Search results for " Chemical Engineering"
showing 10 items of 2965 documents
Start-up and Operation of Laboratory-Scale Thermophilic Upflow Anaerobic Sludge Blanket Reactors Treating Vegetable Processing Wastewaters
1997
Thermophilic anaerobic treatment of hot vegetable processing wastewaters was studied in laboratory-scale UASB reactors at 55°C. The high-strength wastewater streams, deriving from steam peeling and blanching of carrot, potato and swede were used. The reactors were inoculated with mesophilic granular sludge. Stable thermophilic methanogenesis with about 60% COD removal was reached within 28 days. During the 134 day study period the loading rate was increased up to 24 kg COD m−3 day−1. High treatment efficiency of more than 90% COD removal and concomitant methane production of 7·3 m3 CH4 m−3 day−1 were achieved. The anaerobic process performance was not affected by the changes in the wastewat…
Inkjet printing Ag nanoparticles for SERS hot spots
2018
A novel inkjet printing based approach is developed for the fabrication of a customizable platform on glass substrates allowing for surface enhanced Raman spectroscopy (SERS) detection of analytes up to single hot spots generated by the spontaneous aggregation of Ag nanoparticles (Ag NPs) in pL scale droplets. After drying the printed droplets under ambient conditions, trace amounts of the analyte can be detected by SERS given the proximity to NP hot spots. By employing alizarin (10-5M) as a model system and scaling the ink droplet volume from 1 nL to 10 pL, the absolute quantity of hot spots has been derived in the printed droplets allowing detecting up to a few molecules in proximity to i…
Two-Dimensional Indium Selenide for Sulphur Vapour Sensing Applications
2020
Surface-to-volume ratio in two-dimensional (2D) materials highlights among their characteristics as an inherent and intrinsic advantage taking into account their strong sensitivity to surface effects. For this reason, we have proposed in this work micromechanically exfoliated 2D nanosheets of InSe as an optical vapour sensor. As a proof of concept, we used 2-mercaptoethanol as the chemical analyte in vapour phase to monitor the change of the InSe photoluminescence (PL) before and after exposure to the analyte. For short vapour exposure times (at low analyte concentration), we found a PL enhancement of InSe nanosheets attributed to the surface localization of Se defects. For long vapour expo…
Determination of biochemical parameters in human serum by near-infrared spectroscopy
2014
NIR offers multiple advantages for serum analysis, permitting a fast and direct determination of several parameters simultaneously, with low sample handling and without the need for reagents during the measurement step. The aim of this paper was to provide an evaluation of this technique in a real world scale, for the simultaneous determination of several parameters and based on a considerable number of samples. Direct near infrared (NIR) absorbance measurements were used to determine the concentration of clinical parameters in human serum that are required in routine biochemical tests. Total protein, albumin, total cholesterol, high-density lipoprotein (HDL cholesterol), low-density lipopr…
Determination of the crystallinity of TiO2 photocatalysts
2018
Abstract This study reports a new simple method to determine the crystallinity of anatase and rutile TiO2 photocatalysts. The crystallinity degree of various anatase and rutile samples was estimated by XRD analysis from the ratio among the full width at half maximum intensities of the main diffraction peaks of anatase or rutile and the (111) peak of CaF2 as internal standard. The photocatalytic activity of selected powders was tested employing the photodegradation of 4-nitrophenol in aqueous solution as probe reaction. The results showed that the photoactivity of the investigated samples increased with increasing crystallinity and crystallite size.
Visible light photocatalytic activity of macro-mesoporous TiO2-CeO2inverse opals
2018
Macro-mesoporous TiO2 inverse opal materials were synthesized and they were tested as photocatalysts under visible light irradiation. The influence of cerium oxide addition towards the Rhodamine B (RhB) photodegradation activity was evaluated. Structural, textural, spectral and surface properties of the TiO2-CeO2 inverse opal nanocomposites were studied by XRD, XPS, SEM, TEM, N2 adsorption-desorption, Diffuse Reflectance UV–vis and Photoluminescence spectroscopies. Compared to commercial TiO2 anatase, the macro-mesoporous TiO2 inverse opal exhibited six times higher kinetic rate constant in the RhB degradation under visible light irradiation. The good photocatalytic activity was related to …
Influence of metallic silver and of platinum-silver bimetallic deposits on the photocatalytic activity of titania (anatase and rutile) in organic and…
1998
Abstract The influence of deposited silver upon the photocatalytic activity of titania in the rutile and anatase allotropic forms has been studied in three different reactions. The common feature found for these three reactions was an electron transfer from illuminated TiO 2 to silver particles. In the first reaction (platinum photodeposition). it has been shown that the initial presence of metallic silver orientates the localization of subsequent Pt photodeposits with, in particular, a 100% selectivity to Pt deposition on top of silver particles or agglomerates previously deposited on anatase. In the second reaction (2-propanol oxidation), Ag deposit was found beneficial for the activity o…
Photon absorption by aqueous TiO2 dispersion contained in a stirred photoreactor
1991
We present a simple experimental method which allows the evaluation of the absorbed photon flow. The method is based on measurements of transmitted photon rates (by means of standard actinometer solutions) for different reactor thicknesses and/or catalyst concentrations. The method was applied to phenol degradation reaction carried out in a stirred batch phtotoreactor containing aqueous TiO 2 (anatase) dispersion, directly irradied by a 1,500 W Xe lamp
Hybrid TiO2 @ phthalocyanine catalysts in photooxidation of 4-nitrophenol: Effect of the matrix and sensitizer type
2020
Abstract Microcrystalline and nanocrystalline anatase (TiO2) based hybrid photocatalysts including selected phthalocyanine sensitizers were explored in photooxidation of 4-nitrophenol (4-NP) in water. Composites obtained with the homemade pure nano-anatase displayed a very poor catalytic performance compared to the other ones prepared from the commercial Tioxide-Huntsman (micro) and Evonik P25 (nano) products. In particular, the microcrystalline anatase impregnated with sandwich phthalocyanines of Gd or Yb showed excellent results both in photooxidation of 4-NP and hydroquinone, and proved the only ones which completely removed these two compounds from the system during the same reaction cy…
Cr- and Sb-containing TiO 2 inorganic orange nano-pigments prepared by a relative long hydrocarbon chain polyol
2016
Abstract We report the preparation of a series of orange Cr- and Sb-containing TiO 2 nano-pigments by the polyol via using triethylenglycol (TEG). Poorly crystallized anatase nanopowders with nominal stoichiometric compositions Cr x Sb x Ti 1−2x O 2 , with 0 ≤ x ≤ 0.2, were obtained by heating at 180 °C a solution of antimony acetate, chromium acetylacetone and titanium butoxide in TEG. The transition temperature of the chromium- and antimonium-containing anatase nanoparticles into the rutile crystalline form occurred over the range of temperature between 500 and 650 °C, depending on the dopant amount. After annealing at 800 °C for short time the series of samples displaying the rutile stru…