Hydrogen Ion Exchange Research Articles

Deposition-plant-soil interactions

Rainwater reaching the ground as throughfall beneath vegetation usually shows an increase in pH, except in areas where sulphur dioxide deposition can be presumed to be high. Stemflow, however, is almost always reduced in pH. The changed acidity in throughfall results from hydrogen-ion exchange for base cations at leaf surfaces, with evidence that potassium, calcium and magnesium are all involved. Amounts of base cations gained are much greater than the losses of hydrogen ions from bulk precipitation. Either other processes are involved, or the extra base cations exchange for acidity resulting from dry deposition of sulphur dioxide. Further interpretation is confounded by the lack of general agreement as to the relative contributions of dry deposition and of crown leaching to the sulphate gained by throughfall. Usually plants are able to replace leached cations, even when treated with very low pH rain. However, there are suggestions from Germany that exceptional rates of leaching of magnesium from tree foliage may be leading to growth decline and death. For such extreme losses to occur cell membranes must first be dam aged, with gaseous pollutants, such as ozone and sulphur dioxide, and frost both being implicated. Because the base cations gained at leaf surfaces had previously been exchanged for hydrogen ions at the root-soil interface, exchange in the crowns is merely an extension of the soil exchange process and can be regarded as an acid stress upon the soil.

ChemInform Abstract: TETRAAMMINEPLATINUM(II)‐HYDROGEN ION EXCHANGE ON α‐ZIRCONIUM PHOSPHATE AND THE CHARACTERIZATION OF ITS COMPLEX CATION FORM

AbstractBez. der Ionenaustauscher und Katalysator‐Eigenschaften von Zr(H PO4)3‐ H3O ("a‐ZP") wurde der Titel‐ Prozeß durch Messung von pH‐Änderungen sowie XRD, IR, chemische und thermische Analysen (DSC, EGA, TG) des beladenen ZP untersucht.

Determination of Alkalinity Losses Resulting From Hydrogen Ion Exchange in Alkaline Flooding

Abstract Maintaining an effective level of alkalinity during an alkaline flood is of prime importance in design of this EOR process. Alkaline solution can be consumed in the reservoir through interaction with both reservoir rocks and fluids. The rock/alkali interaction can be characterized as either chemical or ion-exchange reaction, and the magnitude of alkalinity consumption and its type must be considered when alkaline floods are designed for specific reservoirs. This is because alkalinity propagation in porous media is directly affected by the type of alkalinity loss. It has been shown previously that kinetically controlled mineral dissolution reactions may cause the produced alkalinity to plateau at a lower concentration than the injected concentration, whereas ion-exchange processes may cause characteristic delay in the produced alkalinity, which in turn delays tertiary oil production.1,2 The type and the magnitude of alkalinity loss therefore must be known to design a flood with alkaline concentration maintained at its optimum for the longest possible time. This paper concerns determining alkalinity loss resulting from hydrogen ion exchange. The model describing the release of initially rock-bound hydrogen ions into solution in the presence of alkali has been previously proposed and investigated for California Wilmington and Huntington sands.1,3 According to this approach the mechanism for reversible alkalinity uptake is described by the following equation.

Tetraammineplatinum(II)–Hydrogen Ion Exchange on α-Zirconium Phosphate and the Characterization of Its Complex Cation Form

Abstract The tetraammineplatinum(II)–hydrogen-ion exchange on α-zirconium phosphate has been investigated. The ion-exchange process was examined by measuring the change in the pH values of the supernatants. α-Zirconium phosphate loaded with tetraammineplatinum(II) was characterized by means of chemical analysis, X-ray diffractometry, infrared spectroscopy, and thermal analysis. The ion-exchange reaction proceeded more easily than the hexaaminecobalt(III)–hydrogen-ion exchange, and about 50% of the hydrogen ions in α-zirconium phosphate were replaced by tetraammineplatinum(II). The interlayer distance of the exchanger expanded from 7.60 to 10.7 Å.

The A‐C Response of Iridium Oxide Films

The dependence of the a‐c response of iridium oxide films upon thickness, potential, and pH was explored in sulfuric and perchloric acid solutions. For concentrations greater than 0.1M, the response function closely resembled that for an injection process diffusively spreading from one interface throughout the film. The response time shifted by a factor of 105 with the potential drop across the film. A porous film model is suggested in which response is determined by the mobility of reduced lattice sites, the diffusion coefficient being controlled by a hydrogen ion exchange current within the pores.

