Elimination Of Sulfate Research Articles

Determination of phosphate in samples with high levels of sulphate by ion chromatography

A comparative study of the separation of phosphate from chloride, nitrate, nitrite, bromide and sulphate by ion chromatography with direct conductimetric detection and indirect photometric detection was performed. The best resolution was obtained using borate-gluconate or hydrogenphthalate as the eluent. Indirect photometry using hydrogenphthalate or naphthalenedisulphonate gave the best detection limit for phosphate (1 ng). The use of ion-exchange resins in the barium form for the elimination of high levels of sulphate prior to the determination of trace amounts of phosphate was evaluated. For the elimination of sulphate in samples containing less than 1000 mg/l (SO 4 2−:PO 4 3− = 100) the column mode can be used, but for samples with high concentrations of sulphate (5000 mg/l) the batch procedure is recommended. The behaviour of commercial cartridges in the barium form was also evaluated. The method was applied to the separation and determination of anions in saline sediments.

Sulfate elimination to improve water quality of mine process effluents. II. Hydrogen sulfide transport in biological reactors

AbstractA hydrogen sulfide bioproduction and mass transfer model was developed to assist in the evaluation of a biological process for the elimination of the sulfate contained in the effluent water of copper mines. The model was based upon the observation of experimental sulfate‐reducing activity and reaction rates of the sulfate‐reducing bacterium (SRB) Desulfovibrio desulfuricans, in experimental systems. The model postulated the following five steps: (1) sulfate transport, from the solution bulk to the interphase formed by the solution with the outer membrane of the bacteria; (2) sulfate transport through the membrane to specific intracellular reaction sites and intracellular reduction of the sulfate to generate HS‐ species; (3) transport of the HS‐ species through the membrane and the membrane—solution interphase to the solution bulk; (4) reaction of the HS‐ species to generate hydrogen sulfide with the consumption of protons; (5) mass transfer of hydrogen sulfide from the solution to the gas phase, diluted by an inert purge gas. The steady state of the model was solved analytically while the dynamic behavior was numerically solved by a numerical integrator. Results show that the model adequately described the process and correlated properly, in order of magnitude, with the operation parameters of a continuous reactor and a sequencing batch reactor. The model is presented with the experimental observations of a batch bioreactor. The model was used to select the optimum combination of operational parameters of a laboratory reactor and to predict those of pilot and industrial scale reactors. © 1993 John Wiley & Sons, Inc.

Sulfate elimination to improve water quality of mine process effluents. I. Sequencing batch bioreactor growth kinetics of desulfovibrio desulfuricans

AbstractThe sulfate reducing bacterium, Desulfovibrio desulfuricans NCIMB 8372, was cultured in a 1‐L biochemical reactor. The reactor was operated in a sequential batch mode and the results of four sequential runs are presented (the first run was a recently inoculated reactor).Results fall within the range of published results, reaching sulfate reduction rates up to 2764.8 mg/L/day. The bacteria attached to the reactor walls and a method was proposed to evaluate the magnitude of the adhered cells fraction, which resulted in a value of 1.2–3.0 · 106 cells/cm2, a value that correlated well with cells counted in scanning microscope photographs taken from a tube in the reactor. © 1993 John Wiley and Sons.

Influence of sulphate impurities on the IR transmission of InF 3-based glasses

Fluoroindate glasses are more transparent in the IR spectrum than standard fluorozirconate glasses. The shift of the multiphonon absorption edge makes it necessary to reduce the residual content of sulphate impurities which induce a strong optical absorption between 8 and 9 μm. The chemical elimination of sulphate has been implemented by a zirconium-assisted reduction or by the incorporation of fluoropolymers before melting.

An Improved Semi-Preparative Liquid Chromatography Technique to Purify A Uremic Toxin Fraction Inhibiting Na+, K+-Atpase

Abstract We reported previously inhibition of Na+,K+-ATPase by a fraction (fraction 2–3) of medium size uremic toxins. Due to considerable amount of sulfates in this fraction, a semi preparative high performance liquid chromatography turned out to be inadequate to isolate the active compound. Therefore we developed a novel chromatographic method using ion exchanger Sephadex QAE A25 in acidic medium. This method allows the elimination of sulfates and the partial purification of the active component.

