Long-Term Releasing Kinetics of Chromium from Leather

2021 ◽  
Vol 116 (12) ◽  
Author(s):  
Wenjun Long ◽  
Liangqiong Peng ◽  
Xiaofeng Jiang ◽  
Faming He ◽  
Wenhua Zhang
Keyword(s):  
Compartment Model ◽  
Total Chromium ◽  
Solid Film ◽  
Elovich Equation ◽  
Pseudo Second Order ◽  
Potential Risks ◽  
Three Compartment Model ◽  
Releasing Process ◽  
Kinetics Of

The release of chromium from leather inevitably results in potential risks and this study is conducted to investigate the long-term releasing behavior. The leaching tests proceed using water at solid to liquid ratio of 1:20 and rotational speed 60 r/min for 240 hours to simulate the release of chrome leather under natural conditions. The experimental data successfully fit with the Pseudo-second-order equation, Elovich equation, and Weber-Morris model, indicating the long-term leaching behavior of chromium in heterogeneous leather is controlled by liquid-solid film, while the interparticle and intraparticle diffusion also play important roles. The leachable chromium accounts for 2.8-4.5% total chromium in leather and increases with temperature. The Three-compartment model depicts the releasing process as rapid, slow, and very slow stages, and temperature mainly affected the very slow stage. The amount of released chromium in rapid and slow stages slightly increases with temperature, which could be used to assess the hazard of chrome leather.

Disposition Kinetics of Disopyramide in Human Healthy Volunteers Described by an Open Three Compartment Model

1989 ◽  
Vol 64 (5) ◽  
pp. 412-416 ◽  
Author(s):  
Jan Bonde ◽  
Niels Melchior Jensen ◽  
Lars E. Pedersen ◽  
Helle R. Angelo ◽  
Seren N. Rasmussen ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Compartment Model ◽  
Disposition Kinetics ◽  
Three Compartment Model ◽  
Kinetics Of

scholarly journals Kinetics of scandium recovery by TVEX-TBP from the solution formed after the salt chlorinator cake leaching

2020 ◽  
Vol 168 ◽  
pp. 00050
Author(s):  
Vadym Korovin ◽  
Yurii Pohorielov ◽  
Yurii Shestak ◽  
Oleksandr Valiaiev ◽  
Jose Luis Cortina
Keyword(s):  
Chemical Interaction ◽  
Extraction Process ◽  
Second Order ◽  
Order Kinetic ◽  
Order Model ◽  
Elovich Equation ◽  
Diffusion Phase ◽  
Leaching Solution ◽  
Pseudo Second Order ◽  
Kinetics Of

Kinetics of scandium recovery by TVEX containing tributyl phosphate was studied from the clarified leaching solution of salt chlorinator cake. To assess the contribution of each diffusion phase, experimental data were analyzed using a graphic method. To define the contribution of chemical interaction into the scandium extraction process, recovery kinetics was quantitatively described using pseudo-first order, pseudo-second order kinetic models and Elovich equation in linearized form. It was established that recovery kinetics was most accurately described with the pseudo-second-order model.

scholarly journals KINETICS OF SCANDIUM SORPTION BY IMPREGNATE CONTAINING PHOSPHINOXIDE

2017 ◽  
Vol 60 (8) ◽  
pp. 28 ◽  
Author(s):  
Pyae Phyo Aung ◽  
Olga A. Veselova ◽  
Irina D. Troshkina
Keyword(s):  
Phosphine Oxide ◽  
Arrhenius Equation ◽  
Correlation Coefficients ◽  
Second Order ◽  
Hypercrosslinked Polystyrene ◽  
Order Model ◽  
Elovich Equation ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Solution Volume

The kinetics of scandium sorption with impregnate-containing extractant – phosphine oxide based on hypercrosslinked polystyrene from nitric acid solutions was studied using a method of limited solution volume. A sample of sorbent obtained by impregnation contained 0.233 g extractant/g impregnate. Under batch conditions, the influence of temperature in the range 293-313 K on the kinetics of scandium sorption by impregnate was studied. It was revealed that the saturation of impregnate by scandium is established in 20-30 min. For the processing of integral kinetic scandium sorption curves, the pseudo-first and pseudo-second-order models, as well as the Elovich equation, were used. The values of the rate constants calculated from the pseudo-second-order model, describing the kinetic data with the best correlation coefficients (R2 0.931-0.995), reach (9.51-10.4) g∙(mmol∙min)-1. The activation energy of scandium sorption, calculated by an equation similar to the Arrhenius equation, is (2.8±0.2) kJ / mol. Due to the improved kinetic characteristics compared with traditional sorbents, hypercrosslinked polystyrene impregnates containing phosphine oxide can be used to extract of scandium from solutions formed during the processing of scandium-containing raw materials.Forcitation:Pyae Phyo Aung, Veselova O.A., Troshkina I.D. Kinetics of scandium sorption by impregnate containing phosphinoxide. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 28-30.

