MID-FTIR-PLS Chemometric Analysis of Cr(VI) from Aqueous Solutions Using a Polymer Inclusion Membrane-Based Sensor.

A partial least squares (PLS) quantitative chemometric method based on the analysis of the mid-Fourier transform infrared spectroscopy (MID-FTIR) spectrum of polymer inclusion membranes (PIMs) used for the extraction of Cr(VI) from aqueous media is developed. The system previously optimized considering the variables membrane composition, extraction time, and pH, is characterized in terms of its adsorption isotherm, distribution coefficient, extraction percent, and enrichment factor. A Langmuir-type adsorption behavior with = 2199 cm/mmol, = 0.

Enhanced performance of glycerol electro-oxidation in alkaline media using bimetallic Au-Cu NPs supported by MWCNTs and reducible metal oxides.

Electrochemical technologies for valorizing glycerol, a byproduct of biodiesel production, into electric energy and value-added chemical products continue to be technologically and economically challenging. In this field, an ongoing challenge is developing more active, stable, and low-cost heterogeneous catalysts for the glycerol electro-oxidation reaction (GlyEOR). This paper reports the influence of the preparation procedure, which involves intermatrix synthesis (Cu and Au NPs), followed by galvanic displacement (Cu-Au NPs) in previously functionalized multi-walled carbon nanotubes (MWCNTs).

Structural Characterization of the Plasticizers' Role in Polymer Inclusion Membranes Used for Indium (III) Transport Containing IONQUEST 801 as Carrier.

Polymer inclusion membranes containing cellulose triacetate as support, Ionquest 801 ((2-ethylhexyl acid) -mono (2-ethylhexyl) phosphonic ester) as extractant, and 2NPOE (o-nitrophenyl octyl ether) or TBEP (tri (2-butoxyethyl phosphate)) as plasticizers were characterized using several instrumental techniques (Fourier Transform Infrared Spectroscopy (FT-IR), Reflection Infrared Mapping Microscopy (RIMM), Electrochemical Impedance Spectroscopy (EIS), Differential Scanning Calorimetry (DSC)) with the aim of determining physical and chemical parameters (structure, electric resistance, dielectric constant, thickness, components' distributions, glass transition temperature, stability) that allow a better comprehension of the role that the plasticizer plays in PIMs designed for In(III) transport. In comparison to TBEP, 2NPOE presents less dispersion and affinity in the PIMs, a plasticizer effect at higher content, higher membrane resistance and less permittivity, and a pronounced drop in the glass transition temperature. However, the increase in permittivity with In (III) sorption is more noticeable and, in general, PIMs with 2NPOE present higher permeability values.

Comparative study of As (V) uptake in aqueous medium by a polymer inclusion membrane-based passive sampling device and two filamentous fungi (Aspergillus niger and Rhizopus sp.).

In this work a polymer inclusion membrane (PIM) is proposed as passive sampler material and compared with two filamentous fungi for As (V) uptake to evaluate its ability as chemical surrogate material for the monitoring of this metalloid in aquatic environments. Results show excellent passive sampling characteristics of the device since a linear uptake profile as a function of time was observed. The correlation coefficients between the PIM passive sampler with Aspergillus niger (r = 0.

Determination of Cadmium (II) in Aqueous Solutions by In Situ MID-FTIR-PLS Analysis Using a Polymer Inclusion Membrane-Based Sensor: First Considerations.

Environmental monitoring is one of the most dynamically developing branches of chemical analysis. In this area, the use of multidimensional techniques and methods is encouraged to allow reliable determinations of metal ions with portable equipment for in-field applications. In this regard, this study presents, for the first time, the capabilities of a polymer inclusion membrane (PIM) sensor to perform cadmium (II) determination in aqueous solutions by in situ visible (VIS) and Mid- Fourier transform infrared spectroscopy (MID-FTIR) analyses of the polymeric films, using a partial least squares (PLS) chemometric approach.

Hybrids based on borate-functionalized cellulose nanofibers and noble-metal nanoparticles as sustainable catalysts for environmental applications.

Polymeric supports from renewable resources such as cellulose nanomaterials are having a direct impact on the development of heterogenous sustainable catalysts. Recently, to increase the potentiality of these materials, research has been oriented towards novel functionalization possibilities. In this study, to increase the stability of cellulose nanofiber films as catalytic supports, by limiting the solubility in water, we report the synthesis of new hybrid catalysts (HC) based on silver, gold, and platinum nanoparticles, and the corresponding bimetallic nanoparticles, supported on cellulose nanofibers (CNFs) cross-linked with borate ions.

