K2SO4 Concentration Research Articles

Factors affecting the precipitation of chromium(III) in jarosite-type compounds

Jarosite precipitation is a useful means of stabilizing toxic species, and accordingly, the factors affecting the precipitation of chromium(III) in jarosite-type compounds was systematically investigated in a series of laboratory experiments. Although end-member Cr(III) analogues of jarosite-type compounds could not be precipitated at temperatures 200 °C, the Cr(III) analogue of potassium jarosite (KCr3(SO4)2(OH)6) is readily precipitated. The Cr(III) analogue has the R\(\bar 3\)m structure characteristic of jarosite-type compounds, with a=7.23±0.02A and c=17.02±0.02 A. The well-crystallized material typically contains (wt pct): ∼7K, ∼25Cr, and ∼41SO4. The composition suggests the partial substitution of hydronium ion for potassium and some chromium vacancies in the structure. The formation of the Cr(III) analogue is promoted by increasing temperatures, retention times, and Cr(III) concentrations. Increasing acid concentrations reduce the amount of product formed but suppress the undesirable precipitation of amorphous phases. Although increasing K2SO4 concentrations result in a greater mass of precipitate, the products formed from concentrated K2SO4 solutions are contaminated with an amorphous phase. In fact, the overall results suggest that an amorphous phase precipitates initially and that the Cr(III) analogue of potassium jarosite forms by the recrystallization, or the dissolution-reprecipitation, of the amorphous phase.

The Activation Effect of K2SO4 on the Hydration of Gypsum Anhydrite, CaSO4(II)

The effect of K2SO4 activator on the hydration of chemical anhydrite obtained from burned FGD‐gypsum has been studied by different experimental techniques. Results obtained show that the degree of hydration increases when the K2SO4 concentrations increase from 0.5 to 3.3 wt%. Their heat evolution rate and maximum value also increase with the increase of K2SO4 concentration. The highest values were obtained when the hydration degree was about 50%. Also a correlation between the hydration degree and the total heat evolved was obtained. The X‐ray and SEM/EDX studies have shown that K2SO4 is adsorbed at the surface of CaSO4 even within 5 min of hydration and a syngenite—a double salt K2SO4·CaSO4·H2O is formed (even in the presence of 1.0 wt% K2SO4). Also, important changes in the morphology of the dihydrate crystal are detected. Finally, in the presence of 1.0 wt% K2SO4 (water/anhydrite (W/A) ratio=0.33), it was found that the resonance frequency, modulus of elasticity, compressive strength, and tensile strength increase with the degree of hydration whereas the total porosity decreases.

