Exchange Of Sodium For Potassium Research Articles

Application of 3A Zeolite Prepared from Venezuelan Kaolin for Removal of Pb (II) from Wastewater and Its Determination by Flame Atomic Absorption Spectrometry

This work consists in the use of a 3A zeolite (K-LTA) obtained by a process of exchange of sodium for potassium (4A zeolite), synthesized from Venezuelan kaolin for the removal of Pb (II) ions from aqueous solutions by batch process mode in order to consider its application in treating industrial wastewaters. The 3A zeolite was characterized for X-ray powder diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and scanning electron microscopy and energy dispersive X-ray microanalysis (SEM-EDX). The metal concentration in the equilibrium Ce (mg·L-1) after adsorption with 3A zeolite was analyzed using flame atomic absorption spectrometry (FAAS). The influences of the solution pH, contact time, metal initial concentration and adsorbent dosage have been studied. The retention of metal occurring at pH values around 6.5 and the adsorption equilibrium was obtained at 60 min. The equilibrium process was well described by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The Langmuir parameters qm (mg·g-1) and b (L·mg-1) (which are related to the sorption capacity and constant of sorption energy) obtained were 14.64 and 5.42 respectively. The Pb (II) experimental uptake was about 14.56 mg·g-1, a little smaller than the theoretical one given by Langmuir isotherm model. The regression parameters and correlation coefficients (R) indicate that the adsorption data for Pb (II) removal fit better the Langmuir isotherm model. Moreover, 0 1/n 1 (1/n is 0.13), indicating that adsorption of metal ions on the zeolite, is a favorable physical process. The application of removing of the metal lead from real samples was examined by industrial wastewater samples. For all samples, the percentage of recovery was found with accuracy of more than 98%. The present work suggests 3A zeolite used as a sorbent material with relatively low cost, obtained from Venezuelan raw material; it is a candidate for removal lead ion and probably other cationic heavy metal species from wastewater.

Study on Sodium and Potassium Balance During Hemodialysis

To acquire data for adequate ultrafiltration (UF) control, sodium and potassium balance was investigated during hemodialysis (HD) in 16 hemodialyzed patients. Overall balances were evaluated from concentration measurements of the in- and outflowing dialysate and pre- and postdialysis plasma. The diffusive and convective part of the electrolyte removal and its intra- and extracellular space (ICS, ECS) component were calculated. During a 5-h HD, 40-110 mmol of potassium is removed, predominantly by diffusion (72-88%). Calculation shows that 40-70% of the removed amount is taken from the ICS. Sodium's overall HD showed much higher scatter, ranging from positive values to 500 mmol removal. The diffusive component was positive in most cases. By ultrafiltration sodium is removed in all cases. Calculations also showed in all cases that sodium was delivered to the ICS. This is in contradiction with the general belief that exchangeable sodium is distributed solely in ECS (1,2,6,7). This may be a sign of the effort to keep changes of ICS osmotic load at a minimum. Based on the finding of the exchange of sodium for potassium in the cellular wall, a method has been devised to calculate the UF fraction removed from EC (UFEC) expressed as a coefficient KEC = UFEC/UFToT, with UFToT being the total fluid volume removed during the HD session.

Coupled Chemical and Diffusion Model for Compacted Bentonite

AbstractA chemical equilibrium model has been developed for ion-exchange and to a limited extent for other reactions, such as precipitation or dissolution of calcite or gypsum, in compacted bentonite water systems. The model was successfully applied to some bentonite experiments, especially as far as monovalent ions were concerned. The fitted log-binding constants for the exchange of sodium for potassium, magnesium, and calcium were 0.27, 1.50, and 2.10, respectively. In addition, a coupled chemical and diffusion model has been developed to take account of diffusion in pore water, surface diffusion and ion-exchange. The model was applied to the same experiments as the chemical equilibrium model, and its validation was found pardy successful. The above values for binding constants were used also in the coupled model. The apparent (both for anions and cations) and surface diffusion (only for cations) constants yielding the best agreement between calculated and experimental data were 3.0×10-11 m2/s and 6.0×10-12m2/s, respectively. These values are questionable, however, as experimental results good enough for fitting are currently not available.

Simultaneous Characterization of Surface and Buried Waveguides Produced by Ion-exchange in Glass

Abstract A simultaneous modelling of surface and buried waveguides is presented. It is based on an approximate solution of the nonlinear diffusion equation solved under different boundary and initial conditions. Experimental results of buried waveguides produced by potassium-sodium exchange in soda-lime glass are presented.

Aldosterone does not stimulate the Na:K pump in isolated turtle colon.

