Ultraviolet Spectroscopic Study of Ferric Iron Solutions

1980 ◽  
Vol 34 (3) ◽  
pp. 377-380 ◽  
Author(s):  
Mary F. Brown ◽  
Dana R. Kester
Keyword(s):  
Ionic Strength ◽  
Ferric Iron ◽  
Gaussian Function ◽  
Low Ph ◽  
Absorption Bands ◽  
Experimental Conditions ◽  
Band Maximum ◽  
Ultraviolet Absorbance ◽  
Constant Ph ◽  
Absorbance Spectra

Ultraviolet absorbance spectra of ferric iron solutions of varying iron concentrations maintained at a constant pH of 1.0 and a constant ionic strength of 0.1 were studied. The experimental conditions of low pH minimized the formation of the hydrolytic FeOH2+ and Fe(OH)2+ species; thus, the spectra of iron solutions containing principally the Fe3+ species were recorded. The digitized spectral data were used to establish a model for the Fe3+ absorption spectrum that involves a Gaussian function with three parameters for each of the two absorption bands. These parameters were the wavenumber of the band maximum, ν̄max, the full width at half maximum intensity, Δν̄1/2, and the absorptivity of the band maximum, εmax. This study provided estimates for these parameters at 25°C for 0.1 ionic strength media.

Decolorisation of natural organic matter by Phanerochaete chrysosporium: the effect of environmental conditions

2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson
Keyword(s):  
Organic Matter ◽  
Ionic Strength ◽  
Natural Organic Matter ◽  
Phanerochaete Chrysosporium ◽  
Fungal Growth ◽  
Low Ph ◽  
Colour Removal ◽  
Humic Material ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Content

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.

scholarly journals The Effect of pH, Ionic Strength and the Presence of PbII on the Formation of Calcium Carbonate from Homogenous Alkaline Solutions at Room Temperature

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 783
Author(s):  
Fulvio Di Lorenzo ◽  
Kay Steiner ◽  
Sergey V. Churakov
Keyword(s):  
Ionic Strength ◽  
Deep Understanding ◽  
Inhibitory Effect ◽  
Alkaline Solutions ◽  
Nucleation Kinetics ◽  
Experimental Conditions ◽  
Calcium Carbonates ◽  
Natural Systems ◽  
Geological Processes ◽  
System Variables

Precipitation of calcium carbonates in aqueous systems is an important factor controlling various industrial, biological, and geological processes. In the first part of this study, the well-known titration approach introduced by Gebauer and coworkers in 2008 s used to obtain reliable experimental dataset for the deep understanding of CaCO3 nucleation kinetics in supersaturated solutions over a broad range of pH and ionic strength conditions. In the second part, the effect of impurities, i.e., 1 mol% of Pb2+, was assessed in the same range of experimental conditions. Divalent lead has been shown to have an inhibitory effect in all ranges of the conditions tested except for pH 8 and low ionic strength (≤0.15 mol/L). Future investigations might take advantage of the methodology and the data provided in this work to investigate the effect of other system variables. The investigation of all the major variables and the assessment of eventual synergic effects could improve our ability to predict the formation of CaCO3 in complex natural systems.

Identification of Plant Material by Its Phenolic Content

1967 ◽  
Vol 50 (3) ◽  
pp. 727-734
Author(s):  
M Bonner Duggan
Keyword(s):  
Thin Layer ◽  
Plant Material ◽  
Phenolic Content ◽  
Pyrus Communis ◽  
Flavonol Glycosides ◽  
Ultraviolet Absorbance ◽  
Flavonoid Compounds ◽  
Phenolic Constituents ◽  
Minor Compounds ◽  
Absorbance Spectra

Abstract Methods have been developed to extract and chroniatograph phenolic constituents of Mains sylvestris and Pyrus communis fruits. Differences in the occurrence of flavonoid compounds between the two fruits and between pulp and peel in a given fruit were compared; the flavonol glycosides most conveniently demonstrated the differences. Five major and three minor flavonol glycosides from Stayman apples and two major and two minor ones from Packingham pears were separated by thin layer chromatograpliy. All of the major and some of the minor compounds were also described by ultraviolet absorbance spectra. Studies show that fruits can be distinguished on the basis of chromatographic patterns of the flavonol glycosides and that the results can be confirmed by their ultraviolet absorbance spectra

ELECTROPHORESIS OF HISTONES ON POLYACRYLAMIDE GELS

1963 ◽  
Vol 41 (12) ◽  
pp. 2507-2516 ◽  
Author(s):  
A. Driedger ◽  
L. D. Johnson ◽  
A. M. Marko
Keyword(s):  
Ionic Strength ◽  
Gel Electrophoresis ◽  
Starch Gel Electrophoresis ◽  
Polyacrylamide Gels ◽  
Optimum Conditions ◽  
Constant Ph ◽  
Starch Gel

Histories extracted from various organs of the rat have been fractionated by electrophoresis on Polyacrylamide gels. The most convenient reagents to form the gel were selected and the effects of varying concentrations of these reagents on the resolution of histones were investigated. Optimum conditions for the separation of histones were found to be the same as those for starch gel electrophoresis. More consistent results were obtained with the use of Polyacrylamide gels because these gels were equilibrated to constant pH and ionic strength prior to electrophoresis and the gels were electrophoretically destained to demonstrate the histone bands.