FACTORS AFFECTING THE INCORPORATION OF COBALT AND NICKEL IN JAROSITE-TYPE COMPOUNDS

Laboratory studies have shown that minor amounts of cobalt and nickel are structurally incorporated in sodium jarosite, potassium jarosite and ammonium jarosite and that the extent of incorporation increases as the concentration of dissolved cobalt or nickel increases. Potassium jarosite incorporates more cobalt or nickel (∼1% Co or Ni) than does sodium jarosite or ammonium jarosite (∼0.4% Co or Ni). Elevated temperatures increase the incorporation of Co or Ni in the jarosite precipitates, but the increase is modest. Increasing concentrations of Na2SO4, K2SO4 or (NH4)2SO4 result in an increase in the Co and Ni contents of the jarosite precipitates. The extent of Co or Ni incorporation also increases as the pH of the synthesis solution increases. In contrast, elevated concentrations of ferric sulphate reduce the extent of Co or Ni incorporation in the jarosite precipitates. The above parametric dependencies suggest that Co(II) and Ni(II) substitute to a limited extent for Fe(III) in the jarosite structure and the X-ray diffraction analyses of the precipitates support this hypothesis. Efforts to extend the level of incorporation by the coupled substitution of Co(II) + Cu(II) for K(I) + Fe(III) or by the precipitation of lead jarosite were not successful. The oxidation of Co(II) to Co(III) resulted in a modest increase in the Co content of the jarosite precipitates, but the presence of poorly crystalline Co(III) oxyhydroxide (heterogenite) sometimes accounts for part of the increase.Une étude de laboratoire a montré que des quantités mineures de cobalt et de nickel étaient incorporées structurellement dans la jarosite de sodium, la jarosite de potassium et la jarosite d’ammonium et que le degré d’incorporation augmentait à mesure que la concentration de cobalt et de nickel dissous augmentait. La jarosite de potassium incorpore plus de cobalt ou de nickel (∼1% Co ou Ni) que ne le fait la jarosite de sodium ou la jarosite d’ammonium (∼0.4% Co ou Ni). Les températures élevées augmentent l’incorporation du Co ou du Ni dans les précipités de jarosite, mais l’augmentation est modeste. L’augmentation des concentrations de Na2SO4, K2SO4 ou (NH4)2SO4 résulte en une augmentation du contenu en Co et en Ni des précipités de jarosite. Le degré d’incorporation de Co ou de Ni augmente également à mesure que le pH de la solution de synthèse augmente. Par contre, des concentrations élevées de sulfate ferrique réduisent le degré d’incorporation du Co ou du Ni dans les précipités de jarosite. Les dépendances paramétriques mentionnées ci-dessus suggèrent que le Co(II) et le Ni(II) se substituent de façon limitée au Fe(III) dans la structure de la jarosite et les analyses de diffraction des rayons x des précipités supportent cette hypothèse. Les efforts pour étendre le niveau d’incorporation par la substitution couplée de Co(II) + Cu(II) pour le K(I) + Fe(III) ou par la précipitation de la jarosite de plomb n’ont pas eu de succès. L’oxydation du Co(II) en Co(III) a résulté en une augmentation modeste de la teneur en Co dans les précipités de jarosite, mais la présence de l’oxyhydroxyde Co(III) (hétérogénite) faiblement cristallin tient parfois compte d’une partie de l’augmentation

The use of molecular dynamics for the study of solution properties of guar gum

Size exclusion chromatography with dual detection, i.e., employing a refractive index, concentration sensitive, detector together with a multiangle light scattering detector which is sensitive to molecular size, has been applied to study the solution properties of guar gum in water with different concentrations of K2SO4 at 25 °C. The analysis of a single highly polydisperse sample is enough for obtaining calibration curves for molecular weight and radius of gyration and the scaling law coefficients. The influence of the ionic strength on the conformational properties of the polymer can also be analyzed. Moreover, unperturbed dimensions can be obtained by extrapolation of the values measured in a good solvent. The value of the characteristic ratio of the unperturbed dimensions thus obtained is Cn=〈r2〉0/nl2≈19±1. A theoretical analysis is also included. Thus, molecular dynamics procedures were employed to analyze the conformational properties of an oligomer of guar gum under different conditions; namely, standing alone in vacuo, in bulk solid state and in water solution, both with and without salt. These conformational properties were then employed to compute molecular dimensions of Monte Carlo generated chains with different lengths according to standard procedures of the matrix multiplication scheme, thus allowing the evaluation of both perturbed and unperturbed dimensions which are in very good agreement with the experimental values. Moreover our result permits the explanation of the discrepancies among experimental and theoretical values reported in the literature.

Effects of pressure on the behavior of (hydroxypropyl)cellulose in aqueous solution

The effects of pressure and temperature on the phase behavior of aqueous solutions of (hydroxypropyl)cellulose (HPC) were in¶vestigated at low and high concentrations. In dilute solutions, the transition temperature (Tt) as measured by apparent light scattering increased with an increase in pressure at lower pressures, but decreased with increasing pressure above 100 MPa. At lower temperatures, the transition pressure (Pt) increased slightly with increasing temperature, but decreased with at temperatures above 10–15 °C. Both Tt and Pt showed a moderate polymer-concentration dependence and they also showed strong concentration dependence on salt; Tt and Pt decreased with increasing concentrations of KCl and K2SO4, whereas the addition of KI or KSCN increased Tt and Pt. The apparent absorbance of concentrated solutions (62.5%) of HPC, in a cholesteric (chiral nematic) mesophase, was also measured. The spectrum shifted to a longer wavelength under high pressure. These results could be explained by assuming that the helicoidal pitch was increased under elevated pressure, probably due to a decrease in the angle between the two semiflexible and twisted HPC molecules in adjacent planes under high pressure.

