Effect ammonia concentration

To overcome the suppression effect of amines in the determination of ammonia, Hampson [56] investigated the effect of nitrite ions added either as nitrite or as nitrous acid. Figure 5.2 indicates that very considerable suppression by nitrite does occur, although it is not as strong as with any of the amines. Again, it is not great so long as the nitrite N concentration is less than the ammonia N concentration, but rapidly increases as the nitrite concentration exceeds the ammonia concentration. In fact, the nitrite modified method was found to be satisfactory in open seawater samples and polluted estuary waters. 

In solutions with relatively high ammonia concentrations, NH3 reacts with NP to give Fe(CN)5(H20)3 plus N2, effecting comproportionation of NH3 and NO+ to N2 (60,52c). Likewise, primary amines (RNH2) are diazotized by aqueous NP to give the alcohols (ROH) plus N2, with the maximum rate occurring about pH 10.5 (55). The rates of these reactions are first-order in [NP] and [RNH2] and increase with the basicity of the amines. 

Comparative evaluation of anti-human thyroid stimulating hormone (hTSH) antibody, bound to the fifth-generation ammonia core (N5) or the fifth-generation ethylenediamine core (E5) dendrimer (1), did not show any differences in either the effective protein concentrations or the shape of the dose-dependent response curves (calibration curves) as determined from the recovery of standard controls. All the other experiments described here were thus carried out with the fifth-generation (i.e. dia. = 70 A) particles of ethylenediamine core (E5) de-ndrimers. The later particles were selected for their ability to be produced reproducibly on a large scale. 

Data on the effect of temperature on salting out of ammonia are even less satisfactory than those for carbon dioxide. Perman obtained some data on a potassium sulfate solution at temperatures of 40° to 59°C and on two ammonium chloride solutions at temperatures from 19° to 58°C.(54). His ammonia concentrations were in the range of 5 to 13 molal. His data indicate only small changes in the salting-out coefficient, but the coefficient for ammonium chloride increases with temperature, which is contrary to the effect found with carbon dioxide. 

The effect of concentration of free (molecular) ammonia on the activity of the electrolyte was derived mainly from two 80 C data points of Miles and Wilson having 16 to 17 molal free ammonia concentration. Data points below 0.2 ionic strength were fitted by application of Kielland s estimation of ionic activity coefficients(6 2). Details are presented elsewhere(45), together with graphs giving partial pressures of ammonia and hydrogen sulfide for temperatures from 80 to 260 F over a range of liquid concentration. 

The concentration of ammonia in the liver is not saturating for carbamoyl phosphate synthetase, so that the greater the flux of ammonia into or within the liver, the higher the concentration of ammonia and the higher the activity of the synthetase. The effect of ammonia concentration is, therefore, a mass-action effect. 

Mechanism of Action A lactose derivative that retains ammonia in colon and decreases serum ammonia concentration, producing osmotic effect. Therapeutic Effect Promotes increased peristalsis and bowel evacuation, which expels ammonia from the colon. 

Arriagada FJ, Osseo-Asare K (1999) Synthesis of nanosize silica in a nonionic water-in-oil microemulsion Effects of the water/surfactant molar ratio and ammonia concentration. J Colloid Interface Sci 211 210-220... 

For a given surfactant, the ability to form a single-phase w/o microemulsion is a function of the type of oil, nature of the electrolyte, solution composition, and temperature (54-58). When microemulsions are used as reaction media, the added reactants and the reaction products can also influence the phase stability. Figure 2.2.4 illustrates the effects of temperature and ammonia concentration on the phase behavior of the NP-5/cyclohexane/water system (27). In the absence of ammonia, the central region bounded by the two curves represents the single-phase microemulsion region. Above the upper curve (the solubilization limit), a water-in-oil microemulsion coexists with an aqueous phase, while below the lower curve (the solubility limit), an oil-in-water water microemulsion coexists with an oil phase. It can be seen that introducing ammonia into the system results in a shift of the solubilization... 

Fig. 2.2.13 Effect of the water-to-surfactant molar ratio (R) on the mean diameter of Si02 particles prepared with different ammonia concentrations. (From Ref. 27.)...