Influence of some physicochemical parameters on the passive sampling of copper (II) from aqueous medium using a polymer inclusion membrane device.

Recently polymer inclusion membranes (PIMs) have been proposed as materials for passive sampling, nonetheless a theoretical base to describe the mass transfer process through those materials, under such conditions of monitoring, has not been elucidated. Under the assumption that: (i) the transport of the metal ion occurs at steady state conditions, (ii) the concentration gradients are linear, and (iii) the kinetics of the chemical reactions in the extraction process on the membrane are elemental; an equation for the passive sampling of copper (II) using a PIM system containing Kelex-100 as carrier is derived. The prediction capacity of this sampler under different conditions of temperature, metal concentration, flow velocity, ionic strength and pH is analyzed as well.

Simultaneous Au Extraction and In Situ Formation of Polymeric Membrane-Supported Au Nanoparticles: A Sustainable Process with Application in Catalysis.

A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of Au salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for Au extraction.

Evaluation of a hollow fiber supported liquid membrane device as a chemical surrogate for the measurements of zinc (II) bioavailability using two microalgae strains as biological references.

The environmental bioavailability of zinc (II), i.e., the uptake of the element by an organism, was determined using two microalgae species, Scenedesmus acutus and Pseudokirchneriella subcapitata, and estimated using hollow fiber supported liquid membrane (HF-SLM) device as the chemical surrogate.

Evaluation of the measurement of Cu(II) bioavailability in complex aqueous media using a hollow-fiber supported liquid membrane device (HFSLM) and two microalgae species (Pseudokirchneriella subcapitata and Scenedesmus acutus).

The environmental bioavailability of copper was determined using a hollow-fiber supported liquid membrane (HFSLM) device as a chemical surrogate and two microalgae species (Scenedesmus acutus and Pseudokirchneriella subcapitata). Several experimental conditions were studied: pH, the presence of organic matter, inorganic anions, and concomitant cations. The results indicated a strong relationship between the response given by the HFSLM and the microalgae species with free copper concentrations measured by an ion selective electrode (ISE), in accordance with the free-ion activity model (FIAM).

Semi-interpenetrating hybrid membranes containing ADOGEN® 364 for Cd(II) transport from HCl media.

Cd(II) transport from 1moldm(-3) HCl media was investigated across semi-interpenetrating hybrid membranes (SIHMs) that were prepared by mixing an organic matrix composed of ADOGEN(®) 364 as an extracting agent, cellulose triacetate as a polymeric support and nitrophenyloctyl ether as a plasticizer with an organic/inorganic network (silane phase, SP) composed of polydimethylsiloxane and a crosslinking agent. The stripping phase used was a 10(-2)mol dm(-3) ethanesulfonic acid solution. The effects of tetraorthoethoxysilane, phenyltrimethoxysilane and N',N'-bis[3-tri(methoxysilyl)propyl]ethylendiamine as crosslinking agents on the transport were studied.

Cr(VI) transport via a supported ionic liquid membrane containing CYPHOS IL101 as carrier: system analysis and optimization through experimental design strategies.

Chromium(VI) transport through a supported liquid membrane (SLM) system containing the commercial ionic liquid CYPHOS IL101 as carrier was studied. A reducing stripping phase was used as a mean to increase recovery and to simultaneously transform Cr(VI) into a less toxic residue for disposal or reuse. General functions which describe the time-depending evolution of the metal fractions in the cell compartments were defined and used in data evaluation.

Nickel (II) Preconcentration and Speciation Analysis During Transport from Aqueous Solutions Using a Hollow-fiber Permeation Liquid Membrane (HFPLM) Device.

Nickel (II) preconcentration and speciation analysis using a hollow fiber supported liquid membrane (HFSLM) device was studied. A counterflow of protons coupled to complexation with formate provided the driving force of the process, while Kelex 100 was employed as carrier. The influence of variables related to module configuration (acceptor pH and carrier concentration) and to the sample properties (donor pH) on the preconcentration factor, E, was simultaneously studied and optimized using a 3 factor Doehlert matrix response surface methodology.

Design, synthesis and evaluation of diazadibenzocrown ethers as Pb(2+) extractants and carriers in plasticized cellulose triacetate membranes.

