Attendant Anions Research Articles

Time effect on the stabilization of technogenic copper compounds in solid phases of Haplic Chernozem

We studied the regularities of Cu stabilization in Haplic Chernozem contaminated with easily soluble (acetates, nitrates, sulfates, chlorides) and poorly soluble (acetates, nitrates, sulfates, chlorides) metal compounds in a five-year model experiment were studied. A low contents of Cu loosely bound compounds (LBC) (no >5% of total content) unchanging over time were revealed in the uncontaminated soil, which is indicative of the stability of soil processes. The Cu LBC content decreased over time in the soils contaminated with easily soluble compounds and increased in the soils contaminated with poorly soluble compounds. In both cases, the contents of Cu LBCs after 5 years of incubation remained higher than in the original uncontaminated soil. The effect of the attendant anions on the Cu LBC content was more apparent under the Cu application of 2000 mg kg−1 than at 300 mg kg−1. An inverse process characterized by an increase in the concentration of Cu LBCs over time was observed in the soil contaminated with Cu orthophosphate and oxide. Soil contaminated with different Cu compounds results in soil acidification. According to the effect on the decrease in soil pH, the attendant anions form the following series: SO42− ≈ Cl− > NO3− > Ac− > PO42− > O2−, which correlates with the Cu LBC content. Thus, the stabilization of Cu compounds in the soil is affected by the attendant anions and the interaction time of the metal with the soil solid phases.

A bifunctional adsorbent of silica gel-immobilized Schiff base derivative for simultaneous and selective adsorption of Cu(II) and SO42−

Abstract A ditopic zwitterionic Schiff base modified silica gel adsorbent SG-H 2 L 2 was prepared and it was characterized by Fourier transform infrared spectroscopy, elemental analysis, solid state NMR, thermogravimetry and porous structure analysis. SG-H 2 L 2 could simultaneously adsorb metal ions and attendant anions from the aqueous solution of metal salts . SG-H 2 L 2 exhibited a cooperative effect between the adsorption of metal cations and the attendant anions, and the adsorption efficiency decreased in the order MSO 4 > M(NO 3 ) 2 > MCl 2 (M = Cu, Co, Ni, Mn, Cd). SG-H 2 L 2 displayed good adsorption selectivity for Cu(II) and SO 4 2− from the aqueous solutions containing mixed metal ions of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) or mixed anions of SO 4 2− , NO 3 − , and Cl − . The preliminary mechanism for simultaneous and selective adsorption of the metal ions and attendant anions were discussed. The effect of different parameters including pH, contact time and initial concentrations of Cu(II) and SO 4 2− on the simultaneous adsorption of Cu(II) and SO 4 2− ions were investigated. The efficient adsorption of Cu(II) and SO 4 2− could be achieved in neutral pH region and the maximum adsorption capacities for Cu(II) and SO 4 2− , respectively, were the same of 0.42 mmol g −1 at 25 °C. The adsorption isotherms for Cu(II) and SO 4 2− fitted well with Langmuir model, while their adsorption kinetics followed the pseudo-second order model. Regeneration of SG-H 2 L 2 was realized by adjusting the solution pH with diluted H 2 SO 4 and ammonia solution, respectively. SG-H 2 L 2 exhibited good recyclability and reusability for four cycles use without deterioration in its functionality. SG-H 2 L 2 was also applied in different water samples and good recoveries and the selective adsorption of Cu(II) and SO 4 2− were achieved. This study provides a new bifunctional adsorbent which may be used for the effective removal of Cu(II) and SO 4 2− from water effluents containing mixed metal ions and anions.

Contribution of attendant anions on cadmium toxicity to soil enzymes

Sorption and desorption are critical processes to control the mobility and biotoxicity of cadmium (Cd) in soils. It is known that attendant anion species of heavy metals could affect metal adsorption on soils and might further alter their biotoxicity. However, for Cd, the influence of attendant anions on its sorption in soils and subsequent toxicity on soil enzymes are still unknown. In this work, four Cd compounds with different salt anions (SO42−, NO3−, Cl−, and Ac−) were selected to investigate their impact of on the sorption, soil dehydrogenase activity (DHA) and alkaline phosphatase activity (ALP). Thus, a series of simulated Cd pollution batch experiments including measuring adsorption-desorption behavior of Cd on soils and soil enzyme activities were carried out. Results showed that CdSO4 exhibited highest sorption capacity among the tested soils except in Hunan soil. The Cd sorption with NO3− displayed a similar behavior with Cl− on all tested soils. Compared with soil properties, all four kinds of anions on Cd sorption played a more significant role affecting Cd ecological toxicity to soil DHA and ALP. Cd in acetate or nitrate form appears more sensitive towards DHA than sulphate and chloride, while the later pair is more toxic towards ALP than the former. These results have important implications for evaluation of Cd contamination using soil enzyme as bioindicator.