The diffusion of 75Se(IV) in Beishan granite – temperature, oxygen condition and ionic strength effects

2018 ◽  
Vol 107 (1) ◽  
pp. 39-54
Author(s):  
Chunli Wang ◽  
Xiaoyu Yang ◽  
Jiangang He ◽  
Fangxin Wei ◽  
Zhong Zheng ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Effective Diffusion ◽  
Aerobic Condition ◽  
Double Layers ◽  
Solution Viscosity ◽  
Formation Factor ◽  
Experimental Conditions ◽  
Beishan Granite ◽  
Oxygen Condition ◽  
The Difference

Abstract To explore the diffusion behavior of 75Se(IV) in Beishan granite (BsG), the influences of temperature, oxygen condition and ionic strength were investigated using the through-diffusion experimental method. The effective diffusion coefficient De of 75Se(IV) in BsG varied from 4.21×10−14 m2/s to 3.19×10−13 m2/s in our experimental conditions, increased with increasing temperature. The formation factor Ff of BsG was calculated to be nearly constant in the range of temperatures investigated, suggesting that the inner structure of BsG had no significant change in the temperature range of 20–55°C. Meanwhile, the De values of 75Se(IV) in BsG under anaerobic condition was significantly larger than that under aerobic condition, which may be attributed to the difference in the sorption characteristics and species distribution of Se and pH values. Moreover, the diffusion of 75Se(IV) was promoted with ionic strength increased from 0.01 M to 0.1 M, and then decreased at 0.5 M, mainly due to the combined effects of reduced double layers with increased ionic strength and increase of the solution viscosity at higher ionic strength.

scholarly journals Effects of Saline, an Ambient Acidic Environment, and Sodium Salicylate on OXA-Mediated Carbapenem Resistance in Acinetobacter baumannii: TABLE 1

2016 ◽  
Vol 60 (6) ◽  
pp. 3415-3418 ◽  
Author(s):  
Esther Zander ◽  
Harald Seifert ◽  
Paul G. Higgins
Keyword(s):  
Gene Expression ◽  
Acinetobacter Baumannii ◽  
Sodium Salicylate ◽  
Carbapenem Resistance ◽  
Low Ph ◽  
Wild Type ◽  
Experimental Conditions ◽  
Content Type ◽  
Reference Strains

Different physiological conditions, such as NaCl, low pH, and sodium salicylate, have been shown to affect antibiotic resistance determinants inAcinetobacter baumanniiisolates. Therefore, the aim of this study was to investigate the effects of NaCl, sodium salicylate, and low pH on the susceptibility ofA. baumanniito carbapenem. We cloned genes encoding oxacillinases (OXA) of different subclasses, with their associated promoters, from carbapenem-resistantA. baumanniiisolates into the same vector and transferred them to theA. baumanniireference strains ATCC 19606 and ATCC 17978. Carbapenem MICs were determined at least in triplicate by agar dilution under standard conditions, as well as in the presence of 200 mM NaCl or 16 mM sodium salicylate, or at pH 5.8. OXA-58-like gene expression was determined by reverse transcription-quantitative PCR (qRT-PCR). Under some experimental conditions, significant MIC reductions were shown for some transformants but not for others. Only in one instance were all transformants harboring the same OXA affected by the same condition: at pH 5.8, the imipenem and meropenem MICs for strains expressing OXA-58-like enzymes decreased from a resistant level (32 to 64 mg/liter) to an intermediate-susceptible level (8 mg/liter). However,blaOXA-58-likegene expression remained the same. MICs for both wild-type reference strains were not affected by the conditions tested. Our results indicate that the effects of the experimental conditions tested on OXAin vivoare mostly strain dependent. MICs were not reduced to wild-type levels, suggesting that the conditions tested do not lead to complete OXA inhibition in the bacterial cell.

scholarly journals Speciation Studies of L-Histidine Complexes of Pb(II), Cd(II), and Hg(II) in DMSO-Water Mixtures