Effect of Na + on sulphation and related reactions over a commercial claus alumina catalyst

The influence of Na + on the nature of sulphate species, alumina sulphation and the regeneration of spent Claus alumina catalyst either by hydrogen sulphide reduction or water leaching has been studied by Fourier transform-IR spectroscopy and microgravimetry. Na + strongly modifies the nature of sulphate species on alumina, leading to mixed sodium aluminium sulphate and sodium sulphate species. Na + appears to promote sulphur dioxide adsorption and catalyst sulphation, the latter occurring at a lower temperature. It does not affect the reducibility of sulphate by hydrogen sulphide, which is found to be a slow process, but Na + facilitates the removal of sulphate species by water leaching and this appears to be an efficient process for elimination of sulphate.

The substrate specificity of heparan sulphate lyase and heparin lyase from Flavobacterium heparinum

The substrate specificity of heparan sulphate lyase and heparin lyase has been examined by using various oligosaccharides produced by deaminative cleavage or periodate oxidation—base-catalysed elimination of heparan sulphate. The saccharides were separated by gel and ion-exchange chromatography into fractions having high proportions of the following linkages: 2-acetamido-2-deoxy- d-glucosyl→ d-glucuronic acid (type I), 2-deoxy-2-sulphoamino- d-glucosyl→ d-glucuronic acid (type II), 2-deoxy-2-sulphoamino- d-glucosyl→ l-iduronic acid (type III), or 2-deoxy-2-sulphoamino- d-glucosyl→2- O-sulpho- l-iduronic acid (type IV). Heparan sulphate lyase cleaved heparan sulphate preparations containing high proportions of type I linkages. In contrast, oligosaccharides obtained after deaminative cleavage and rich in the type I linkage were poor substrates; longer saccharides were better substrates than shorter ones. Saccharides generated via periodate oxidation were cleaved when the type I linkage was present but resistant when the linkages were of types II-IV. The presence of ester sulphate on the 2-acetamido-2-deoxy- d-glucose residue in a type I linkage seems to hinder the enzyme. Heparan sulphate lyase was able to degrade intact chains to the same extent as did two cycles of periodate oxidation—base-catalysed elimination, suggesting that all the regular type I linkages were accessible to the enzyme. The heparin lyase could cleave saccharides which contained type IV linkages. When type II and III linkages were the only ones present, the saccharides were resistant. This enzyme also appears to require ester-sulphation of the 2-deoxy-2-sulphoamino- d-glucose residue.

Single and multiple dose pharmacokinetics of oral quinidine sulfate and gluconate

The pharmacokinetics of oral quinidine sulfate and quinidine gluconate were compared in seven healthy volunteers In a two part pharmacokinetic study. Part I was a single dose crossover trial assessing absorption and elimination of quinidine sulfate (400 mg, equivalent to 331 mg of quinidine base) and quinidine gluconate (495 mg, equivalent to 309 mg of quinidine base). Mean kinetic values for the sulfate and gluconate preparations, respectively, were: peak serum quinidine level 2.07 versus 1.24 μg/ml ( P < 0.025); time of peak concentration 1.61 versus 3.64 hours after the dose ( P < 0.02); first order absorption half-life 41.1 versus 61.2 minutes ( P < 00.1); elimination half-life 6.1 versus 6.3 hours (difference not significant); absolute systemic availability (based upon comparison with intravenous data from the same subjects) 86.0 versus 76.5 percent (difference not significant) using area under the serum concentration curve, or 83.7 versus 73.6 percent ( P < 0.05) using cumulative 48 hour urinary excretion of quinidine. The findings indicate that absorption of quinidine gluconate is slightly less complete but much less rapid than that of quinidine sulfate. Part II evaluated steady state kinetics of both preparations in a cross-over trial in the same subjects. Maintenance dosing schedules were 200 mg of quinidine sulfate every 6 hours versus 495 mg of quinidine gluconate every 12 hours. Systemic availability of the gluconate at the steady state level was 10 percent less (based upon area under the serum concentration curve) or 7 percent less (based upon urinary excretion of quinidine) than that of the sulfate, but the differences were not significant. Interdose fluctuation in serum quinidine concentrations during the gluconate trial averaged 70 percent, which was not significantly different from the average of 67 percent during the sulfate trial. However, variation within and between subjects in minimal steady state levels with quinidine gluconate (15.6 and 16.0 percent, respectively) was greater than with quinidine sulfate (7.2 and 9.9 percent, respectively). Steady state concentrations during the multiple dose trial were not accurately predicted from single dose pharmacokinetics, either for quinidine sulfate ( r = 0.45) or quinidine gluconate ( r = −0.12), but deviation of observed from predicted concentrations tended to be greater with quinidine gluconate. The slow absorption of quinidine from the gluconate preparation allows maintenance therapy on a 12 hourly dosage schedule with acceptable interdose fluctuation in serum levels. Variability within and between subjects in absorption kinetics tends to be greater with quinidine gluconate than with the more rapidly absorbed sulfate salt.

