthesis of these photocatalysts, followed by their applications for the remov…
Preparation of Polymer-Supported Polyazamacrocycles. The Role of the Polymeric Matrix in the Preparation of Polymer-Supported Polyazamacrocycles
2000
Different approaches have been studied for the preparation of resins containing different polyazamacrocycles. Preparation of monolithic resins by polymerization of vinylic derivatives of the corresponding macrocycles is shown to be a more versatile strategy for this purpose. The use of energy-dispersive analysis by X-ray has revealed to be a very useful tool for the rapid evaluation of the interaction of those materials with both anions and cations and has allowed the corresponding selectivity trends to be obtained in a fast and simple way. Important effects of the polymeric matrix are observed in some cases.