Adsorption of copper by ordinary and southern chernozems from solutions of different salts

The aim of this work was to study the effect of the attendant anions and particle-size distribution on the adsorption of copper by chernozems of Rostov region (Russia). The samples of soil in the natural cationic form were treated with solutions of copper nitrates, acetates, chlorides, and sulfates at a soil: solution ratio of 1:10. The concentrations of the initial copper solutions varied in the range from 0.05 to 1mM/L. The suspensions were shaken for 1h, left to settle for a further 24h and then filtered. The metal concentrations in the filtrates were determined by atomic absorption spectrometry. The concentrations of the adsorbed copper cations were calculated from the difference between the metal concentrations in the initial and equilibrium solutions. The effect of the attendant anions Cl−, SO42−, Ac−, and NO3− and particle size distribution on the adsorption of copper by chernozems of the Rostov region has been studied under laboratory conditions. The shape of the adsorption isotherms varies depending on the attendant anion and is described by the Henry, Freundlich, and Langmuir equations. The adsorption of copper by the soil is accompanied by the acidification of equilibrium solutions (рНeq): 0.53≤ΔрНeq≤2.06, which depends on the attendant anion. The highest value of ΔpHeq corresponds to the adsorption of Cu2+ from the copper sulfate solution and its lowest value, from the copper chloride solution. The effect of the attendant anions decreases in the series: Cu(Ac)2>CuCl2>Cu(NO3)2 >>CuSO4. In the southern chernozems, a close correlation is observed between the maximum copper adsorption and the content of clay and silt (R=0.99). No correlation is found between the values of adsorption constants and particle size distribution, which is related to the changes in the chemistry and mineralogy of the soils studied.

Desorption of Exchangeable Cations at Adsorption of Lead Ions by Chernozem in the Presence of Attendant Anions

The effect of Cl–, Ac‾ and NO3‾ anions on the adsorption of Pb cations by an ordinary chernozem and desorption of exchangeable cations in the soil-solution system has been assessed under model laboratory conditions. It has been shown that the attendant anions affect the shape of the adsorption isotherms, which are described by the Langmuir equation. The greatest influence on the affinity constant of Pb with soil has anion Ac‾. It has been found that the uptake of the Pb cations by chernozem from solutions of different salts is accompanied by the displacement of the exchangeable cations to the solution in the following order: Ca2+ > Mg2+ > Na+ > K+. The sum of the displaced exchangeable cations in most cases exceeds the amount of the adsorbed metal cations. The content of Pb cations desorbed by the ammonium acetate buffer solution (pH 4.8) makes up 6-39% of the total Pb adsorbed cations. According to the effect of the anions on the displacing capacity of cations for Pb the following series are formed: Cl¯ > Ac‾ > NO3¯.

Effect of an attendant anion on the balance of cations in the soil-solution system with an ordinary chernozem as an example

The effect of different anions on the balance of heavy metal cations in the soil-solution system has been assessed under model laboratory conditions. It has been found that the uptake of the Cu, Zn, and Pb cations by an ordinary chernozem from solutions of different salts is accompanied by the displacement of the exchangeable cations to the solution in the following order: Ca2+ > Mg2+ > Na+ > K+. The sum of the displaced exchangeable cations in most cases exceeds the amount of the adsorbed heavy metal cations. According to the effect of the anions on the displacing capacity of the metal cations, the following series are formed: for copper, SO42− ≫ Cl− > OAc− > NO3−; for lead, Cl− ≫ NO3− > OAc−; and, for zinc, SO42− ≫ Cl− ≫ OAc− > NO3−.

Effect of attendant anions on zinc adsorption and transformation in chernozem

The effect of anions on the adsorption and mechanism of interaction of zinc cations with a solid soil phase was established. Acetic acid anions had the greatest influence on bond strength between metal and soil particle surfaces, while the effect of nitric acid anions was the lowest. The difference in amount of mobile forms of zinc extracted by the soil depends on the dose and form of the zinc. The influence of the attendant anions on the content of mobile metal forms in the soil decreases in the order: PO42−≈Cl−>NO3−>SO42−>СН3СОО−>О−.