DSC and electrical conductivity studies of (Li1−xKx)2SO4 mixed crystals

(Li1−Kx)2SO4 mixed crystals were prepared by the precipitation technique where x = 0.5, 0.7, 0.9 and 0.99. The phase transformations of the mixed crystals have been analyzed by the DSC technique. The DSC curves of (Li1−xKx)2SO4 mixed crystals reveal that as the potassium content increases the first high temperature phase of the intermediate LiKSO4 phase at T = 436°C disappears and a two- phase mixture of LiKSO4 and K2SO4 is found for x = 0.7 and 0.9. It is observed from the electrical conductivity measurements of (Li1−xKx)2SO4 mixed crystals that the electrical conductivity increases as the K2SO4 concentration increases with average activation energy of 1.04 eV. The enhancement in the electrical conductivity is primarily a result of the presence of two ionically conducting constituents and the formation of a diffuse space charge layer at the interface region between these two phases.

Kaolinization of the Kimolos Island volcanics, Cyclades, Greece

AbstractPrimary kaolins, related to Pliocene-Pleistocene volcanic rocks of acid to intermediate composition from the southern part of Kimolos island contain kaolinite and quartz ± cristobalite. Smectite is rarely present whereas alunite is common and more prevalent than baryte or gypsum. The kaolinites show structural disorder (Hinckley indices ranging from 0·6 to 1·1) and contain faults along the c*-axis. The elements Nb, Th, Ce and Sr, La, V constitute two groups with a strong intercorrelation and the kaolins are enriched in these elements compared to the parent rocks. K, Rb, Y and Ba are positively correlated with feldspar content and decrease with the intensity of kaolinization. The mineral assemblages suggest a zonal pattern which is thought to be related to different types of hydrothermal alteration. Starting from the triple point of the alunite-K-feldspar-K-mica-quartz association encountered in Kimolos, a tentative path is presented showing the approximate ranges in concentrations of K2SO4 and H2SO4 required for the formation of the various mineral assemblages.

Effect of Anions (Cl−, SO2−4) on the Interfacial Properties of Akaganeite (β-FeOOH) in Aqueous Electrolyte Solutions

The point of zero charge (pHpzc) of the sample (β-FeOOH) is shifted from 7.50 to 8.20 and 8.55, respectively, in KCl and K2SO4 electrolyte media. Intrinsic surface acidity and complexation constants have been calculated by single and double extrapolation methods using Potentiometrie titration data obtained for different concentrations of KCl and K2SO4 in aqueous media. Complexation con stants for K+, Cl− and SO2−4 have also been calculated from adsorption data by the same two methods. Close agreement exists between the two sets of values. Chloride ions form SOH2−4 – Cl− surface complexes on a β-FeOOH surface, whereas sulphate ions form two types of surface complex i.e. SOH+2 – SO2−4 and SOH+2 – SO4H−. Various parameters such as σ0, ψ0, ψd, dσ0/dψ0, etc. associated with the electrical double layer at the oxide/aqueous KCl and K2SO4 electrolyte solution interface have been calculated from Potentiometrie and adsorption data, and are discussed.