The ligands 4,7-diaza-2,3,8,9-dibenzo-15-crown-5 (L1), 4,10-diaza-2,3,11,12-dibenzo-18-crown-6 (L2), 4,10-diaza-2,3,11,12-di(4'-tert-butylbenzo)-18-crown-6 (L3) and N,N-di(methylenecarboxyethoxy) 4,10-diaza-2,3,11,12-dibenzo-18-crown-6 (L4) have been prepared. Partition coefficients and acid dissociation constants for these four diazadibenzocrown ether compounds were determined in water-chloroform. Their effectiveness was assessed in solvent extraction of Pb(2+) from aqueous solutions into toluene.

Up-regulation of S100A8 and S100A9 protein in bronchial epithelial cells by lipopolysaccharide.

Increased serum levels of the S100A8 (MRP-8) protein have been reported in inflammatory conditions including bacterial infection, arthritis, and cystic fibrosis (CF). This protein is expressed constitutively with S100A9 (MRP-14) in neutrophils and is regulated by inflammatory stimulants. It has been hypothesized that increased inflammatory response to persistent bacterial infection is a major feature of CF lung disease.

Lysophospholipid generation and phosphatidylglycerol depletion in phospholipase A(2)-mediated surfactant dysfunction.

Pulmonary surfactant's complex mixture of phospholipids and proteins reduces the work of breathing by lowering alveolar surface tension during respiration. One mechanism of surfactant damage appears to be the hydrolysis of phospholipid by phospholipases activated in the inflamed lung. Humans have several candidate secretory phospholipase A(2) (sPLA(2)) enzymes in lung cells and infiltrating leukocytes that could damage extracellular surfactant.

Arsenic(V) removal with polymer inclusion membranes from sulfuric acid media using DBBP as carrier.

Polymer inclusion membranes (PIMs) based on cellulose triacetate (CTA) and dibutyl butyl phosphonate (DBBP) were tested for arsenic(V) separation from H2SO4 for its recovery from copper electrolytes. Solvent extraction experiments allowed the determination of the As(V)-DBBP and H2SO4-DBBP complexes formed in the organic phase. Application of a transient model to membrane transport experiments in solutions containing only arsenic or H2SO4 indicated that it occurred under a kinetically controlled regime by formation of H3AsO4[DBBP]2 and H2SO4[DBBP] species, respectively.

Multicenter phase II study of brequinar sodium in patients with advanced breast cancer.

In this study, 34 patients with advanced breast cancer were treated with brequinar sodium: 75% of the patients were postmenopausal, and 94% had received chemotherapy previously; 50% had previously received an anthracycline-containing regimen. Brequinar was administered intravenously at a median weekly dose of 1,200 mg/m2. The toxicity was moderate, with 17 patients (50%) experiencing grade 3 or 4 toxicity.

Multicenter phase II study of brequinar sodium in patients with advanced gastrointestinal cancer.

Eighty-six patients with advanced colorectal, gastric or pancreatic carcinoma and no prior exposure to chemotherapy were treated with brequinar sodium. Brequinar was administered at a median weekly dose of 1200 mg/m2 intravenously. The toxicity was moderate, with thirty patients (35%) experiencing grade 3 or 4 toxicity.

Multicenter phase II study of brequinar sodium in patients with advanced lung cancer.

A total of 53 patients with advanced lung cancer [non-small-cell (NSC), 21; small-cell (SC), 32] were treated with brequinar sodium. All of the NSC patients were chemotherapy-naive, but 31/32 (97%) SC patients had failed a multiagent chemotherapy program prior to study entry. Brequinar was given intravenously at a median weekly dose of 1200 mg/m2.

Multicenter phase II trial of brequinar sodium in patients with advanced melanoma.

Seventeen patients with advanced melanoma and no prior exposure to chemotherapy were treated with brequinar sodium as first-line chemotherapy. Brequinar was given at a median weekly dose of 1200 mg/m2 intravenously. In 14 patients evaluable for efficacy, there were no objective responses.

Multicenter phase II trial of brequinar sodium in patients with advanced squamous-cell carcinoma of the head and neck.

A total of 19 patients with advanced squamous-cell carcinoma of the head and neck who had not previously been exposed to chemotherapy were treated with brequinar sodium as first-line chemotherapy. Brequinar was given intravenously at a median weekly dose of 1,200 mg/m2. The toxicity was moderate, with 7 patients (37%) experiencing grade 3 or 4 toxicity.