Anion and aluminium interference phenomena in the flamephotometric determination of calcium.

The most typical interfering species in flamephotometric determination of calcium are sulphuric acid, phosphoric acid, and aluminium. In the previous reports by the other authors, it has been proved that the formations of some refractory compounds of these species in light sources decrease the emission intensity of calcium spectrum line. A chelate formation of EDTA in solution has been proved effective in the elimination of sulphate and phosphate interferences. But in the case of aluminium, it was not successful. In this report strong fluoride complex of aluminium is proved to be effective in the elimination of the formation of refractory material calcium aluminate.

Effect of hemodialysis on kinetics of acetaminophen elimination by anephric patients.

The pharmacokinetics of acetaminophen elimination were determined in 4 anephric patients during hemodialysis and on an interdialysis day. The biologic half-life of acetaminophen ranged from 119 to 147 min on an interdialysis day and was decreased by 42% to 53% during hemodialysis. Individual mean dialyzer extraction ratios, based on assay of plasma samples from blood flowing into and out of the dialysis unit, were 0.46 to 0.78 for acetaminophen, 0.53 to 0.57 for acetaminophen glucuronide, 0.13 to 0.60 for acetaminophen sulfate, and 0.70 to 0.87 for urea nitrogen. There was a strong correlation between the extraction ratios of acetaminophen and urea nitrogen. Hemodialysis was the major or sole routine of elimination of acetaminophen glucuronide and sulfate in the anephric patients.

Effect of stress on the pharmacokinetics of sodium salicylate and quinidine sulphate in rats.

Studies on the influence of foot shock stress on the absorption, distribution and overall serum elimination of sodium salicylate and guinidine sulphate were performed in rats. Foot shock stress was produced by grid floor electrical stimulation. The animals were stressed 1 hr before administration of the drugs and then throughout the experimental period. A significant induced stress was demonstrated by increased blood glucose levels and increased whole brain turnover of noradrenaline. Gastric emptying and intestinal transit as well as tissue levels of the drugs in the serum, heart, brain, liver, muscle and fat were determined. Results were obtained indicating that stress produced a significant increase in the gastro-intestinal absorption of quinidine sulphate while no change in the distribution pattern of overall elimination was noted. On the other hand, sodium salicylate did not show any marked change in the pharmacokinetic parameters during a stressful situation.

Reaction of pyridoxal 5'-sulfate with apoenzyme of aspartate aminotransferase. Covalent labeling of the protein with elimination of sulfate.

Reaction of pyridoxal 5'-sulfate with apoenzyme of aspartate aminotransferase. Covalent labeling of the protein with elimination of sulfate.

Recherches sur la formation et la transformation des esters LXXII. Aryl(ou aralcoyl ou alcoyl)amino‐2‐tétrahydro‐m‐thiazines ou aryl(ou aralcoyl ou alcoyl)amino‐2‐dihydro‐Δ2‐m‐thiazines et dérivés

Abstract3‐Aminopropanol reacts with aryl(or aralkyl or alkyl)isothiocyanates RNCS to yield the corresponding thio‐ureas RNHCSNH(CH2)3OH which, refluxed with hydrochloric acid, are cyclized by elimination of water. The cyclization products are identical with the hydrothiazines resulting by elimination of sulfate or phosphate from the sulfuric or phosphoric monoesters of these thio‐ureas. The resulting hydrothiazines are either 2‐(R‐imino)‐tetrahydro‐m‐thiazines (I) or 2‐(R‐amino)‐dihydro‐Δ2‐m‐thiazines (II). Their structure has been established by comparison of their spectra with those of model compounds in one of which the CN double bond is certainly endocyclic (2‐methyl‐dihydro‐Δ2‐m‐thiazine), the other presenting an exocyclic CN double bond (3‐methyl‐2‐phenylimino‐tetrahydro‐m‐thiazine). When R is an aryl group, the CN double bond is exocyclic (structure I with &gt;CNAr), and one may presume that this structure is stabilized by resonance. When R is an aralkyl or an alkyl group, the CN double bond is endocyclic (structure II). The nmr spectra were taken with three types of solvent: CDCl3 or CCl4; (CD3)2SO; CF3COOH. In CF3COOH solution the benzylic protons of the hydrothiazine with R = pFC6H4CH2 couple with NH (J=5,5cps) which confirms the endocyclic position of the CN double bond in this case.