X‐Ray Radiography Investigations of Solid Solutions with Limited Miscibility in K2SO4‐(NH4)2SO4‐H2O System

AbstractThe measurements of crystal lattice parameters (a, b, c) were conducted and the volumes (v) and densities (∂) of solid solutions of (K, NH4)2SO4 were calculated. It was established that in the system K2SO4‐(NH4)2SO4‐H2O at 25 °C mixed crystals with limited miscibility were formed. The gap in the continuity of solid solutions occurred in a very narrow range of concentrations of (NH4)2SO4 in mixed crystals, namely from 69.5 to 72.5%.In order to get the confirmation of the above, the detailed equilibrium investigations nearby the peritonic point (the concentration of K2SO4 −3.32%, the concentration of (NH4)2SO4 −38.66%) were carried out.

KCl leakage from microelectrodes and its impact on the membrane parameters of a nonexcitable cell.

Microcapillary electrodes filled with a variety of salt solutions, including 1m KCl, have been used to measure the membrane potentials and resistances of spherical cells from the mycelial fungusNeurospora (cell diameters 15–25 μm, cell volumes 3–8 pl). During impalements with electrodes containing 0.3–1.0m KCl, membrane potential and resistance decayed over a period of 3–10 min. In contrast, electrodes filled with 0.1m KCl gave stable membrane potentials of −180 mV and membrane resistivities of 40 kΩ cm2, values comparable to earlier results from the fungal hyphae. Salt leakage from 1.0m KCl-filled electrodes (tip diameters 0.2–0.3 μm, resistances 50–75 MΩ) occurred at rates of 4–5 fmol sec−1, as indicated by direct intracellular measurements with ion-sensitive microelectrodes. Depending on cell size, such leakage rates could elevate cytoplasmic KCl content at initial rates of 30–170 mM min−1, and actual values as high as 70mm min−1 were observed. Salt leakage and changes in cytoplasmic KCl concentration were reduced five- to sevenfold when impalements were made with electrodes containing 0.1m KCl. The effects on cell membrane parameters of salt leakage from microelectrodes could be attributed to chloride ions. Substitution of the KCl electrolyte with half-molar K2SO4 or Na2SO4 and molar concentrations of K- and Na-MES [potassium and sodium 2-(N-morpholino)ethanesulfonate] gave stable membrane potentials in excess of −200 mV and membrane resistivities greater than 50 kΩ cm2, while the permeant anions NO 3 − and SCN− depressed the membrane parameters in a manner similar to that observed with 1m KCl. Furthermore, modest elevation of cytoplasmic chloride concentration (below ca. 50 mM) affected both membrane potential and resistance in direct proportion to the concentration, and could be quantitatively described by the Constant Field Theory with a fixed membrane permeability (P Cl∼4×10−8 cm sec−1). Higher cytoplasmic chloride levels produced a collapse of the membrane resistance and drastic depolarization in a fashion requiring large changes of membrane permeability. At least for cells with volumes of 10 pl or less, the standard practice of filling electrodes with 1 or 3m KCl should be abandoned. Half-molar (and lower) concentrations of K2SO4 or Na2SO4 are suggested as satisfactory replacements.

Oxide-Sulfate equilibria in the Mg, Ni, and Mn systems measured by a solid K2SO4 concentration cell

Oxide-Sulfate equilibria in the Mg, Ni, and Mn systems measured by a solid K2SO4 concentration cell

Oxide-Sulfate equilibria in the Mg, Ni, and Mn systems measured by a solid K2SO4 concentration cell

An emf cell with a solid K2SO4 electrolyte and a circulating SO2/air gas mixture as the reference electrode has been employed as a gas probe to measure the thermodynamic properties of chemical reactions of the type: MSO4(s) = MO(s) + SO3(g). The three systems MgO-MgSO4, NiO-NiSO4, and Mn2O3-MnSO4 have been investigated in the temperature range 873 to 1173 K. The results for the magnesium and nickel systems are generally in good agreement with thermodynamic data from the recent literature, thus validat.ng the use of solid K2SO4 as an SO3 (and SO2) probe. The standard free energy change on sulfation of Mn2O3 determined here is in good agreement with values determined indirectly from the literature. Combination of the present results with the literature data provides additional evidence of solid-state transitions in MnSO4 and MgSO4 with an associated enthalpy of transition that is the same order of magnitude as the enthalpies of fusion for these compounds.