Mechanism of ion exchange in zirconium phosphates. 28. Calorimetric determination of heats of rubidium(1+)-hydrogen ion exchange on .alpha.-zirconium phosphate

Mechanism of ion exchange in zirconium phosphates. 28. Calorimetric determination of heats of rubidium(1+)-hydrogen ion exchange on .alpha.-zirconium phosphate

Sorption of uranyl by humic acids

Sorption of (UO 2) 2+ from a UO 2Cl 2 solution was carried out on a substrate of humic acids complexes extracted from the peat bog of Mirochov (Bohemia). The ash-free substrate of the acids contained 53.44% C, 5.37% H, 39.68% O and 1.51% N. The ash content was 0.4%. The total acidity was 7.61 mequiv./g, the content of carboxyl 4.20 mequiv./g and that of phenolic hydroxyls 3.35 mequiv./g. The sorption capacity of (UO 2) 2+ by humic acids at 20.00 ± 0.03°C depends on the acidity of the environment, and decreases with decreasing pH value. The accumulation of U on humic acids takes place mostly by an exchange of hydrogen ions for uranyl cations. The sorption rate is independent of the acidity of the environment. Within the concentration range from 10 −5 to 2·10 −3 mol (UO 2) 2+/l, the uranyl sorption obeys Langmuir's equation.

ChemInform Abstract: STUDIES ON THE AMMONIUM FORM OF CRYSTALLINE ZIRCONIUM PHOSPHATE. III. AMMONIUM‐HYDROGEN ION‐EXCHANGE ON α‐ZIRCONIUM PHOSPHATE PREPARED BY THE DIRECT PRECIPITATION METHOD

AbstractDie Hinreaktion (Zr‐phosphat ‐ NH4‐For1n) des Ionenaustausches läuft einstufig bei einem Gleichgewichts‐pH von 5.9‐6.0 ab und der α‐Zr‐phosphat‐Austauscher wird direkt in die NH4‐Form umgewandelt.

Studies on the Ammonium Form of Crystalline Zirconium Phosphate. III. Ammonium–Hydrogen Ion-exchange on α-Zirconium Phosphate Prepared by the Direct Precipitation Method

Abstract The ammonium–hydrogen ion-exchange on α-zirconium phosphate prepared by the direct precipitation method has been investigated by means of pH titration and X-ray diffractometry. In the forward process (α-zirconium phosphate to the ammonium form) the ion-exchange reaction took place in one stage at the equilibrium pH of 5.9–6.0 and the α-zirconium phosphate exchanger was directly converted into the ammonium form. In the reverse process (the ammonium form to α-zirconium phosphate) the reaction proceeded in three stages, that is, the ammonium form→ a half-exchanged form→ an intermediate form→α-zirconium phosphate. The chemical composition of the half-exchanged form has been represented as Zr(NH4PO4)(HPO4)·nH2O (n>0.5). A small amount of ammonium ions in the exchanger could not be easily replaced with protons in the solution.

Bicarbonate and fluid absorption by renal proximal straight tubules

Rabbit proximal straight tubules from superficial nephrons were perfused in vitro in order to elucidate the mechanism of fluid and bicarbonate absorption. Both processes were greatly inhibited when sodium was replaced in the perfusate and bath by other cations, when ouabain was added to the bath, or when potassium was removed from the bath. We infer that these experimental manipulations inhibit active sodium tranport, and that active sodium transport is a primary process leading to fluid and bicarbonate absorption. Fluid absorption also decreased (but only by 22 to 36%) when bicarbonate was replaced by chloride in the perfusate and bath or when acetazolamide (10(-3)M) was added, suggesting that fluid and sodium transport depend in part on bicarbonate. We infer that the links between fluid, sodiu, and bicarbonate transport are complex and involve at least two mechanisms: 1) a sodium for hydrogen ion exchange mechanism located in the brush border membrane and 2) the transepithelial concentration difference for bicarbonate, which results from its absorption and which acts as an additional driving force for fluid and sodium absorption. Finally, bicarbonate absorption was unaltered when chloride was replaced by nitrate in the perfusate and bath, suggesting that chloride is not necessary for acidification in this nephron segment.

A proton magnetic relaxation study on kinetic isotope effects and hydrogen lifetimes in acid groups of acetic acid and poly (methacrylic acid) in aqueous solutions enriched with 17O

Rates of hydrogen ion exchange between water and L 3O + species, and between water and carboxylic groups of acetic acid or poly(methacrylic acid) in aqueous solutions at several pL-values are reported; where L is used to denote hydrogen and deuterium atoms. It is found that only the second exchange process shows a substantial kinetic isotope effect. This exchange process is interpreted in terms of hydrogen transfer within a hydrogen-bonded complex consisting of one acid group and two watermolecules.