Adsorption features of Cu(II), Pb(II), and Zn(II) by an ordinary chernozem from nitrate, chloride, acetate, and sulfate solutions

The effect of Cl−,SO42−, CH3COO−, and NO3− anions on the adsorption of copper, lead, and zinc by an ordinary chernozem has been studied. The effect of the anions on the adsorption of Cu2+, Pb2+, Zn2+ ions is significant but uncertain. It has been shown that the attendant anions affect the shape of the adsorption isotherms, which are described by the Langmuir, Freundlich, or Henri equations. The constants of the adsorption from a nitrate solution calculated from the Langmuir equation (KL) decrease in the following order: Cu2+ > Pb2+ >> Zn2+. The values of the maximum adsorption (Cmax) decrease in the following order: Cu2+ ≥ Zn2+ > Pb2+ for acetate solutions and in the series Pb2+ > Zn2+ ≥ Cu2+ for nitrate solutions. The values of the Henry constants (KH) calculated for the adsorption of the same cations from chloride solutions decrease in the same order as the values of KL. The CH3COO− anion has the highest effect on the constant values. The NO3− and Cl− anions “switch their places” depending on the attendant cation, but their effect is always lower than that of the acetate anion. The values of Cmax for copper and zinc are most affected by the CH3COO− anion, and the adsorption of zinc is most affected by the Cl− and NO3− anions. The assessment of the mobility of the adsorbed cations from the extraction with ammonium acetate (pH 4.8) has shown that the content of the desorbed metals is always lower than the content of the adsorbed cations and varies from 0.025 to 83%. According to their mobility, the adsorbed metals form the following order: Zn2+ > Pb2+ > Cu2+. The effect of the attendant anions on the extractability of the adsorbed cations decreases in the following order: chlorides > sulfates > acetates > nitrates.

A Clinical Approach to the Treatment of Chronic Hypernatremia

Hypernatremia is a commonly encountered electrolyte disorder occurring in both the inpatient and outpatient settings. Community-acquired hypernatremia typically occurs at the extremes of age, whereas hospital-acquired hypernatremia affects patients of all age groups. Serum sodium concentration is linked to water homeostasis, which is dependent on the thirst mechanism, arginine vasopressin, and kidney function. Because both hypernatremia and the rate of correction of hypernatremia are associated with significant morbidity and mortality, prompt effective treatment is crucial. Chronic hypernatremia can be classified into 3 broad categories, hypovolemic, euvolemic, and hypervolemic forms, with each form having unique treatment considerations. In this teaching case, we provide a clinically based quantitative approach to the treatment of both hypervolemic and hypovolemic hypernatremia, which occurred in the same patient during the course of a prolonged illness.

Effect of attendant anions on the adsorption of zinc, copper, and lead by chernozem

The adsorption of Cu, Zn, and Pb from acetate solutions is accompanied by higher values of the affinity constants compared to the adsorption of the same cations from nitrate solutions. The observed differences are due to the formation of stable charged complexes of acetate ions with heavy metal cations, whose binding strength with the surface of soil particles is higher than that of free ions, and also due to the possible precipitation of poorly soluble metal compounds in a calcareous ordinary chernozem.

A different hypothesis on hyponatremia in psychiatric patients: Treatment implications and experiences

Polydipsia, chronic or intermittent, with or without hyponatremia, frequently occurs among chronic patients with schizophrenia. The pathogenesis of polydipsia remains poorly understood. The key assumption of our hypothesis is that in some of these patients, polydipsia and hyponatremia are consequences of patients’ adjustment to a prolonged intake of an insufficient diet, dominantly poor in potassium. Deficits of potassium, without significant hypokalemia, may cause impairment of the urine-concentrating ability with polyuria-polydipsia. A fall of intracellular tonicity, dominantly due to a decreased amount of K+ and attendant anions in cells, should be accompanied with a fall of extracellular osmolality. Because of the diminished content of ions that may diffuse out of cells and because osmotic equilibrium between the ECF and ICF compartments cannot be established in a short period of time, these patients have a diminished ability to adapt to an excessive intake of fluids. These mechanisms might be related to the development of polydipsia and water intoxication in patients with different mental and somatic disorders. The experiences with the therapeutic effects of diets containing an sufficient amount of potassium in two patients with schizophrenia are described. Further investigations are needed, and we suggest a possible approach to test our hypotheses.