Some effects of aldosterone on sodium kinetics and distribution in porcine arterial wall

1983 ◽  
Vol 244 (4) ◽  
pp. R553-R557
Author(s):  
J. G. Llaurado ◽  
J. A. Madden ◽  
G. A. Smith
Keyword(s):  
Rate Constants ◽  
Compartment Model ◽  
Transport Rate ◽  
Tissue Water ◽  
Intracellular Space ◽  
Three Compartment Model ◽  
Carotid Wall ◽  
Kinetics Of ◽  
Total Tissue

Transport rate constants for Na+ exchanges and relative Na+ compartment distribution in isolated pig carotid wall were determined with the aid of 22Na+ as tracer that was continuously washed out. A three-compartment model consisting of 1) extracellular, 2) intracellular, and 3) subcellular spaces was found to represent adequately the kinetics of 22Na+. It was found that d-aldosterone (0.85 X 10(-6) M) added to the incubating medium for 3 h causes significant changes in two transport rate constants and in the distribution of sodium within different compartments. Total tissue water, nonradioactive sodium (tracee), and potassium are not altered by aldosterone; however, when amounts of Na+ tracee are calculated for each compartment, aldosterone significantly reduces the amount of Na+ in compartment 2. Overall, the results indicate that aldosterone induces a translocation of Na+ into the extracellular space at the expense of the intracellular space. The findings are interpreted in the light of recent reports on the role of altered function of the Na+-K+ pump under aldosterone influence or arterial hypertension.

scholarly journals Vitamin E kinetics in sheep

1987 ◽  
Vol 58 (1) ◽  
pp. 113-125 ◽  
Author(s):  
M. Hidiroglou ◽  
K. Karpinski
Keyword(s):  
Vitamin E ◽  
Jugular Vein ◽  
Compartment Model ◽  
The Other ◽  
Intravenous Route ◽  
Biological Availability ◽  
Blood Samples ◽  
Two Compartment Model ◽  
Three Compartment Model ◽  
Kinetics Of

1. Kinetics of physiological doses of D-α-[5-Me-3H]tocopherol(200 μCi) administered to twenty-four sheep were studied using one of four routes: intravenous, oral (capsules), intraruminal and intramuscular.2. Blood samples were withdrawn from the jugular vein periodically for 96 h after the intravenous and oral administrations, for 168 h after the intraruminal administration and for 216 h after the intramuscular administration.3. The study indicated that the biological availability of α-tocopherol followed the order intravenous > intramuscular > oral > intraruminal.4. The rate of elimination was in the order intravenous > oral > intraruminal ˜ intramuscular.5. The intravenous route was fitted with a three-compartment model, whereas the other routes exhibited a good fit for either a one- or two-compartment model.

Sodium Distribution in Mesenteric Arterial Wall of Rats with Hypertension Induced by Drinking Saline

1979 ◽  
Vol 56 (5) ◽  
pp. 471-478 ◽  
Author(s):  
Jane A. Madden ◽  
G. A. Smith ◽  
J. G. Llaurado
Keyword(s):  
Rate Constant ◽  
Arterial Wall ◽  
Compartment Model ◽  
Smooth Muscle Contraction ◽  
Transport Rate ◽  
Cellular Compartment ◽  
Blood Pressure Elevation ◽  
Chemical Measurements ◽  
Three Compartment Model ◽  
Kinetics Of

1. Hypertension was induced in rats by substituting 2% (w/v) sodium chloride solution for drinking water. Sodium distribution in isolated mesenteric arterial wall was studied with the aid of 22Na, which was continuously washed out. Data were analysed by digital computer simulation without recourse to ancillary chemical measurements of extracellular space. 2. A three-compartment model consisting of (i) extracellular, (ii) intracellular and (iii) subcellular space was found to represent adequately the kinetics of 22Na. Transport rate constants were chosen as primary parameters describing intercompartmental sodium exchanges; the ratio of extra- to intra-cellular sodium compartments was calculated. 3. Results show the following significant changes in mesenteric arterial wall of salt-loaded hypertensive rats: (i) slowed sodium turnover; (ii) a decrease of the transport rate constant, which is presumed to reflect sodium movements from the intra- to the extra-cellular compartment; (iii) an increase of the transport rate constant, presumed to reflect sodium movements from the extra- to the intra-cellular compartment; (iv) a diminution of the extra- to intra-cellular compartment ratio for sodium. 4. The results suggest net movement of sodium into the cells; this change may be relevant to smooth muscle contraction and hence to the pathogenesis of blood pressure elevation in this model.

scholarly journals Application of Kinetic Models to the Sorption of Copper(II) on to Peat

2002 ◽  
Vol 20 (8) ◽  
pp. 797-815 ◽  
Author(s):  
Y.S. Ho ◽  
G. McKay
Keyword(s):  
Sorption Capacity ◽  
Fractional Power ◽  
Sorption Process ◽  
Order Equation ◽  
Second Order ◽  
Process Models ◽  
Elovich Equation ◽  
Pseudo Second Order ◽  
High Degree ◽  
Kinetics Of