The solution pH influences a number of factors, and it is not always simple to predict its effect. Thus, thiourea decomposition (in alkaline solution) is generally faster at higher pH. The probability of the presence of a solid phase of Cd(OH)2 and its concentration in the solution are both increased at higher pH (higher OH concentration). The pH is determined, in the example given earlier, by the concentration of ammonia. However, it can be adjusted independent of the ammonia concentration. Addition of an ammonium salt, which with ammonia, acts as a buffer, will lower the pH through the following equilibrium ... 

In ammoniacal solutions of copper salts, the oxidation products are likely to contain nitrogen thus, hexoses give oxalic acid, imidazoles, hydrogen cyanide, and urea. Kinetic studies have been reported for the reaction of Cu(II) in the presence of ammonia with maltose, lactose, melibiose, and cellobiose.190 For the oxidation by tetraamminecopper(II) in ammoniacal and buffered media the rate of reaction is first order in disaccharide concentration, order one-half in ammonia concentration, but it is independent of Cu(II) concentration. The reaction rate is decreased by the addition of ammonium chloride, because of the common ion effect. These kinetics suggested mechanisms involving an intermediate enediolate ion, with the rate of reaction being equal to the rate of enolization.191 A similar mechanism has been proposed for the oxidation of D-fructose by a copper-pyridine complex in an excess of pyridine.192... 

Solvent to feed ratios as well as the effect of ammonia concentration in the solvent were independently varied to match the experimental data. The effect of increasing ammonia concentration at constant pressure and temperature in both ethylene/ammonia and ethane/ammonia solvent mixtures are shown in Table V. 

Chemical and thermal burns. The causes of chemical bums include the effect of concentrated acids, alkali, liquid ammonia, chlorosilanes and other aggressive substances. Thermal bums are caused with boiling solutions, hot water, vapour, inflamed gases, incandescent contact mass. Preventive and protective measures mostly include strict observance of all the established technological regulations and equipment maintenance order. 

When ammonia enters the body, it is converted to urea and excreted by the kidneys. The capacity for detoxification via urea is sufficient to eliminate the ammonium ion when ammonia is inhaled in non-irritating concentrations. Repeated inhalation can cause a higher tolerance because the mucous membranes become increasingly resistant. Ammonia is not considered to be carcinogenic nor is it mutagenic. The effects of different ammonia concentrations are summarized in Table 8.374. 

Table 8.3. Health Effects of Different Ammonia Concentrations...

Ammonia is not considered to be carcinogenic nor is it mutagenic. The effects of different ammonia concentrations are summarized in Table 22.12.74... 

Soto HJ, Woo KL, Van-Zee JW, Murthy M (2003) Effect of transient ammonia concentrations on PEMFC performance. Electrochem Solid-State Lett 6 A133-5... 

Neumann, R., G.Mehlhorn, I.Buchholz, U.Johannsen, and D.Schimmel. 1987. Experimental studies on the effect of chronic aerogenous toxic gas burden of suckling pigs with different ammonia concentrations. II. The reaction of cellular and humoral... 

Coprecipitation with the hydrous oxides, such as of iron(III) and aluminum, occurs by adsorption and possibly also by compound formation. The precipitates, coming down in either amorphous or finely crystalline form with extensive surface, adsorb large amounts of water and adsorb hydroxide ions as potential-determining ions. Figure 9-1 illustrates the effect of varying the concentration of ammonium chloride and ammonium hydroxide on the amount of coprecipitation of divalent metal ions with hydrous iron(III) oxide. When the concentration of ammonium chloride is increased at a constant ammonia concentration, the adsorption is decreased... 

Evidently a low ammonia concentration (0.003 Af) and a high ammonium chloride concentration (1.5 to 2 M) are favorable for efficient separation of metal ions that do not form ammine complexes (Ca" ", Mg" ). In fact, a single precipitation has been found to be effective under these conditions.To separate iron(III) from copper, zinc, and nickel, high concentrations of both ammonia and ammonium chloride produced excellent results in a single precipitation. 

---