Impaired renal haemodynamic response to L-arginine in essential hypertension: role of buffering anion and tubuloglomerular feedback

To investigate whether changes in tubuloglomerular feedback (TGF) dependent upon the tubular effects of buffering anions affect the renal haemodynamic response to L-arginine in healthy (control) individuals and patients with essential hypertension. Mean arterial pressure (MAP), glomerular filtration rate (GFR), renal blood flow (RBF) and fractional excretion of sodium (FENa), chloride (FECl) and lithium (FELi) were measured in 10 control individuals and 10 hypertensive patients during two 3-h infusions of 0.012 mmol/kg per min L-arginine buffered with either HCl or citric acid. FELi, FECl and FENa increased (P < 0.001) comparably in controls and hypertensive individuals with arginine-HCl and decreased with arginine-citrate (P < 0.001). MAP was unchanged in controls with arginine-HCl and decreased by 3% with arginine-citrate (P < 0.001), and decreased in hypertensive individuals with both arginine-HCl and arginine-citrate (by 3 and 7%, respectively; P < 0.001). GFR increased with arginine-citrate in controls and hypertensive individuals (by 6.1 and 5.4%, respectively; P < 0.001), but did not change with arginine-HCl in controls and declined by 4.6% in hypertensive individuals (P < 0.05). RBF increased equally after arginine-citrate in controls and hypertensive individuals (by 34 and 33%, respectively; P < 0.001); it also increased after arginine-HCl (22 and 13%, respectively; P < 0.001), but less than after arginine-citrate (P < 0.001), and 41% less in hypertensive individuals than in controls (P < 0.001). Because arginine-HCl, unlike arginine-citrate, inhibits tubular reabsorption and elicits much less renal vasodilatation than does arginine-citrate, renal haemodynamics in response to L-arginine are modulated by changes in reabsorption and TGF according to the tubular effects of the attendant anion. As renal vasodilatation in hypertensive individuals was reduced only with arginine-HCl, which activates TGF, the blunted vasodilatation of the hypertensive kidney in response to arginine-HCl reflects an exaggerated response to an activated TGF.

Plasma Osmolality and Urinary Concentration and Dilution during and after Pregnancy

In nine women studied serially before conception and through the first trimester, plasma osmolality (Posm) started to decline with the first missed menstrual period, was significantly decreased by the fifth week of pregnancy and was 10 mosmol/kg lower than preconception values by the tenth week, changing little thereafter. Changes in plasma sodium (and its attendant anion) accounted for the majority of the decrement. In separate studies, urinary concentration and dilution, assessed by water deprivation and loading, studied in nine women during their last trimester and again 10-12 weeks post partum. Basal Posm was 9 mosmol/kg lower in the last trimester than post partum (p less than 0.001) but the results of concentration and dilution tests were similar during and after pregnancy. Basal urinary arginine vasopressin (AVP) excretion was similar during and after pregnancy and water loading suppressed AVP excretion in both pregnant and postpartum women. An unanticipated observation was that lateral recumbency interfered with urinary concentration tests in both pregnant and postpartum women. The results demonstrate that the decrement in Posm during pregnancy is an early event. The data (urinary AVP excretion, its suppression by water loading and normal concentration and dilution despite a lower plasma tonicity) also suggest that human pregnancy is accompanied by a resetting of the threshold for vasopressin secretion to a lower Posm.

Plasma osmolality and urinary concentration and dilution during and after pregnancy: evidence that lateral recumbency inhibits maximal urinary concentrating ability.

In nine women studied serially before conception and through the first trimester, plasma osmolality (Posm) started to decline with the first missed menstrual period, was significantly decreased by the fifth week of pregnancy and was 10 mosmol/kg lower than preconception values by the tenth week, changing little thereafter. Changes in plasma sodium (and its attendant anion) accounted for the majority of the decrement. In separate studies, urinary concentration and dilution, assessed by water deprivation and loading, studied in nine women during their last trimester and again 10-12 weeks post partum. Basal Posm was 9 mosmol/kg lower in the last trimester than post partum (p less than 0.001) but the results of concentration and dilution tests were similar during and after pregnancy. Basal urinary arginine vasopressin (AVP) excretion was similar during and after pregnancy and water loading suppressed AVP excretion in both pregnant and postpartum women. An unanticipated observation was that lateral recumbency interfered with urinary concentration tests in both pregnant and postpartum women. The results demonstrate that the decrement in Posm during pregnancy is an early event. The data (urinary AVP excretion, its suppression by water loading and normal concentration and dilution despite a lower plasma tonicity) also suggest that human pregnancy is accompanied by a resetting of the threshold for vasopressin secretion to a lower Posm.

Micropuncture study of composition of loop of Henle fluid in desert rodents.

Using micropuncture techniques, fluid was collected from loops of Henle at the tip of the renal papilla in anesthetized hamsters and Psammomys, and its composition compared with that of collecting duct urine. The osmolalities of the two fluids were essentially the same. Sodium and attendant anions constituted 64% and urea 19% of the osmotically active solute in loop fluid. In collecting duct urine, urea was the major solute present, and sodium was present in low concentration. Inulin ratios indicated that 9% of the filtered water reached the tip of these loops at a time when 0.9% was in the final urine. The data support the countercurrent hypothesis for urine formation.