Developments in Malo-Lactic Fermentation of Australian Red Table Wines

Control of malo-lactic fermentation in red table wines is one of the most important technical problems in Australian winemaking. These wines are usually higher in pH (3.4-4.3; mean 3.85) than wines of the same type from other countries (reasons are postulated), and malo-lactic fermentation raises pH still further (0.05-0.35 increase), frequently resulting in lower quality, and in serious cases, bacterial spoilage. The most important and frequently the only contribution of malo-lactic fermentation is bacteriological stability of the wine, providing that the fermentation goes to completion. Quality may or may not be impaired, depending on the wine and the climatic area in which the grapes are grown (malolactic fermentation is considered to be desirable in very cool areas), but the fruit and varietal character is frequently lost. The malic acid content of wines which have not undergone malo-lactic fermentation ranges from about 1-1.5 (the minimum level has not been established precisely) to 4 grams per liter. Residual malic acid after malo-lactic fermentation is usually less than 0.1 gram per liter, though some wines contain between 0.1 and 1.0 gram per liter. This indicates that either malo-lactic fermentation has commenced and not gone to completion (as has recently been shown to occur) or that wines with and without malic acid have been blended. Since malo-lactic fermentation can recommence, these wines are still bacteriologically unstable and have to be handled accordingly. Precise enzymatic analysis of malic acid to detect these low levels is now being used in winery laboratories to supplement semi-quantitative paper chromatography. Acidification is practiced, either by acid addition or hydrogen-ion exchange, to adjust pH to within the range 3.5-3.8. If malo-lactic fermentation occurs, the resultant increase in pH is usually corrected. Induction of malo-lactic fermentation by bacterial inoculation with <i>Leuconostoc oenos</i> has only been partly successful and is little used at present. Since malo-lactic fermentation occurs readily in warm areas in wines with high pH values, prevention is difficult. Nevertheless, routine prevention is now being achieved by pH reduction (preferably before the yeast alcoholic fermentation), early clarification and sterile filtration, sulfur dioxide addition, cool storage, and sterile filtration into the bottle. Fumaric acid addition shows promise as a bacterial growth inhibitor, though more winery data are needed. Most winemakers would prefer malo-lactic fermentation not to take place if they can prevent it.

Developments in Malo-Lactic Fermentation of Australian Red Table Wines

Control of malo-lactic fermentation in red table wines is one of the most important technical problems in Australian winemaking. These wines are usually higher in pH (3.4-4.3; mean 3.85) than wines of the same type from other countries (reasons are postulated), and malo-lactic fermentation raises pH still further (0.05-0.35 increase), frequently resulting in lower quality, and in serious cases, bacterial spoilage. The most important and frequently the only contribution of malo-lactic fermentation is bacteriological stability of the wine, providing that the fermentation goes to completion. Quality may or may not be impaired, depending on the wine and the climatic area in which the grapes are grown (malolactic fermentation is considered to be desirable in very cool areas), but the fruit and varietal character is frequently lost. The malic acid content of wines which have not undergone malo-lactic fermentation ranges from about 1-1.5 (the minimum level has not been established precisely) to 4 grams per liter. Residual malic acid after malo-lactic fermentation is usually less than 0.1 gram per liter, though some wines contain between 0.1 and 1.0 gram per liter. This indicates that either malo-lactic fermentation has commenced and not gone to completion (as has recently been shown to occur) or that wines with and without malic acid have been blended. Since malo-lactic fermentation can recommence, these wines are still bacteriologically unstable and have to be handled accordingly. Precise enzymatic analysis of malic acid to detect these low levels is now being used in winery laboratories to supplement semi-quantitative paper chromatography. Acidification is practiced, either by acid addition or hydrogen-ion exchange, to adjust pH to within the range 3.5-3.8. If malo-lactic fermentation occurs, the resultant increase in pH is usually corrected. Induction of malo-lactic fermentation by bacterial inoculation with <i>Leuconostoc oenos</i> has only been partly successful and is little used at present. Since malo-lactic fermentation occurs readily in warm areas in wines with high pH values, prevention is difficult. Nevertheless, routine prevention is now being achieved by pH reduction (preferably before the yeast alcoholic fermentation), early clarification and sterile filtration, sulfur dioxide addition, cool storage, and sterile filtration into the bottle. Fumaric acid addition shows promise as a bacterial growth inhibitor, though more winery data are needed. Most winemakers would prefer malo-lactic fermentation not to take place if they can prevent it.