A comparison of the kinetics of the sorption of copper(II) on to peat from aqueous solution at various initial copper(II) concentrations and peat doses was made. The Elovich model and the pseudo-second order model both provided a high degree of correlation with the experimental data for most of the sorption process. There was a small discrepancy at the initial stages of sorption which suggested that film diffusion or wetting of the peat may be involved in the early part of the sorption process. Models evaluated included the fractional power equation, the Elovich equation, the pseudo-first order equation and the pseudo-second order equation. The kinetics of sorption were followed based on the sorption capacity of copper(II) on peat at various time intervals. Results show that chemical sorption processes may be rate-limiting in the sorption of copper(II) on to peat during agitated batch contact time experiments. The rate constant, the equilibrium sorption capacity and the initial sorption rate were calculated. From these parameters, an empirical model for predicting the concentrations of metal ions sorbed was derived.

Increased endothelin-1 production in patients with chronic heart failure

2004 ◽  
Vol 286 (3) ◽  
pp. H1141-H1145 ◽  
Author(s):  
John D. Parker ◽  
Jake J. Thiessen
Keyword(s):  
Heart Failure ◽  
Compartment Model ◽  
Normal Subjects ◽  
Volume Of Distribution ◽  
Endothelin 1 ◽  
Normal Individuals ◽  
Three Compartment Model ◽  
Total Body ◽  
Body Production ◽  
Kinetics Of

Endothelin-1 (ET-1) concentrations are elevated in patients with congestive heart failure (CHF), although the cause of this increase remains uncertain. We hypothesized that abnormalities in ET-1 production, clearance, or a combination of these may be the cause of elevated ET-1 concentrations in chronic CHF. The kinetics of clearance of ET-1 were measured with 125I-labeled ET-1 in eight patients with CHF and five age-matched normal individuals. In both normal subjects and the CHF group, the kinetics of ET-1 clearance were best described by a three-compartment model. The steady-state volume of distribution of ET-1 was significantly greater in the CHF group compared with normal subjects (25.2 ± 3.9 vs. 13.8 ± 2.1 l/kg; P < 0.05). The total clearance rate from plasma was greater in the CHF group (0.119 ± 0.018 vs. 0.047 ± 0.013 l·kg–1·min–1; P = 0.05). The total body production rate of ET-1 was also significantly higher in patients with CHF (0.21 ± 0.03. vs. 0.06 ± 0.02 ng·kg–1·min–1; P < 0.05). It appears that increased ET-1 production rather than decreased clearance is the cause of elevated ET-1 concentrations in patients with chronic CHF.

Kinetics of Bicarbonate in Humans: Identification and Validation of a Three-Compartment Model

1991 ◽  
Vol 24 (3) ◽  
pp. 799-804
Author(s):  
M.P. Saccomani ◽  
E. Caveggion ◽  
C. Cobelli ◽  
R. Bonadonna ◽  
R. Bonadonna
Keyword(s):  
Compartment Model ◽  
Three Compartment Model ◽  
Kinetics Of

scholarly journals Isotopic and modeling investigation of long-term protein turnover in rat tissues

2013 ◽  
Vol 304 (3) ◽  
pp. R218-R231 ◽  
Author(s):  
Nathalie Poupin ◽  
Jean-François Huneau ◽  
François Mariotti ◽  
Daniel Tomé ◽  
Cécile Bos ◽  
...  
Keyword(s):  
Compartment Model ◽  
Rat Tissues ◽  
Product Model ◽  
New Approach ◽  
Two Compartment Model ◽  
Fractional Synthesis ◽  
Tracer Methods ◽  
Kidney Liver ◽  
Kinetics Of

Fractional synthesis rates (FSR) of tissue proteins (P) are usually measured using labeled amino acid (AA) tracer methods over short periods of time under acute, particular conditions. By combining the long-term and non-steady-state 15N labeling of AA and P tissue fractions with compartmental modeling, we have developed a new isotopic approach to investigate the degree of compartmentation of P turnover in tissues and to estimate long-term FSR values under sustained and averaged nutritional and physiological conditions. We measured the rise-to-plateau kinetics of nitrogen isotopic enrichments (δ15N) in the AA and P fractions of various tissues in rats for 2 mo following a slight increase in diet δ15N. Using these δ15N kinetics and a numerical method based on a two-compartment model, we determined reliable FSR estimates for tissues in which P turnover is adequately represented by such a simple precursor-product model. This was the case for kidney, liver, plasma, and muscle, where FSR estimates were 103, 101, 58, and 11%/day, respectively. Conversely, we identified tissues, namely, skin and small intestine, where P turnover proved to be too complex to be represented by a simple two-compartment model, evidencing the higher level of subcompartmentation of the P and/or AA metabolism in these tissues. The present results support the value of this new approach in gaining cognitive and practical insights into tissue P turnover and propose new and integrated FSR values over all individual precursor AA and all diurnal variations in P kinetics.

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