The study of the mechanisms by which mineralocorticoids stimulate sodium absorption across distal epithelia has focused on three possible sites of action: apical sodium permeability, the basolateral Na:K pump, and the production of high-energy substrates. Recently we developed a method for direct measurement of the current generated by the basolateral Na:K pump of the turtle colon [15]. In the presence of mucosal amphotericin-B and serosal barium the short-circuit current across the colon can be equated with the current produced by active electrogenic exchange of sodium for potassium across the basolateral membrane. This pump current is a measure of the transport capacity of the epithelial Na:K pump that is uncomplicated by changes in apical membrane sodium permeability. Pump currents, thus defined, were compared in control tissues and tissues treated with aldosterone in vitro. After 9 h Na absorption was increased 4-fold in the aldosterone-treated tissues but the values of the pump current were identical in the two groups. This result indicates that acute stimulation of sodium absorption by aldosterone does not occur by stimulating the Na:K pump directly.

Plasma Membrane ATPase of Fungi and Plants as a Novel Type of Proton Pump

Publisher Summary This chapter presents the evidence obtained at different levels of biological organization that characterizes the plasma membrane ATPase of fungi and plants as a novel type of proton pump. It presents a parallel discussion of studies with fungal and plant cells to stress the similarities of their bioenergetic mechanisms that plant physiologists and microbial biochemists may have failed to appreciate. The membranes of bacteria, mitochondria, and chloroplasts contain a similar ATPase involved in proton transport. These enzymes are sensitive to azide and dicyclohexylcarbodiimide and, in the case of mitochondria and photosynthetic bacteria, to oligomycin. They do not form phosphorylated intermediates and they have alkaline pH optima and very complicated structures. These enzymes have a hydrophilic catalytic part with five different subunits protruding from the membrane and a hydrophobic part embedded in the membrane with three different subunits that form a proton channel blocked by dicyclohexyl-carbodiimide. A different type of ATPase is found in the microsomes and plasma membranes of animal cells. These enzymes catalyze the exchange of sodium for potassium and of protons for potassium and calcium transport. The ATPase activities are dependent on the presence of the transported cations and the pH optima are neutral.

Interrelationships between the renal kallikrein-kinin and prostaglandin systems in furosemide-induced diuresis.

The relationships between the renal kallikrein-kinin (K-K) and prostaglandin (PG) systems under conditions of furosemide-induced diuresis were studied in normal rats. Urinary PGE and PGF2 alpha were measured by radioimmunoassay, and urinary kallikrein by enzymatic activity. The diuretic and natriuretic effects of furosemide were accompanied by a concomitant increase in the urinary excretion of kallikrein and PGE. The urinary excretion of kallikrein and PGE was closely related to the urinary excretion of sodium, potassium and chloride. The urinary excretion of kallikrein also showed a highly significant correlation with the urinary excretion of PGE. Pretreatment of the animal with indomethacin or aprotinin inhibited furosemide-induced diuresis and natriuresis. Aprotinin inhibited the urinary excretion of PGE, while indomethacin did not exert any inhibitory action on the urinary excretion of kallikrein. Although the urinary excretion of kallikrein was closely related to the urinary excretion of potassium, both indomethacin and aprotinin had no effect on the urinary excretion of potassium. The results indicate that the potassium-sodium exchange caused by furosemide in the distal nephron might stimulate the renal K-K system to result in increasing synthesis of PGE, which would, at least in part, participate in the diuretic and natriuretic effects of furosemide.

EXCHANGE EQUILIBRIA OF POTASSIUM VERSUS CALCIUM AND SODIUM IN SOILS FROM A SEMIARID REGION, INDIA

We studied the potassium-calcium and potassium-sodium exchange equilibria on three soil samples differing in their organic carbon content (OC) and cation exchange capacity (CEC). Homoionic (Ca or Na saturated) soils were equilibrated, with the solutions having a large range of potassium adsorption ratios (PARs) at 50 meq L-1 total electrolyte concentration. We analyzed the data on exchange equilibria, using a thermodynamic approach and various selectivity coefficients. The normalized exchange isotherms for K+-Ca2+ systems suggested higher specificity for K+ to Ca2+ in the first 50 to 75 percent of K+ saturation. In the K+-Na+ system the specificity for K+ to Na+ was, however, higher for the whole range of exchange isotherms. The soil high in OC (Soil 1) had higher preference for K+ than the soils low in OC (Soils 2 and 3). The values of standard free energy change of the exchange reactions (ΔGr°) for K+-Ca2+ and K+-Na+ systems were negative for all the three soils tested. These values were, however, more negative for K+-Na+ than for K+-Ca2+ systems, suggesting higher preference for K+ in the former. A comparison of ΔGr° values suggested that the effect of CEC on the K+ specificity of these soil samples was only marginal, though that of OC was quite spectacular. The values of the Gapon selectivity coefficient (KG) decreased first sharply and then gradually with the increase in exchangeable potassium percentage (EPP). On the basis of (KG), the exchange isotherms were divided into three zones, representing exchange sites with high, medium, and low specificities for K+. The arbitrary limits for the three zones were < 5, 5 to 38, and >38; > 4, 4 to 15, and >15; and > 5, 5 to 15, and > 15 for Soils 1, 2, and 3, respectively. The exchange selectivity coefficient (KN) and AGr° for K+-Na+ systems were different only marginally for Soils 1 and 2. However, for K+-Ca2+ systems, the values of different selectivity coefficients (viz., KG, Vanselow selectivity coefficient, and Krishnamoorthy-Davis-Overstreet selectivity coefficient) and AGr° for Soils 1 were considerably different from those for Soil 2. This suggested a differential role of OC on changing the selectivity of soil for K+ in K+-Ca2+ and K+-Na+ systems.