Hydrogen ion exchange on amorphous silica in seawater

The amount of hydrogen ion exchange on the surface of amorphous silica in seawater was measured as a function of pH at 2 and 25°C. Hydrogen ion exchange with the cations present in seawater is pH dependent and at 25°C the fraction of the surface in the cation form increases from 9% at pH 7 to 22% at pH 8. The exchange is temperature dependent and at 2°C and pH 8, 14% of the exchange sites are occupied by cations, as opposed to 22% of the exchange sites at 25°C. These results were used to calculate the buffer capacity of a model sediment consisting of pore water and amorphous silica. For a sediment of 70% porosity, pH 7.7, and 25°C, the buffer capacity of sediment plus pore water is 67 times the buffer capacity of pure seawater.

Investigation of Methods for Adjusting the Acidity of Wines

Different methods of acid and pH adjustment of musts and wines were compared. CaCO₃ precipitation, anion exchange, and malo-lactic fermentation for acid reduction all have limitations. CaC0₃ causes the least flavor distortion, while anion-exchange treatment causes the greatest. The double salt-precipitation procedure with CaCO₃ is applicable only to low-pH high-acid musts or wines with high tartrate contents. Neutralization of low-pH high-acid wines with CaCO₃ appears to be equally effective. Hydrogen-ion exchange or tartaric-acid addition are equally effective in reducing the pH of high-pH low-acid wines where the potassium content is high.

Investigation of Methods for Adjusting the Acidity of Wines

Different methods of acid and pH adjustment of musts and wines were compared. CaCO₃ precipitation, anion exchange, and malo-lactic fermentation for acid reduction all have limitations. CaC0₃ causes the least flavor distortion, while anion-exchange treatment causes the greatest. The double salt-precipitation procedure with CaCO₃ is applicable only to low-pH high-acid musts or wines with high tartrate contents. Neutralization of low-pH high-acid wines with CaCO₃ appears to be equally effective. Hydrogen-ion exchange or tartaric-acid addition are equally effective in reducing the pH of high-pH low-acid wines where the potassium content is high.

An automated method for determination of chloride and sulfate in freshwater using cation exchange and measurement of electrical conductance

A simple automated adaptation of Mackereth’s manual method for determining chloride and sulfate in freshwater is described, using hydrogen ion exchange to convert salts of chloride and sulfate to their free acids with detection by electrical conductance. The use of silver‐saturated exchange resin to precipitate chloride permits distinction between chloride and sulfate. Detection limit is good at 2 µeq liter−1 with excellent precision (± I.5% at 200 µeq liter−1) . High levels of nitrate, orthophosphate, and fluoride give positive interference for sulfate; bromide and iodide similarly interfere with chloride estimates.

Adsorption and kinetics in a batch heterogeneous catalytic reactor

AbstractThe utility of a new dynamic experimental technique is illustrated for the specific case of the vapor phase dehydration of ethanol over a hydrogen ion exchange resin. Adsorbed phase composition data are obtained simultaneously with complete vapor phase information, providing new insight into the catalytic behavior. A mathematical model, based upon Langmuir‐Hinshelwood kinetics, comprises simply five first‐order ordinary differential equations. The model describes all of the important transient and equilibrium characteristics of the reacting system qualitatively and most quantitatively. Experimental data alone are used to show that the surface reaction is the rate controlling step.

Familial renal dysplasia with sodium wasting and hypokalemic alkalosis.

The fatal illnesses of two siblings were characterized by failure to thrive; impairment of renal clearance and concentrating ability; metabolic alkalosis; and sodium, potassium, and chloride depletion. Pathological examination of the kidneys of each infant revealed immaturity and dysplasia of almost all glomeruli and tubules. In these patients, the pathogenic defect appears to be a failure of sodium reabsorption in the dysplastic proximal tubules of a genetically abnormal kidney. Presumably, the resultant delivery of a large sodium load to the dysplastic distal tubules resulted in excessive potassium and hydrogen ion exchange and secretion.

A batch reactor to study concomitant adsorption and heterogeneous catalysis

Abstract A batch reactor has been devised in which adsorption phenomena important to a heterogeneous catalytic reaction can be followed simultaneously with the overall reaction process. The experimental technique is illustrated with the vapor phase dehydration of ethyl alcohol to diethyl ether as catalyzed by hydrogen ion exchange resin. Directly measured data are vapor phase composition, total adsorption, and total pressure as functions of time. Derived results are adsorbed phase composition data, fractional conversion, the thermodynamic equilibrium constant, and an independent check on internal consistency. The method inherently provides insights characteristic of dynamic experiments while retaining the simplicity of a set of first-order ordinary differential equations for any mathematical treatment desired. For this catalytic reaction the adsorption processes are shown, without recourse to theoretical analysis, to be much faster than the surface reaction.