Cation‐stimulated H+ efflux by intact roots of barley

Abstract. Rates of proton extrusion and potassium (86Rb) influx by intact roots of barley (Hordeum vulgare cvs. Fergus, Conquest and Betzes) plants were simultaneously measured in short‐term (15min) experiments. The nature and extent of apparent coupling between these ion fluxes was explored by manipulating conditions of temperature, pH and cation composition and concentration during flux determinations. In addition, the influence of salt status upon these fluxes was examined. At low K+ concentrations (0.01 to 1 mol m−3), H+ efflux and K+ influx were strongly correlated in both low‐ and high‐K+ roots, although K+: H+ exchange stoichiometries were almost consistently greater than 2:1. At higher concentrations (1 to 5 mol m−3), H+ efflux was either reduced or remained unchanged while K+ influxes increased. In the presence of Na2SO4, rates of H+ extrusion demonstrated similar cation dependence, although below 10 mol m−3 Na2SO4, H+ fluxes were generally 50% lower than in equivalent concentrations of K2SO4. These observations are considered in the context of current hypotheses regarding the mechanisms of k+/H+ exchange.

Adeno-associated virus DNA replication complexes in herpes simplex virus or adenovirus-infected cells.

A complex which is active in in vitro synthesis of adeno-associated virus (AAV) DNA was solubilized from Vero cells that were co-infected with AAV and either adenovirus (Ad5) or a herpes simplex virus type 1 (HSV-1) as the helper virus. The complexes from the Ad5 and HSV-1-infected cells sedimented at 23 S and 28 S, respectively. The optimal conditions for in vitro DNA synthesis for the two types of complex using the endogenous AAV template and the endogenous DNA polymerase, differed with respect to the effect of KCl and K2SO4 concentration. In addition the complex from HSV-1-infected cells, but not that from Ad5-infected cells, was inhibited by phosphonoacetic acid. Thus, the two complexes appear to contain different DNA polymerase activities. This was verified by phosphocellulose chromatography of the DNA polymerases solubilized from the isolated complexes. The major activity in the complex from HSV-1 infected cells was the HSV-induced DNA polymerase with lesser amounts of cellular DNA polymerase alpha and gamma or both. The complex from the Ad5-infected cells contained mainly a cellular DNA polymerase gamma.

The Effect of Various Alkaline Salts on the Glycolate Oxidase of Salicornia europaea and Pisum sativum in vitro

AbstractThe response of glycolate oxidase from shoots of Salicornia europaea L. and from leaves of Pisum sativum L. to salt treatment during assay was studied by DCPIP reduction and O2 uptake. In Pisum there was found up to five times more glycolate oxidase activity per gram fresh weight than in Salicornia. However, the calculation of the specific activity pointed out that this result was caused only by the high level of enzyme protein in Pisum, and that specific activity from both species was of equal size.By the DCPIP method it was shown that in test media containing up to 1.0 M NaCl or KCl glycolate oxidase of Salicornia was of equal size compared with the control (medium without additional salts). With 2.0 M NaCl or KCl the activity decreased by about 80 and 30% respectively. Glycolate oxidase of Pisum was somewhat more salt sensitive. 1.0 M NaCl or KCl reduced the activity by about 35%. In the presence of 2.0 M NaCl or KCl the enzyme activity from Pisum was inhibited to about 80 and 60% respectively. By substituting sulfates for chlorides the activity of glycolate oxidase from both Salicornia and Pisum was stimulated strongly. 1.5 M Na2SO4 and 0.5 M K2SO4 (both are saturated solutions) caused an increase of glycolate activity from Salicornia of about 225 and 185% respectively, and from Pisum of about 50 and 30% respectively.Studying the response of glycolate oxidase to salt treatment by O2 uptake one must establish that with this method the degree of inhibition of enzyme activity at higher salt concentrations was always more severe than with dye reduction. Addition of 1.0 M NaCl or KCl to the assay medium caused an inhibition of glycolate oxidase activity from Salicornia of about 50% and from Pisum of about 60%. 2.0 M NaCl or KCl reduced the enzyme activity of both Salicornia and Pisum to nearly 10% of control activity. Furthermore, in contrast to DCPIP reduction no stimulating effect of sulfates on glycolate oxidase activity was detectable. Indeed, the inhibitory effect of sulfates was very slight. 1.0 M Na2SO4 caused a mean inhibition of glycolate oxidase activity of only 15% with both species, and in the presence of 1.5 M Na2SO4 50% of control activity was measured. At maximal K2SO4 concentrations (0.5 M) glycolate oxidase from both Salicornia and Pisum was also unaffected.It is supposed that the described salt tolerance of glycolate oxidase in vitro, possibly is due to an adaptation of the enzyme to high salt levels within peroxisomes in vivo.