Séparation chromatographique du plomb contenue dans des solutions concentrées de sulfate de zinc

Spectrographic analysis of lead traces in concentrated zinc sulphate solutions is only possible after elimination of zinc and sulphate ions. Two methods of separation on ion exchangers are proposed : the first method consists in a separation of Pb from Zn on an anion exchanger after elimination of sulphate on a cation exchanger; in the second method, the two steps of the separation are realized on the same cation-exchanger column. Both methods are satisfactory, but the second is faster and simpler. The blank of the method is about 1.5 μg Pb (i.e. 0.15 mg Pb/l) for a separation made with 10 ml of electrolyte. The method is therefore suitable for accurate determinations of Pb contents as low as 1 mg/l of concentrated zinc sulpliate electrolyte.

Improvements in the Electrowinning of Chromium

Improvements in the electrowinning of chromium from trivalent or “chrome alum” solutions, made since publication of a previous paper, are disclosed. Elimination of sodium sulfate from the electrolyte and changes in cell design have decreased the cost of electrowinning chromium metal. Details of the new cell design and data obtained with a 120‐pound‐per‐day cell are discussed.The sensitivity of laboratory‐size cells to certain critical impurities and other variables tends to obscure the possibilities of this type of electrolyte. Research in pilot‐plant cells has shown that proper cell design and operation on a sufficiently large scale can largely overcome the sensitivity of chromium sulfate electrolytes to impurities and, to a lesser extent, to pH and other variables.

Ionic regulation in some marine invertebrates.

ABSTRACT Analyses have been made of the ionic composition of the body fluids of some twenty marine invertebrates belonging to five phyla. The body fluids were again analysed after dialysis in collodion sacs against samples of the original sea water in which the animals had been kept. Comparison of the two analyses in terms of weight of water gives a true measure of ionic regulation by taking into account such factors as the Donnan equilibrium and the formation of calcium-protein complexes in those animals with significant concentrations of protein in their blood. Some ionic regulation is found in all the animals examined, but it is most pronounced in the cephalopod Mollusca and the decapod Crustacea. The mesogloeal tissue fluid of the jelly-fish Aurelia showed the following composition (expressed as percentage of concentration in the dialysed fluid): Na 99%, K 106%, Ca 96%, Mg 97%, Cl 104%, SO4 47%. This regulation seems to be brought about by elimination of sulphate and accumulation of potassium by the epithelia bounding the mesogloea, with resultant alteration in the remaining ions in conformity with osmotic equilibrium between the jelly and sea water. In the echinoderms studied only potassium is regulated, values in the perivisceral fluid not exceeding 111 % being found, with higher values in the ambulacral fluid. Polychaetes regulated potassium (up to 126%) and sometimes reduced sulphate (92%). Regulation extends to all ions in the decapod Crustacea. In six species the range was Na 104-113 %, K 77-128%, Ca 108-131 %, Mg 14-97%, Cl 98-104%, SO4 32-99%. There is a series Lithodes, Cancer, Carcinus, Palinurus, Nephrops and Homarus in which magnesium falls from 97 to 14%; the series is roughly in accordance with increase of activity. Analyses given of the secretion from the antennary glands emphasize the importance of these organs in controlling the composition of the blood. They eliminate magnesium, sulphate, and sometimes calcium, and conserve the other ions. Lamellibranchs and gastropods accumulate potassium and calcium, and eliminate sulphate to a small degree. Range of values in six species was Na 97-101%, K 107-155%, Ca 103-112%, Mg 97-103%, Cl 9-101%, SO4 87-102%. Considerable ionic regulation exists in the Cephalopoda, ranges being Na 95-98%, K 152-219%, Ca 94-107%, Mg 102-103%, Cl 101-104%, SO4 29-81%. In Eledone and Sepia differential excretion by renal organs is an important factor in this. Sulphate and sodium are eliminated in quantities greater than would be present in an ultrafiltrate of the plasma, tending to lower these values, whereas the other ions are excreted in proportions below those of an ultrafiltrate, tending to elevate their concentrations in the blood. The ratio of equivalents Na + K/Ca + Mg in the body fluids of these marineinvertebrates remains at the sea-water figure of 3-8 in Aurelia, echinoderms, annelid worms, and lamellibranchs, but decreases in the gastropods and cephalopods to 3-5. In the decapod Crustacea, owing principally to reduction of magnesium, it increases from 3.8 in Lithodes to 9 and 12 in the Palinura and Astacura genera.