Search results for " mixture"

Lignin-based activated carbon-supported metal oxide catalysts in lactic acid production from glucose

2021

In this study, heterogeneous biomass-based activated carbon-supported metal oxide catalysts were prepared and tested for lactic acid production from glucose in aqueous solution. Activated carbons were produced from hydrolysis lignin by chemical (ZnCl2) or steam activation and modified with a nitric acid treatment and Sn, Al, and Cr chlorides to obtain carbon-based metal oxide catalysts. The modification of the carbon support by nitric acid treatment together with Sn and Al oxides led to an increase in lactic acid yield. The highest lactic acid yield (42%) was obtained after 20 minutes at 180 °C with the Sn/Al (5/2.5 wt.%) catalyst on steam-activated carbon treated by nitric acid. Reusabilit…

Effective Recovery Process of Copper from Waste Printed Circuit Boards Utilizing Recycling of Leachate

2020

AbstractThis study presents an optimized leaching and electrowinning process for the recovery of copper from waste printed circuit boards including studies of chemical consumption and recirculation of leachate. Optimization of leaching was performed using response surface methodology in diluted sulfuric acid and hydrogen peroxide media. Optimum leaching conditions for copper were found by using 3.6 mol L−1 sulfuric acid, 6 vol.% hydrogen peroxide, pulp density of 75 g L−1 with 186 min leaching time at 20°C resulting in complete leaching of copper followed by over 92% recovery and purity of 99.9% in the electrowinning. Study of chemical consumption showed total decomposition of hydrogen pero…

How mixing ionic liquids affects a Diels-Alder reaction

On the characterization of some [bmim][X]/co-solvent binary mixtures: a multidisciplinary approach by using kinetic, spectrophotometric and conductom…

2008

Abstract In order to study the intrinsic characteristics and to evaluate the structural variations determined by the addition of a co-solvent to 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]) we examined the behaviour of some probes in [bmim][BF 4 ]/co-solvent binary mixtures. The rate constants of the piperidino-catalyzed rearrangement of the Z -phenylhydrazone of the 3-benzoyl-5-phenyl-1,2,4-oxadiazole into the relevant 4-benzoylamino-2,5-diphenyl-1,2,3-triazole as well as the spectrometric properties of pyrene and Nile Red were evaluated. With the same purpose also 1 H NMR and conductivity measurements were carried out. By comparison the behaviour of 1-butyl-3-methylimidaz…

Ionic liquid binary mixtures: Promising reaction media for carbohydrate conversion into 5-hydroxymethylfurfural

2014

Abstract The conversion of carbohydrates into 5-hydroxymethylfurfural (5-HMF) has been studied in binary mixtures of ionic liquids (ILs), using strongly acidic resin Amberlyst 15 as the catalyst. In particular, both mono- and disaccharides, such as fructose, glucose and sucrose have been investigated. Considering the favorable effect exerted by chloride-based ionic liquids in the dissolution of carbohydrates, we used binary mixtures of 1-butyl-3-methylimidazolium chloride ([bmim][Cl]) with [bmim + ] based ionic liquids differing in size, shape and coordination ability of the anion ([bmim][BF 4 ], [bmim][N(CF 3 SO 2 ) 2 ], [bmim][N(CN) 2 ], [bmim][SbF 6 ] and [bmim][CF 3 SO 3 ]). Carbohydrat…

Latent growth mixture modeling : a simulation study

2007

Sensitivity of transatlantic dust transport to chemical aging and related atmospheric processes

2017

We present a sensitivity study on transatlantic dust transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the dust outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral dust, by using the EMAC model following Abdelkader et al. (2015). To characterize the dust outflow over the Atlantic Ocean, we distinguish two geographic zones: (i) dust interactions within the Intertropical Convergence Zone (ITCZ), or the dust–ITCZ interaction zone (DIZ), and (ii) the adjacent dust transport over the Atlantic Ocean (DTA) zone. In the latter zone, the dust loading shows a steep …

Aerosol properties, source identification, and cloud processing in orographic clouds measured by single particle mass spectrometry on a central Europ…

2016

Cloud residues and out-of-cloud aerosol particles with diameters between 150 and 900 nm were analysed by online single particle aerosol mass spectrometry during the 6-week study Hill Cap Cloud Thuringia (HCCT)-2010 in September–October 2010. The measurement location was the mountain Schmücke (937 m a.s.l.) in central Germany. More than 160 000 bipolar mass spectra from out-of-cloud aerosol particles and more than 13 000 bipolar mass spectra from cloud residual particles were obtained and were classified using a fuzzy c-means clustering algorithm. Analysis of the uncertainty of the sorting algorithm was conducted on a subset of the data by comparing the clustering output with particle-by-par…

Suction controlled drying and wetting cycle effects on the volumetric behaviour of a lime-treated high plasticity clay

2016

The paper presents some experimental results collected on samples recovered from an experimental embankment obtained by compacting a lime-treated clay. Samples were collected soon after the in situ compaction and they were cured in controlled environmental conditions for at least 18 months. Mercury intrusion porosimetry tests (MIP) were carried out on freeze-dried specimens to characterize the microstructure of the material. In order to assess the durability of the improved material, laboratory tests focused on the effects of cyclic variations of the degree of saturation on the water retention properties and the volumetric behaviour of the stabilized clay. Collected results show that the li…

Evaluation of plankton communities in small highly humic bog lakes in Latvia

1998

This paper reports the results of a study performed at the Teici State Reserve in Latvia The results indicated that algal communities in brown water lakes were formed by species that were tolerant to a low pH and high humic substance concentration. The composition of the species of phytoplankton and zooplankton was comparatively simple. A significant correlation was found between the number of species of phytoplankton, zooplankton, and the pH value. Similarly there was a clear relationship between the taxonomic composition of phytoplankton, zooplankton, and the trophic state of the lakes. Dyseutrophic lakes were characterized by comparatively higher biodiversity of planktonic communities th…