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
K. Bharath Kumar Naik ◽  
B. Ananda Kumar ◽  
S. Raju ◽  
G. Nageswara Rao
Keyword(s):  
Dielectric Constant ◽  
Ionic Strength ◽  
Complex Formation ◽  
Species Distribution ◽  
Statistical Parameters ◽  
Experimental Conditions ◽  
Equilibrium Study ◽  
Predominant Species ◽  
Chemical Models ◽  
Best Fit

Equilibrium study on complex formation of L-histidine with Pb(II), Cd(II), and Hg(II) has been investigated pH metrically in DMSO-water mixtures (0–60% v/v) at 303 K and 0.16 mol L−1 ionic strength. The predominant species detected for Pb(II) and Cd(II) are ML2H4, ML2H3, ML2H2, ML2H, and ML2 and those for Hg(II) are ML2H4, ML2H3, ML2, and ML. The appropriateness of experimental conditions is verified by introducing errors intentionally in the concentrations of ingredients. The models containing different numbers of species were refined by using the computer program MINIQUAD75. The best-fit chemical models were arrived at based on statistical parameters. The trend in variation of stability constants of the complexes with dielectric constant of the medium is attributed to the electrostatic and nonelectrostatic forces. The species distribution and the plausible equilibria for the formation of the species are also presented.

Spectrophotometry of Human Hemoglobin in the near Infrared Region from 1000 to 2500 nm

1994 ◽  
Vol 2 (2) ◽  
pp. 59-65 ◽  
Author(s):  
J. Todd Kuenstner ◽  
Karl H. Norris
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Second Derivative ◽  
Human Hemoglobin ◽  
Absorption Bands ◽  
Near Infrared Region ◽  
Absorbance Spectra

Absorbance and first and second derivative absorbance spectra and quarter-millimolar absorptivity coefficients for hemoglobin species including oxy-, deoxy-, carboxy- and methemoglobin in the visible and in the near infrared regions from 620 nm to 2500 nm are presented. At wavelengths longer than 1500 nm, the absorbance and second derivative absorbance spectra of hemoglobin species are similar for all of the species. Absorption bands are present centred at 1690, 1740, 2056, 2170, 2290 and 2350 nm.

Rheology and structure of ovalbumin gels at low pH and low ionic strength

2002 ◽  
Vol 16 (3) ◽  
pp. 269-276 ◽  
Author(s):  
M Weijers ◽  
L.M.C Sagis ◽  
C Veerman ◽  
B Sperber ◽  
E van der Linden
Keyword(s):  
Ionic Strength ◽  
Low Ph ◽  
Low Ionic Strength

scholarly journals Synthesis of CoFe2O4 Nanoparticles: The Effect of Ionic Strength, Concentration, and Precursor Type on Morphology and Magnetic Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Izabela Malinowska ◽  
Zuzanna Ryżyńska ◽  
Eryka Mrotek ◽  
Tomasz Klimczuk ◽  
Anna Zielińska-Jurek
Keyword(s):  
Magnetic Properties ◽  
Ionic Strength ◽  
Saturation Magnetization ◽  
Calcination Temperature ◽  
Metal Concentration ◽  
Double Electric Layer ◽  
Cofe2o4 Nanoparticles ◽  
Constant Ph ◽  
Metal Sulphates ◽  
Repulsive Forces

The present study highlights the effect of metal precursor types (SO42¯, Cl¯, and NO3¯), their concentration, and the influence of ionic strength of reaction environment on the morphology, surface, and magnetic properties of CoFe2O4 particles. The magnetic nanoparticles were obtained by chemical coprecipitation in alkaline medium at increasing metal concentration in the range of 0.0425 mol·dm-3 to 0.17 mol·dm-3 and calcination temperature from 400°C to 800°C. It was found that the chemistry of precursors can be directly correlated with magnetic properties. The CoFe2O4 particles from metal sulphate precursors showed the highest saturation magnetization and the lowest coercivity. The adjustment of ionic strength in the range of 1.25–5 M was achieved by adding an appropriate quantity of metal sulphates into aqueous solutions at a constant pH or by adding an appropriate quantity of NaClO5 under similar conditions. The average hydrodynamic size of CoFe2O4 increased from 46 nm to 54 nm with increasing metal concentration and ionic strength. An explanation of magnetic properties, caused by ionic strength and metal concentration, is given based mainly on the reduction in repulsive forces at the particle interface and compensation of the double electric layer in the presence of anions. The observed coercivity was lower for the particles obtained in solutions with the highest ionic strength, whereas the concentration of metals and calcination temperature affected the saturation magnetization and morphology of the obtained cobalt ferrite particles.

Sign in / Sign up

Export Citation Format

Share Document