Negative potential level in the outer layer of the toad skin.

The isolated skin of the toad Bufo marinus ictericus when impaled from the outer surface by glass microelectrodes filled with 3 M KCl shows a voltage profile which is a continuous function of the depth of impalement. The superficial intraepithelial potential difference measured with reference to the external solution (PDi) is negative with NaCl-Ringer's solution on both sides of the skin, displaying a minimum of -26.7+/-3.6 mV at 6+/-2 mum. Null value is obtained at 19+/-3 mum, with positive values for deeper impalements. Indications of cell impalements (abrupt voltage and resistance jumps) were frequently observed at sites deeper than 25 mum from the outer surface. Measurements of the electrical resistance between the microelectrode and the external solution, made with single- and double-barreled microelectrodes, showed great discrepancies, which may be attributed to distinct pathways of different resistances in the stratum corneum. PDi measured at a depth of 5 mum was a logarithmic function of Na2SO4 or K2SO4 concentration in the external solution, increasing in negativity with a reduction in concentration. Substitution of Na by K in the external solution had only minor effects on PDi. Acidification of the external solution from pH 9 is accompanied by a reduction in the negative value of PDi. At pH 3 PDi was positive. PDi was interpreted as a diffusion potential at the tip of the microelectrode due to KCl diffusion from the electrode into the matrix of the stratum corneum. Differences in K and Cl mobilities, responsible for the origin of PDi, were attributed to fixed charges in the matrix of the stratum corneum, with density and polarity determined by their degree of proponation, controlled by the hydrogen ion concentration of the external solution. Skin potential, short-circuit current and their relationship to PDI were discussed.

The effects of aqueous neutral-salt solutions on the melting temperatures of deoxyribonucleic acids.

AbstractThe helical stability of a variety of DNA samples, ranging in base composition from 0 to 72 mole‐% GC, has been studied by heat denaturation at neutral pH in increasing concentrations of LiCl, NaCl, KCl, CsCl, Li2SO4, and K2SO4. The variation of melting temperature with average base composition, dTm/dXGC, was found to decrease drastically in the concentrated salt media, e.g., from 41°C in 0.006M LiCl to 29°C in 3.2M LiCl, and from 39°C in 0.003M Li2SO4 to 18°C in 1.6M Li2SO4. At the same time, the thermal transition is much more cooperative in the concentrated salt solutions than at low ionic strength. Indeed, at limiting salt concentrations, the transition breadth seems to reach a minimum value irrespective of the compositional heterogeneity of the DNA samples. Attempts to correlate the observed decrease of dTm/dXGC with predicted changes in the enthalpy of melting, deduced from a simple theoretical treatment, experimental data on the binding of counterions and water to DNA, and experimental data on thermal denaturation, were unsuccessful. However, the strongly reduced composition dependence of the melting temperature can be understood in terms of a destabilizing effect of the concentrated salt media on GC‐base pairs. It is suggested, though not proven, that the destabilization involves the displacement of water molecules from the DNA helix.