Experimental test of the time-dependent Ising model

The one dimensional Ising model and its variations have been successfully used to describe the statistical properties of polymers, such as polypeptides, DNA, etc. Recently one of us solved the hydrodynamic solution of Glauber’s time-dependent Ising model. This solution is suitable for describing kinetic processes of Ising systems. The recent data on the potassium–sodium exchange in human lymphocytes provide an ideal case for testing the theory. It was previously found that the intracellular K+ and Na+ concentrations vs extracellular K+ concentration follow the Ising isotherm. In this paper we show that the kinetic data of potassium uptake in potassium-depleted, sodium-loaded cells agree with the theoretical result.

Rate of potassium-sodium exchange by human lymphocytes: prediction of the cooperative adsorption model.

The equilibrium parameters of potassium-sodium distribution in human lymphocytes, determined experimentally in the preceding study (Negendank and Shaller, '79), were incorporated into a stochastic treatment of the cooperative adsorption model in order to predict the kinetics of "active" potassium-sodium exchange. The rate of uptake of potassium, in potassium-depleted, sodium-loaded cells, is complex and deviates markedly from simple exponential functions. The sigmoid form of the exchange data closely followed the predicted curve. This result enhances one's confidence in the usefulness and applicability of the cooperative adsorption model, and adds further support to the association-induction hypothesis as a coherent theory of cell physiology.

Site group interaction effects in zeolite Y. Part 3.—K–Na equilibrium

A selectivity study has been made on the potassium–sodium equilibrium in zeolite Y in the supercages, using cesium as a reference cation, and in the small cages, by blocking the supercages with either cesium or cobalt ions. The overall free energy effect for the potassium–sodium exchange in the whole crystal differs from the value predicted on the basis of data for supercages and small cages. Site heterogeneity has been demonstrated in the small cages on the basis of selectivity reversals which are dependent on the nature of the ions in the supercages. The observed effects are analysed in terms of interactions between supercage and small cage.

Sequential changes in body composition during infection: electron probe study IV

Alterations occur in human muscle electrolyte and water composition in response to infection. There appear to be at least two basic mechanisms; the first is an exchange of sodium for potassium without alteration in water content of muscle. The second is an increase in cellular Na and water without a loss of K on a dry weight basis. In a series of studies in monkeys, Salmonella typhimurium sepsis was induced as an experimental model. Both patterns of muscle response to infection were detected. Electron probe microanalysis revealed that the loss of K concentration was due to an accumulation of intracellular saline which dilute the K content. The mechanism of this is unclear; however, a concomitant increase in undertermined osmoles in the serum suggests that there may be an increase in organic osmoles within the cell which leads to the dilution of intracellular K concentration.

Effect of adrenergic blocking agents on running ability in the rat.

High doses of subcutaneously administered adrenergic blocking agents, Hydergine, Dibenamine, Dibenzylene, Benodaine and Regitine, in that order, gradually decreased the running ability of rats. Weakness in the muscles of the extremities, varying from mild to complete flaccid paralysis was observed. There was a clear parallel between decrease of cation exchange, increase of blood lactic acid and loss of work performance. After intravenously administered Regitine, Benodaine and Dibenzylene the paralytic symptoms were more pronounced, with flaccid paralysis frequently observed. The blood lactic acid and glucose levels were high and the plasma Na and hematocrit decreased as did plasma K. These findings support the view that potassium-sodium exchange is a primary source of energy for muscle contraction. Glycolysis as a secondary anaerobic source of energy was not able by itself to provide the metabolic energy required for contraction, presumably because of the immediate and large increase of blood lactic acid.