Search results for "aqueous solution"

Pd-Cu catalysts supported on anion exchange resin for the simultaneous catalytic reduction of nitrate ions and reductive dehalogenation of organochlo…

2019

International audience; The present work proposes the simultaneous removal of these classes of pollutants by a catalytic hydrotreatment processes. For this purpose, bimetallic Pd-Cu catalysts (with mass ratio Pd:Cu of 4:1) supported on macroporous strong base anion resin were prepared by different methods. The catalysts were characterized (by XRD, SEMEDX, XPS, AAS and H-2 chemisorption) and tested in a continuous flow system. The selected catalyst preparation protocol consists in a two-step method, which implies the deposition of palladium by ion exchange and the subsequent deposition of copper by controlled reaction on the surface of the pre-reduced palladium. The effectiveness of the cata…

Photocrosslinking of dextran and polyaspartamide derivatives: a combination suitable for colon-specific drug delivery.

2007

Abstract The aim of this study was to prepare and characterize novel hydrogels with polysaccharide–polyaminoacid structure, able to undergo an enzymatic hydrolysis in the colon and potentially useful for treating inflammatory bowel diseases (IBD). Starting materials were methacrylated dextran (DEX-MA) and methacrylated α,β-poly(N-2-hydroxyethyl)- dl -aspartamide (PHM). These polymers were photocrosslinked by exposure of their aqueous solutions at 313 nm without photoinitiators. Different samples, shaped as microparticles, were obtained as a function of polymer concentration and irradiation time. FT-IR analysis confirmed the occurrence of a co-crosslinking between DEX-MA and PHM in all exper…

The young hard active Sun: soft X-ray irradiation of tryptophan in water solutions

2010

AbstractThe X-ray emission of the young Sun was much harder and intense than today and might have played a significant role in the evolution of complex organics in protoplanetary environments. We investigate the effects of soft X-rays on tryptophan molecules in aqueous solutions at room temperature. As results of the irradiation experiments we detect several light species indicative of fragmentation, together with large molecular structures such as tryptophan dipeptide and tripeptide. Complexification is more evident in H2O solution than in D2O, probably due to isotopic effects. The abundances of peptides depend on the irradiation dose and decrease with increasing energy deposition. Radical…

Enrichment of amino acids by supported liquid membrane extraction using Aliquat 336 as a carrier

1998

Abstract The possible application of Aliquat 336 (trioctylmethyl ammonium chloride) as a carrier for liquid membrane extraction of amino acids was investigated. The extraction is performed from an aqueous donor phase with pH > 11 to an acceptor phase containing a salt solution through a supported liquid membrane with Aliquat 336 as a carrier in the membrane to facilitate amino acid transport. Counter-coupled transport of chloride anions from the acceptor phase to the donor phase is the driving force of the mass transfer in this system. The extraction efficiency depends on the donor phase pH, the carrier concentration in the liquid membrane, the composition of the acceptor phase and the hydr…

Photodegradation of lincomycin in aqueous solution

2006

Aqueous solutions of lincomycin were irradiated with UV light in homogeneous and heterogeneous systems. Lincomycin disappeared in both systems but the presence ofTiO2noticeably accelerated the degradation of the antibiotic in comparison with direct photolysis. The rate of decomposition was dependent on the concentration of lincomycin and followed a pseudo-first-order kinetics. Photolysis involved only the oxidation of lincomycin without mineralization. Differently, the treatment withTiO2and UV light resulted in a complete mineralization of the antibiotic. The degradation pathways involved S- and N-demethylation and propyldealkylation. The mineralization of the molecule led to the formation …

Protein and glycerol contents affect physico-chemical properties of soy protein isolate-based edible films

2010

Abstract This study was conducted to determine the effect of both soy protein and glycerol contents on physico-chemical properties of soy protein isolate-based edible (SPI) films. The aim of this study was to better understand the influence of SPI and GLY contents on the behavior of the physico-chemical properties of soy protein isolate-based films. Films were casted from heated (70 °C for 20 min) alkaline (pH 10) aqueous solutions of SPI at 6, 7, 8, and 9 (w/w %), glycerol (50%, w/w, of SPI) and SPI at 7 (w/w %), glycerol (40, 60, 70 %, w/w of SPI). Water vapor permeability (WVP), was measured at 25 °C and for four different relative humidities (30–100%, 30–84%, 30–75%, 30–53%). Surface pr…

Growth and characterization of anodic films on Sc in aqueous solutions

2008

A novel TiO2-assisted magnetic nanoparticle separator for treatment and inactivation of bacterial contaminants in aquatic systems

2014

Ferromagnetic nanoparticles (Fe-nanoparticles) have been functionalized with recombinant poly- Glu [glutamic acid]-tagged silicatein, a biomineral-synthesizing enzyme from siliceous sponges that forms the inorganic silica skeleton of those animals. The biocatalytic activity of silicatein was used to form a titania (TiO2) shell around the iron nanoparticle core, using the water-soluble non- natural substrate titanium bis(ammonium lactato)-dihydroxide (TiBALDH). Thereby the diameter of the nanoparticles increases from 7 nm to ≈22 nm. This procedure also allows the layer-by-layer fabrication of titania/silica- Fe-nanoparticles. SEM/EDX analysis confirmed the presence of the Ti and Si signals i…

Chromogenic Detection of Aqueous Formaldehyde Using Functionalized Silica Nanoparticles

2016

Silica nanoparticles functionalized with thiol reactive units and bulky polar polyamines were used for the selective colorimetric detection of formaldehyde. The reaction of thiols groups in the nanoparticles surface with a squaraine dye resulted in loss of the pi-conjugation of the chromophores, and the subsequent bleaching of the solution. However, when formaldehyde was present in the suspension, the thiol-squaraine reaction was inhibited and a chromogenic response was observed. A selective response to formaldehyde was observed only when the thiol and polyamine groups were anchored to the silica surface. The observed selective response was ascribed to the fact that bulky polyamines generat…

Temperature effect on solubility of aroma compounds in various aqueous solutions

2005

International audience; Solubility of nine aroma compounds (methyl ketones, ethyl esters, aldehyde and alcohol) in various aqueous solutions was measured by the mutual solubility method from -10 to +10degreesC. Influence of both, the nature (carbohydrates and polyols) and the substrate concentration (from 0 to 57.5g/100g) on aroma solubility in aqueous solutions was studied. Aroma solubility in water decreased when aroma hydrophobicity increased. Aroma solubility in various aqueous solutions decreased when substrate concentration increased; their solubility was higher in polyols solutions than in polysaccharides ones. Temperature effect on aroma solubility showed a noncontinuous evolution f…