The Effect of Selected Anions of Potassium Salts on the Gel Strength of Carrageenan High in the Kappa Fraction

SUMMARYBreaking‐force‐deformation curves and total energy data were obtained for kappa‐carrageenan gels prepared with increasing concentrations of CH3COOK, KBr, KCl, K3C6H5O7, KNO3, K2C2O4, and K2SO4. Increasing the concentrations of each potassium salt, used in combination with kappa‐carrageenan, produced gels which gave significantly higher breaking‐force and total energy values and lower deformation readings. Moreover, significant differences for all three measures of gel strength occurred among kappa‐carrageenan gels prepared with each normality of the various potassium salts; therefore the anion as well as the cation used as a gelling agent affected the characteristics of the kappa‐carrageenan gels. In general the effectiveness of the potassium salts in producing gels from kappa‐carrageenan, in decreasing order, were: chloride, acetate, sulfate, nitrate, bromide, citrate, and oxalate.

The Effect of Selected Anions of Potassium Salts on the Viscosities of Lambda‐Carrageenan Dispersions

SUMMARYViscosity readings with three rates of shear for each of six time intervals were obtained for 0.5% dispersions of lambda‐carrageenan in de‐ionized water and in solutions of increasing concentrations of CH3COOK, KBr, K2CO3, KCl, K3C3H5O7, KNO3, K3C2O4, K3PO4, and K2SO4. The addition of any of these salts to the water in which lambda‐carrageenan was dispersed caused a highly significant decrease in viscosity. Significant differences also occurred among the viscosity readings for lambda‐carrageenan dispersed in different concentrations of one salt; however, the same concentrations of the different salts did not show comparable effects on the reduction of carrageenan viscosity. No significant differences occurred among viscosity readings for carrageenan dispersed in the various potassium salts at the 0.05N level of concentrations nevertheless, differences did occur at both the 0.10N and 0.20N levels of concentration. All solutions tested showed significant differences among viscosity readings due to rate of shear. Differences were minimal among viscosity values attributable to aging time of the dispersions.

THE IONIC ACTIVITY OF GELATIN

2.5 and 1.25 per cent gelatin have been titrated potentiometrically in the absence of salts and in the presence of two concentrations (0.0750 and 0.0375micro) of NaCl, MgCl(2), K(2)SO(4), and MgSO(4). The data have been used to calculate values of +/- S = v(z) - (v - 1)(z), where v(z) = v(2) - (v(2) - v) r(x)/18. The maximum and minimum values of S with NaCl were used to calculate the mean distance (r(x)) between like charges in gelatin. This is found to be 18 A.u. or over (between acid or basic groups) which agrees with the probable value and the titration index dispersion. Thus the data with NaCl are shown to be normal and to obey the equation found to hold for simple weak electrolytes; namely, pK' - pK = Sa See PDF for Equation where S is related to the valence and distance by the above equations. Using the NaCl data as a standard the deviations (DeltaS) produced by the other salts are calculated and are found to agree quantitatively with the deviations calculated from equations derived for the simple weak electrolytes. This shows that in gelatin, as in the simple electrolytes, the deviations are related to the "apparent valences" (values which are a function of the true valence and the distance between the groups). The maximum "apparent valences" of gelatin are 2.4 for acid groups (in alkaline solution) and 1.8 for basic groups (in acid solution). These values correspond to the hypothetical condition of zero distance between the groups. They have no physical significance but have a practical utility first as mentioned above, and second in that they may be used in the unmodified Debye-Hückel equation to give the maximum effect of gelatin on the ionic strength. The true effect is probably even lower than these values would indicate. The data indicate that gelatin is a weak polyvalent ampholyte having distant groups and that the molecule has an arborescent structure with interstices permeated by molecules of the solvent and other solutes. The size and shape probably vary with the pH.